Loading...
HomeMy WebLinkAbout20053486.tiff SUBSURFACE EXPLORATION REPORT ADMINISTRATION AND MAINTENANCE BUILDINGS WASTE MANAGEMENT FACILITY WELD COUNTY ROADS 25 AND 84 WELD COUNTY,COLORADO EEC PROJECT NO. 1052038A 2005-3486 EEC April 21,2005 EARTH ENGINEERING CONSULTANTS, INC. Rothberg Tamburini Winsor Engineers&Consultants 419 Canyon Avenue, Suite 220 Fort Collins,CO 80521 Attn: Ms. Bret Icenogle Re: Subsurface Exploration Report Administration and Maintenance Buildings Waste Management Facility Weld County Roads 25 and 84 Weld County, Colorado EEC Project No. 1052038A Mr. Icenogle: Enclosed, herewith, are the results of the geotechnical subsurface exploration you requested for the administration/operations building and the container/maintenance building at the Waste Management Facility at Weld County Roads 25 and 84 in Weld County, Colorado. In summary, the subsurface materials encountered in the test borings consisted of stiff to very stiff lean clay to the depths drilled, approximately 15 feet below present ground surface. The near surface clay soils showed moderate to high swell potential at current moisture and density conditions. Groundwater was not encountered in the completed test borings at the time of drilling. Based on the materials encountered in the test borings, it is our opinion the proposed lightly loaded buildings could be constructed with conventional footing foundations and floor slabs bearing on at least 4 feet of moisture-conditioned and compacted overexcavation backfill. The moisture conditioned near surface materials would reduce the potential for post-construction expansion of the subgrade and bearing soils and resultant heaving of the overlying improvements. However,the risk of movement can not be eliminated. Geotechnical recommendations concerning subgrade preparation, design and construction of the foundations and support of floor slabs are provided in the attached report. 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 224-1522 FAX (970)663-0282 Earth Engineering Consultants,Inc. EEC Project No. 1052037A April 2l,2005 Page 2 We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information, or if we can be of further service to you in any other way, please do not hesitate to contact us. Very truly yours, Earth Engineering Consultants,Inc.iy).,:30.• ,--:-.., 23067 •. Lio, Lester L. Litton,P.E. Principal Engineer LLL/dmh SUBSURFACE EXPLORATION REPORT ADMINISTRATION AND MAINTENANCE BUILDINGS WASTE MANAGEMENT FACILITY WELD COUNTY ROADS 25 AND 84 WELD COUNTY,COLORADO EEC PROJECT NO. 1052038A April 21,2005 INTRODUCTION The subsurface exploration for the proposed administration/operations building and the container/maintenance building to be constructed at the Waste Management facility near Weld County Road 25 and 84 in Weld County,Colorado,has been completed. As requested, one (1) soil boring was completed at each approximate building location to obtain information on existing subsurface conditions. Individual boring logs and a diagram indicating the approximate boring locations are provided with this report. We understand the proposed buildings will be single-story, lightly loaded slab-on-grade structures. Foundation loads for the structure are expected to be less than 3 kips per lineal foot for continuous walls with individual column loads in the range of 50 to 100 kips. Small grade changes are expected on the site to develop final site grades. The purpose of this report is to describe the subsurface conditions encountered in the borings, analyze and evaluate the test data and provide geotechnical recommendations concerning design and construction of the foundations and support of floor slabs. EXPLORATION AND TESTING PROCEDURES The proposed boring locations were provided by Waste Management personnel. Those locations were established in the field by representatives of Earth Engineering Consultants, Inc.