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HomeMy WebLinkAboutSoils reportGtech HEPWORTH - PAWLAK CEOTECHN1CAL Hepworth.-Pawlak Geotechnical,1nc. 5020 County Road 154 Glenwood Springs, Colorado 81601 Phone: 970.945-7988 Fax: 970-945-8454 email: hpgeo@hpgeorech.com PRELIMINARY GEOTECHNICAL STUDY PROPOSED SPRINGRIDGE PLACE PHASE II COUNTY ROAD 125 GARFIELD COUNTY, COLORADO JOB NO. 101 126 JUNE 22, 2004 PREPARED FOR: THE GREENWALD CHILDREN'S TRUST CIO GLENWOOD BROKERS, LTD. ATTN: PAT FITZGERALD P.O. BOX 1330 GLENWOOD SPRINGS, COLORADO 81602 Parker 303-841-7119 • Colorado Springs 719-633-5562 • Silverthorne 970.468-1989 TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY - 1 - PROPOSED CONSTRUCTION - 1 - SITE CONDITIONS - 2 - GEOLOGIC CONDITIONS - 2 - FORMATION ROCK - 3 - SURFICIAL SOILS - 4 -. SUBSURFACE EXPLORATION - 4 - SUBSURFACE CONDITIONS - 5 - GEOLOGIC SITE ASSESSMENT - 5 - ROCKFALL -5- STREAM FLOODING - 6 - ALLUVIAL FAN FLOODING - 6 - MOISTURE SENSITIVE SOILS - 7 - CONSTRUCTION RELATED SLOPE INSTABILITY - 7 - REGIONAL EVAPORITE DEFORMATIONS - 7 - EARTHQUAKE CONSIDERATIONS - a - RADIATION POTENTIAL - 8 - ENGINEERING ANALYSIS - S - PRELIMINARY DESIGN RECOMMENDATIONS - 9 - FOUNDATIONS - 9 - FLOOR SLAB - 9 - BELOW GRADE CONSTRUCTION - 10 - ROADWAY GRADING -10 - SURFACE DRAINAGE -10 - WATER TANK SITE -11 - LIMITATIONS - I 1 - REFERENCES -13 - FIGURE 1- VICINITY MAP FIGURE 2 -PRELIMINARY GEOLOGY MAP AND EXPLORATORY PIT LOCATIONS FIGURE 3 - LOGS OF EXPLORATORY PITS FIGURES 4 - 6 - SWELL -CONSOLIDATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS PURPOSE AND SCOPE OF STUDY This report presents the results of a preliminary geotechnical study for the proposed Springridge Place Phase II to be located along County Road 125, about five miles south of Glenwood Springs, Garfield County, Colorado. The project site is shown on Figures 1 and 2. The purpose of the study was to evaluate potential geologic hazard impacts, and to develop recommendations for preliminary design cite building foundation and site grading. The study was conducted in accordance with our agreement for professional engineering services to The Greenwald Children's Trust, dated April 6, 1994 and subsequent proposal to Glenwood Brokers, Ltd. dated May 28, 2004. This report is an update of our previous study for the proposed development (Hepworth - Pawlak Geoteclmical, 2001). A field exploration program consisting of a geologic reconnaissance and exploratory pits was conducted to obtain information on the site and subsurface conditions. Samples obtained during the field exploration were tested in the laboratory to determine their compressibility, classification and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for planning and preliminary design for building foundation and site grading. This report summarizes the data obtained during this study and presents our conclusions, recommendations and other geotechnical engineering considerations based on the proposed development and the subsurface conditions encountered. PROPOSED CONSTRUCTION Development plans for the Phase lI part of the property consist of 81 single family residential lots having sizes between about 1 acre to greater than 4 acres. Six of the lots will be located uphill of County Road 125 and the rest of the lots will be located in the valley bottom to eastern valley side. All of the building areas will be on slopes less than 40%. A private roadway system will provide access to the east of County Road 125. The development plan is shown on Figure 2. Water and sewer services will be from central Job No. 101 126 -2 - systems. The roadway grading is assumed to be minor with cuts and fills up to about 10 feet deep. The Atkinson Ditch will be piped through the development. SITE CONDITIONS The development is situated on. an upland surface adjacent to the east flank of the Grand Hogback, a large northwest trending ridge. The elevations vary from about 6400 feet at the north end to 7200 feet on top of the ridge at the southwest boundary. Building