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HomeMy WebLinkAbout22 Timber Ridge -Geotechnical Report 5-6-20 Rawhide EngineeringInc. 6871 King Avenue West,Suite G1 K,Billings,MT 59106(406)969-5305 GEOTECHNICAL INVESTIGATION REPORT TIMBER RIDGE APARTMENTS 2725 TSCHACHE LANE BOZEMAK MONTANA PREPARED FOR: Mr. Chad Householder Summit Housing Group, Inc. 283 West Front Street, Suite 1 Missoula, MT 59802 Rawhide Engineering,Inc. December 11,2019 RRawhide E En�lineerin l Inc. December 11, 2019 Summit Housing Group, Inc. 283 West Front Street, Suite 1 Missoula, MT 59802 SUBJECT: Geotechnical Investigation Report Timber Ridge Apartments 2725 Tschache Lane Bozeman, Montana Dear Mr. Householder: This report presents the results of our geotechnical investigation for the Timber Ridge Apartments Project. The site location and test pit locations are shown on the Vicinity/Site Map shown on Plate 1 at the end of this report. The projects consists of one new apartment building and the associated driveways/parking lot and recommendations for utility installation. Our recommendations contained in this report are based on exploratory test pits, laboratory testing, engineering analysis and preparation of this report. The recommendations required to design commercial foundations, asphalt parking section design and construction, and utility installation are contained in the attached report. These conclusions and recommendations, along with restrictions and limitations on these conclusions, are discussed in the attached report. We appreciate this opportunity to be of service to you, and look forward to future endeavors. If you have any questions regarding this report or need additional inforrnatipn or services, please feel free to call the undersigned. oNr... ROBERT WAYNE Sincerely, KUKES RAWHIDE ENGINEERING, INC. a 10 Jason A. Frank Rob -E. Principal Principal" Enclosures: Report (1 hard copy, 1 pdf) Rawhide Engineering, Inc. December 11,2019 TABLE OF CONTENTS PAGE INTRODUCTION ...........................................................................................................................I ProjectDescription..............................................................................................................1 Scopeof Service.................................................................................................................1 Authorization ......................................................................................................................1 Professional Statements and Limitations............................................................................1 PROPOSEDCONSTRUCTION......................................................................................................2 FIELDINVESTIGATION .................................................................................................................2 LABORATORYTESTING ..............................................................................................................3 MoistureContent Tests........................................................................................................3 SoilClassification Tests.......................................................................................................3 SITE CONDITIONS.........................................................................................................................4 SUBSURFACE SOILS AND GROUNDWATER.........................................................................4 RECOMMENDATIONS ...................................................................................................................4 Excavations ......................................................................................................................4 Material .................................................................................................................5 Placement and Compaction ....................................................................................5 FOUNDATIONS........................................................................................................................6 Conventional Spread Footings............................................................................................6 StructuralFill................................................................................. ........7 Compaction Requirements...................................................................................................7 CONCRETESLAB-ON-GRADE.....................................................................................................7 PAVEMENTSECTIONS.....................................................................................8 