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HomeMy WebLinkAboutSoils Report.pdfG& tech HEPWORTH•PAWLAK GEOTECHNICAL �¢o 33 Hepworth-Pawlak Geotechnical, Inc. 5020 County Road 154 Glenwood Springs, Colorado 81601 Phone: 970.945.7988 Fax: 970.945-8454 email: hpgeo@hpgeotech.cons SUBSOIL STUDY FOR FOUNDATION DESIGN AND PERCOLATION TESTING PROPOSED RESIDENCE PARCEL 3, FARANHYLL RANCH GARFIELD COUNTY, COLORADO JOB NO. 110 360A NOVEMBER 19, 2010 PREPARED FOR: GAIL ANDERSON 7871 E. 6°i AVENUE DENVER, COLORADO 80203 Parker 303-841-7119 • Colorado Springs 719-633-5562 • Silverthorne 970-468-1989 TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY - I - PROPOSED CONSTRUCTION - 1 - SITE CONDITIONS - 2 - FIELD EXPLORATION -2 SUBSURFACE CONDITIONS - 2 - FOUNDATION BEARING CONDITIONS - 3 - DESIGN RECOMMENDATIONS - 3 - FOUNDATIONS FOUNDATION AND RETAINING WALLS - 5 - FLOOR SLABS - 6 - UNDERDRAIN SYSTEM - 7 - SITE GRADING - 7 - SURFACE DRAINAGE - 8 - PERCOLATION TESTING - 8 - LIMITATIONS - 9 - FIGURE 1- LOCATION OF EXPLORATORY BORINGS FIGURE 2 - LOGS OF EXPLORATORY BORINGS FIGURE 3 - LEGEND AND NOTES FIGURE 4 and 5- SWELL-CONSOLIDATION TEST RESULTS PIGURES 6 and 7 - GRADATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS TABLE 2- SUMMARY OF PERCOLATION TEST RESULTS PURPOSE AND SCOPE OF STUDY This report presents the results of a subsoil study for a proposed residence to be located at Parcel 3, Faranhyll Ranch, Garfield County, Colorado. The project site is shown on Figure 1. The purpose of the study was to develop recommendations for the foundation design. The study was conducted in accordance with our proposal for geotechnical engineering services to you c/o Structural Associates dated October 11, 2010. Structural Associates requested percolation testing by email on October 20, 2010. A field exploration program consisting of exploratory borings was conducted to obtain information on the subsurface conditions. Samples of the subsoils obtained during the field exploration were tested in the laboratory to detennine their classification, compressibility or swell and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for foundation types, depths and allowable pressures for the proposed building foundation. This report summarizes the data obtained during this study and presents our conclusions, design reconunendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. PROPOSED CONSTRUCTION The proposed residence will be one story wood frame construction above a walkout level with an attached garage. Lower level and garage floors will be slab -on -grade. Grading for the structure is assumed to be relatively minor with cut depths between about 3 to 9 feet. We assume relatively light foundation loadings, typical of the proposed type of construction. If building loadings, location or grading plans change significantly from those described above, we should be notified to re-evaluate the recommendations contained in this report. Job No. 110 360A Ge&tech -2 - SITE CONDITIONS The property is located on the west side of County Road 117 and Four Mile Creek. The site is vacant of structures and vegetated with grass and weeds. Evergreen trees, willows and tall grass are located along the creek. The ground surface slopes moderately down to the northeast in the building area and becomes steep along the creek bank. Scattered basalt boulders are visible on the ground surface. FIELD EXPLORATION The.field exploration for the project was conducted on November 1, 2010. Three exploratory borings and a profile boring were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions. The borings were advanced with 4 inch diameter continuous flight augers powered by a truck -mounted CME -45B drill rig. The borings were logged by a representative of Hepworth-Pawlak Geotechnical, Inc. Samples of the subsoils were taken with PA inch and 2 inch I.D. spoon sarnplers. The samplers were driven into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM Method D-1586. The penetration resistance values are an indication of the relative density or consistency of the subsoils. Depths at which the samples were taken and the penetration resistance values arc shown on the Logs of Exploratory Borings, Figure 2. The samples were retuned to our laboratory for review by the project engineer and testing. SUBSURFACE CONDITIONS Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. The