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6.6. SR 08-19-2002City TO: FROM: DATE: SUBJECT: Item # 6 _ 6. MEMORANDUM Mayor and City Council Scott Harlicker, Senior Plannef/~ August 19, 2002 Case No. P 02-05 Request by Tollefson Development for Preliminary Plat Approval - Twin Lakes Crossing Request Consider a request by Tollefson Development for the Preliminary Plat of Twin Lakes Crossing Location South of County Road 13 at the Tyler Street intersection Zoning/Land Use Rlc (Single Family Residential) and Rle (Single Family Residential) / MR (Medium Density Residential) Attachments · Location map · Memo from the City Engineer · Preliminary plat · Development plans Overview The applicant is requesting to plat 109 acres. The project will include a mix of single family lots (64 lots) and townhouse units (192 units) for a total of 256 units. On July 15, 2002 the City Council considered and denied a request by the applicant to rezone this property to R3 (Townhouse District). Existing Conditions The 109 acre parcel is located on the east side of Twin Lakes Road north of Trott Brook farms at the Twin Lakes Road/Tyler Street intersection. The property is a mix of open fields and woodlands. About 37 acres of the parcel is wetland. The site is also hilly and is bounded by Trott Brook in the southeast corner. Adjacent land uses include single family residential to the south, farmland and Trott Brook to the east, Twin Lakes Road and single family lots to the west and north. Project Description The proposed project is a mix of 192 townhouses and 64 single family residences on 109 acres. The single family lots are located in the southern portion of the plat, adjacent to Trott Brook Farms. The townhouses are located in the northern portion of the plat, adjacent to Twin Lakes Road. Analysis The proposed plat is not consistent with requirements of the Rlc and Rle (Single family Residential) zoning districts for the following reasons: The plat includes townhouses which are not an allowed use in either the Rlc or Rle zoning districts. · The plat includes numerous lots that do not comply with the minimum lot width of 80 feet for the Rlc and Rle districts. The proposed grading will result in the removal of all the trees on the site. The subdivision ordinance states that trees should be preserved to the maximum extent possible; staff does not feel that that the proposed plat accomplishes this. Recommendation The Planning Commission recommended that the City Council deny the request for preliminary plat based on the following findings: 1. The rezoning was denied. 2. The plat does not comply with the dimensional requirements. 3. Public opposition to the request. Staff recommends that the City Council deny the request for preliminary plat approval for Twin lakes Crossing based on the following findings: 1. The request to rezone the property, to R3 (Townhouse District) was denied. 2. The proposed plat is not consistent with requirements of the Rlc and Rle (Single Family Residential) zoning districts for the following reasons: o The plat includes townhouses which are not an allowed use in either the Rlc or Rle zoning districts. o The plat includes numerous lots that do not comply with the minimum lot width of 80 feet for the Rlc and Rle districts. 3. The plat does not comply with the Subdivision Ordinance in that it does not make adequate provision for storm drainage. 4. The plat does not comply with the Subdivision Ordinance in that the topography, vegetation, soil types and drainage are not suitable for the type and density of this development. 5. The plat does not comply with the Subdivision Ordinance in that the proposed subdivision will cause substantial environmental damage in that the entire site will be clear cut and graded. Howard R, Green Gompany August 13, 2002 File: 817250J-0240 Mr. Scott Hadicker Senior Planner City of Elk River 13065 Orono Parkway Elk River, MN 55330 RE: TWIN LAKES CROSSING ADDITION PRELIMINARY PLAT APPROVAL Dear Mr. Hadicker: Several weeks ago, we received a revised submittal package for the Twin Lakes Crossing Addition. This package was submitted after the developer received direction from the Technical Evaluation Panel (TEP) relative to wetland issues on the property. The submittal we received had two different grading plan: one noted "Option A" and one noted "Option B." Upon initial review of these grading plans, we noted that the grading plan scale was much too small to allow for a detailed review. On July 16, 2002, we contacted the developer through his engineer and asked for a larger-scale grading plan. A couple of days later, the developer's engineer responded that the plan was going to change and that when the changes were complete they would submit a revised grading plan at a larger scale for our review. As of today's date, we have not received any revised grading plan from the developer through his engineer. Therefore, at this point in time, we are not prepared to make a recommendation to approve the preliminary plat since we have been unable to review the grading and drainage plan. If you have any questions regarding this plat, please call. Sincerely, Howard R. Green Company Te~.fi. TJM:mw Ltr-081302-Harlicker 1326 Energy Park Drive · St. Paul, MN 55108 · 651/644-4389 fax 651/644-9446 toll free 888/368-4389 PARCEL B OUTLOT C OUTLOT L Case Number: Location Map ZC 02-07 / P 02-05 / CU 02-21 N TWIN LAKES CROSSING -- W.NIMUkl LOT 0EPYH N/A FT b'~ A~ YARD I --i- l -- ~ Sm££r DRAINAGE AND UTILITY EASEMENTS ARE SHOWN THUS: .... L_:~J__~; , ': .... TYPICAL MULTTPLE LOT A~EAS TOTAL AREA ~ :09.49 AC. OU~OT A- 8,62 AC. LOT AREA --.68.49 AC. R.O.W. AREA 17--.38 AC. NO. OF~NGLE FAMILY 75' LOT. NO. O~~INGL~ FAMILY 85' LOT- -32 NO.OFMULTIPLE LOTS -192 ASSOCIATION COMMON AREA LOTS (LllS. B.~. L15. 8.2, & L55. 8.8)__3 TOTAL NUMBER OF LOTS- 259 LARGEST LOT -- --719.858 S.F. ~M ALLEST LOT- -12,016 MIN. AREA OF 85' LOTS' 12.000 S.F. MIN. AREA OF 75' LOTS 10,$00 AVERAGE SINC~E-FAMILY LOT -38,52! NET DENSITY (idULTIPt. E AREA)--.--5.07 LOT~/AC. ~'T1.ANO AREA- 57.50 AC, / / / / / / / / / / / ...........^n~ 200.22 200.~ i 3UTL.OT , ,x,..,, : PRELIMINARY PLAT 2611.62 PRELIMINARY PLAT OF TWIN LAKES CROSSING NO SO~LF " 928.4,9 ,;" TOLLEFSON DEVELOPUENT 0UTU~T A TWIN LAKES CROSSING /3~GEND NOTES SITE DATA TOTAL &REA 109.49 AC. W~'f~AND AR'=A· 37.50 AC ....." "- - _- -... ~-" ': "' -~-',, -- >t' 'N-',,, -:'::"::':' .......,. '-..~'~ . ...... ~ ..... -, .............. - ., -...~. ,, %..". . -... - .., . \ ,. , , . . ,, .6-~--;.::~.'?;.--':- _;...:, ... , . ...... , , ,¢. / . \, ._ /; , ~,~,\ : ~; ~' '.-' ,.' - ' , / :,~ ~ L ., -- ~. .... - .'/ (- : !,~,.. . ,. , ,. ,~ ,:'. . / ~'~ , ..... .~.-- ~ ..... . 1 ~'~,, ", .. .... ., , ,o,,z,,,,,...->~: . .~, ; ,. .. - ._~- ~ ... ' .. x " .... Ch. ~.,~ ,',,',':.'~ .- ' ,' ,,- ~ :, / '~" -~-.~' , ~" , , \ ?---:-/' ~ ,' , \ '., .... ~ , , , ' ', ~. ,' ~.;" ' ,~ ', ! / , / (%- , ' ~,' ¢ .-' '~,,.~? ', o ~.'"'~7.'.~_ , . (~, Purcn ' ' ". , ! ~, ' ' -.', ~-.."~. 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( ./ -- , . .., .,, , . . ... . . , :../' --... -:. '.,~ . / ~ _:';.,j,);,..:.' .',, , , ~ ' ,.'J~,'..'--:'-'-". , "'''" . , '~ '. ' .' /.'. ' . ' ' , ' ' " · ,'.: /.'LTL'.'.',,"',~'. i ...,;,..,~:~ . ,. ~; , ...... '/.'~.'.. ~-- .~--.- ...... . '""~. '.~_. /"-. ~ ..... ~,~, ~ . ~ I . ,, ..... , :.-_ _ . ~ . -~ .~ .. ~ ~ :.. .. , .... ~, >~,., / ~ .......... .. .., ,_.: .., . .,.. , ,. ......... . . , ..., ~ , . /.. ,, ,.,,.,,,.,,'. :_.. -. - ....... ..- ., .,,,, , ,, .. ........ ~ .\ ~.---. ~..:..-:: _.-.:.::..-.- .... .~. . , ,! , .... ::. , ........ .c:- ...~.:/ PART 27 0 UNDA £ Y ,- o{~ OF SECTIONS 26, 35, .& 36, ~ ~LK RIVE~ MINNESOTA ~ TOLL£FSON GRAPHIC g28. 4g SURVEY TO IYNSHIP 33, RANGE 26 ~ SHERBURNE COUNTY ~ to( DEVELOPMENT, /NC. T N NOTES BOUNDARY SURVEY TOLLEFSON DEVELOPMENT, iNC. TWIN LAKES CROSSING / / 115 __ s.~_~ ~.~,~_ PRELIMINARY SITE & UTILITY PLAN / / / / / / '\ \ / / / /// / TOLLEFSON DEVELOPMENT INC. TWIN LAKES CROSSING SUBGRADE CORRECTION DETAIl, / ;' h," LOT BENCHING DETAIL I W['~.ANO KEY I / WE'f~ANO li0,PACT (1.8.~ AC.) O~TCH R~ O~q AC, FOR REST~A~ON OF H~R~OGY 0¢ ~ND ~8 * TOTAL MI'GA'ON REQU,~D :~' - - FEMA ~LC}OOWAY ~ PRELIMINARY GRADING PLAN TOLLEFSON DEVELOPMENT INC. TWIN LAKES CROSSING 20207( ...... .... ., _. . ~ ~ ~ , ~.~, .: ,. . ..... ~ ~. ~ . ... ~ , ~,~ ..., /~.. . , ~ ,,. ~. ~-.. ~ · ~- ~ ..~ ~ /, ,, .~ , ~ ,. ~ , ~ ~ ..~ ,,. ~ , .: ~/..,..:,.~ . · .. %~- ~ .~. ~ . ~.., -- :.: ~.., ~, / ~., ,, ~ ~ .... ~~¢--~ __~ .. ...::: ...... . :~ . ,, ~ ,~ ..... , ,, ~ ~ , ..... , ~.z ~. -. ', ~'.,: ~ ~ ' -.,~,_~..~ '--. ~ --~ , ~ . ~ __.~ ~ . . ' · i ---" // m--~ ...... ~~.~~.~.~~~~.. -. '.,, .", ; "'... '~"'~ .~'~ ~ K ~~_ . ' 1,~)~.11: ~ ~ . ....... - ~ .' .- ' -~.,'-~..~, ,,,~.~_.~. ~ ,,t~,..,~..~_..~__ ,~~._ ,'~ ~:, ~ .. x.~ ~1"'~.~.~:~ ~" ''~ .: , ,' ~ ~ )~ -- ' ' .... .*- .............. 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'. ~ :~ ---'"~ 5- '~ >~-~ ' ~ ~ ~ ' ~' ' .~ x ~5X "~-' ~,,, '.^~s~m~v.,,.,,,~ ~ ~,,~-8~ -.~ . ./'//2 · I.', /,.' i 1 =20 ' .... ', · ~:~U:~=,-~,=,~='.~..i /~,.y~ ~ ,~,.,..~ , v ~ ...~ ~_ ~ ~ ...~,~,.co..,.~.~.,.o.~,~.~.. ROWHOME DETAIL ............................ ~~~ ,/1,,.. '7~:~/A~LX~ 7~a , ~ ~/' ,'~ ~ ~" .. ~ ........... ~;~,~,~,~,'~J .... ~~ ~ (,'/~ ~' ~ ~..-/~;'~ k~'~:~.[[ ~.' . ' /'//~~} ~ --'-T ~[ r'' ..'. ~ JAP~ ~1~ ~REA/SPIR~A JAPONICA ~ POT · : ~ tN~IOR ~ CORN~ PLANING DETAIL .,,-,,: 'N ~--~. ~ ' ~ ' ~ ,m '~ '~ t ~" ,I ..-- .... ~ '- '---.~ 7/ i / , - ,,'~I~:~... '~, ~I : '~ x ~{... / / .- -.,~ ~ 'i , 7 .,?~,.,/f~'~ ~ ~.. . ~ ' ~ ~/A ' r I / " ~ '-, ' ,I ...... ' ....... ~ · ~ ~-'- ~ ~'"~ , '-'- ' / ~ ~', '.. 4~'~,'. -~~.-.:" ' ~.~ ... ,~t ,. ~t ,k .... ~Eo .... ,,~',.~,.~:~.-~. n ~'~,,'~,'-~ -::~' :j/ .- . / ~--' ',' b:.~r'~ ~... .*._ · ....... , .... ~,, - - ~ ~ ....... .... ;,;; ........ I ................ - -' - ~ ....... ~, ~ .~, , ~ ~ TOLLEFSON DEVELOPMENT ~IN LAK R I ROBERT L. HOFFMAN GERALD H. FRIEDELL EDWARD J. DRISCOLL JOHN D. FULLMER FRANK I. HARVEY CHARLES S. MODELL CHRISTOPHER J. DIETZEN LINDA H. FISHER THOMAS P. STOLTMAN MICHAEL C. JACKMAN JOHN E. DtEHL JON S. S~NIER2~NSKI THOMAS J. FLYNN JAMES P. QUINN TODD I. FREEMAN GERALD L SECK JOHN B. LUNCQUIST DAYLE NOLAN * JOHN A. COTTER * PAUL B. PLUNK~TT KATHLEEN M. PICOTTE NEWMAN GREGORY E. KORSTAD GARY ~ VAN CLEVE * TIMOTHY J. KEANE MICHAEL W. SCHLEY TERRENCE E. BISHOP GARY ~ RENNEKE CHRISTOPHER J. HARRISTHAL KENDEL J. OHLROGGE SRUCE J. DOUGI-~S WILLIAM C. GRIFFITH, JR JOHN R. HILL PETER J. COYLE LARRY D. MARTIN JANE E. BREMER JOHN J. BTEFFENHAGEN MICHAEL J. SMITH ANDREW F. PERRIN FREDERICK W. NIEBUHR LARKIN, HOFFMAN, DALY & LINDGREN, LTD. ATTORNEYS AT LAW 1500 WELLS FARGO PLAZA 7900 XERXES AVENUE SOUTH BLOOMINGTON, MINNESOTA 55431-1194 TELEPHONE (952) 835-3800 FAX (952) 896-3333 WILLIAM G. THORNTON DOUGLAS M. RAMLER LYNN M. STARKO~CH STEPHEN J. KAMINSKI THOMAS F. ALF-Y~NDER DANIEL T. KADLEC ADAM S. HUHTA * KENNETH COREY-EDSTROM ANN M. MEYER JAMES M. SUSAG * DANIEL J. BALLINTINE JEFFREY D. CAHILL SEAN D. KELLY JOSEPH J. FI3-rANTE, JR. THOMAS J. OPPOLD ** JONATHAN J. FOGEL CYNTHIA M. KLAUS MARK D. CHRISTOPHERSON NEAL J. BLANCHE3-r TAMARA O'NEILL MORELANO JAMES A. MCGREEVY, [11 THOMAS A. GUMP * TODD A~ TAYLOR CHRISTOPHER J. DEIKE GENEVIEVE A. BECK MARIA M. ZACK DIONNE M. BENSON JEREMY C. STIER JOANI C. MOBERG CHRIS M. HEFFELBOWER MICHAEL A. ESS~EN OF COUNSEL JAMES P. LARKIN ' JACK F. DALY D. KENNETH LINDGREN · ALSO ADMITTED IN WISCONSIN · * ONLY ADMI~rED IN iOWA August 19, 2002 Mayor and City Council Members City of Elk River 13065 Orono Parkway Elk River, MN 55330-5600 Re: Twin Lakes Crossing Preliminary Plat Approval; Our File 24,134-14 Dear Mayor and Council Members: We represent Tollefson Development, Inc. ("Tollefson") with regard to Twin Lakes Crossing preliminary plat (the "Plat") under your consideration by the City Council this evening. The City Staff Report lists five reasons for denial of the preliminary plat. We believe none of these reasons is sufficient to support denial as set forth below. We therefore request that you approve the Plat. 1. The Request to Rezone Is Approved As set forth in our correspondence to you dated July 15, 2002, and to the City Attorney, dated August 1, 2002, Tollefson's application to rezone has been approved by operation of law. On April 30, 2002, Tollefson requested a rezoning to R3 for Twin Lakes Crossing. The application was deemed complete and the City considered it, including public hearing before the Planning Commission. Minnesota's 60-Day Rule (Minn. Stat. § 15.99) requires the City to decide any application "related to zoning" within 60 days of submittal. If the City does not render a decision within that time period, then "Failure of an agency to deny a request within 60 days is approval of the request." Id., subd. 2. The City may grant itself a 60-day extension at any time, for virtually any reason, before the initial 60 days expires, or it may request that the applicant waive the timeline or grant an extension. However, Minnesota law makes it clear that the burden is on the City to secure an adequate extension if needed. An applicant's waiver of rights under the 60-Day Rule must be explicit and clear; silence or failure to immediately press rights is not waiver. (See #C3-02-65 Northern States Power Co., d/b/a Xcel Energy, petitioner/plaintiff, vs. City of Mendota Heights, Power Line Task LARKIN, HOFFMAN, DALY & LINDGKEN, LTD. Mayor and City Council Members August 19, 2002 Page 2 Force, Inc.) If the City fails to secure an adequate extension, then the 60-Day Rule is clear and unambiguous: the application is deemed approved. No further action is required. Gun Lake Ass'n v. County of Aitkin, 612 N.W.2d 177, 181, fn.2 (Minn. App.2000). 