Subgrade and Aggregate Base...........................................................................................8 Asphalt Concrete Pavement..........................:......................................................................9 SITEDRAINAGE.............................................................................................................................9 APPENDICES A Plates December 11, 2019 Rawhide Engineering,Inc. GEOTECHNICAL INVESTIGATION REPORT TIMBER RIDGE APARTMENTS 2725 TSCHACHE LANE BOZEMAN, MONTANA INTRODUCTION Project Description This project will consist of one new apartment building which will be a 3 story wood framed structure with a concrete slab-on-grade. The building will be approximately 13,000 f12 with the associated parking lot and utility installation located at 2725 Tschache Lane in Bozeman, Montana. The site is currently undeveloped commercial property covered with some vegetation and fill soils. Scope of Services Our scope of services for this project consisted of the following: 1. Excavating 4 exploratory test pits to depths ranging from 8 to 8.5 feet below existing site grades. Rawhide also performed several borings on this site for a previous apartment building. 2. Laboratory testing to determine the characteristics of the site soils for use in engineering design. 3. Engineering analysis to aid in the design of structure foundations, utility installation and asphalt pavement structural sections. 4. Provide information as to the existing groundwater conditions at the time of our exploration. 5. Provide recommendations for earthwork and construction on the site. This study did not include evaluations of site seismicity, liquefaction, faulting, or other potential geologic or environmental hazards. This study did not include a groundwater study or the design of a dewatering system. Authorization Authorization to proceed with our work on this project was provided on November 25, 2019. Rawhide Engineering, Inc. 1 December 11, 2019 Professional Statements and Limitations Recommendations presented in this report are governed by the physical properties of the soils encountered in the exploratory test pits, laboratory testing, current groundwater conditions, the project layout and design data described in the following proposed construction section. The recommendations presented in this report are based on exploratory test pit locations shown on the site map. Variations in soils may exist between the explored locations and the nature and extent of soil variations may not be evident until construction occurs. If subsurface conditions other than those described in this report are encountered and if project design and layout is substantially altered from the information in this report, Rawhide Engineering should be notified so that recommendations can be reviewed and amended, if necessary. This report has been prepared for design purposes for our client and specifically for this project in accordance with the generally accepted standards of practice at the time the report was written. No warranty, either expressed or implied, are intended or made. Other standards or documents referenced in any given standard cited in this report, or otherwise relied upon by the authors of this report, are only mentioned in the given standard; they are not incorporated into it or "included by reference," as that latter term is used relative to contracts or other matters of law. PROPOSED CONSTRUCTION It is our understanding that this project will include the construction of a 3 story apartment building which will be wood framed. The building will be 13,000 ft2 in plan view. The building will have conventional concrete stem wall foundations. The project will also have utility installation and the associated driveways/parking areas. Rawhide Engineering has estimated that the structural loads for these structures will have continuous footings loads of 2 to 3 kips per lineal foot and maximum interior column loads of 50 kips for long term loading conditions. This project will also include the construction of utilities to service the building and an asphalt parking lot. FIELD INVESTIGATION In order to determine and evaluate the subsurface conditions across the site, 4 exploratory test pits were completed using an excavator provided by Rawhide Engineering. Test pit depths ranged from 8 to 8.5 feet below the existing ground surface. Rawhide Engineering also had borings on this site from the previous apartment on this site. The location of the test pits shown on the Vicinity/Site Map were provided by Rawhide Engineering based on the information provided. This location should be considered accurate only to the degree implied