subsoils below about 12 to 18 inches of topsoil, consist of 6 to 8 feet of stiff to very stiff sandy clay overlying relatively dense clayey sandy gravel with cobbles and probable boulders at depths of 7 to 9/ feet. Drilling in the dense granular soils with auger Job No. 1 10 360A G ted" -3 - equipment was difficult due to the cobbles and boulders and drilling refusal was encountered at Borings 1 and 2 at depths of 13 and 18 feet, respectively in the deposit. Laboratory testing performed on samples obtained from•the borings included natural moisture content, density and gradation analyses. Results of swell -consolidation testing . performed on relatively undisturbed drive samples, presented on Figures 4 and 5, indicate low to moderate compressibility under conditions of loading and wetting. Samples tested from Borings 1 and 2 showed a minor to low expansion potential when wetted and a shallow sample from Boring 3 showed a moderate to high expansion potential upon wetting. Results of gradation analyses performed on a small diameter drive sample (minus 1'1/2 inch fraction) ofthe coarse granular subsoils are shown on Figure 5. Results of gradation and hydrometer analyses performed on a small diameter drive sample from the profile boring (minus 11/2 inch fraction) are shown on Figure 6. The laboratory testing is summarized in Table 1. Free groundwater was encountered in building area at a depth of 9 feet at the time of drilling and at 8 to 10 feet one day following drilling. No free water was encountered in the profile boring at the time of drilling or when checked 1 day later and the upper subsoils were moist. FOUNDATION BEARING CONDITIONS The residence as planned will bear on the natural sandy clay soils. Groundwater was encountered near the expected foundation grade. Groundwater levels should be expected to rise in the spring and summer. The upper sandy clay soil showed a moderate risk of expansion when wetted. The upper sandy clay soil could be removed to a depth of 3 feet and replaced with structural fill to reduce the risk of differential settlement. DESIGN RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratory borings and the nature of the proposed construction, we recommend the building be founded with spread Job No. 110 360A -4 - footings bearing on the natural soils or structural fill. Structural fill should be compacted to 98 percent standard Proctor density at a moisture content near optimum. The design and construction criteria presented below should be observed for a spread footing foundation system. 1) Footings placed on the undisturbed natural soils or structural fill should be designed for an allowable bearing pressure of 2,000 psi. Based on experience, we expect settlement of footings designed and constructed as discussed in this section will be about 1 inch or less. The subgrade should be further evaluated at the time of construction and expansive clay should be removed from below footing and slab -on -grade areas. If expansive clay is encountered, it should be subexcavated to a depth of 3 feet and replaced with compacted structural fill. The structural fill should consist of' imported % inch aggregate base course, 2) The footings should have a minimum width of 16 inches for continuous walls and 2 feet for isolated pads. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Placement of foundations at least 36 inches below exterior grade is typically used in this area. 4) Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least 12 feet. Foundation walls acting as retaining structures should also be designed to resist lateral earth pressures as discussed in the "Foundation and Retaining Walls" section of this report. 5) All topsoil, expansive clay and any loose or disturbed soils should be removed and the footing bearing level extended down to the relatively undisturbed natural soils. The exposed soils in footing area should then be moistened and compacted. If water seepage is encountered, the footing areas should be dewatered before concrete placement. Job No. 110 360A -5- 6) A representative of the geotechnical engineer should observe all footing excavations prior to concrete placement to evaluate bearing conditions. FOUNDATION AND RETAINING WALLS Foundation walls and retaining structures which are laterally supported and can be expected to undergo only a slight amount of