2. The Proposed Plat is Consistent with the Zoning District The Staff Report analyzes the plat under the former Rle and Rlc zoning districts. As discussed above, the property that is the subject of this application has been rezoned to R3. Townhouses are an allowed use in the R3 zoning district. The City Planner's report to the Planning Commission May 28, 2002, noted that "The lots in the townhouse portion of the project comply with the dimensional requirements of the R3 district." For instance, the applicable lot width requirement is is 20 feet, not 80 feet as stated by staff. (Staff Report at p. 3). 3. The Plat Provides Adequate Storm Drainage The City requires "adequate storm water drainage" and provides that a subdivision may be "premature if it does not so provide." City Code, Section 1008.08.1 (D)(viii). The City requires information (City Code, Section 1008.10.4(C)) but the only objective standards appear at City Code, Section 1008.14(9). The May 28th, 2002 Staff Report did not indicate that the plat failed to conform in any respect. By letter dated August 13, 2002, the City's consulting Engineer stated "we are not prepared to make a recommendation to approve the preliminary plat." Obviously neither of these comments provides a factual basis for denial. Furthermore, Twin Lakes Crossing includes a storm sewer and five ponds. The project Engineer, Pioneer Engineering, has calculated stormwater drainage and containment, and concluded that it is adequate. 4. The Plat Topography, Vegetation, Soil Types, and Drainage are Suitable for the Development The revised grading plan corrects topography and drainage issues raised during City review. The site will be revegetated in compliance with City standards. The AET finn, acting as consultant to the Applicant, completed a geotechnical investigation and determined that the site is suitable for development. In the same August 13th letter referenced above, the City's Consulting Engineer expressed no opinion on the grading plan. Neither the May 28, 2002 nor the current August 19th, 2002 Staff Report supports denial on these bases. The August 19, 2002 Staff Report is silent as to topography, vegetation (other than trees), soil types, and drainage. The May 28th Staff Report noted the extent of grading and stated that removal of all trees does not satisfy the subdivision ordinance. Currently, the 109-acre Site is approximately 60 acres of woodland. Half the wooded area, approximately 30 acres, will be preserved. In addition, 516 new trees are planned to be planted. Further, the plat is laid out to minimize wetland impacts. Of 37 acres of wetland on the site, only 2.5 acres will be altered. Of these 2.5 acres, 1.5 acres are contained within a man-made ditch. The Subdivision ordinance does not contain topography, vegetation, or soil types standards, other than tree and erosion/sedimentation guidelines. The Plat will comply with these standards as LARKnq, HOFFMAN, DALY & LINDGREN, LTD. Mayor and City Council Members August 19, 2002 Page 3 noted above. The drainage issue is not a basis for denial, as discussed above. The information submitted does not support topography, vegetation, soil types, and drainage as a basis for denial. 5. The Plat Will Comply with Tree and Grading Ordinances Any economically beneficial development of the site requires some grading and tree removal. As Tollefson stated at the Planning Commission, the trees are mainly on the high ground, and the only feasible way to configure access is by using that high ground. Any feasible development, including single-family R1 e and R1 c for which the site was formerly zoned would create similar impacts. As noted above, approximately 30 acres, or half the existing woodlands, will be preserved. The development will not cause substantial environmental damage, because grading will be in compliance with City regulations, erosion and sedimentation protection will be utilized during construction, and the area will be revegetated with 516 new trees upon completion. Conclusion The bases cited as support for denial do not support denial. The site has been rezoned by operation of law, and the Plat complies with the new R3 zoning classification. The project's engineer has calculated stormwater drainage and found that it is adequate; there is no information indicating this conclusion is not correct. The City has no objective standards regarding several factors cited as possible bases for denial, such as topography and soil types. Even if such standards existed, the City staff has previously recommended project approval without noting non-conformance. The Plat will not create environmental damage, because it is planned to comply with state and local regulations for environmental protection during construction, and will preserve existing woodlands and reforest many areas within the property. Based upon the rezoning to R3 and the Plat's compliances with applicable ordinances, the City Council must approve the preliminary plat of Twin Lakes Crossing. ~el~ "-"LARKIN, HOFFMAN, DALY 8~ LINDGREN, Ltd. CCl Peter Beck, City Attorney Mr. Doc Bohlman, Tollefson Development 789151.1 ! : I I~ TREES REMOVED (30 AC) ~*"~"~ TREES (31 AC.) PRESERVED ii EXTENT OF GRADING SCAPE PLAN AMERICAN ENGINEERING TESTING, INC. CONSULTANTS · GEOTECHNICAL · MATERIALS · ENVIRONMENTAL St. Paul, MN Duluth, MN Mankato, MN Marshall, MN Rochester, MN Ashland, NE Pierre, SD Rapid City, SD La Crosse, WI Wausau, WI REPORT OF GEOTECHNICAL EXPLORATION AND REVIEW Residemial Addition Elk River~ Minnesota AET//20-02044 Date: March 18, 2002 Prepared for: Tollefson Development 17271 Kenyon Avenue Lakeville, Minnesota 55044 AMERICAN ENGINEERING TESTING, INC, CONSULTANTS · GEOTECHNICAL · MATERIALS · ENVIRONMENTAL March 18, 2002 Tollefson Development 17271 Kenyon Avenue Lakeville, Minnesota 55044 Attn: Timothy Bohlman Geotechnical Exploration and Review Residential Addition Twin Lakes Road Elk River, Minnesota AET//20-02044 Dear Mr. Bohlman: This report presents the results of a subsurface exploration program and geotechnical engineering review for your proposed development in Elk River, Minnesota. We are submitting three copies of the report to you, with additional copies being sent as noted below. Please call if you have any questions about the report. I can also be contacted for arranging construction observation and testing services during the earthwork phase. Sincerely, Gary A. Larson Senior Engineering Assistant Phone: (651) 659-1363 Fax: (651) 659-1379 CC: Pioneer Engineering Atto: Terry Rothenbacher GAL/gl This document shall not be reproduced, except in full, without written approval of American Engineering Testing, Inc. 550 Cleveland Avenue North. St. Paul, MN 55114, 651-659-9001 · Fax 651-659-1379 Duluth · Mankato ° Marshall. Rochester · Wausau o Rapid City o Pierre AN AFFIRMATIVE ACTION AND EQUAL OPPORTUNITY EMPLOYER TABLE OF CONTENTS SUMMARY ..................................................... 1 Purpose ..................................................... 1 Scope ....................................................... 1 Findings ....................... : ............................. ! Recommendations ............................................... 1 INTRODUCTION ................................................. 2 Scope of Services ............................................... 2 PROJECT INFORMATION .......................................... 2 Foundation Design Assumptions ..................................... 3 SITE CONDITIONS ............................................... 3 Surface Observations ............................................. 3 Subsurface Soils/Geology .......................................... 3 Water Level Measurements ......................................... 4 LABORATORY TESTING ........................................... 5 GEOTECHNICAL CONSIDERATIONS .................................. 5 Review of Soil Properties .......................................... 6 Effect of Ground Water ........................................... 7 Approach/Discussion ............................................. 8 RECOMMENDATIONS ............................................ 9 Building Grading ............................................... 9 Foundations .................................................. 11 Floor Slabs .................................................. 12 Building Backfilling ............................................ 12 Pavement Subgrade Preparation ..................................... 13 Exterior Site Drainage ........................................... 15 CONSTRUCTION CONSIDERATIONS ................................. 15 Potential Difficulties ............................................ 15 Excavation Sidesloping .......................................... 15 Observation and Testing .......................................... 16 SUBSURFACE EXPLORATION ...................................... 16 General .................................................... 16 Drilling Methods .............................................. 16 TABLE OF CONTENTS Sampling Methods ............................................. 16 Classification Methods ........................................... 17 Water Level Measurements ........................................ 18 Sample Storage ............................................... 18 LIMITATIONS .................................................. 18 STANDARD OF CARE ............................................ 19 SIGNATURES .................................................. 19 STANDARD DATA SHEETS Basement/Retaining Wall Baclcf'fll and Water Control ....................... 20 Freezing Weather Effects on Building Construction ........................ 21 Bituminous Pavement Subgrade Preparation and Design ..................... 22 Floor Slab Moisture/Vapor Protection ................................. 