by the method used. Rawhide Engineering, Inc. 2 December 11, 2019 The field investigation was under the direct control of an experienced member of our geotechnical staff who logged the soil conditions for each test pit. Samples were obtained from driving a 2-inch Standard Penetration Sampler 18 inches using a 140 pound hammer falling 30 inches. The blow counts recorded on the test pit logs were determined by counting the number of blows for the last 12 inches of the drive sample. The blow counts used in this report were from previous work on the same site. Bulk auger cuttings were also obtained for further testing. The SPT and bulk samples were examined by field personnel, logged and sealed to prevent moisture loss prior to laboratory testing. After completion, the groundwater level in the test pit was recorded and the test pits were backfilled using drill cuttings. The test pit logs included at the end of this report are labelled TP-1 through TP-4. A test pit log legend and a description of the Unified Soil Classification System used to identify the soils is included with the test pit logs. LABORATORY TESTING A laboratory testing program was utilized to provide the necessary data for engineering analysis of this project. The testing was used to evaluate the index and engineering properties specifically for the conditions encountered during our field exploration. The following program was used for this project. Moisture Content Tests—ASTM D2216 Moisture content tests were conducted on selected samples obtained from the site. These tests were used to aid in identifying the current soil conditions and aid in classifying the soils. Moisture content tests are shown on the test pit logs. Soil Classification Tests—ASTM D422, D1140, D4318, D2487 and D2488 In order to classify the soils according to the Unified Classification System, soil gradations and Atterberg Limits test were conducted on selected samples. The results of this testing is shown below and on the test pit logs. Rawhide Engineering, Inc. 3 December 11,2019 Gradations and Atterberg Limits Tests Percent Passing Sieve Size TP-2 @ 2.0—4.0' No. 4 100 No. 10 100 No. 20 98 No. 40 96 No. 80 92 No. 200 81 Plastic Index 5.3 Unified Classification Silty Clay with Sand (CL-ML) SITE CONDITIONS The site is located at 2725 Tschache Lane. The site is currently undeveloped commercial land which slopes gently to the north. A total relief of 1 to 2 feet is currently present across the site. The site is bordered by developed and undeveloped commercial and residential property. Drainage on the site consists of infiltration and runoff to the north. SUBSURFACE SOILS AND GROUNDWATER The soil conditions encountered on the site generally consist of a layer of fill) with some vegetation extending to a depth of 1.0 feet below the existing surface. The fill consists of clay, silt, sand and cobbles. Beneath the fill layer we encountered silty clay with sand to depths ranging from 4.5 to 5.0 feet below existing site grades. The silty clay with sand soils were medium stiff near the surface and became soft at depths below 3 feet. The silty clay with sand soils have a low plastic index and a high potential for consolidation, especially below 3 feet. Beneath the fine grained soil layer we encountered gravel with clayey sand to the depths explored of 8 to 8.5 feet below existing site grades. The gravel with clayey sand was dense and has a low plastic index to granular non-plastic. Groundwater was encountered in test pits at depths ranging from 4.8 to 5.5 feet (at the gravel interface) below existing site grades and is may impact utility installation. The groundwater levels were measured in December 2019 and may change with seasonal precipitation and irrigation practices. Rawhide Engineering, Inc. 4 December 11, 2019 RECOMMENDATIONS Prior to construction, surface fill soils should be removed from the site or stockpiled for use in non-structural areas. It appears about 1.0 feet can be used as a reasonable estimate for average depth of stripping. All trash and vegetation should be removed from the site if they are present. Excavations resulting from removal operations should be cleaned of all loose material and widened as necessary to permit access to compaction equipment. Excavations The contractor is ultimately responsible for the safety of workers and should strictly observe federal and local OSHA requirements for excavation shoring and safety. All temporary slopes should comply with OSHA requirements for Type A soils. During wet weather, runoff water should be prevented from entering excavations. It appears that excavation for footings and utility trenches can be readily made with either a conventional backhoe or