sites only extend to about elevation 6,550 feet on the east flank of the hogback (west side of the development). Two smaller hogbacks occur to the east. A few bedrock outcrops occur on the hogbacks. An ephemeral stream drains toward the north. A tributary joins the main drainage near the center of the site. Arroyo cutting is occurring at the south end of these drainages. Several irrigation ditches are located on the development. The central portion of the site is mostly a fairly flat valley floor. The south, west and east sides have steep slopes. County Road 125 runs through the development from northwest to southeast, paralleling the lower slope of the Grand Hogback. A ranch house and out buildings are located near the center of the development. The existing development is located to the north. The valley bottoms have been used for hay and pasture. Some trash was noted adjacent to the east drainage at one location. Otherwise, the development area is typically natural. Vegetation on the slopes consisted of sage, pinon, juniper and other brush. The valley bottoms have grass and sage. An existing above ground, steel water tank is located west of Lot 6. GEOLOGIC CONDITIONS The project site is located on the limb of the Grand Hogback monocline. This first order regional structure defines the boundary between the Pieance basin that lies to the west and the Carbondale evaporite collapse center that lies to the east (Kirkham and Widmann, 1997). The rnonocline was formed during the Laramide progeny about 40 to 70 million Job No. 101 126 Gtech -3 - years ago as a result of regional compressional stresses. The sedimentary rocks on the monocline limb in the project area have an average strike of about N 300 W. The average dip of the monocline limb in this area is about 45° to the southwest, but dips in the project area vary from 90 to 78° because of secondary folding (Kirkham and Others, 1996). Locally the bedding is overturned and the bedding dips are as much as 28° to the northeast in the eastern part of the project area. Faults have not been mapped at the project site, but regional mapping has identified several northwest trending, down to the southwest normal faults to the west of the project area (Kirkham and Others, 1996). These faults appear to be bedding plane faults in the Mancos Shale and Mesa Verde Group that result from shallow crustal strains associated with evaporite solution and flow in the Carbondale evaporite collapse center. The faults displace and form scarps in Pleistocene and possibly Holocene age debris flow deposits (Kirkham and Others, 1996). This indicates that some of the faults may have movements that are younger than 10,000 years. FORMATION ROCK Formation rock at the project site includes the Cretaceous Dakota Sandstone (Kd), the Jurassic Morrison Formation (Jm) and Entrada Sandstone (Te), the Triassic and Permian Chinle and State Bridge Formations (TRPcs) and the Permian and Pennsylvanian Maroon Formation (PPm), see Figure 2. The project site is located in a strike valley between two hogback ridges. The resistant Entrada Sandstone forms the crest of the hogback along the western side of the project area and resistant beds in the Maroon Formation forms the hogback along the eastern side of the project area. All of the proposed development will be in areas underlain by the Maroon Formation. The Maroon Formation is made up of red interbedded sandstone, siltstone, mudstone and shale with some minor, thin gray limestone beds. The rock is usually hard and cemented. The rock mass is cut by joints that parallel the bedding and at high angles to the bedding. Job Aro. 101 126 4 SURFICIAL SOILS Formation rock in the project area is usually covered by surficial soils. Relatively shallow colluvium (Qc) and local rock outcrops are present on the boundary hogbacks and upland ridges on the valley floor. Small alluvial fans (Qat) have developed at the mouths of several ephemeral drainages on the eastern hogback. Alluvial aprons (Qaa) have developed along the