23 APPENDIX A Figure 1 Boring Locations Soil Boring Logs Boring Log Notes Classification of Soils for Engineering Purposes General Terminology Notes GEOTECHNICAL EXPLORATION AND REVIEW FOR RESIDENTIAL ADDITION TWIN LAKES ROAD ELK RIVER, MINNESOTA AET #20-02044 SUMMARY Purpose You are proposing a new residential development at a site in Elk River, Minnesota. The purpose of our work on this project is to perform an exploration of subsurface conditions and provide geotechnical engineering recommendations to assist you and the project team in planning and consa'uction. Scope To accomplish the above purpose, you have authorized our firm to drill fourteen test borings at the site, conduct laboratory testing, and prepare this geotechnical engineering report. Findings The borings indicate a general soil profile consisting of topsoil or swamp deposits over naturally deposited alluvial and till soils. Ground water was present at nine of the borings at the time of drilling at depths ranging from about 0.3' to 6.5' below the ground surface. Perched water may at times be present where free draining sands are underlain by, or interlayered within, alluvial clays or tills. Recommendations These recommendations are condensed for your convenience. Study our entire report for detailed recommendations. The proposed buildings can be supported by conventional spread footings after soil correction. Foundations for the structures should be designed for an allowable soil bearing pressure of 2,000 pounds per square foot. Soil correction should include removing existing topsoil or swamp deposits and the near surface very soft to soft or very loose (N-value less than 5 bpf) f'me alluvium or mixed alluvium, and placing and compacting new fill to establish final grades. If the site soils are to be used as compacted fill, some of the site soils may have to be mechanically dried in order to reduce water contents to obtain proper compaction. AET #20-02044 - Page 2 INTRODUCTION This report presents the results of a subsurface exploration program and geotectmical engineering review for the proposed residential development located east of Twin Lakes Road in Elk River, Minnesota. To protect you, American Engineering Testing, Inc. (AET), and the public, we authorize use of opinions and recommendations in this report only by you and your project team for this specific project. Contact us if other uses are intended. Even though this report is not intended to provide sufficient information to accurately determine quantities and location of particular materials, we recommend that your potential contractors be advised of the report availability. Scope of Services Our scope of services for this project was presented to you in our February 25, 2002, proposal letter. You authorized our work on this project on February 14. A review of our agreed upon scope of services is as follows: Fourteen standard penetration test borings. Soil laboratory testing. Geotechnical engineering analysis based on the above and preparation of this report. The scope of our work is intended for geotechnical purposes only. This scope is not intended to explore for the presence or extent of environmental contamination at the site. PROJECT INFORMATION You are proposing to develop the site for construction of residential structures. The buildings will be single-family structures. We understand the buildings may be of full basement or shallow basement construction. The elevations of the basement floors have not yet been established. The AET #20-02044 - Page 3 above grade construction will be wood-framed. The development will also include installation of major underground utilities and bituminous surfaced roads and driveways. Foundation Design Assumptions Our spread foundation design assumptions include a minimum factor of safety of 3 with respect to a shear or base failure of the foundations. We assume the structure will be able to tolerate total settlements of up to 1 ", and differential settlements over a 30' distance of up to 1/~,,. The presented project information represents our understanding of the proposed construction. This information is an integral pan of our engineering review. It is important that you contact us if there are changes from that described so that we can evaluate whether changes in our recommendations are appropriate. SITE CONDITIONS Surface Observations The site is located east of Twin Lakes Road at about Tyler Street NW in Elk River, Minnesota. The site is mostly rolling agricultural land with several wetlands scattered over the site. The northern and eastern parts of the site are wooded and generally not accessible to soil boring equipment. The site topography plan indicates the surface elevations range from about 908 to about 945. Surface elevations at the boring locations range from 908.2 at Boring #11 to 944.9 at Boring #2. Subsurface Soils/Geology Logs of the test borings are included in Appendix A. The logs contain information concerning soil layering, soil classification, geologic description, and moisture. Relative density or consistency is also noted, which is based on the standard penetration resistance (N-value). The boring logs only indicate the subsurface conditions at the sampled locations. Variations often occur between and beyond borings. AET//20-02044 - Page 4 General Profile The borings indicate a general soil profile consisting of topsoil or swamp deposits underlain by interlayered fmc, coarse, and mixed alluvium, and glacial till. Topsoil/Swamp Deposits The topsoil or swamp deposits (where present) is about 1' to 4' thick at the boring locations, and consists primarily of dark brown to black clayey sands, silty sands, lean clays, silty clays and organic clays. Alluvium Fine alluvium or mixed alluvium is present at many borings and consists of lean clays, silts, sandy lean clays, clayey sands, and silty sands. The fmc and mixed alluvium are often interlayered within the coarse alluvium or till. Coarse alluvium consisting of silty sands, sands with silt, and sands is present at most of the borings. The cohesive parts of the fmc or mixed alluvium is very soft to very stiff and the more granular portions are very loose to medium dense. The coarse alluvium ranges from very loose to medium dense. Till Glacial till, some of which is weathered, is present beneath the topsoil and/or alluvium. The glacial till consists of lean clays, clayey sands, and silty sands. The till ranges from soft/loose to very stiff/medium dense. Some lenses of waterbearing sands are present in parts of the till. Water Level Measurements The boreholes were probed for the presence of ground water and water level measurements were taken. The measurements are recorded on the boring logs. A discussion of the water level measurement methods is presented in the SUBSURFACE EXPLORATION section of this report. AET ~0-~0~-P~e5 Ground water was measured in nine of the borings at the time of drilling. The water was encountered at depths ranging from 0.3' at Boring//6, to 6.5' at Boring//3. The primary soils encountered are moderately slow to slow draining materials. Some relatively free draining sands were present within the profiles at some of the borings. It takes an extended observation period to reliably establish the ground water level in the slower draining soils. Such an extended observation period is beyond the scope of this work. The measured water levels or absence of water levels may not be a reliable indication of the groundwater table. At some locations, observation of the samples retrieved indicated water may be present at shallower depths. Notation indicating the apparent depth of water based on sample appearance are noted on the boring logs. It is likely perched water may at times be present within the interlayered soils at variable depths. Ground water levels usually fluctuate. Fluctuations occur due to varying seasonal and yearly rainfall and snow melt, as well as other factors. LABORATORY TESTING Water content tests and sieve analysis tests were performed on selected soil samples to aid in judging engineering properties and soil classification. The results of the tests appear on the boring logs, opposite the samples upon which they were performed. GEOTECHNICAL CONSIDERATIONS The following geotechnical considerations are the basis for the recommendations presented later in this report. AET #20-02044 - Page 6 Review of Soil Properties Strength Based on the N-values and sample appearance, the fine alluvium and mixed alluvium soils are judged to be low to moderate strength materials. The coarse alluvium sands and the glacial till are judged to be moderate to high strength materials. Compressibility The topsoil/swamp deposits are judged to be compressible, and should be removed from building areas. Some of the very soft/very loose to soft alluvial soil are also judged to be compressible, if present at depths near foundation elevations. The recorded N-values in some of the deeper alluvial soils are also low. However, in our judgement these N-values are likely affected by the water pressure and these soils are typically not compressible under the anticipated light loadings. The remainder of the alluvial and till soils are not judged to be significantly compressible under the anticipated light loadings. Expansive/Shrinkage Potential The site soils depicted by the soil characteristics. borings typically do not have expansive or shrinkage Frost Susceptibility It is our judgment many of the near surface soils are at least moderately frost susceptible, depending upon their water contents. If the frost susceptible soils remain in-place and are allowed to freeze, heaving of the subgrade will occur. The magnitudes of heave may be on the order of 1/4" to 3/8" for each foot of frost penetration within the soil, which could translate to 1" to 3" of total movement. This could be exaggerated further if free water is available, which could lead to the formation of ice lenses. AET #20-02044 - Page 7 Movements of exterior sidewalks, slabs and stoops is especially important at building doorway areas. These exterior features should be designed to accommodate frost heave movements of the magnitudes described, or the on-site soils should be removed and replaced with non-frost susceptible sands. In bituminous parking and drive areas, frost heaving is not necessarily a problem unless the heave occurs as an abrupt differential movement. For this reason, consistency of soil conditions or gradual changes of the soil conditions across the pavement area is favorable. Drainage Properties The fine or mixed alluvial soils, glacial tills and the f'me grained silty sand parts of the coarse alluvium are judged to be slow to moderate draining soils. The coarse alluvial sands and sands with silt are judged to be moderately fast to fast draining. Pavement Stability Properties The fine alluvial lean clays and silts are judged to have low strength and pavement stability. The mixed alluvium, coarse alluvium and till soils are judged to have moderate strength and pavement stability. However, if these soils are wet, they can become unstable if subjected to repeated traffic. If they become unstable, they can be improved by subcutting, moisture conditioning, and then recompacting. This correction should be performed during favorable weather conditions, but is difficult to perform during the Spring and Fall of the year. Effect of Ground Water Basements should be positioned a safe distance above the water levels to allow for future fluctuations. The basement construction should include a perimeter draintile system to collect and dispose of perched or infiltrating surface runoff water. If larger quantities of water are present, use of additional trench drain systems may be needed in parts of the site. Since the soils are interlayered, there is a potential for water at variable elevations and use of trench drains may be AET #20-02044 - Page 8 required, especially in some of the "cut" areas. If needed, the trench drains should discharge into the storm sewer system or storm water ponding areas. Excavation to install underground utilities may extend below the groundwater levels. We anticipate that use of a dewatering system may be required. The soils excavated during utility construction in the lower areas will likely be too wet to reuse in the trench backfill and place to specified compaction levels. Approach/Discussion Based on the soil boring data, it is our opinion that the deeper layers of very loose silty sand mixed alluvium at Borings//6 and #9 are potentially compressible and may densify under the weight of new fill needed to establish finish grades and the building foundation loadings. In our opinion, the potential for detrimental post construction settlement is greatest in areas where substantial thicknesses of fill are required. On the basis of the limited information available, we anticipate that removal of these soils can be avoided if the site development and grading plan and schedule can incorporate a building construction delay after placement of fill, and possible use of a temporary surcharging, dependent upon finish grades. We request we be allowed to review fmal development plans, when available, to judge whether this alternative remains feasible. If f'mal grades or project schedule do not allow this construction delay, deeper excavation will be needed. The recommendations presented in the following sections of this report are based on our assumption that the removal of the potentially compressible materials will not be required. _ AET #20-02044 - Page 9 RECOMMENDATIONS Building Grading Excavation To prepare the building areas for structural support, we recommend removing the topsoil or swamp deposits and the very soft or very loose to soft fine or mixed alluvium, when presem near the existing ground surface (N-value less than 5) to expose the underlying competent soils. Excavation of the deeper very loose silty sands or clayey sands at Borings//3, #6, and #9 should not be required (as discussed in the "Approach/Discussion" section). The following table indicates the recommended minimum excavation depths and anticipated bottom elevations at the boring locations. 