deflection should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 55 pcf for backfill consisting of the on-site sandy clay soils. Cantilevered retaining structures which are separate from the residence and can be expected to deflect sufficiently to mobilize the full active earth pressure condition should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 45 pcf for backfill consisting of the on-site soils. All foundation and retaining structures should be designed for appropriate hydrostatic and surcharge pressures such as adjacent footings, traffic, construction materials and equipment. The pressures recommended above assume drained conditions behind the walls and a horizontal backfill surface. The buildup of water behind a wall or an upward sloping backfill surface will increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain should be provided to prevent hydrostatic pressure buildup behind walls. Backfill should be placed in uniform lifts and compacted to at least 90% of the maximum standard Proctor density at a moisture content slightly above optimum. Backfill in pavement and walkway areas should be compacted to at least 95% of the maximum standard Proctor density. Care should be taken not to overcompact the backfill or use large equipment near the wall, since this could cause excessive lateral pressure on the wall. Some settlement of deep foundation wall backfill should be expected, even if the material is placed correctly, and could result in distress to facilities constructed on the backfill. Job No. 110 360A Gtech -6 - The lateral resistance of foundation or retaining wall footings will be a combination of the sliding resistance of the footing on the foundation materials and passive earth pressure against the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated based on a coefficient of friction of 0.30. Passive pressure of compacted backfill against the sides of the footings can be calculated using an equivalent fluid unit weight of 325 pef. The coefficient of friction and passive pressure values recommended above assume ultimate soil strength. Suitable factors of safety should be included in the design to limit the strain which will occur at the ultimate strength, particularly in the case of passive resistance. Fill placed against the sides of the footings to resist lateral loads should be compacted to at least 95% of the maximum standard Proctor density at a moisture content slightly above optimum. FLOOR SLABS The natural on-site soils should be further evaluated at the time of construction for support of slab -on -grade. Shallow expansive clay should be removed to a depth of 3 feet and replaced with compacted structural fill (compacted'/ aggregate base course) exclusive of topsoil. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minnnum 4 inch layer of free -draining gravel should be placed beneath basement level slabs to facilitate drainage. This material should consist of minus 2 inch aggregate with at least 50% retained on the No. 4 sieve and less than 2% passing the No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 95% of maximum standard Proctor density at a moisture content near optimum. Required fill should consist of imported'/ inch aggregate base course. Job No. 110 360A Ga' tech -7- UNDERDRAIN SYSTEM Free water was encountered during our exploration at expected excavation grade. It has been our experience in mountainous areas that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can also create a perched condition. We recommend below -grade construction, such as retaining walls and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain system. The drains should consist of drainpipe placed in the bottom of the wall backfill surrounded above the invert level with free -draining granular material. The drain should be placed at each level of excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1% to a suitable gravity outlet. Free -draining granular material used in the underdrain system should contain less than 2% passing the No. 200 sieve, less than 50% passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at least 1% feet deep and extend up to any seepage observed in the side of the excavation. SITE GRADING The risk of construction -induced slope instability at the site appears low provided the building is located as planned and cut and fill depths are