lower part of the western hogback and lower slopes of the upland ridges on the valley floor. The relatively flat valley floor at the project site is underlain by alluvium (Qal) that grades to a•low terrace level along Four Mile Creek to the north of the project area. This terrace lies about 10 to 20 feet above the modern creek chatlnel and most of the valley floor alluvium in the project area was probably deposited during the late Pleistocene. The exploratory pits show that the surficial soils at the project site are typically sandy clay and silty sand with angular rock fragments from gravel- to boulder -size. Formation rock was less that five feet deep in several of the pits located on the lower parts of the boundary hogbacks and upland ridges on the valley floor. SUBSURFACE EXPLORATION The subsurface exploration for the project was conducted on April 13, 22 and 29, 1994. Eleven exploratory pits were excavated at the approximate locations shown on Figure 2 to evaluate the subsurface conditions. The pits were dug with a rubber tired backhoe and logged by a representative of Hepworth-Pawlak Geotechnical, Inc. Samples of the subsoils were taken with relatively undisturbed and disturbed sampling methods. Depths at which the samples were taken are shown on the Logs of Exploratory Pits, Figure 3. The samples were returned to our laboratory for review by the project engineer and testing. Job No. I01 126 sated" -5 - SUBSURFACE CONDITIONS Graphic Togs of the subsurface conditions encountered at the site are shown on Figure 3. The subsoils encountered in the valley bottom areas consist of about 1 to 1 'fz feet of topsoil above sandy silty clay and silty sand with rock fragments. On the valley side slope areas, sandstone bedrock was encountered. between depths of 1/2 to 6 feet below rocky, silty sand and clay colluvial soils. The bedrock is generally hard to very hard and could not be effectively dug with the backhoe. The soil moisture was relatively low and no free water was encountered to the pit depths of 8 to 11 feet. The central field area was being flood irrigated at the time of our April 29, 1994 site visit. Laboratory testing performed on samples obtained from the pits included natural moisture content and density, gradation analyses, and Liquid and plastic limits. Results of consolidation testing performed on relatively undisturbed liner samples of the sandy clay and silt soils, presented on Figures 4, 5 and 6, indicate Low compressibility under initial low moisture conditions and moderate to high compressibility when wetted and loaded. The samples generally showed a low to moderate collapse potential. The liquid and plastic limits testing indicates the soils are generally low plasticity. The laboratory testing is summarized in Table 1. GEOLOGIC SITE ASSESSMENT There are several conditions of a geologic nature that should be considered in project planning and design. These conditions and their expect influence on the proposed development are discussed below. ROCKFALL In some places outcrops of Entrada Sandstone along the western hogback crest are potential start areas for rockfall that could potentially reach building sites on Lots 1 Jab No. 1 U1 126 Gate -6 - through 5. The presence of a potential rockfall start zone on the eastern hogback in the vicinity of Lots 63 through 81 was field reviewed for the current study update and found to not be a potential impact to the lots. An analysis should be conducted to assess the potential rockfall risks to Lots 1-5. The potential risk of rockfall to the building envelopes on Lots 1-5 appears low, but if the analysis shows that the rockfall risk is unacceptable, then mitigation should be considered. Mitigation could consist of removing unstable rock blocks before development, outcrop stabilization, rockfall catching structures, or a combination of these methods. The potential rockfall start area that could potentially impact Lots 1 through 5 is not located on. the property. Outcrop mitigation in this area would require the cooperation