excavator in the native soil materials. We expect the walls of the footing trenches in the near surface fine grained soils to stand near vertically without significant sloughing. If trenches are extended deeper than five feet or are allowed to dry out, the excavations may become unstable and should be evaluated to verify their stability prior to occupation by construction personnel. Shoring or sloping of any deep trench walls may be necessary to protect personnel and provide temporary stability. All excavations should comply with current OSHA safety requirements for Type A soils. (Federal Register 29 CFR, Part 1926). The groundwater levels are currently 4.8 to 5.5 feet below the current site grade. If the site is not raised, the utility installation may require a dewatering plan. Our scope of service did not include a groundwater study or the design of a dewatering system. If dewater is required, the system should be designed by a competent person with experience designing dewatering systems and there effects on adjacent structures. Backfills for trenches or other excavations within pavement areas should be compacted in six to eight inch layers with mechanical tampers. Jetting and flooding should not be permitted. We recommend all backfill be compacted to a minimum compaction of 97% of the maximum dry density as determined by ASTM D698. The moisture content of compacted backfill soils should be within 2% of the optimum. Poor compaction in utility trench backfill may cause excessive settlements resulting in damage to the pavement structural section or other overlying improvements. Compaction of trench backfill outside of improvement areas should be a minimum of 90% relative compaction. Material - Pipe bedding shall be defined as all material within six inches of the perimeter of the pipe. Backfill shall be classified as all material within the remainder of the trench. Material for use as bedding shall consist of clean, granular materials, and shall conform Rawhide Engineering, Inc. 5 December 11,2019 to requirements for bedding material listed in Section 02221 of the Standard Specifications. Placement and Compaction - Pipe bedding shall be placed in thin layers not exceeding eight inches in loose thickness, and conditioned to the proper moisture content for compaction. All other trench backfill shall be placed in thin layers not exceeding eight inches in loose thickness, conditioned to the proper moisture content, and compacted as required for adjacent fill. If not specified, backfill should be compacted to at least 97% relative compaction in areas under structures, utilities, roadways, parking areas, concrete flatwork, and to 90% relative compaction in undeveloped areas. Foundations At the time of this report, it is assumed that the building will have conventional shallow stem wall foundations. Due to the high potential for consolidation in the silty clay with sand soils, the exterior continuous and interior load bearing footings should be over excavated down to the native gravel layer located 4.5 to 5 feet below existing site grades and backfilled with compacted structural fill to the bottom of footing elevations. Utilizing the structural loads provided and an allowable bearing pressure of 4,000 pounds per square for compacted structural fill over laying the native gravel, a settlement of 1/2 inch was estimated. Structural fill under foundations shall be placed in layers, moisture conditioned, and compacted to 98% of ASTM D698. Exterior continuous foundations should be embedded a minimum of 4.0 feet below lowest adjacent exterior finish grade for frost protection and confinement. Interior footings should be bottomed at least 12 inches below lowest adjacent finish grade for confinement. Wall foundation dimensions should satisfy the requirements listed in the latest edition of the International Commercial Code. Reinforcing steel requirements for foundations should be provided by the design engineer. The allowable bearing pressures, indicated above, are net values, therefore, the weight of the foundation and backfill may be neglected when computing dead loads. Allowable bearing pressures may be increased by one-third for short-term loading such as wind or seismic. Resistance to lateral loads in the upper silty clay with sand soils may be calculated using an allowable passive equivalent fluid unit weight of 230 pounds per cubic foot and an allowable coefficient of friction of 0.38 applied to vertical dead loads. Both passive and frictional resistances may be assumed to act concurrently. An allowable active equivalent fluid pressure of 38 pounds per cubic foot may be used. The International Building Code (IBC) site class for this project is