(EEC)by pacing and estimating angles and distances from identifiable site features. The locations of the borings should be considered accurate only to the degree implied by the methods used to make the field measurements. Earth Engineering Consultants,Inc. EEC Project No. 1052038A April 21,2005 Page 2 The borings were performed using a truck mounted, CME-45 drill rig equipped with a hydraulic head employed in drilling and sampling operations. The boreholes were advanced using 4-inch nominal diameter continuous flight augers and samples of the subsurface materials encountered were obtained using split-barrel and California-barrel sampling procedures in general accordance with ASTM Specification D-1586. Subsurface samples were also obtained by pushing thin-walled"Shelby"tubes in general accordance with ASTM Specification D-1587. In the split-barrel and California-barrel sampling techniques,standard sampling spoons are driven into the ground by means of a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the standard samplers is recorded and is used to estimate the in-situ relative density of cohesionless materials and,to a lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered bedrock. In the California barrel and "Shelby" tube sampling procedures, relatively undisturbed samples are retrieved in the field. All samples obtained in the field were sealed and returned to the laboratory for further examination,classification and testing. Moisture content tests were performed on each of the recovered samples. In addition, the unconfined strength of appropriate samples was estimated using a calibrated hand penetrometer. Washed sieve analysis and Atterberg limits tests were completed on selected samples to evaluate the quantity and plasticity of fines in the subgrades. Swell/consolidation tests were completed on selected samples to evaluate the soil's tendency to change volume with variation in moisture content. Results of the outlined tests are indicated on the attached boring logs and summary sheets. As a part of the testing program,all samples were examined in the laboratory by an engineer and classified in accordance with the attached General Notes and the Unified Soil Classification System based on the soil's texture and plasticity. The estimated group symbol for the Unified Soil Classification System is indicated on the boring logs and a brief description of that classification system is included with this report. Earth Engineering Consultants,Inc. EEC Project No. I052038A April 21,2005 Page 3 SITE AND SUBSURFACE CONDITIONS The approximate locations of the proposed buildings are indicated on the attached location diagram. The project site is sparsely vegetated and relatively level. Evidence of prior building construction was not observed at the referenced location by EEC personnel. An EEC engineer was on site during drilling to evaluate the subsurface conditions encountered and direct the drilling activities. Field logs prepared by EEC site personnel were based on visual and tactual observation of disturbed samples and auger cuttings. The final boring logs included with this report may contain modifications to the field logs based on the results of laboratory testing and evaluation. Based on the results of the field borings and laboratory evaluation, subsurface conditions can be generalized as follows. Approximately 3 to 6 inches of topsoil and/or vegetation was encountered at the surface at the boring locations. The topsoil/vegetation was underlain by brown lean clay. The cohesive soils were stiff in consistency,moderately plastic,and very dry at the time of drilling. The lean clay overburden soils show moderate to high swell potential at current moisture and density conditions. The cohesive soils extended to the bottom of the borings at depths of approximately 15 feet below ground surface The stratification boundaries indicated on the boring logs represent the approximate locations of changes in soil types; in-situ,the transition of materials may be gradual and indistinct. GROUNDWATER CONDITIONS Observations were made while drilling and after completion of the borings to detect the presence and depth to hydrostatic groundwater. Free water was not observed in any of