of the adjacent land owner. STREAM FLOODING Small ephemeral stream channels are locally present in the valley floor alluvium (Qa I) and alluvial aprons (Qaa) in the proposed development areas. A civil engineer specializing in hydrology should evaluate the flood potential along these drainages as part of the overall storm water management plan for the development. Channel improvements and drainage easements may be needed in some areas. ALLUVIAL FAN FLOODING The small alluvial fans in the eastern part of the project area are potential sites of occasional thunderstorm related, high sediment concentration flash flooding. Lots that may be impacted by this condition are Lots 63 though 72 and Lot 81. A civil engineer specializing in hydrology should evaluate the potential flash flood routing on the alluvial fans as part of the overall storm water management plan for the development. Channel improvements, drainage easements, and deflection berms may be needed in some areas. Job No. 101 126 G4Stech MOISTURE SENSITIVE SOILS Our experience in the area and the laboratory tests show that some of the surficial soils in the project area are moisture sensitive. These soils have a moderate to high compressibility when wetted and loaded. Preliminary recommendations for foundations on moisture sensitive soils are presented in the Preliminary Design Recommendations section of this, report. CONSTRUCTION RELATED SLOPE INSTABILITY We do not expect unusual problems with construction related slope instability if the proposed grading is engineered and extensive cuts and fill are not needed. Grading on the steeper slopes may require retaining walls and slope reinforcement to Iimit the extent .of slope disturbance. Grading plans for roads, building sites and other facilities should be evaluated by a geotechnical engineer on a site specific basis. These evaluations should consider potentially adverse bedding in deep cuts in formation rock. Preliminary recommendations for roadway grading are presented in the Preliminary Design Recommendations section of this report. REGIONAL EVAPORITE DEFORMATIONS The faults to the west of the project area and other features in the Carbondale evaporite collapse center to the east of the project area are associated with regional ground deformations related to evaporite solution and flowage. Some of this deformation may be younger than 10,000 years, but it is uncertain if the deformations are still active or if they have stopped. If ground deformations are still occurring their rates are low and would be occurring over broad areas. Because of this the risk of potential problems to residential buildings is viewed to be Iow. We are not aware of problems associated with possible regional evaporite deformations in the project area. Job No. 101 126 -8 - EARTHQUAKE CONSIDERATIONS The project area could experience moderately strong earthquake related ground shaking. Modified Mercalli Intensity VI ground shaking should be expected during a reasonable service life for the development, but the probability for stronger ground shaking is low. Intensity VI ground shaking is felt by most people and causes general alarm, but results in negligible damage to structures of good design and construction. Occupied structures should be designed to withstand moderately strong ground shaking with little or no damage and not to collapse under stronger ground shaking. Considering the nature of the faults to the west of the project area, in our opinion, these faults although geologically young do not increase the earthquake potential at the project site. The region is in the 1997 Uniform Building Code, Seismic Risk Zone 1. Based on our current understanding of the earthquake hazard in this part of Colorado, we see no reason to increase the commonly accepted seismic risk zone for the area. RADIATION POTENTIAL The project site is not located in an area where geologic deposits are expected to have unusually high concentrations of radioactive minerals. However, there is a potential that radon