Class C. Rawhide Engineering, Inc. 6 December 11, 2019 Structural Fill Structural fill will be used beneath the entire building envelope and should consist of dense gravel with sand and conforming to the following gradation and plastic index. Sieve Size Percent Passing 3 Inch 100% No. 4 25-65% No. 200 <20% Plastic Index 12 or less All structural fill shall be placed in eight inch loose lifts and uniformly moisture conditioned to within +/-2% of optimum moisture content. The contractor shall provide and use sufficient equipment of a type and weight suitable for the conditions encountered in the field. The equipment shall be capable of obtaining the required compaction in all areas, including those that are inaccessible to ordinary rolling equipment. Compaction Requirements The following table lists the compaction requirements for structural fill, foundation backfill, utility trench backfill and street subgrade preparation. COMPACTION REQUIREMENTS Structural Fill Beneath Foundations 98% of ASTM D698 Backfill Against Foundations 95% of ASTM D698 Utility Trench Backfill 97% of ASTM D698 Subgrade for Paved Parking Areas 95% of ASTM D698 Concrete Slab-on-Grade Construction Prior to constructing concrete slabs, the upper six inches of slab subgrade should be scarified, moisture conditioned to within 2% of optimum, and uniformly compacted to at least 95% of maximum dry density as determined by ASTM D698. Scarification and compaction will not be required if floor slabs are to be placed directly on undisturbed compacted structural fill. All concrete floor slabs should have a minimum thickness of four inches. Slab thickness and structural reinforcing requirements within the slab should be determined by the design engineer. At least one foot of crushed base aggregate should be placed beneath slab-on-grade floors to provide uniform support. The aggregate base should be compacted to a minimum of 95% relative compaction. Rawhide Engineering, Inc. 7 December 11,2019 We recommend that the base course be placed within three to five days (depending on the time of year) after moisture conditioning and compaction of the subgrade soil. The subgrade should be protected against drying until the concrete slab is placed. In floor slab areas where moisture sensitive floor coverings are planned, an impermeable membrane (e.g. 10-mil thick polyethylene) should be placed over the base course to reduce the migration of moisture vapor through the concrete slabs. The impermeable membrane should be installed as required by the flooring manufacturer. Current literature from the American Concrete Institute and the Portland Cement Association recommend that impermeable membrane is placed on top of the base course immediately below the concrete slab. Pavement Sections The recommended pavement structural section for the project presented below was calculated using the AASHTO pavement design procedure. Traffic loading information was not available at the issue of this report. If traffic loading information becomes available or if loading is anticipated to exceed assumed loading conditions, alternative pavement structural sections should be determined based on the provided loading information. In our analysis, we have assumed light-duty loading conditions of 90,000 18-kip equivalent single axle load (18-kip ESAL) for the lifetime of the pavement for the parking areas. A CBR value of 4.5 was used for design of the pavement section. PAVEMENT STRUCTURAL SECTIONS Traffic Condition Recommended Minimum Structural Section Light Duty Asphalt Section 3 inches of Asphaltic Concrete, 4 inches of 1 %" Crushed Base Course and 8 inches of 6" minus pitrun gravels Aggregate base course thickness may be reduced in each alternate pavement structural section by approximately 20% with the use of geotextile fabric meeting AASHTO M 288-2000 class 1 requirements. If this alternative is selected, we can provide addition pavement structural sections. It should be noted that the subgrade soils are likely to be prone to frost action during the winter and saturation during the wet spring months. The primary impact of frost action and subgrade saturation is the loss of subgrade and aggregate base strength. Pavement life will be increased if efforts are made to reduce the accumulation of excess moisture in the subgrade soils. Subgrade and Aggregate Base Subgrade Preparation -After completion of the utility trench backfill and prior to placement of aggregate base, the upper six inches of subgrade soil shall be Rawhide Engineering, Inc. 8 December 11,2019 uniformly compacted to at least 95% relative compaction. This may require scarifying, moisture conditioning, and compacting in both cut and fill areas. Aggregate