1 929.3 4~/~ 925 2 944.9 1 944 3 924.0 2 922 4 930.3 1 929% 5 918.3 I~A 917 6 913.6 6* 907~A 7 922.1 1/~ 9211~ 8 913.3 8 9051,6 9 911.6 8** 903¥6 10 920.2 11/~ 919 11 908.2 6 902 AET #20-02044 - Page 10 12 931.3 1 ~,6 930 13 915.4 4~,4 911 14 941.8 2 940 Notes: * - Excavation depth based on assumption of a building construction delay after filling. If no construction delay is possible, excavation will have to extend to about 9'. · * - Excavation depth based on assumption of a building construction delay after filling. If no construction delay is possible, excavation will have to extend to about 14'. Soil conditions can be expected to vary away from the soil boring locations. For this reason, excavation depths will vary throughout the site. Deeper excavation may be needed in some areas, especially near the wetlands. Due to the potential variation, the soils in the bottoms of the excavations should be observed and evaluated by AET geotechnical personnel prior to new fill or footing placement. In areas where fill is required below foundations, the excavation should be oversized laterally at the bottom so the new fill system can provide support for the lateral loads exerted. Based on the conditions encountered, we recommend the excavation bottom include a 1:1 oversizing. That is, for each vertical foot of fill required below the foundations, the excavation should be oversized laterally beyond the edge of the footing a similar distance. Fill Placement and Compaction After completion of the required excavation, fill required to attain building grade should be uniformly compacted in thin lifts. We recommend the fill be compacted to a minimum of 95 % AET #20-02044 - Page 11 of the Standard Proctor maximum dry density (ASTM:D698). Where the thickness of fill below foundations exceeds 10', the fill should be compacted to a minimum of 98%. We recommend that fill be placed in lift thicknesses appropriate for the type of equipment used and the conditions at the time of the actual earthwork. The thickness should be such that the entire lift attains the minimum specified compaction level. The fill should consist of a suitable inorganic soil. The soils described on the boring logs as coarse alluvium, the dryer parts of the fmc or mixed alluvium and the glacial till should be suitable for reuse within a compacted fill system. However, these soils must be placed at a proper water content in order to attain compaction. If the existing soils are too wet for use as compacted fill, these soils may require mechanical aeration to reduce water content prior to compaction. Such aeration can be time consuming and will require favorable weather conditions. Based on our observation of the samples retrieved and the results of the water content tests, it is our opinion that aeration of some of the site soils will be required to achieve proper compaction. In areas where new fill will be placed on sloping ground, we recommend benching the surface prior to placing the fill. Benching is recommended where slopes are steeper than 4 horizontal to 1 vertical (4:1 slope). Foundations The structure can be supported on conventional spread foundations placed on the compacted fill or the competent natural soils. We recommend perimeter foundations adjacent to heated building space be placed such that the bottom is a minimum of 42" below exterior grade. We recommend exterior foundations not bordering heated building space (such as canopy/pier foundations or garage foundations) be extended to a minimum of 60" below exterior grade. AET//20-02044 - Page 12 Based on the conditions encountered, and the recommended compaction levels, it is our opinion the building foundations can be designed based on a maximum allowable soil bearing pressure of 2,000 psf. It is our judgment this design pressure will have a factor of safety of at least 3 against localized shear or base failure. We judge that total settlements under this loading should not exceed 1 ". We also judge that differential settlements of conditions depicted by the borings should not exceed ~/~ ". Floor Slabs The recommended grading procedures should prepare the building areas for floor slab support. The floor slab can be supported by the new fill that is placed and compacted to grades or the naturally deposited soils. All fill supporting the floor slab should be compacted to a minimum of 95 % of the Standard Proctor maximum dry density. This includes all utility and foundation trench backfill. For recommendations relating to moisture/vapor protection of the slab, we refer you to our standard sheet entitled "Floor Slab Moisture/Vapor Protection" (page 23) at the end of the report. Building Backfilling Other recommendations for backfilling the structures appears on two standard data sheets which we have attached to this report. These sheets are entitled: Freezing Weather Effects on Building Construction (Page 21) Basement/Retaining Wall Backfill and Water Control (Page 20) These sheets present information on preferred soil types, frost considerations, drainage, and lateral pressures. AET #20-02044 - Page 13 Pavement Sub.ode Preparation We have attached a data sheet entitled "Bimminons Pavement Subgrade Preparation and Design" which presents considerations and recommendations for bituminous subgrade grading work. Refer to this sheet for more complete recommendations for the subgrade preparation work. The primary near surface soils (below the topsoil) consist of alluvial lean clay, silt, silty sand, clayey sand, and sandy lean clay. These soils can become weak and unstable during wet periods or when present near the ground water levels and are frost susceptible. The lean clays and silts are typically poor subgrade soils even when placed at proper water contents and compacted to specified compaction levels. As a minimum, we recommend removing all vegetation, topsoil and swamp deposits. We also recommend the frae alluvial lean clays and silts be removed when present in the top 3' of the subgrade. This excavation should also include ~A:i (H:V) lateral oversizing outside the curb line for lateral support of the fill and pavements. If the excavation terminates at elevations within the top 3' of the subgrade, the bottom of the excavation should be test-rolled to judge the stability of the exposed subgrade. If unstable soils are exposed, they should be subcut and replaced with drier fill; or aerated, dried and recompacted in-place if weather conditions permit. Fill placed in the subgrade areas could be the site sands, sands with silt, clayey sands, or silty sands. All fill placed in the pavement areas should be compacted according to Mn/DOT Specification 2105.3Fl (Specified Density Method). This specification requires the fill placed in the top 3' of the pavement subgrade be compacted to a minimum of 100% of the Standard Proctor Maximum dry density. Any fill placed below the top 3' of the subgrades should be compacted to a minimum of 95 %. The soils should be compacted within the water content requirements of this Mn/DOT specification. We anticipate that mechanical aeration of some of the site soils may be required to satisfy the water content requirements and obtain proper compaction. AET #20-02044 - Page 14 After final grades are established, and prior to the placement of the aggregate base layer, the subgrade should be test-rolled to delineate any areas of unstable soils. If unstable soils are found, they should be subcut and replaced with drier fill or they should be aerated, dried and recompacted back into place if weather conditions permit. For subgrades prepared as discussed above, and assuming the limiting subgrade soil consists of silty sands, clayey sand, and sandy lean clay which successfully pass a test roll, we recommend the pavement be designed based on an assumed R-value of 20. Sand Subbase We strongly recommend that a sand subbase layer be used at this site. It is our opinion a sand subbase layer (typically 1' thick or more) can be used to improve the long term performance of the pavements (see attached sheet for details). The use of a sand subbase may increase initial construction costs; however, these higher costs can be offset due to the improved long term performance, reduced maintenance costs, improved constructability and the use of thinner pavement sections. The sand should be placed over a stable subgrade (prepared as described above). The subbase should be included as part of the upper 3' zone where 100% compaction is required. We recommend using sand which has no more than 12% of the particles (by weight) finer than the #200 sieve, meeting the requirements of Mn/DOT Specification 3149.2B2 for Select Granular Borrow. If a 1' thick sand subbase is used (and silty sands are the limiting soils), the pavement can be designed based on an assumed R-value of 35. If a 2' thick sand subbase is used, the design can be based on an assumed R-value of 55. Subsurface drainage is important for long-term pavement performance. If the sand layer is used for the upper subgrade layer, you should consider providing subsurface drainage methods such that water cannot build-up within the granular soils above the poorer draining soils. This can be handled by strategically placing draintile lines or french drains which can then be directed to AET #20-02044 - Page 15 outfall areas or storm utilities. Where sand fill is to be placed over clays near the surface, we recommend sloping or shaping the clays towards areas where they can drain. Exterior Site Drainage Because infiltration of ground water into the subgrade soils can result in increased frost heaving problems and weakening of subgrade soils in both pavement and sidewalk areas, proper site drainage is important. The pavements, sidewalks and exterior slabs should be properly sloped and maintained to allow runoff of surface water. CONSTRUCTION CONSIDERATIONS Potential Difficulties Many of the site soils are susceptible to disturbance by the action of construction equipment. If these soils become disturbed during excavating, they should be subcut to underlying undisturbed soils. Use of backhoe excavating equipment, especially in Iow areas should reduce the potential for disturbance. Some of the site soils may be wet, and may require scarification and drying to allow compaction to specified levels. Excavation Sidesloping We recommend that unretained trench excavation sideslopes meet requirements established in OSHA Regulations (Standards-29 CFR), Part 1926, Subpart P, "Excavations." The contractor should be responsible for trench safe~. AET g20-02044 - Page 16 Observation and Testin The recommendations in this report are based on the subsurface conditions found at our test boring locations. Since the soil conditions can be expected to vary away from the soil boring locations, we recommend on-site observation by a geotechnlcal engineer/technician during construction to evaluate these potential changes. Soil compaction testing should be performed on new fill placed in order to document that project specifications for compaction have been satisfied. SUBSURFACE EXPLORATION General The geotechnical exploration program for