the completed site borings at the time of drilling. Fluctuations in groundwater levels can occur over time depending on variations in hydrologic conditions and other conditions not apparent at the time of this report. Zones of perched Earth Engineering Consultants,Inc. EEC Project No. 1052038A April 21,2005 Page 4 and/or trapped water can be encountered at times throughout the year in more permeable zones in the subgrade soils. The location and amount of perched water can also vary over time depending on hydrologic conditions and other conditions not apparent at the time of this report. ANALYSIS AND RECOMMENDATIONS Subgrade Development The clay overburden soils are moderately plastic and,at the time of drilling,were relatively dry. In their current moisture-density state, those materials have a high potential for increasing moisture content and expanding subsequent to construction causing heaving of footing foundations or floor slabs supported directly on or above those materials. To reduce the potential for post-construction movement caused by expansion of the dry,in- situ materials, we recommend those materials be removed from beneath the site improvements,moisture-conditioned and replaced to develop a zone of material immediately beneath the improvements which is not subject to volume change with further increases in moisture content. In the building areas,we recommend the undercut zone extend at least 4 feet below foundation bearing level and top of floor slab subgrade. The overexcavation in the footing areas should extend laterally in all directions at least 2 feet beyond the edges of the footings. The soils replaced in the overexcavation areas to develop foundation bearing and/or floor subgrades should consist of approved materials which are free from organic matter and debris and contain a minimum of 15%fines(material passing the#200 size sieve)in order to reduce the potential of those materials to pond and transmit water. The on-site lean clay soils could be used as overexcavation backfill in these areas provided the recommended minimum moisture contents are developed in those materials at the time of placement and maintained in the subgrades prior to construction of the footings and floor slabs. Earth Engineering Consultants,Inc. EEC Project No. 1052038A April 21,2005 Page 5 Any existing vegetation and/or topsoil should be removed from the building areas. After completing all cuts and prior to placement of any fill or overexcavation backfill soils, we recommend the exposed subgrades be scarified to a minimum depth of 9 inches,adjusted in moisture content and compacted to be within the range of 94 to 98%of maximum dry density as determined in accordance with ASTM Specification D-698, the standard Proctor procedure. The moisture content of the scarified soils should be adjusted to be within the range of-Ito+3%of standard Proctor optimum moisture at the time of compaction. The fill and overexcavation backfill materials should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content and compacted as outlined for the scarified soils. After placement of the fill materials,care should be taken to avoid wetting or drying of those materials. Subgrade materials which are loosened or disturbed by the construction activities or materials which become dry and desiccated or wet and softened should be removed and replaced or reworked in place prior to construction of the overlying improvements. Particular care will be necessary to avoid drying of the subgrade soils thereby creating expansion potential. The outlined steps for preparing bearing materials and subgrades will reduce but not eliminate the potential for movement of the building with moisture-induced volume changes in the underlying materials. The in-place materials below the moisture conditioned zone can increase in moisture content and create some structure movement. Overexcavation of a greater depth of material and/or alternative foundation and floor slab systems could be considered to further reduce the potential for post-construction