Base - Aggregate materials shall meet the requirements of the appropriate sections of the "Standard Specifications" for 1 '/2 Minus Crushed Base Rock. The aggregate base materials must be approved by the Geotechnical Engineer prior to use. After the subgrade is properly prepared, the aggregate base shall be placed in layers, moisture conditioned as necessary, and compacted by rolling to at least 95% relative compaction. The compaction thickness of aggregate base shall be as shown on the approved plans. Asphalt Concrete Pavement Materials - Aggregate materials for asphalt concrete in light and heavy traffic areas shall conform to the requirements listed for Type B bituminous aggregates of the "Standard Specifications." Asphalt concrete mixes shall utilize asphalt cement meeting the requirements of Section 02510 of "Standard Specifications". The mix design shall be based on the Marshall Method. Placement and Compaction - The asphalt concrete material and placement procedures shall conform to appropriate sections of the "Standard Specifications." The asphalt concrete material shall be compacted to a minimum of 93% of the Theoretical Maximum Rice Specific Gravity. Site Drainage Final elevations at the site should be planned so that drainage is directed away from all foundations and concrete slabs. Parking areas should be designed to drain surface water off the sight and away from structures. In accordance with the International Commercial Code, downspouts with 6 foot extensions should be used. Positive drainage away from all foundations should have 6 inches of fall in the first 10 feet away from the foundations. If sufficient room is not available to construct the 10 foot slope, drainage swales should be constructed as far from the foundations as possible. Rawhide Engineering, Inc. 9 December 11,2019 I APPENDIX A Plates Site / Vicinity Map rim 4574� �R tr �9� ttg J 11 i• - TURBULENCE-LACL 6 onsveot spaces N-3 o•o•o e•••o TP-4 •• • C4 f r • 8 �' • _ 'ram; CRO.V 4• Cq 1�1 - p• 4 TP-1 It activity area TSCHACHE LANE TEST PIT LOG LOGGED BY: J. Frank PROJECT: Timber Ridge Apartments DRILL METHOD: Excavator 2725 Tschache Lane DRILLER: Duneman Const. R Rawhide CLIENT: Summit Housing Group DATE: 12/4/19 E Engineering Inc. LOCATION: Bozeman, Montana ELEVATION: SAMPLES LABORATORY TESTING �_ TEST PIT NUMBER: 1 N o ^ o V OCn v cc s MATERIAL DESCRIPTION AND COMMENTS 3 c FILL Fill -Clay, Silt, Sand with Gravels/Cobbles and Vegetation - 1 Dark Brown, Moist, Medium Stiff 2 CL-ML Silty Clay with Sand - Brown, Moist, Medium Stiff to Soft, Low/Moderate Plastic Index 3 4 5 Groundwater Level at 5.1 Feet 6 GP Gravel and Cobbles with Clayey Sand - Brown/Gray. Moist to Wet, Dense, Low Plastic Index 7 8 Test Pit Ends at Approximately 8.0 Feet Depth 9 Groundwater Was Encountered at 5.1 Feet 10 11 12 13 14 15 16 17 18 19 20 6871 King Ave. West, Suite G1 K, Billings, MT 59106 (406) 969-5305 Fax:(406) 969-5307 TEST PIT LOG LOGGED BY: J. Frank ��141 1b. PROJECT: Timber Ridge Apartments DRILL METHOD: Excavator 2725 Tschache Lane DRILLER: Duneman Const. R Rawhide CLIENT: Summit Housing Group DATE: 12/4/19 E Engineering Inc. LOCATION: Bozeman, Montana ELEVATION: SAMPLES LABORATORY TESTING ell TEST PIT NUMBER: 2 N o .. o Cz u u c rCZ VR `" = MATERIAL DESCRIPTION AND COMMENTS U 3 G FILL Fill -Clay, Silt, Sand with Gravels/Cobbles and Vegetation - 1 Dark Brown, Moist, Medium Stiff 2 CL-ML Silty Clay with Sand - Brown, Moist, Medium Stiff to Soft, Low/Moderate Plastic Index 3 F 26.1 5.3 81.1 2.0 4 5 Groundwater Level at 5.3 Feet 6 GP Gravel and Cobbles with Clayey Sand - Brown/Gray. Moist to Wet, Dense, Low Plastic Index 7 8 9 Test Pit Ends at Approximately 8.5 Feet Depth Groundwater Was Encountered at 5.3 Feet 10 11 12 13 14 15 16 17 18 19 20 6871 King Ave. West, Suite G1 K, Billings, MT 59106 (406) 969-5305 Fax:(406) 969-5307 TEST PIT LOG LOGGED BY: J. Frank PROJECT: Timber Ridge Apartments DRILL METHOD: Excavator 2725 Tschache Lane DRILLER: Duneman Const. R Rawhide CLIENT: Summit Housing Group DATE: 12/4/19 E Engineerinq Inc. LOCATION: Bozeman, Montana ELEVATION: SAMPLES _ LABORATORY TESTING TEST PIT NUMBER: 3 f MATERIAL DESCRIPTION AND COMMENTS 3 — FILL Fill - Clay, Silt, Sand with Gravels and Vegetation - 1 Dark Brown, Moist, Medium Stiff 2 CL-ML Silty Clay with Sand - Brown. Moist, Medium Stiff to Soft, 3 Low/Moderate Plastic Index 4 Groundwater Level at 4.8 Feet 5 GP Gravel and Cobbles with Clayey Sand - Brown/Gray, 6 Moist to Wet. Dense, Low Plastic Index 7 8 Test Pit Ends at Approximately 8.0 Feet Depth 9 Groundwater Was Encountered at 4.8 Feet 10 11 12 13 14 15 16 17 18 19 20 6871 King Ave. West, Suite G1 K, Billings, MT 59106 (406) 969-5305 Fax:(406) 969-5307 TEST PIT