the Project consisted of drilling fourteen standard penetration test borings at the site. These borings were drilled at the site from February 25 through February 28, 2002. The boring locations and surface elevations were measured by the project surveyors. Driiline Methods The borings were drilled with an all-terrain mounted rig using 3.25" diameter hollow stem augers. Sampling Methods Disturbed Samples (DS) Hollow-stem auger samples (disturbed samples) were collected in the surface soils in general accordance with ASTM:D1452. The samples were taken by drilling the hollow-stem auger into the soil, stopping at regular intervals to allow the soil to spin to the surface from that depth. Only disturbed samples are retrieved using this method, therefore, the depths and thicknesses of the different soil layers should only be considered approximate. AET//20-02044 - Page 17 Split-Spoon Samples (SS) Standard penetration (split-spoon) samples were collected in general accordance with ASTM:D1586. This method consists of driving a 2" O.D. split-barrel sampler into the in sim soil with a 140-pound hammer dropped from a height of 30". The sampler is driven a total of 18, into the soil. After an initial set of 6", the number of hammer blows to drive the sampler the fmal 12" is known as the standard penetration resistance or N-value. Sampling Limitations Unless actually observed in a sample, contacts between soil layers are estimated based on the spacing of samples and the action of drilling tools. Cobbles, boulders, and other large objects generally cannot be recovered from test borings, and they may be present in the ground even if they are not noted on the boring logs. Classification Methods Soil classifications shown on the boring logs are based on the Unified Soil classification (USC) system. The USC system is described in ASTM:D2487 and D2488. Where laboratory classification tests (sieve analysis and Atterberg Limits) have been performed, classifications per ASTM:D2487 are possible. Otherwise, soil classifications shown on the boring logs are visual- manual judgments. We have attached charts (Appendix A) illustrating the USC system, the descriptive terminology, and the symbols used on the boring logs. The boring logs include judgments of the geological depositional origin. This judgment is primarily based on observation of the soil samples, which can be limited. Observations of the surrounding topography, vegetation, and development can sometimes aid this judgment. AET//20-02044 - Page 18 Water Level Measurements The ground water measurements are shown at the bottom of the boring logs. The following information appears under "Water Level Measurements" on the logs: · Date and Time of measurement · Sampled Depth: lowest depth of soil sampling at the time of measurement · Casing Depth: depth to bottom of casing or hollow-stem auger at time of measurement · Cave-in Depth: depth at which measuring tape stops in the borehole · Water Level: depth in the borehole where free water is encountered · Drilling Fluid Level: same as Water Level, except that the liquid in the borehole is drilling fluid The true location of the water table at the boring locations may be different than the water levels measured in the boreholes. This is possible because there are several factors that can affect the water level measurements in the borehole. Some of these factors include: permeability of each soil layer in profile, presence of perched water, amount of time between water level readings, presence of drilling fluid, weather conditions, and use of borehole casing. Sample Storage We will retain representative samples of the soils recovered from the borings for a period of 30 days. The samples will then be discarded unless you notify us otherwise. LIMITATIONS The data derived through this sampling and observation program have been used to develop our opinions about the subsurface conditions at your site. However, because no exploration program can reveal totally what is in the subsurface, conditions between borings and between samples and at other times, may differ from conditions described in this report. The exploration we conducted identified subsurface conditions only at those points where we took samples or observed ground water conditions. Depending on the sampling methods and sampling frequency, every soil layer may not be observed, and some materials or layers which are present in the ground may not be noted on the boring logs. AET #20-02044 - Page 19 If conditions encountered during construction differ from those indicated by our borings, it may be necessary to alter our conclusions and recommendations, or to modify construction procedures, and the cost of construction may be affected. The extent and detail of information about the subsurface condition is directly related to the scope of the exploration. It should be understood, therefore, that information can be obtained by means of additional exploration. STANDARD OF CARE Our services for your project have been conducted to those standards considered normal for services of this type at this time and location. Other than this, no warranty, either express or implied, is intended. SIGNATURES Report Prepared by: Gary A. Larson Senior Engineering Assistant Report Reviewed by: oyen, PE Vice President, Geotechnical Division MN Reg.//15978 DRAINAGE AET #20-02044 - Page 20 BASEMENT/RETAINING WALL BACKFILL AND WATER CONTROL Below grade basements should include a perimeter backfill drainage system on the exterior side of the wail. The exception may be where basements lie within free draining sands where water will not perch in the backfill. Drainage systems should consist of perforated or slotted PVC drainage pipes located at the bottom of the backfill trench, lower than the interior floor grade. The drain pipe should be surrounded by properly graded filter rock. A filter fabric should then envelope the filter rock. The drain pipe should be connected to a suitable means of disposai, such as a sump basket or a gravity outfall. A storm sewer gravity outfail would be preferred over exterior daylighting, as the latter may freeze during winter. For non-building, exterior retaining walls, weep holes at the base of the wail can be substituted for a drain pipe. BACKFILLING Prior to backfilling, damp/water proofing should be applied on perimeter basement walls. The backfill materiais placed against basement walls will exert laterai loadings. To reduce this loading by allowing for drainage, we recommend using free draining sands for backfill. The zone of sand backfill should extend outward from the wail at least 2', and then upward and outward from the wall at a 30° or greater angle from vertical. As a minimum, the sands should contain no greater than 12 % by weight passing the//200 sieve, which would include (SP) and (SP-SM) soils. The sand backfill should be placed in lifts and compacted with portable compaction equipment. This compaction should be to the specified levels if slabs or pavements are placed above. Where slab/pavements are not above, we recommend capping the sand backfill with a layer of clayey soil to minimize surface water infiltration. Positive surface drainage away from the building should also be maintained. If surface capping or positive surface drainage cannot be maintained, then the trench should be filled with more permeable soils, such as the Fine Filter or Coarse Filter Aggregates defined in MnDOT Specification 3149. You should recognize that if the backfill soils are not properly compacted, settlements may occur which may affect surface drainage away from the building. Backfilling with silty or clayey soil is possible but not preferred. These soils can build-up water which increases lateral pressures and results in wet wall conditions and possible water infiltration into the basement. If you elect to place silty or clayey soils as backfill, we recommend you place a prefabricated drainage composite against the wail which is hydraulically connected to a drainage pipe at the base of the backfill trench. High plasticity clays should be avoided as backfill due to their swelling potential. LATERAL PRESSURES _Laterai earth pressures on below grade walls vary, depending on backfill soil classification, backfill compaction and slope of the backfill surface. Static or dynamic surcharge loads near the wall will also increase lateral wall pressure. For design, we recOmmend the following ultimate laterai earth pressure values (given in equivalent fluid pressure vaiues) for a drained soil compacted to 95 % of the Standard Proctor density and a level ground surface. Soil Type Equivalent Fluid Density Active (pcf) At-Rest (pc0 Sands (SP or SP-SM) Silty Sands (SM) Fine Grained Soils (SC, CL or ML) 35 50 45 65 70 90 Basement walls are normally restrained at the top which restricts movement. In this case, the design laterai pressures should be the "at-rest" pressure situation. Retaining walls which are free to rotate or deflect should be designed using the active case. Lateral earth pressures will be significantly higher than that shown if the backfill soils are not drained and become saturated. 01REP014(7/01) AMERICAN ENGINEERING TESTING, INC. AET #20-02044 - Page 21 FREEZING WEATI-IER EFFECTS ON BUILDING CONSTRUCTION GENERAL Because water expands upon freezing and soils contain water, soils which are allowed to freeze will heave and lose density. Upon thawing, these soils will not regain their original strength and density. The extent of heave and density/ strength loss depends on the soil type and moisture condition. Heave is greater in soils with higher percentages of fines (silts/clays). High silt content soils are most susceptible, due to their high capillary rise potential which can create ice lenses. Fine grained soils generally heave about 1/4" to 3/8" for each foot of frost penetration. This can translate to 1" to 2" of total frost heave. This total amount can be significantly greater if ice lensing occurs. DESIGN CONSIDERATIONS Clayey and silty soils can be used as perimeter backfill, although the effect of their poor drainage and frost properties should be considered. Basement areas will have special drainage and lateral load requirements which are not discussed here. Frost heave may be critical in doorway areas. Stoops or sidewalks adjacent to doorways could be designed as structural slabs supported on frost footings with void spaces below. With this design, movements may then occur between the structural slab and the adjacent on-grade slabs. Non-frost susceptible sands (with less than 12% passing a//200 sieve) can be used below such areas. Depending on the function of surrounding areas, the sand layer may need a thickness transition away from the area where movement is critical. With sand placement over slower draining soils, subsurface drainage would be needed for the sand layer. High density extruded insulation could be used within the sand to reduce frost penetration, thereby reducing the sand thickness needed. We caution that insulation placed near the surface can increase the potential for ice glazing of the surface. The possible effects of adfreezing should be considered if clayey or silty soils are used as backfill. Adfreezing occurs when backfill adheres to rough surfaced foundation walls and lifts the wall as it freezes and heaves. This occurrence is most common with masonry block walls, unheated or poorly heated building situations and clay backfill. The potential is also increased where backfill soils are poorly compacted and become saturated. The risk of adfreezing can be decreased by placing a low friction separating layer between the wall and backfill. Adfreezing can occur on exterior piers (such as deck, fence or other similar pier footings), even if a smooth surface is provided. This is more likely in poor drainage situations where soils become saturated. Additional footing embedment and/or widened footings below the frost zones (which includes tensile reinforcement) can be used to resist uplift forces. Specific designs would require individual analysis. CONSTRUCTION CONSIDERATIONS Foundations, slabs and other improvements which may be affected by frost movements should be insulated from frost penetration during freezing weather. If filling takes place during freezing weather, all frozen soils, snow and ice should be stripped from areas to be filled prior to new fill placement. The new fill should not be allowed to freeze during transit, placement or compaction. This should be considered in the project scheduling, budgeting and quantity estimating. It is usually beneficial to perform cold weather earthwork operations in small areas where grade can be attained quickly rather than working larger areas where a greater amount of frost stripping may be needed. If slab subgrade areas freeze, we recommend the subgrade be thawed prior to floor slab placement. The frost action may also require reworking and recompaction of the thawed subgrade. 