movement. Footing Foundations Footing foundations could be supported directly on suitable fill/backfill soils placed and compacted as outlined above. For design of footing foundations bearing on the fill/backfill compacted to be at least 94% of standard Proctor maximum dry density, we recommend using a net allowable total load soil bearing pressure not to exceed 1,500 psf. The net Earth Engineering Consultants,Inc. EEC Project No. 1052038A April 21,2005 Page 6 bearing pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure. Total load would include full dead and live loads. Exterior foundations and foundations in unheated areas should be located at least 30 inches below adjacent exterior grade to provide frost protection. We recommend formed continuous footings have a minimum width of 12 inches and isolated column foundations have a minimum width of 24 inches. Trenched or grade beam foundations could be used in the fill materials. If used,we recommend trenched foundations have a minimum width of 12 inches and formed grade beam foundations have a minimum width of 8 inches. No unusual problems are anticipated in completing construction of the footing foundations. Care should be taken to avoid disturbing the bearing soils and to avoid drying of those materials. Soils which are loosened or disturbed by the construction activities or soils which become dry and desiccated or wet and softened should be removed and replaced or reworked in place prior to placement of foundation concrete. We estimate the long-term settlement of footing foundations designed and constructed as outlined above would be less than 1 inch. Floor Slabs Building floor slabs could be supported directly on the newly placed and compacted fill soils. Care should be taken at the time of construction to see that the subgrade materials have not dried appreciably prior to placement of floor slab concrete. For design of the facility floor slab,a modulus of subgrade reaction (k)value of 100 pci could be used for slabs supported on the moisture conditioned site soils. Alternative Foundations Other foundation options could be considered for the proposed buildings including a post- tensioned slab-on-grade foundation or drilled piers. Post-tension slab-on-grade includes a Earth Engineering Consultants,Inc. EEC Project No. 1052038A April 21,2005 Page 7 combination foundation/floor system. The monolithic system moves as a single unit significantly limiting differential movement within the building. Overall movement would still be expected. Other Considerations Positive drainage should be developed away from all site structures with a minimum slope of 1 inch per foot for the first 10 feet away from those improvements in landscape areas. Flatter slopes could be used in hardscape areas. Areas adjacent to the structures should be expected to show movement. Care should be taken when planning landscaping adjacent to the proposed site structures to avoid features which could pond water adjacent to the foundations or stem walls. Placement of plants which require irrigation systems or could result in fluctuations of the moisture content of the subgrade materials should be avoided adjacent to the structures. Watering systems should not be placed within 5 feet of the perimeter of the building and the spray heads should be designed not to spray water on or immediately adjacent to the structures. Roof drains should be designed to discharge at least 5 feet away from the structures and away from the pavement areas. Water which is allowed to pond adjacent to the site improvements can result in unsatisfactory performance of those improvements over time. GENERAL COMMENTS The analysis and preliminary recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations which may occur between borings or across the site. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to re- evaluate the recommendations of this report. It is recommended that the geotechnical engineer be retained to review the plans and specifications so that comments can be made regarding the interpretation and implementation Earth Engineering Consultants,Inc. EEC Project No. 1052038A April 21.2005 Page 8 of our geotechnical recommendations in the design and specifications. It is further recommended that the geotechnical engineer be retained for testing and observations during earthwork and foundation construction phases to help determine that the design requirements are fulfilled. This report has been prepared for the exclusive use of Rothberg Tamburini Winsor Engineers & Consultants for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranty,express or implied, is made. In the event that any changes in the nature,design or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report modified or verified in writing by the geotechnical engineer. • .-., --4, DRILLING AND EXPLORATION DRILLING&SAMPLING SYMBOLS: SS: Split Spoon- 13/8" I.D.,2"O.D.,unless otherwise noted PS: Piston Sample ST: Thin-Walled Tube-2"O.D.,unless otherwise noted WS: Wash Sample R: Ring Barrel Sampler-2.42" I.D.,3"O.D.unless otherwise noted PA: Power Auger FT: Fish Tail Bit HA: Hand Auger RB: Rock Bit DB: Diamond Bit 4",N,B BS: Bulk Sample AS: Auger Sample PM: Pressure Meter HS: Hollow Stem Auger WB: Wash Bore Standard"N"Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D.split spoon,except where noted. WATER LEVEL MEASUREMENT SYMBOLS: WL : Water Level WS : While Sampling WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB : After Boring ACR: After Casting Removal Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils,the indicated levels may reflect the location of ground water. In low permeability soils,the accurate determination of ground water levels is not possible with only short term observations. DESCRIPTIVE SOIL CLASSIFICATION PHYSICAL PROPERTIES OF BEDROCK Soil Classification is based on the Unified Soil Classification DEGREE OF WEATHERING: system and the ASTM Designations D-2488. Coarse Grained Slight Slight decomposition of parent material on Soils have move than 50%of their dry weight retained on a#200 joints. May be color change. sieve;they are described as: boulders,cobbles,gravel or sand. Moderate Some decomposition and color change Fine Grained Soils have less than 50% of their dry weight throughout. retained on a#200 sieve;they are described as : clays,if they High Rock highly decomposed, may be extremely are plastic, and silts if they are slightly plastic or non-plastic. broken. Major constituents may be added as modifiers and minor HARDNESS AND DEGREE OF CEMENTATION: constituents may be added according to the relative proportions Limestone and Dolomite: based on grain size. In addition to gradation, coarse grained Hard Difficult to scratch with knife. soils are defined on the basis of their relative in-place density Moderately Can be scratched easily with knife. and fine grained soils on the basis of their consistency. Example: Lean clay with sand, trace gravel, stiff(CL); silty Hard Cannot be scratched with fingernail. sand,trace gravel,medium dense(SM). Soft Can be scratched with fingernail. CONSISTENCY OF FINE-GRAINED SOILS Shale,Siltstone and Claystone: Hard Can be scratched easily with knife,cannot be Unconfined Compressive scratched with fingernail. Strength,Qu,psf Consistency Moderately Can be scratched with fingernail. Hard < 500 Very Soft Soft Can be easily dented but not molded with 500- 1,000 Soft fingers. 1,001 - 2,000 Medium Sandstone and Conglomerate: 2,00! - 4,000 Stiff Well Capable of scratching a knife blade. 