LOG LOGGED BY: J. Frank lb- PROJECT: Timber Ridge Apartments DRILL METHOD: Excavator R! 2725 Tschache Lane DRILLER: Duneman Const. ERawhide CLIENT: Summit Housing Group DATE: 12/4/19 Ei:gineering Inc. LOCATION: Bozeman, Montana ELEVATION: SAMPLES _ LABORATORY TESTING _ - y TEST PIT NUMBER: 4 o .. Ci u G Ui. v O n `" MATERIAL DESCRIPTION AND COMMENTS 3 — =: FILL Fill -Clay, Silt, Sand with Some Gravels and Vegetation - 1 = Dark Brown, Moist, Medium Stiff 2 CL-ML Silty Clay with Sand - Brown, Moist, Medium Stiff to Soft, 3 Low/Moderate Plastic Index 4 5 Groundwater Level at 5.5 Feet 6 GP Gravel and Cobbles with Clayey Sand - Brown/Gray. Moist to Wet, Dense, Low Plastic Index 7 8 Test Pit Ends at Approximately 8.0 Feet Depth 9 Groundwater Was Encountered at 5.5 Feet 10 11 12 13 14 15 16 17 18 19 20 6871 King Ave. West, Suite G1K, Billings, MT 59106 (406) 969-5305 Fax:(406) 969-5307 TEST PIT LOG LEGEND MATERIAL DESCRIPTION Soil Pattern USCS Symbol USCS Classification -- ---- FILL Artificial Fill GP or GW Poorly/Well graded GRAVEL GM Silty GRAVEL GC Clayey GRAVEL GP-GM Poorly graded GRAVEL with Silt GP-GC Poorly graded GRAVEL with Clay SP or SW Poorly/Well graded SAND SM Silty SAND Sc Clayey SAND SP-SM Poorly graded SAND with Silt SP-SC Poorly graded SAND with Clay SC-SM Silty Clayey SAND ML SILT MH Elastic SILT CL-ML Silty CLAY CL Lean CLAY CH Fat CLAY PCEM PARTIALLY CEMENTED CEM CEMENTED BDR BEDROCK CONSISTENCY Cohesionless Soils Cohesive Soils Cementation VL Very Loose So Soft MH Moderately Hard L Loose F Firm H Hard MD Medium Dense S Stiff VH Very Hard D Dense VS Very Stiff VD Very Dense SAMPLING SPT Shelby Tube NR No Recovery Bulk Sample �7 Water Table RRawhide E Engineering Inc. UNIFIED SOIL CLASSIFICATION SYSTEM Critorla for Assigning Group Symbols and Group Names Usinn Laboratory Tests' Soil Classification Group symbol Group Name' Coarse Grained Solis Gvdvels Clean Gravers Cu 24 and I s Cc s 3' GW Wallgmded g-aY6' More than 50%of ccarse Less than S%fines` Cu<4 and/or 1>Cc>31 GP P d g eel rave" None than SOX retained fraction retained on Poorly No.200 sieve No.4 sieve Gravels w o Faws Fines classify as ML or MH GM Silty gravVr " Moro than 12%fines Fines classify as Cl.or CH GC Clayey gravel", Sands Clean Sands Ci"6 and 1 s Cc s 3' SW We4rsded sand• 50%or more of coarse Less man 5%fines' Ou<6 and/or 1>Cc>3` SIP Poorly graded sand fraction passes No.4 sicvo Sands wlth Fires Fines casslfy as 6t:or AIH SM S;ay santisw Moro than 12%6nese Fines Classify as CL or CH SC Clayey sand" Fine-Grained Solis Sits and Clays Inorganic PI>7 and profs on or above'A'File' CL Lean clad"' 50%or mote passes the Lq"Emit less than 50 PI-c 4 of plots below A'kW ML SW'"" No.200 shove organic Liquid limit-oven dried 40.75 OL Organic clay""" Liquid My*-not dried organic s01'4i'° &I's and Clays kvirpnic PI plots on or above',-line CH Fat day— Liquid limit 50 or more PI plots below','Ono MH Elastic Ste`0 organic Liquid Ilr.3-oven dried <0.75 OH Orpanlo cw"L, Liquid Omit-not dried Organic WWI H!gh'y organic so_s Prknwiy organic matter.dark In color,and organic odor PT Pea, "Based on the material passing the 3,4n.(75-ram)sieve Hif fines are o•ganlc,add 1Mth organic fees'to group name. °If field sample contaned cobbles a boulders.c.both,add Wth cobbles 1 If soli contains t 15%gravel,add'wth gravel'to group name. or boulders.or both'to group name. J If Afterberg:rr is plot in shaded area.so i is a CL-ML.silty day. cr,mvwh wAth S In 171L hire nwrl„'ra r41al cyrnANc• GW-CJA vmr orarinrl Kit coil oonteins 16 to 12M plus No.-'00,add'with send'or with gravel with silL GW-GC well-graded travel with day.GP-GM poorly gravel:whichever is predorr.'nant. graded gravel with silt.GP-GC poorty graded gravel with day. t If soil contains;-.,30%plus No 200 predomrsandy sand.add °Sands with 5 to 12%fines requ'e dual symbols: SW-SM%,*1•graded 'sandy*to group name. sand w3h silt.SW-SC vmll-gradod sand Wth day,SP-Sf.1 poorty graded u sand wth silt.SP-SC poorly graded sand with day If contains:3 plus No.200,predominanCy gravel, add'graveve d to group name. r (13.) API t 4 and pats on or above'A'One. Cu=OWD•o Ce= Do x Ow ° PI<4 0'plots below I:no. °If so!l contains 2 15%sand,add Wth sand'to group name. PPI plots on cr aba+o'A'line. °If fines classify as CLA1L,use dust symbol GC-GIJ•or SC-SM. ° PI pots be!cw'A'line. ao For classification of fine-grained soils and fine-grained fraction 50 of coarse•gralnrd soils —Joe Equation W W•I-w �•' �T\7 Horizontal at PI-4 to LL-25S. W 40 tncr.PI-0.73(LL•20) aG+ Q Eq:taaon of V•11m G� z Voikal at Li..16 to PI•.7. 3o tsen PI-0-9(LL-tn 20 a MHorOH w , 4 - I` r MLorOL 0 0 10 16 20 30 40 so 6o 70 so go 1ao 110 LIQUID LIMIT(ILL) mb- RE Rawhide �� Engineering Inc.