limited. We assume the cut depths for the basement level will not exceed one level, about 10 feet. Fills should be limited to about 8 to 10 feet deep. Embankment fills should be compacted to at least 95% of the maximum standard Proctor density near optimum moisture content. Prior to fill placement, the subgrade should be carefully prepared by removing all vegetation and topsoil and compacting to at least 95% of the maximum standard Proctor density. The fill should be benched into the portions of the hillside exceeding 20% grade. Permanent unretained cut and fill slopes should be graded at 2 horizontal to 1 vertical or flatter and protected against erosion by revegetation or other means. The risk of slope Job No. 110 360A -S - instability will be increased if seepage is encountered in cuts and flatter slopes may be necessary. If seepage is encountered in permanent cuts, an investigation should be conducted to determine if the seepage will adversely affect the cut stability. This office should review site grading plans for the project prior to construction. SURFACE DRAINAGE The following drainage precautions should be observed during construction and maintained at all times after the residence has been completed: 1) Inundation of the foundation excavations and underslab areas should be avoided during construction. 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95% of the maximum standard Proctor density in pavement and slab areas and to at least 90% of the maximum standard Proctor density in landscape areas. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the fust 10 feet in paved areas. Free -draining wall backfill should be capped with about 2 feet of the on- site soils to reduce surface water infiltration. 4) Roof downspouts and drains should discharge well beyond the limits of all backfill 5) Landscaping which requires regular heavy irrigation should be located at least 10 feet from foundation walls. Consideration should be given to use of xeriscape to reduce the potential for wetting of soils below the building caused by irrigation. PERCOLATION TESTING A profile boring and three percolation test holes were excavated on November 1, 2010 at the locations shown on Figure 1. The subsoils exposed in the Profile Boring consisted of Job No. 110 360A -9 - about one foot of topsoil overlying sandy clay to the bottom depth explored of 11 feet. The results of a gradation and hydrometer analysis performed on a sample of sandy clay (minus 3/8 inch fraction) obtained from the profile boring are presented on Figure 6. The sample tested has an USDA Soil Texture Classification of loam. No free water or evidence of a seasonal perched water table was observed in the profile boring at the time of drilling or when checked the following day. The soils were slightly moist to moist. Percolation test holes were soaked with water on November 1, 2010 and protected overnight from freezing with foam insulation. Percolation testing was conducted on November 2, 2010, by a representative of Hepworth - Pawlak Geotechnical, Inc. Soil temperatures at time of testing were 38 to 40 degrees Fahrenheit. The percolation rates varied from 20 minutes per inch to 30 minutes per inch with an average of23 minutes per inch. The percolation test results are summarized on Table 2. Based on the subsurface conditions encountered and the percolation test results, the tested area should be suitable for an on site waste disposal system. A professional civil engineer should design the septic disposal system. • LIMITATIONS This study has been conducted 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 the exploratory borings drilled at the locations indicated on Figure 1, the proposed type of construction and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then a professional in this special field of practice should be consulted. Our findings include interpolation and extrapolation of the subsurface conditions identified at the exploratory borings and variations in the subsurface conditions may not become evident until excavation is performed. If conditions Job No. 110 360A -10 - encountered during construction appear different from those described in this report, we should be notified so that re-evaluation of the recommendations may be made. This report has been prepared for the exclusive use by our client for