gas could be present in the area. It is difficult to assess the potential for future radon gas concentrations in buildings before the buildings are constructed. Testing for radon gas can be done when the residences and other occupied structures have been completed. New building are often designed with provisions for ventilation of lower enclosed spaces should post construction testing show unacceptable radon gas concentrations. ENGINEERING ANALYSIS The subsurface conditions encountered throughout the project area are variable but should be suitable for support of spread footing foundations. The colluvium in the steeper slope areas and the fine-grained soils in the non- irrigated valley bottom areas tend to be Job No. 101 126 -9- hydrocoinpressive. We expect that the soils in the historically irrigated fields have been wetted and should be less prone to hydrocompression. The bedrock will provide excellent support for buildings. Groundwater was not encountered and basement level construction appears feasible in most areas of the property. The bedrock is very hard and may limit the practical use of basements, especially where the rock is cemented and requires blasting t� dig. The soils and bedrock should be suitable for typical roadway grading with the expected relatively minor cut and fill sections. PRELIMINARY DESIGN RECOMMENDATIONS Development of the property should be feasible based on geotechnical considerations. The following recommendations are made for planninggand preliminary design of the buildings and site grading. FOUNDATIONS Spread footings placed on the natural soils below the topsoil should be suitable for support of typical light residential building loads. Allowable soil bearing pressures in the range of 1,000 psf to 2,000 psf should be acceptable. The hydrocompression potential can probably be mitigated by engineered foundation design and should be evaluated on a site specific basis. Compaction of the subgrade can help reduce the settlement potential. Footings placed on the bedrock materials should have allowable bearing pressures in the range of 3,000 psf to 6,000 psf. Additional subsurface exploration should be performed by the individual lot owner when the building location, grading and loading conditions have been determined to provide the site specific bearing recommendations. FLOOR SLAB The natural soils below the topsoil should be suitable for support of lightly loaded slabs - on -grade. The upper soils may be compressible and result in some slab movement. Removal and reconzpaction can reduce the potential for movement. Separating the slab Job M. 101 126 Gterta•ch - 10 - from the bearing walls and columns is usually adequate to allow for slight movement and limit potential distress. Backfill placed beneath slabs should consist of properly placed and compacted soil excluding vegetation, topsoil and oversized rock. BELOW GRADE CONSTRUCTION Basement level construction should not encounter shallow groundwater but seasonal perched water could occur from springtime runoff and local irrigation. We understand that the Atkinson Ditch will be lined with a solid pipe. Subsurface drainage is recommended to protect below grade construction. Typically, this consists of foundation drains and underslab free chaining gravel connected to a gravity outlet. The bedrock is shallow or outcrops in most of the valley side slopes and could make building excavations very difficult to dig. ROADWAY GRADING We assume grading for the roadway development will be relatively minor. Existing topsoil, vegetation and debris should be removed from the cut and embankment fill areas. Slopes greater than 20% should be benched beneath fill areas. The exposed surface should be moistened to optimum and compacted to at least 95% of standard Proctor density. Structural fill should then be placed and compacted to the project specifications and elevations. Cut and fill slopes should be graded at 2 horizontal to 1 vertical or flatter. Embankment fill should be compacted to at least 95% of standard