4,001 - 8,000 Very Stiff Cemented 8,001 - 16,000 Very Hard Cemented Can be scratched with knife. RELATIVE DENSITY OF COARSE-GRAINED SOILS: Poorly Can be broken apart easily with fingers. N-Blows/ft Relative Density Cemented 0-3 Very Loose 4-9 Loose 10-29 Medium Dense 30-49 Dense t E CC Vii` 50-80 Very Dense G i 80+ Extremely Dense UNIFIED SOU,CLASSIFICATION SYSTEM 1 I Soil Classification Group Group Nome Criteria try Assigning Group 5y:rhds and Grp names Using Laboratory Tests Symbol Coarse—Grained Gravels more than Clean Grovels Less Soils more than 50% of coarse than 5% fines Cu>4 and <CcS3` CW Welt—graded grovel' 507. retained an fraction retained • No. 200 sieve on No. 4 sieve Cu<4 and/or 1>Cc>J` GP Poorly--graded gravel' Gravels with Fines Fines classify as ML or MH GM Silty grovel. G,11 more than 12% fines Fines classify as CL or CH GC Clayey Grovel''''' . Sands 50% or Clean Sands Less C1?..5 and 1<Cc≤.3e SW Wall—graded sand' more coarse than 5% fines fraction passes Cu<6 and/or 1>Cc>J` SP Poorly—graded sand' No. 4 sieve --- -- --- Sands with Fines Fines classify as Mt. or NH Sµ Silty sand" more than 12% fines Fines classify as CL or CH SC Clayey sand'" Fine—Grained Silts and Clays inorganic PI>7 and plots on or above "A"Line' CL Lean clay'•'-° Soils 507E or Liquid Limit less rnore passes the then 50 PI<4 or plots below 'A'Line' ML Si!t'"•" No. 200 sieve organic Liquid Limit - oven dried Organic cloy WO <0.75 OL --- Liquid Limit - not dried Organic silt' Silts and Clays inorganic PI plots on or above "A"Line CH Fat cloy' Liquid Limit 50 or more PI plots below -Aline NH Elastic Silt"". organic liquid Limit - oven dried Organic clay'" <0.75 OH Uquid Limit - not dried Organic silt' Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat 'Hosed on the material pressing the 3-ln, (75- ' (0A IP roil contains 15 to 297rplus No. 200.odd mm) stewCup-Uw/U,Ce>• x 'with sand' or"wile grovel". whichever is 'tined sample contained cobbles or boulders, predominanL or bath, odd 'with cobbles or boodle-1. or both' 111 sal contains s Sit' plus No. 20C t`o group name It sal contains 215X sand, aatd•with sane to predomtnanUy sand. odd'sally to group Cravats with 5 to 1211 fines required dual group avae. acme. symbol qr lined classify on cL-ML ass dual symbol "lt sal contains 2 50X plus No. 200 CR-CM stet graded grand with sit GC-Oi or SC-Sit predominantly grovel, odd"g togrove bill-GC well-graded grovel dIP day hi feed ors organic, ad.P.ith organic Anita la AUT0.12'-Gill poorly-graded crowd with sit group name 1154 and plots an or above'A'line. P-GC poorly-graded grovel .4th day of ad contains s15 ravel, odd-with owl' °PIS4 it plots below "iii" Ise. °Sands with 5 ta 12X linen regd.'s dud '� 'P1 plots on or cams A'Ind symbols: group mane w PI N( Att.rberg Omits Oats shaded ore., sal is o plots odor 'A'line. 5W-sd awe-graded sand wile silt (X-Ill_city day. Sw-SC w°tl--groded wind with cloy SP-Sad poorly graded sand with slit SP-5C poorly graded send with day so — ter awrow.11,n.l his-groin d Mils .-.o ir►-srwr.ad Indian ail maw- i grddwe do. i 50- lgwwaw.ci'A'-1.e. / _--_---..- ✓, Norlmntd al 3( - LL-15.4 , br r v lam M-470(LL'70) .fi .0- Trial at I.L.II I.Pb-?.X We.PI..0 (II-s) �' -4-...._.._ • 5 : G 2 I- ' (� Ii so 0 F r \" _ _.J \,° MH oR OH G I r l_ °.1 10 m'-- JO w .- b SO re sit w 100 110 LIQUID LIMIT (LL) A WELD COUNTY ROAD 84 *8-10 8-1 I \ ^ V \ n�aosEo euanh+as *8-9 B-112 *8-8 N NOT TO SCALE $8-7 r G *8-6 C O C 2 I 0 B-s 0 U *8-4 ♦8-3 B-2 ea LAND nu *8-I HIGHWAY 14 BORING LOCATION DIAGRAM WASTE MANAGEMENT ADDITIONS AND IMPROVEMENTS WELD COUNTY, COLORADO .- PROJECT NO: 1052038 DATE: APRIL 2005 EARTH ENGINEERING CONSULTANTS WASTE MANAGEMENT ADDITIONS AND IMPROVEMENTS WELD COUNTY,CO PROJECT NO: 1052038 DATE; Apr11 2005 LOG OF BORING B•11 RIG TYPE: CME4S SHEET 1 OF 1 WATER DEPTH FOREMAN: JK START DATE 41612005 WHILE DRILLING Non. AUGER TYPE: 4"CFA FINISH DATE 4/6/2005 AFTER DRILLING Non. SPT HAMMER: MANUAL SURFACE ELEV NIA 24 HOUR NIA SOIL DESCRIPTION au uc DO A11Yrcs .toe SWELL j1TYE ,FEE7)... (BLOWNFT) 3PSD _ 111 lea_ - t.t. ' PI.... __....,fAJ PRESSURE 14 a 150 PSF 36"of Topsoil end Vegetaton LEAN CLAY WITH SAND brown I - - serf to vary sort 2 '.., CS -3 17 9000. 5.3 ` 4 SS 6 24 9000. 7.6 r -- 6 -7 B 9 CS 10 9 r 9000+ 14.0 111.1 34 16 03.6 1600130 2.5% -1'. 12 scattered gravel 5011.depth 13 14 SS 16 6 9000. 