01REP015(2/01) AMERICAN ENGINEERING TESTING, INC. GENERAL AET #20-02044 - Page 22 BITUMINOUS PAVEMENT SUBGRADE PREPARATION AND DESIGN Bituminous pavements are considered layered "flexible" systems. Dynamic wheel loads transmit high local stresses through the bituminous/base onto the subgrade. Because of this, the upper portion of the subgrade requires high strength/stability to reduce deflection and fatigue of the bituminous/base system. The wheel load intensity dissipates through the subgrade such that the high level of soil stability is usually not needed below about 2' to 4' (depending on the anticipated traffic and underlying soil conditions). This is the primary reason for specifying a higher level of compaction within the upper subgrade zone versus the lower portion. Moderate compaction is usually desired below the upper critical zone, primarily to avoid settlements/sags of the roadway. However, if the soils present below the upper 3' subgrade zone are unstable, attempts to properly compact the upper 3' zone to the 100% level may be difficult or not possible. Therefore, control of moisture just below the 3' level may be needed to provide a non- yielding base upon which to compact the upper subgrade soils. Long-term pavement performance is dependent on the soil subgrade drainage and frost characteristics. Poor to moderate draining soils tend to be susceptible to frost heave and subsequent weakening upon thaw. This condition can result in irregular frost movements and "popouts," as well as an accelerated softening of the subgrade. Frost problems become more pronounced when the subgrade is layered with soils of varying permeability. In this situation, the free-draining soils provide a pathway and reservoir for water infiltration which exaggerates the movements. The placement of a well drained sand subbase layer as the top of subgrade can minimize trapped water, smooth frost movements and significantly reduce subgrade softening. In wet, layered and/or poor drainage situations, the long- term performance gain should be significant. If a sand subbase is placed, we recommend it be a "Select Granular Borrow" which meets MnfDOT Specification 3149.2B2. PREPARATION Subgrade preparation should include stripping surficial vegetation and organic soils. Where the exposed soils are within the upper "critical" subgrade zone (generally 2~/~' deep for "auto only" areas and 3' deep for "heavy duty" areas), they should be evaluated for stability. Excavation equipment may make such areas obvious due to deflection and rutting patterns. Final evaluation of soils within the critical subgrade zone should be done by test rolling with heavy rubber-tired construction equipment, such as a loaded dump truck. Soils which rut or deflect 1" or more under the test roll should be corrected by either subcutting and replacement; or by scarification, drying, and recompaction. Reworked soils and new fill should be compacted per the "Specified Density Method" outlined in Mn/DOT Specification 2105.3F1 (a minimum of 100% of Standard Proctor density in the upper 3' subgrade zone, and a minimum of 95 % below this). Subgrade preparation scheduling can be an important consideration. Fall and Spring seasons usually have unfavorable weather for soil drying. Stabilizing non-sand subgrades during these seasons may be difficult, and attempts often result in compromising the pavement quality. Where construction scheduling requires subgrade preparation during these times, the use of a sand subbase becomes even more beneficial for constructability reasons. SUBGRADE DRAINAGE If a sand subbase layer is used, it should be provided with a means of subsurface drainage to prevent water build-up. This can be in the form of draintile lines which dispose into storm sewer systems, or outlets into ditches. Where sand subbase layers include sufficient sloping, and water can migrate to lower areas, draintile lines can be limited to finger drains at the catch basins. Even if a sand layer is not placed, strategically placed draintile lines can aid in improving pavement performance. This would be most important in areas where adjacent non-paved areas slope towards the pavement. Perimeter edge drains can aid in intercepting water which may infiltrate below the pavement. 01REP016(02/01) AMERICAN ENGINEERING TESTING, INC. AET #20-02044 - Page 23 FLOOR SLAB MOISTURE/VAPOR PROTECTION Floor slab design relative to moisture/vapor protection should consider the type and location of two elements, a granular layer and a vapor membrane (vapor retarder, water resistant barrier or vapor barrier). In the following sections, the pros and cons of the possible options regarding these elements will be presented, such that you and your specifier can make an engineering decision based on the benefits and costs of the choices. GRANULAR LAYER In American Concrete Institute (ACI) 302.1-96, a "base material" is recommended, rather than the convemional cleaner "sand cushion' material. The manual maintains that clean sand (common "cushion" sand) is difficult to compact and maintain until concrete placement is complete. ACI recommends a clean, fmc graded material (with at least 10% to 30% of particles passing a #100 sieve) which is not contaminated with clay, silt or organic material. We refer you to ACI 302.1-96 for additional details regarding the requirements for the base material. In cases where potential static water levels or significant perched water sources appear near or above the floor slab, an underfloor drainage system may be needed wherein a draintile system is placed within a thicker clean sand or gravel layer. Such a system should be properly engineered depending on subgrade soil types and rate/head of water inflow. VAPOR MEMBRANE The need for a vapor membrane depends on whether the floor slab will have a vapor sensitive covering, will have vapor sensitive items stored on the slab, or if the space above the slab will be a humidity controlled area. If the project does not have this vapor sensitivity or moisture control need, placement of a vapor membrane may not be necessary. Your decision will then relate to whether to use the ACI base material or a conventional sand cushion layer. However, if any of the above sensitivity issues apply, placement of a vapor membrane is recommended. Some floor covering systems (adhesives and flooring materials) require a vapor membrane m maintain a specified maximum slab moisture content as a condition of their warranty. VAPOR MEMBRANE/GRANULAR LAYER PLACEMENT A number of issues should be considered when deciding whether to place the vapor membrane above or below the granular layer. The benefits of placing the slab on a granular layer, with the vapor membrane placed below the granular layer, include reduction of the following: Slab curling during the curing and drying process. · Time of bleeding, which allows for quicker finishing. · Vapor membrane puncturing. · Surface blistering or delamination caused by an extended bleeding period. · Cracking caused by plastic or drying shrinkage. The benefits of placing the vapor membrane over the granular layer include the following: · The moisture emission rate is achieved faster. · Eliminates a potential water reservoir within the granular layer above the membrane. · Provides a "slip surface", thereby reducing slab restraint and the associated random cracking. If a membrane is to be used in conjunction with a granular layer, the approach recommended depends on slab usage and the construction schedule. The vapor membrane should be placed above the granular layer when: · Vapor sensitive floor covering systems are used or vapor sensitive items will be directly placed on the slab. · The area will be humidity controlled, but the slab will be placed before the building is enclosed and sealed from rain. · Required by a floor covering manufacturer's system warranty. The vapor membrane should be placed below the granular layer when: · Used in humidity controlled areas (without vapor sensitive coverings/stored items), with the roof membrane in place, and the building enclosed to the point where precipitation will not intrude into the slab area. Consideration should be given to slight sloping of the membrane to edges where draintile or other disposal methods can alleviate potential water sources, such as pipe or roof leaks, foundation wall damp proofing failure, fire sprinkler system activation, etc. There may be cases where membrane placement may have a detrimental effect on the subgrade support system (e.g., expansive soils). In these cases, your decision will need to weigh the cost of subgrade options and the performance risks. AMERICAN ENGINEERING TESTING, INC. Figure 1 - Boring Locations Soil Boring Logs Boring Log Notes Classification of Soils for Engineering Purposes General Terminology Notes L AMERICAN ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET JOB NO: 20-02044 LOG OF BORING NO. 1 (p. 1 of 1) PROJECT: Residential Development; Elk River~ MN DEPTH SURFACE ELEVATION: 929.3 IN GEOLOGY N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL ~-200 Sandy lean clay, a little gravel, dark brown, :' '~ MIXED 4 F/M SS 12 1 - frozen, soft (CL) ALLUVIUM_/ SLOPEWASH 3- Sandy lean clay, brown mottled, soft(CL) : 21 1~I I SS 10: 28 4- 5- Silty sand, a little gravel, medium grained, brown 12 W I SS 12 6 - mottled, wet, medium dense (SM) 1 [. : . COARSE 7- ' ' ALLUVIUM 22 WI SS 14 8 - Silty sand, a little gravel, fine to medium - grained, brown mottled, wet, medium dense 9- (SM) 10- 26 W I SS 4 · 11- '" ' 12 M SS 16 13 - Clayey sand, a little gravel, reddish brown, stiff TILL 14 - to very stiff(SC) 1615- ~ 24 M I SS 16 END OF BORING DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-14½' 3.25" HSA DATE TIIvlE SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/25/02 11:15 6.0 4.5 5.3 3.8 SHEETS FOR AN 2/25/02 11:50 16.0 14.5 16.0 None EXPLANATION OF BORING COMPLETED: 2/25/02 2/25/02 12:00 16.0 None 5.7 TERMINOLOGY ON CC: GL CA: BL Rig: 3R 2/25/02 3:45 16.0 None 7.0 2.3 THIS LOG 2/99 ENGINEERING SUBSURFACE BORING LOG _ _ ~,. TESTING, INC. /LET JOB NO: 20-02044 LOG OF BORING NO. 2 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 944.9 IN GEOLOGY N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL %-201 Clayey sand, dark brown, frozen, a few organics ~ TOPSOIL ~,~, 10 F SS 12 2 Clayey sand, a little gravel, brown mottled, stiff i'~" TILL 3- tofh-m(SC) 8 M SS 8 4- 5- 10 M I ss 16 7- Silty sand, a little gravel, apparent cobbles or : TILL boulders, brown, moist, loose to medium dense : ' 23 M I SS 15 8- (SM) 1 9- .' .: 30/.6 M I SS 16 OBSTRUCTED AT 10.7' · DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-10.7' 3.25" HSA DATE TIME SAIvlPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/25/02 1:30 NA 10.7 10.5 None SHEETS FOR AN 2/25/02 1:35 NA None 6.0 None EXPLANATION OF BORING COMPLETED: 2/25/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 'AMERICAN ENGINEEREqG SUBSURFACE BORING LOG TESTING, INC. AET/OB NO: 20-02044 LOG OF BORING NO. 2A (p. 1 of 1) VROJ~CT: Residential Development; Elk River, MN I FIELD & LABORATORY TESTS DEPTH SURFACE ELEVATION: GEOLOGY SAMPLE REC. IN N MC FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL %-20£ 1- 2- 3- 4- 5- 6- No Samples Taken 7- 8- 9- 10- 11- 12 25 M I SS 18 13- ~.... Silty sand, a little gravel, brown, reddish brown, ':" 5 TILL 14 - moist, medium dense (SM) ' 26 M I SS 18 16 END OF BORING DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-14½' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACI-IED 