Proctor density near optimum moisture content. The on-site soils devoid of vegetation, topsoil, debris and oversized rock should be suitable for use as structural fill. Positive drainage away from the road surface and subgrade should be provided. SURFACE DRAINAGE Positive surface drainage should be provided around the buildings and throughout the site to prevent ponding adjacent to structures and roadways. The Atkinson Ditch through the Job No. 101 126 Ggritecri -11 - building area should be lined to prevent seepage impact on adjacent sites. The natural drainages from the upper valley areas and the valley side scopes can probably be used to provide positive drainage through the property. The soils are susceptible to erosion, particularly after the vegetation is stripped. Gullying can be expected on unprotected . slopes unless properly protected. WATER TANK SITE An above ground steel water tank is proposed near the southeast end of the project above County Road 125 (see Figure 2). The tank will be similar to the existing tank located uphill of County Road 125 west of Lot 6. The proposed tank site is located on a northeast sloping hillside that consists of relatively stable colluvial deposits above Maroon Formation. We assume that the tank pad will be developed mainly by cutting and could transition the colluvial soils and formation rock. The site should be suitable for the proposed tank based on geotechnical considerations. The bearing conditions could be variable and have differential settlement potential between soil and rock areas. The site specific subsurface conditions should be evaluated for the tank and grading designs. LIMITATIONS This report has been prepared in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either express or implied. The conclusions and recommendations submitted in this report are based upon the data obtained from our site reconnaissance, the exploratory pits dug at the location indicated on Figure 2, the assumed type of construction and our experience in the area. Our findings include interpolation and extrapolation of the subsurface conditions identified at the exploratory pits. Additional exploration and analysis is recommended for the individual building foundation design. Job No. 101 126 Gc.-i _12 - This report has been prepared for the exclusive use by our client for planning and preliminary design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves, we should provide continued consultation to verify that the recommendations have been appropriately interpreted. We recommend observation of excavations for bearing conditions and testing of structural fill by a representative of ow office. If you have any questions or if we can be of further assistance, please let us know. Sincerely, HEPWORTH-PAWLAK GEOTECHNICAL, INC. Steven L. Pawlak, P.E. and By: Ralph G. Mock Engineering Geologist SLP/ksw cc: Sopris Engineering — Attn: Yancy Nichol Job No. 101 126 C ljtech -13 - REFERENCES Hepworth — Pawlak Geotechnical, ,Inc. 2001, Preliminary Geotechnical Study, Proposed Springridge Place Phase 11, County Road 125, Garfield Count}; Colorado, Prepared for The Greenwald Children's Trust, Job No. 101 126, dated February 26, 2001. Kirkham, R.M. and Others, 1996, Geology Map of the Cattle Creek Quadrangle, Garfield County, Colorado: Colorado Geological Survey Open File 96-1. Kirkham, R.M. and Widmann, B.L., 1997, Geology Map of the Carbondale Quadrangle, Garfield County, Colorado: Colorado Geological Survey Open File 97-3. Job No. 101 126 QCIPPm 0 1000f. 1 1 Scale: 1 In. =1000 ft. Contour Interval: 10 ft. June 2004 Explanation: gal Qaa Qaf Qc Kd Jm Jo TRPcs PPm Valley Floor Alluvium Alluvial Apron Alluvial Fan Colluvium Dakota Sandstone Morrison Formation Entrada Sandstone Chine & State Bridge Formations Maroon Fonnatian 101 126 HEPWORTH-PAWLAK GEOTECHNICAL, Inc. ■ Contact: Approximate boundary of map units. Exploratory Pit Approximate location of exploratory pit. Potential Rockiall Start Area: Approxhnate location of potential rockfall start zone. Springridge Place Phase II Figure 2 Preliminary Geology Map and Exploratory Pit Locations -•0 -'5 -p . - 10 Pit 1 Elev=8632' Pit 8 Elev Q 6502' wC=8.1 an -w3 -200=68 LLp27 PI=12 ' Pit 2 Elev=NA Pit9 Elev =6570' Pita Elev=6522' WC=9.8 013= 104 -200-58 Pit 19 Eley a 6428' Pit 4 Elev.