6.3 BOTTOM OF BORING 15 5' 18 1-7 18 19 2-0 2-1 2-2 23 2-4 2-5 Earth Engineering Consultants WASTE MANAGEMENT ADDITIONS AND IMPROVEMENTS WELD COUNTY,CO PROJECT NO: 105209+5 DATE: April 2005 LOG OF BORING B-12 RIG TYPE: CME45 SHEET 1 OF 1 WATER DEPTH FOREMAN: JK START DATE 4/9/2005 WHILE DRILUNG None --------------AUGER TYPE: 4-CFA FINISH DATE 4/6/2005 AFTER DRILLING Non. SPT HAMMER: MANUAL SURFACE ELEV WA 24 HOUR NIA SOIL DESCRIPTION o N ou roc OD ASJ*T3 -200 SWELL TYPE FE BL X ►C lA Fl X PRESSURE % ISO PIS 3-6"of Topsoil aril Vegetation LEAN CLAY WITH SAND 1 brown stiff to very Stiff 2 3 ICS 5 11 9O0047.8 107.0 33 19 73.3 5000psf 5.4% 6 e -9 1 SS 10 9 9000, 9.5 11 1-2 -13 -14 -- 33 - 1-9 -- 9000* 10.0 -- BOTTOM OF BORING 15 5' 1-6 1-7 15 19 20 2-1 2-2 2-3 2-4 25 Earth Engineering Consultants SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand Sample Location: B-11, S-1 @ 2' Liquid Limit: -- 1Plasticity Index: -- I % Passin #200: -- Beginning Moisture: 4.7% Dry Density: 112pcf 1Endinn Moisture: 20.8% Swell Pressure: 370 psf _% Swell @ 150 psf: 1.2% 10 8 d co 8 : _ - I • • • • 4 I , • : __. . _. • • I i Z. 2 j —.._.. . . • — i m i• — I I E e oo • ,---- 2i . m Water Added • C ' 1 o . ca ' . I O -6 I 8 I I. _ i i • f t • i I -10 I 0 of o.1 1 10 Load (TSF) Project: Waste Management Additional Improvements Weld County, Colorado Project No: 1052038 Date: April 2005 ' EEC ) .-. �. SWELL / CONSOLIDATION TEST RESULTS Material Description: Brown Lean Clay with Sand Sample Location: B-11, S-3 @ 9' Liquid Limit: 34 (Plasticity Index: 18 1 % Passing #200: 83.6 Beginning Moisture: 15.2% Dry Density: 111.8pcf 'Ending Moisture: 22.8% Swell Pressure: 1800 psf % Swell @ 150 psf: 2.5% ---- — 10 it 8 t t cn6 i • _ I : . I I I lit . i • i i • I i co • c i l • • --1 C i m m Water Added I • -4 t i . I• i I o I • I ' I o it 1 1 . c.) I �• l i i l ! i I I I I ` , -8 i 'IT- 1 I • • • ii ' I 10 I . 0.01 0.1 1 10 Load (TSF) Project: Waste Management Additional Improvements Weld County, Colorado Project No: 1052038 Date: April 2005 • EEC . SUBSURFACE EXPLORATION REPORT ADMINISTRATION AND MAINTENANCE BUILDINGS WASTE MANAGEMENT FACILITY WELD COUNTY ROAD,2$AND 84 WELD COUNTY,COLORADO EEC PROJECT NO, 1052038A rte. April 21,2005 EARTH ENGINEERING CONSULTANTS, INc. Rothberg Tamburini Winsor Engineers&Consultants 419 Canyon Avenue, Suite 220 Fort Collins,CO 80521 Attn: Ms.Bret Icenogle Re: Subsurface Exploration Report Administration and Maintenance Buildings Waste Management Facility Weld County Roads 25 and 84 Weld County, Colorado EEC Project No. 205203 8 A Mr. Icenogle: Enclosed, herewith, are the results of the geotechnical subsurface exploration you requested for the administration/operations building and the container/maintenance building at the Waste Management Facility at Weld County Roads 25 and 84 in Weld County, Colorado. In summary, the subsurface materials encountered in the test borings consisted of stiff to very stiff lean clay to the depths drilled, approximately 15 feet below present ground surface. The near surface clay soils showed moderate to high swell potential at current moisture and density conditions. Groundwater was not encountered in the completed test borings at the time of drilling. Based on the materials encountered in the test borings, it is our opinion the proposed lightly loaded buildings could be constructed with conventional footing foundations and floor slabs bearing on at least 4 feet of moisture-conditioned and compacted overexcavation backfill. The moisture conditioned near surface materials would reduce the potential for post-construction expansion of the subgrade and bearing soils and resultant heaving of the overlying improvements. However,the risk of movement can not be eliminated. Geotechnical recommendations concerning subgrade preparation, design and construction of the foundations and support of floor slabs are provided in the attached report. 4396 GREENFIELD DRIVE WINDSOR, COLORADO 80550 (970) 224-1522 FAX(970)663-0282 Earth Engineering Consultants,Inc. EEC Project No. 1052037A April21,2005 Page 2 We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information, or if we can be of further service to you in any other way,please do not hesitate to contact us. Very truly yours, Earth Engineering Consultants,Inc. • 23057 Y ` Lester L.Litton,P.E. Principal Engineer LLL/dmh Hello