2/25/02 2:00 16.0 14.5 16.0 None SHEETS FOR AN 2/25/02 2:05 16.0 None 8.0 None EXPLANATION OF BORING COMPLETED: 2/25/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 '~ AMERICAN ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET JOB NO: 20-02044 LOG OF BORING NO. 3 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 924.0 I FIELD & LABORATORY TESTS IN GEOLOGY N MC SAMPLE REC. FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL %-20C 1 - SiltY1.5, (CL-]V[L)clay' apparent roots, dark brown, ti'ozen to TOPSOIL F I SS 16 2 Silt, brown and dark brown, dry, loose (ML) FINE* 16 M SS 16 3 Silty sand, a little gravel, apparent cobbles, I 4 - brown, moist, medium dense (SM) 5 - Sand with silt and gravel, apparent cobbles, COARSE 18 M I SS 14 medium grained, brown, moist, medium dense ALLUVIUM 1 6- (se-sM) ~r 7- Sand with silt, a little gravel, medium to frae 17 W I SS 14~ 8 - grained, brown, medium dense (se-sM) 9 Silty sand, a little gravel, medium grained, ] ] 10 - brown, wet, loose (SM) 8 v vl ss 18 12 - Clayey sand, a little gravel, brown, soft, lenses 13 - of silty sand and lean clay (SC/SM) 2I ss 22 14_ 15- 2 W · SS 20 Sand with silt, a little gravel, frae to medium 1 16 - grained, brown, waterbearing, very loose 17- (se-sM) 18 5 W I SS 18 19- Sand, a little gravel, medium grained, brown to 20 - grayish brown, waterbearing, loose (se) 10 W I SS 18 21- 22 END OF BORING *ALLUVIUM DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-20' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACI~D 2/25/02 2:45 8.5 7.0 8.0 7.2 SHEETS FOR AN 2/25/02 3:30 22.0 None 6.7 6.6 EXPLANATION OF BORING COMPLETED: 2/25/02 2/26/02 11:25 22.0 None 6.7 6.5 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 - ~ AMEKICAN ENGINEERING SUBSU~ACE BO~NG LOG - ~ I ~ST~G,~C. AET JOB NO: 20-02044 LO6 OF BORING NO. 4 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 930.3 IN GEOLOGY N MC : SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC 'DEN LL PL %-200 Clayey sand, a little gravel, apparent roots, dark ~ TOPSOIL F DS brown, fi'ozen (SC-SM) 1 Clayey sand, a little gravel, brown mottled, firm ~ WEATHEREI 2 (SC)~ TILL OR - ~ MIXED -- ALLUVIUM Silty sand, a little gravel, medium grained, " COARSE 7 M I SS 12 3 - brown, moist, loose (SM) ALLUVIUM 6- 7- ~ 14 8-~/A~ 17 Mii SS 9 - Lean clay, reddish brown, very stiff, lenses of ~ FINE silty sand (CE) ALLUVIUM 10- ~/, ORTILL 20, M SS 18 12- 13- ~ 22MIss 18 14-~ 15- ~, 20 M SS 18 END OF BORING DEPTH: DRILLING METHOD WATER LEVEL MEASLrREMENTS NOTE: REFER TO 0-14½' 3.25" I-ISA DATE TI/VIE SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/26/02 12:30 16.0 14.5 16.0 None SHEETS FOR AN 2/26/02 12:35 16.0 None 12.2 None EXPLANATION OF BORING COMPLETED: 2/26/02 TERMINOLOGY ON CC: GL CA: BL R/g: 3R THIS LOG 2/99 - ~ AMERICAN ENGINEERING SUBSURFACE BORING LOG _ _ ~ TESTING, INC. AETJOBNO: 20-02044 LOG OF BORING NO. 5 (p. 1 ofl) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 918.3 IN GEOLOGY N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL ?L %-200 1 - LeanfrozenClaY(cL)with roots, black and dark brown,~~'/J/~' TOPSOIL 6 F/M I SS 18 2 Sandy lean clay, brown, finn (CL) 3 - 4 M/W I SS 22 4 - Clayey sand, a little gravel, brown mottled, soft TILL to fu-m, lenses of waterbearing sand below about 5 - 6' (sc) 8 1 6- 7 (SM/sc)Siltysand'alittlegravel'br°wn'm°ist'l°°se 5 M--· SS 18 9 Sand with silt, frae grained, brown, 10 - waterbearing, loose, lenses of lean clay (SP-SM) 8 W I SS 18 11- 12- Silty sand, fine to medium grained, brown, wet, COARSE 14 W I ss 14 13 - medium dense, lenses ofwaterbearing sand ALLUVIUIvI 14- (SM) 15- 14 W I SS 12 16 END OF BORING Note: Based on sample appearance, water may be present at about 3'. DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-14½' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/26/02 1:15 11.0 9.5 10.6 6.9 SHEETS FOR AN 2/26/02 1:20 11.0 9.5 10.6 6.1 EXPLANATION OF BORING COMPLETED: 2/26/02 2/26/02 1:50 16.0 None 5.4 TERMINOLOGY ON CC: GL CA: BL Rig: 3R TH/S LOG 2/99 - ~ AMERICAN ENGINEERING SUBSURFACE BORING LOG _ -m TESTING, INC. AET JOB NO: 20-02044 LOG OV BOm~a NO. 6 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 913.6 / GEOLOGY SAMPLE REC. FIELD & LABORATORY TESTS IN~ N MC TYPE IN. WC DEN LL PL %-200 FEET MATERIAL DESCRIPTION · 1- 1 M I SS 10 1 2 - Organic clay, back and dark brown (OH/PT) ~ SWAMP 3 - WHM/W SS18 4:e n clay, gray, very so , le es ofwaterbear g 5- sand(CL) IUM 1~ W I SS 16 6 7- Silty sand, a little gravel, gray, wet, very loose, 2 W I SS 15 8 - lenses ofwaterbearing sand (SM) 10 - Clayey sand, a little gravel, gray, fn'm (SC/SM) 6 W I SS 16 11- 12 Silty sand, trace of organic material, frae · "ii COARSE 7 W I ss 13- grained, gray, wet, loose(SM) .t:::t]ALLUVIUM 14 15 - 17 M/W1 SS 16 16- (ML)Silt' brownish gray, wet, medium dense to loose ~LUVIUM 1 18- 10M/WI SS 14 19 Clayey sand, a little gravel, gray, very stiff ~TILL · 20- (SC/SM) 16 M SS 16 1 21 END OF BORING I DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-19~~ 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEP~ Dg?TH VLUm LEVEL LEVEL ~m ^Tr^CH~D 2/27/02 8:45 2.0 2.2 1.9 SHEETS FOR AN 2/28/02 None 3.0 0.3 EXPLANATION OF BOLLING TERMINOLOGY ON COMPLETED: 2/27/02 CC: GL CA: BL Rig: 3R Tills LOG 2/99 - ~ AMERICAN ENGINEERING SUBSURFACE BORING LOG _ _ m TESTING, INC. AET JOB NO: 20-02044 LOC OF BOmNO NO. 7 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 922.1 I FIELD & LABORATORY TESTS IN GEOLOGY N MC SAMPLE REC. FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL i%-200 Clayey sand with roots, dark brown, frozen (SC) ~/////~, TOPSOIL 1- Silty sand, frae grained, brown, wet, loose (SM) :i[l :]::] ALLUVIuMCOARSE 4 M·· ss 12, 2 Sandy lean clay, reddish brown, soft (CL) ?///~.~, WEATHEREr Clayey sand, a little gravel, apparent cobbles 4 - above about 5', brown mottled to reddish brown, 5 - stiffto very stiff(SC) 22 M I SS 18 7- 8- 20 M I SS 18 9- Silty sand, a little gravel, brown mottled, moist, ). )'"TILL medium dense to dense, lenses of clayey sand, a .' .. 10 - lense oflean clay at about 10.75' :. 15 M I SS 18 I 11- 14 !. Clayey sand, a little gravel, brown to gray, very 15 - stiff, lenses ofwaterbearing sand (SC) ~ 16 w/M I SS 16 16 END OF BORING Note: Based on sample appearance, water may be present at about 12'. DEPTH: DRILLING METHOD WATER LEVEL lvI~ASUREMENTS NOTE: REFER TO 0-14~' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL TI~ ATTACHED 2/27/02 11:20 16.0 14.5 15.2 14.2 SHEETS FOR AN 2/27/02 11:25 16.0 None 13.5 None EXPLANATION OF BORING COMPLETED: 2/27/02 2/28/02 11:20 None 13.6 13.4 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 AMERICAN ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET JOB NO: 20-02044 LOG OF BORING NO. 8 (p. 1 of 1) PROJECT:Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 913.3 IN GEOLOGY N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL %-20C Sandy lean clay with roots, cobbles at surface,~ ~ TOPSOIL I 1 - dark brown, fxozen (CL) ~ 8 F SS 18 Lean clay, trace roots, black and dark brown,~ FINE 3 - C~_~ -/Sandy lean clay, black and dark brown, firm / ~,MIXEDc~LLUViUM 5 M/WI SS 18 FINE Leancla dark a to a ishbrown £m CL 4 Lean clay with sand, brown and gray mottled, - Cmn (CL) S MIXED 1M/W· SS la ALLUVIUM 1 6- Silty sand, a little gravel, fmc to medium grained, brown, wet, very loose to loose, lenses 7 - of clayey sand and waterbearing sand (SM) · · 5 w I ss 18 10 - Lean clay, gray to brown, fm-n (CL) FINE ALLUVIUM 7 M SS 15 11- 12 13 - Silty sand, a little gravel, gray, wet, loose (SM) "'.'MIXED 9 W I SS 16 i- ALLUVIUM 1 Lean clay, gray, very stiff, lenses of silty sand at FINE 15- 16'(CL) ALLUVIUM 16 M I SS 14 I END OF BORING Note: Based on sample appearance, water may be present at about 3 ½'. DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-14~' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/27/02 12:10 6.5 4.5 6.4 6.2 SHEETS FOR AN 2/27/02 12:20 6.5 4.5 6.3 5.3 EXPLANATION OF BORING COMPLETED: 2/27/02 2/27/02 12:35 10.0 None 4.0 3.9 TERMINOLOGY ON ¢C: GL CA: BL Rig: 3R THIS LOG 2/99 AMERICAN ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET JOB NO: 20-02044 LOG OF BORING NO. 9 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 911.6 IN GEOLOGY N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCR.IPTION TYPE IN. WC DEN LL PL %-20C I ss 0 I - Organic clay, dark brown, very soft (OH/PT) ~ SWAMP 2- ~ ~ WH M/W I SS 16 3 Clayey sand, dark brown, very soft (SC) ~ MIXED 4 7~./.d¢~ ALLUVIIJM Silty sand, a little gravel, f'me to medium COARSE 5 - grained, grayish brown to brownish gray, moist ~:' : . ALLUVIUM 2 M/W · SS 16 6 to wet, very loose (SM) .... ~r - 7 - Lean clay, light gray, soft (CL/CH)~ ~ FINE I ALLUVIUM 3 M SS 22 28 8- 9- 10 - Silty sand, a little gravel, brownish gray, wet, ' MIXED very loose, lenses of clayey sand and ALLUVIUM 2 W · SS 20 11 - waterbearing sand (SM) I Silty sand, trace of organic material, frae 3 M/W I SS 20 13 - grained, brownish gray, wet, very loose (SM) I 14 ~ COARSE 15 - ' :::' ':- ALLUVIUIvl Silty sand, f'me to medium grained, brownish 6 IWW 1 SS 20 16 - gray, wet, loose (SM) I 17 Silty sand, a httle gravel, brown, wet, medium :' :' ' TILL OR 18 - dense (SM) . . ALLUVIUMCOARSE 15 M/W I SS 16 I END OF BORING Note: Based on sample appearance, water may be present near ground surface. DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-15' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/28/02 None 10.0 6.0 SI-IEETS FOR AN EXPLANATION OF BORING COMPLETED: 2/28/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 AMERICAN ENGINEERING SUBSURFACE BORING LOG i TESTING, INC. 2/99 AET JOB NO: 20-02044 LOG OF BORING NO. 10 (p. 1 of 1) PROJECT: Residential Development; Elk River~ MN DEPTH SURFACE ELEVATION: 920.2 GEOLOGY IN N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL %-20£ Silty sand, apparent roots, dark brown, moist, : '.: TOPSOIL F DS 1 - frozen (SM) Silty sand, fine grained, brown, moist, medium~1~. i:!1 I 2 - dense (SM) Ii'.~i:'t'i:~COARSE -- ALLUVIUM 17 M SS 16 3 Silty sand with gravel, apparent cobbles, fme 4 grained, brown, moist, medium dense (SM) 5 - Clayey sand, a little gravel, brown mottled, very TILL 20 M I SS 18 6- stiff(SC) 1 7- Sand with silt, a little gravel, medium to fine 9 M I SS 18 8 9 - grained, brown, moist, loose (SP-SM) 10- 7~ M I SS 15 11 - Sand, a little gravel, fine to medium grained, 12 - brown, moist, loose (SP) 13- 9 M I SS 15 Sand with silt, a little gravel, fine to medium 15 - grained, brown, moist, loose, lenses of silty sand 10 M · SS 16 (SP-SM) 1 16 END OF BORING DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-14~' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/28/02 9:30 16.0 14.5 16.0 None SHEETS FOR AN 2/28/02 9:35 16.0 None 8.0 None EXPLANATION OF BORING COMPLETED: 2/28/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R TH/SLOG AMERICAN ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET$OBNO: 20-02044 LOOOFBOmNGNO. 11 (p. 1 ofl) PRO'CT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 908.2 / I Sm'4PLE REC. FIELD & LABORATORY TESTS IN.~] GEOLOGY N MC TYPE IN. WC DEN LL PL ~-200 FEET MATERIAL DESCRIPTION [J~j~ TOPSOIL OR F DS I - (maySilty claYbe fill)with roots, black, fiozen (CL-ML) ~ FILL 2 Silty sand, frae grained, dark brown, moist, very I: '[:i1 :l COARSE -- 3 loose (SM) (may be fill) [[/[i:l ALLUVIUM 3 F/W I SS 19 OR FILL 4 - Lean clay, trace roots, brown mottled, soft (CL) ~////MFINE 5- 3 ~ SS 18 29 6 Silty sand, fine grained, brown, moist to wet, 1: l:i 1':1 COARSE 7 very loose (SM) J.:.[::i{:~ALLUVIUM Sand with silt, medium grained, brown, ~waterbearing, loose (SP-SM) / 5 W I SS 18 I LUVIUM 9 Sand with silt, a little gravel, a cobble at about 9',~ ALLUVIUM 1:: :[ :l.:l COARSE I medium grained, gray, waterbearing, loose 10- (SP-SM) 10 W SS 14 Clayey sand, a little gravel, grayish brown, stiff l~- (sc) 12 13 - mediumSilty sand,densea little(sM)gravel, brownish gray, moist, TILL 16 M I SS 14 14 Silty sand, a little gravel, gray, moist, medium 15- dense(SM/SC) 17 M I ss 16 16 END OF BORING Note: Based on sample appearance, water may be present at about Y. DEPTH: DRILLING METHOD WATER LEVEL MEASLrREMENTS NOTE: REFER TO 0-14~' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL TI-rE ATTACHED 2/27/02 3:05 16.0 None 5.7 5.4 SHEETS FOR AN EXPLANATION OF BORING COMPLETED: 2/27/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET SOB NO: 20-02044 LOG OF BORING NO. 12 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 931.3 IN GEOLOGY N MC SAMPLE REC. FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTIONI TYPE IN. WC DEN LL PL %-200 , _ brown, frozen (SM) 2 Clayey sand, a little gravel, brown, frozen (SC) ~?