= 9428' 'el.WC=8.8 :OA=87 .7,00=74 .P1. 4 • Pit 11 Eiev= 6501' LADIES. 1. Exploratory pits were dug on April 22 and 29, 1884 with a rubber tired backhoe. 2. locations of the exploratory pits were measured approximately by pacing` from features shown on the site plan provided and later by Instrument survey by High Country Engineering. 3. Elevations of exploratory pits were determined by High Country Engineering. • 4. The exploratory pit locations and elevations should be considered. accurate only to the degree implied by the method used. • 5. No free water was encountered in the pits at the time of excavation. Fluctuations in water level may occur with time. E. Laboratory Testing Results: WC = Moisture Content {95} Li. Liquid Limit % DI) = Dry Density (paf} PI = Plasticity Index % -200 = Percent passing No. 200 sieve 101 126 Springridge Development 0- 10" Pit 5 Slav= 6438' -v WC=13.0 nDa96 ,20071 P1=9 P t 8 Elev= 6443' oeii i Pik 7 EIev-8506' LEGEND: TOPSOIL; siltyclay, sandy, organic, brown. WC=7.6 DD=93 -200=84 CLAY (CL}; silty, sandy, stiff, slightly moist, brown and red, slightly • calcareous, slightly to moderately. porous. 1/1 8113 AND SAND (IiAL,SM}, clayey, scattered gravel, stiff, slightly moist, red -brown. Slightly porous and calcareous. FAYI GRAVEL (GM); sandy, silty, rock fragments, medium dense, sllghtiy moist, red -brown. 111 SANDSTONE BEDROCK; very hard, dry, red -brown. Disturbed Bulk Semple. 2" Diameter Hand Driven Liner Sample. 'F Practical refusal to digging with backhoe. Logs of Exploratory Pits Pig. 3 4 3 02 1. to w ce 03 5 6 7 8 0.1 1.0 10 APPLIED PRESSURE ksf 1 Moisture Content =g,8 Ory Unit Weight = 97 sampled! Sandy Clay From: Pit 4 at 6 feet Camp Upon ressi n Wetting percent pcf Af 0.1 1.0 10 APPLIED PRESSURE — ksf 100 101 126 >`iEITH-P�4WLA SWELL-CONSOLJDAT1ON TEST RESULTS GEOTECHNICAL, Inc.. Fig. 4 Moisture Content = 9.8 percent Unit Weight = 104 PO Sample of: Clayey Sandy Silt Front: Pit 3 @ 5.feet �.--. • Cainressi� Upon ett_ng H , _ i 0.1 1.0 10 APPLIED PRESSURE ksf 1 Moisture Content =g,8 Ory Unit Weight = 97 sampled! Sandy Clay From: Pit 4 at 6 feet Camp Upon ressi n Wetting percent pcf Af 0.1 1.0 10 APPLIED PRESSURE — ksf 100 101 126 >`iEITH-P�4WLA SWELL-CONSOLJDAT1ON TEST RESULTS GEOTECHNICAL, Inc.. Fig. 4 COMPRESSION-% 3 4 5 Moisture Content = 13.0 Dry Unit Weight = 95 sampie of:Sandy Clay From: pit 5 at 6 feet percent Pci 0.1 1.0 APPLIED PRESSURE 10 kst 100 101 126 HEPWORTH-PAWLAK GEOTECHNICAL, Inc. SWELL -CONSOLIDATION TEST RESULTS Fig. 5 0 1 O 2 w O 3 U 4 5 6 7 we1 0 tn2 w 0 3 U APPLIED PRESSURE — ksf Moisture Concent = 8.1 Dry Unit Weight = 103 Sample of Sandy clay From: Pit 8' at 5 feet Compressio Upon Wetti g percent pcf 0.1 1.0 10 APPLIED PRESSURE — ksf 100 101 126 HEPWORTH-PAWLAK GEOTECHNICAL, Inc. SWELL -CONSOLIDATION TEST RESULTS Fig. Moisture Content = 7.6 percent Dry Unit Weight = 93 Pc( Sample of Sandy Clay From: Pit 7 at 5 feet i, Wetting' Compression . . NUpon IIEI ri: 1G 1n tnn APPLIED PRESSURE — ksf Moisture Concent = 8.1 Dry Unit Weight = 103 Sample of Sandy clay From: Pit 8' at 5 feet Compressio Upon Wetti g percent pcf 0.1 1.0 10 APPLIED PRESSURE — ksf 100 101 126 HEPWORTH-PAWLAK GEOTECHNICAL, Inc. SWELL -CONSOLIDATION TEST RESULTS Fig. HEPWORTH-PAWLAK GEOTECHNICAL, INC. TABLE! SUMMARY OF LABORATORY TEST RESULTS JOB NO. 101 126 SAMPLE LOCATION NATURAL MOISTURE CONTENT {961 . NATURAL GRADATION PERCENT ATTERBERG UNITS UNCONFINED COMPRESSIVE STRENGTH IPSFI SOIL OR BEDROCK TYPE PIT DEPTH Ueetl DRY DENSITY Ipcfl GRAVEL 1%i SAND MI PASSING NO. 200 • SIEVE LIQUID LIMIT 19121, PLASTIC INDEX 1%1 3 - 5 9.8 104 56 Clayey Sandy Silt 4 6 8.8 97 74 26 8 Sandy Clay 5 6 '13.0 95 71 25 9 Sandy Clay 7 5 7.6 93 64 Sandy Clay 8 5 8.1 103 68 27 12 Sandy Clay