/?'~ WEATHEREE Silty sand, trace of roots, fine grained, reddish ['.f../:'[TILL OR 10 M SS 15 3 - brown, moist (SM) I: 't:I t::[cOARsE 5 - Silty sand, frae grained, reddish brown, moist, 5 M · SS 16 40 6 - loose, lenses of silt (SM) 7 8 - looseSilty sand,(sM)fine grained, reddish brown, moist, 8 M I SS 18 16 9 .I Sand with silt, fine grained, light brown, moist, 12 M I SS 12 11 - lenses of light grayish brown silty sand (SP-SM) 12- Sand with silt, a little gravel, medium to fine 16 M I 13 SS 15 grained, light brown, moist, medium dense, a ~4 - lense of fine grained sand at about 12' (SP-SM) 16 M I SS 15 16 END OF BORING DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-14½' 3.25" I-ISA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2~27~02 1:40 16.0 14.5 15.5 None $I-IEETS FOR AN 2~27~02 1:45 16.0 None 8.0 None EXPLANATION OF BORING COMPLETED: 2~27~02 TERMINOLOGY ON ¢C: GL CA: BL Rig: 3R THIS LOG 2/99 ENGINEERING SUBSURFACE BORING LOG TESTING, INC. 20-02044 AET JOB NO: LOG OF BORING NO. 13 (p. 1 of 1) PROJECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 91S.4 / SAMPLE REC. FIELD & LABORATORY TESTS IN,~._1 GEOLOGY N MC TYPE IN. WC DEN LL PL ~-200 FEET MATERIAL DESCRIPTION Organic sandy lean clay with roots, black to dark~~'~ TOPSOIL I 1 - brown, very soft (OH) 1 M/W SS 6 2- 3 - (cL)Sandy lean clay, light grayish brown, very soft ~////~//////~ TILLWEATHER'E[oR WH M/W·l SS 10 26 ~MIXEDALLUViUM Clayey sand, a little gravel, light grayish brown, 5- fa-tn(SC) 6 M I SS 16 Clayey sand, a little gravel, reddish brown, firm ~ 7 (SC) 8 - sandLean(Sc)clay' reddish brown, fa-m, lenses of clayey 1ALLUVIUMMIXED 7 Mil SS 18: 9 Silt, reddish brown, wet, loose (ML) I 6 W SS 18 Sand, f'me grained, brown, waterbearing, loose, /COARSE 8 W I SS 16 13 - lenses of silt below about 15' (SP) [ALLUVIUM 8 W SS 16 END OF BORING Note: Based on sample appearance, water may be present at about 2'. DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-15' 3.25" HSA DATE TIME SAMPLED~ CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL THE ATTACHED 2/26/02 10:00 11.0 9.5 8.5 4.2 SHEETS FOR AN EXPLANATION OF BORING COMPLETED: 3/26/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R THIS LOG 2/99 AMERICAN ENGINEERING SUBSURFACE BORING LOG TESTING, INC. AET JOB NO: 20-02044 LOG OF BORING NO. 14 (p. 1 of 1) PRO~ECT: Residential Development; Elk River, MN DEPTH SURFACE ELEVATION: 941.8 IN GEOLOGY N MC SAMPLE REC FIELD & LABORATORY TESTS FEET MATERIAL DESCRIPTION TYPE IN. WC DEN LL PL %-200 . Sandy lean clay with roots, cobbles at the 7~X//~TOPSOIL F DS 1- surface dark brown fi'ozen CL __/ ' '' W'EATHEKEE Sandy lean clay, brown, fi'ozen (CL) ~ TILL 2 __ 3- 7 MI SS 8 4- Silty sand, a little gravel, brown, moist, loose, ' ' TILL 5 - lenses of clayey sand (SM) · '-. , 7 M · SS 14 "" 6 M I SS 14 8- 9- 10 .... · ".:. 3 M · SS 16 1 11 - Sand, a little gravel above about 12', f'me to ~' '.'.. medium grained, light brown, moist, loose to 12- very loose(SP) '... 13 - ' : '. .:'i COARSE 5 M · SS 18 .... ALLUVIUM 15- ' ~. 4 M I SS 18 16 - ' ':.' ' 17 ..... 18 . '~..' 19- Sand, fine grained, light brown, moist, loose, ' ~' lenses of silt at about 20' (SP) ..'~ '. 20- 10 M I SS 18 21 :. END OF BORING DEPTH: DRILLING METHOD WATER LEVEL MEASUREMENTS NOTE: REFER TO 0-19½' 3.25" HSA DATE TIME SAMPLED CASING CAVE-IN DRILLING WATER DEPTH DEPTH DEPTH FLUID LEVEL LEVEL ~ ATTACHED 2/26/02 11:20 21.5 19.5 21.0 None SI-IEETS FORAN 2/26/02 11:30 21.5 None None EXPLANATION OF BORING COMPLETED: 3/26/02 TERMINOLOGY ON CC: GL CA: BL Rig: 3R ~ THIS LOG 2/99 BORING LOG NOTES DRILLING AND SAMPLING SYM~BOLS Symbol Definition AC: B,H,N: BX: CA: CAS: CC: COT: DC: DM: DR: DS: FA: HSA: LG: MC: N (BPF): NQ: PQ: RD: REC: REV: SS: WASH: 94mm: ~'. At completion of boring Size of flush-joint casing BX double tube core barrel Crew Assistant (initials) Pipe casing, number indicates nominal diameter in inches Crew Chief (initials) Clean-out tube Drive casing; number indicates diameter in inches Drilling mud or bentonite slurry Driller (initials) Disturbed sample from auger flights Flight auger; number indicates outside diameter in inches Hand auger; number indicates outside diameter Hollow stem aUger; number indicates inside diameter in inches Field logger (initials) Column used to describe moisture condition of samples and for the groUnd water level symbols Standard penetration resistance (N-value) in blows per foot (see notes) NQ wireline core barrel PQ wire!ine core barrel Rotary drilling With fluid and roller or drag bit In split-spoon (see notes) and thin-walled tube sampling, the recovered length (in inches) of sample. In rock coring, the length of core recovered (expressed as percent of the total core run). Zero indicates no sample recovered· Revert drilling fluid Standard split-spoon sampler (steel; 1¥8" is inside diameter; 2" outside diameter); unless indicated otherwise Thin-walled tube; number indicates inside diameter in inches Sample of material obtained by screening returning rotary drilling fluid or by which has collected inside the borehole after "falling" through drilling fluid Sampler advanced by static weight of drill rod and 140-poUnd hammer Sampler advanced by static weight of drill rod 94 millimeter wireline core barrel Water level directly measured in boring Estimated water level based solely on sample appearance TEST SYMBOLS Symbol Definition CONS: DEN: DST: E: I-IYD: LL: LP: OC: PERM: PL: q~: ch: ch: R: RQD: SA: TRX: VSR: VSU: WC: %-200: One-dimensional consolidation test Dry density, pcf Direct shear test Pressuremeter Modulus, tsf Hydrometer analysis Liquid Limit, % Pressuremeter Limit Pressure, tsf Organic Content, % Coefficient of permeability (K) test; F - Field; L - Laboratory Plastic Limit, % Pocket Penetrometer strength, tsf (approximate) Static cone bearing pressure, tsf Unconfined compressive strength, psf Electrical Resistivity, ohm-cms Rock Quality Designator in percent (aggregate length of core pieces 4" or. more in length as a percent of total core run) Sieve analysis Triaxial compression test Vane shear strength, remoulded (field), psf Vane shear strength, undisturbed (field), psf Water content, as percent of dry we. ight Percent 'of material fmer than #200 sieve STANDARD PENETRATION TEST NOTES The standard penetration test consists of driving the sampler with a 140-pound hammer and counting the number of blows applied in each of three 6" increments of penetration. If the sampler is driven less than 18" (usually in highly resistant material), permitted in ASTM:D1586, the blows for each complete 6" increment and for each partial increment is on the boring log. For partial increments, the number of blows is shown to the nearest 0.1' below the slash. The length of sample recovered, as shown on the "REC' column, may be greater than the distance indicated in the N column. The disparity is because the N-value is recorded below the initial 6" set (unless partial penetration defined in ASTM:D1586 is encoUntered) whereas the length of sample recovered is for the entire sampler drive (which may even extend more than 18"). 01FLD012(02/02) AMERICAN ENGINEERING TESTING, INC. CLASSIFICATION OF SOILS FOR ENGINEERING PURPOSES ASTM Designation: D 2487 (Based on Unified Soil Classification System) AMERICAN ENGINEERING TESTING, INC. Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Soil Classification Group Group Namee Symbol Coarse-Grained Soils Gravels Clean Gravels More than 50% retained on More than 50% coarse Less than 5% finesc No. 200 sieve fraction retained on No. 4 sieve Cu_>4 and 1_,5Cc~3~= GW Well graded gravel~ Cu~4 and/or 1~'Cc=,3E GP Poorly graded gravel~ Gravels with Fines More than 12% finesc Fines classify as ML or MH GM Silty gravel~'G'~/ Fines classify as CL or CH GC Clayey gravelF's'~ Sands Clean Sands .50% or more al' coarse Less than 5% fines° fraction passes No. 4 sieve Cu~6 and t_~ Cc~3~ SW Well-graded sand; Cu<6 and/or 1>Cc>3E SP Poorly graded sand/ Sands with Fines More than 12% tines° Fines classify as ML or MH SM Silty sandG.'~,/ Fines classify as CL or CH SC Clayey sands'H'; Fine-Grained Soils Silts and Clays inorganic PI~,7 and plots on or above CL Lean clay~('L''~ 50% or more passes the Liquid limit less than 50 "A" lineJ No. 200 sieve PI c4 or plots below "A" ML SiltK'cM lineJ organic Liduid limit - oven dried aL Organic cJ~.yK'L'M'N <0.75 · Liquid limit - not dried Organic siltK'/-'M'° Silts and Clays inorganic Liquid limit 50 or more PI plots on or above "A" line CH Fat ~'layK'cM PI plots below "A" line MH Elastic siltK'L'M organic Liquid limit - oven dried OH Organic clayK'L'M'~' <0.75 Liquid limit - not dried Organic siltK'L'M'° Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat ABased on the material passing the 3-in. (75-mm) sieve, Bit field sample contained cobbles or boulders, or both, add "with cobbies or boulciers, or both" to group name, CGravels with S to 12% fines reciuire dual symbols: OW-GM well-graded gravel with silt GW-GC welPgraded gravel with clay GP-GM poorly graded gravel with silt GP-GC poorly graded gravel with clay ~Sands with 5 lo 12% fines reciuire dual symbols: SW-SM well-graded sand with silt SW-SC well~gracied sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay '~F~~~-° PARTICLE SIZE IN MILLIMETERS C o]cLs°2 (5/oo) ECu - DSO /D10 Cc ~ {D30)2 D10 x 050 Fit soil contains:~-15% senti, acid "with sand" to group Git fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. Hit fines are organic, add "with organic lines" to group Ill so. ii contains_15% gravel add "with gravel" to group Jif Atterberg limits plot in belched area, soll is a CL~ML. silty clay. Kit soil contains 15 to 29% plus No. 200, acid "with sand" or "with gravel." whichever is preciominanL Lit soil contains_30% plus no. 200, predominantly sand, add "sandy" to to group name. Mit soil contains-~30% plus No. 200, predominantly gravel, add "gravelly" to group name. NpI_~4 and plols on or above "A" line. °PI.,~4 or plots below "A' line. PPI plots on or above "A" line. OPI plots below "A" line. x I-- I-. 1.1 6O For classi'ficotion of fJne-~r~ined soils '/ and fine-~roined fraction aY coarse-stained/ _ soils. Horizontal at PI-4 to LL-25.5,~ then PI-0.7, (LC-Z0) / , O~ ..~ Vertical at LL=I6 t0 P // then Pi = 0.9 (LL-8} / /// ' 50 I0 Ia IS Z0 ~0 40 50 60 ?0 BO SO IIX) Il0 LIQUID LIMIT (LL} GENERAL TERMINOLOGY NOTES FOR SOIL IDENTIFICATION AND DESCRIPTION GRAIN SIZE Term ASTM Boulders Over 12" Cobbles 3" to 12" Gravel #4 sieve to 3" Sand #200 to #4 sieve Fines (silt & clay) Pass #200 sieve CONSISTENCY OF PLASTIC sOILs Term N-Value, BPF Very Soft less than 2 Soft 2-4 Medium 5-8 Stiff 9-15 Very Stiff 16-30 Hard Greater than 30 MOISTURE#FROST CONDITION (MC Column) D (Dry): M (Moist): W (Wet/ Waterbearing): F (Frozen): Absence of moismre, dusty, dry to touch. Damp, although free water not visible. Soft may still have a high water content (over "optimum"). Free water visible. Intended to describe non-plastic soils. Soil frozen. FIBER CONTENT OF PEAT Terln Fibric: Heroic: Sapric: Fiber Content (Visual Estimate) Greater than 67 % 33-67% Less than 33 % GRAVEL PERCENTAGES .T.e. rm Percent A Little Gravel 3 %- 15 % With Gravel 15 %-30 % Gravelly 30 %-50 % RELATIVE DENSITY OF NON-PLASTIC SOILS Term N-value, BpF Very Loose 0-4 Loose . 5-10 Medium Dense 11-30 Dense 31-50 Very Dense Greater than 50 Laminations.: Lenses: LAYERING NOTES Layers less than 1/2" thick of differing material or color. Pockets or layers greater than ½" thick of differing material or color. ORGANIC DESCRIPTION Non-peat soils are described as organic, if soil is judged to have sufficient organic content to influence the soil properties. blCLS011(4/96) AMERICAN ENGINEERING TESTING, INC.