design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves, we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation of excavations and foundation bearing strata and testing of structural fill by a representative of the geotechnical engineer. Respectfully Submitted, HEPWO H - PAWLAIC GEOTECHNICAL, INC. Louis E. Eller Reviewed by: �oou 1wi uib;u� Qp� R 04,yr��i.: Ao att a eeso�Fi'+ Daniel E. Hardin, P.Es f CSo 2444 LEE/ksw %/31/(0.,41 SYtl cc: Structural Associategin,$weans (shane ,,structuralassoc.com) Job No. 110 360A Gecetech APPROXIMATE SCALE 7" = 50' 0 I \ �Eqs ` rn I �' \ F \ moo o \\ \T \ N 11 \ P-3 P_2 \ IP1 1 \ BORING \ �� PROFILE \\ \ \ \\ • ' ---I \ o • • • • \ \ \ \ \•. \\ • \ •• \ 1 6610 \ \ BORING 3 I `• `•• \\ \\\ROBIN \ \ \ \\ \ 6620_ \ \ \ • • \\ \ \ \\ \ \ \ \ 11 \\ ; BORING 2 \ 1 �l \\\ 1\\ 11 1\ ,/ �cr C c. \ \ 110 360A He.Grtgitech LOCATION OF EXPLORATORY BORINGS AND PERCOLATION TEST HOLES Figure 1 Elevation - Feet BORING 1 ELEV.= 6587' BORING 2 ELEV.= 6585' BORING 3 ELEV.= 6582' PROFILE BORING ELEV.= 6580' 6590 6590 _ 6570 6565 _ 6560 16/12 13/12 WC=20.3 00=103 24/12 WC=15.9 D0=114 16/12 22/12 WC=19.8 DD=108 21/12 WC=10.9 DD=112 6585 ._. 6580 _. N WC=8.9 D0=116 10/12 +4=1 11/12 r .� -200=84 43/12 16/12 6575 51/12 +4=58 -200=14 0 1� 65/12 29/12 70/11 Note: Explanation of symbols 1s shown on Figure 3. 15/12 6570 — 6565 6560 _ Elevation - Feet 110 360A iHcrwortmawwwCGEOTCCHNICAJ. Gatech LOGS OF EXPLORATORY BORINGS Figure 2 LEGEND: ® TOPSOIL; organic sandy silt and clay, soft, very moist, dark broom. CLAY (CL); sandy, silty, medium stiff to stiff, moist to wet with depth, brown. GRAVEL (GM); with cobbles and probable boulders, sandy, clayey, medium dense to dense, wet, brown. Relatively undisturbed drive sample; 2 -inch I.D. California liner sample. -7 4 - Drive sample; standard penetration test (SPT), 1 3/8 Inch I.D. split spoon sample, ASTM D-1586. 15 tt/���12 Drive sample blow count; indicates that 15 blows of a 140 pound hammer falling 30 inches were required to drive the California or SPT sampler 12 inches. - �'1 Free water level In boring and number of days following drilling measurement was taken. --> Depth at which boring had caved when checked on November 2, 2010 Practical drilling refusal. NOTES: 1. Exploratory borings were drilled on November 1, 2010 with 4 -inch diameter continuous flight power auger. 2. Locations of exploratory borings were measured approximately by pacing from features shown on the site plan provided. 3. Elevations of exploratory borings were obtained by interpolation between contours shown on the site plan provided. 4. The exploratory boring locations should be considered accurate only to the degree Implied by the method used. 5. The lines between materials shown on the exploratory boring logs represent the approximate boundaries between material types and transitions may be gradual. 6. Water level readings shown on the logs were made at the time and under the conditions indicated. Fluctuations in water level may occur with time. 7. Laboratory Testing Results: WC = Water Content (%) DD = Dry Density (pot) +4 = Percent retained on the No. 4 sieve -200 = Percent passing No. 200 sieve 110 360A I rr¢PWORTM_-W KGEOTECHNICAL I LEGEND AND NOTES I Figure 3 0 w 1 o. E 0 U 2 Compression % 0 1 2 3 Moisture Content = 20.3 percent Dry Density = 103 pcf Sample of: Sandy Clay From: Boring 1 at 5 Feet Expansion upon wetting 0.1 .0 10 APPLIED PRESSURE - ksf 100 Moisture Content = 15.9 Dry Density = 114 Sample of: Sandy Clay From: Boring 1 at 10 Feet percent pcf No movement upon wetting 0.1 .0 10 APPLIED PRESSURE - ks 100 110 360A Gaigteicah Hepworth-powlok Godd SWELL -CONSOLIDATION TEST RESULTS Figure 4 0 0 1 E 8 2 Compression - Expansion 6 5 4 3 2 1 0 1 Moisture Content = 19.8 percent Dry Density = 108 pcf Sample of: Sandy Clay From: Boring 2 at 5 Feet C— Expansion upon wetting 0.1 .0 10 APPLIED PRESSURE - ksf 100 Moisture Content = 10.9 Dry Density = 112 Sample of: Sandy Clay From: Boring 3 at 2 Feet percent pcf Expansion upon wetting 0.1 .0 0 APPLIED PRESSURE • ksf 100 110 360A Hepworth-_P'awla c 6eoka led SWELL -CONSOLIDATION TEST RESULTS Figure 5 kiW k RET• 24Ir HYDROMETER ANALYSIS ITIME SIEVE ANAL1 CLEAR YSIS 024 MIR, 75 MM.60MMn8RMEI�STANDARDINGS U.S. N.4 MIN I MIN. #200 #100 #50 #30 # BIS#e SDUfA1R OPENINGS S, 100 10 20 30 40 50 60 70 80 90 SMI ------ Sem Bat al S NNW Ima. il See MIN la MIN 60111/11IS la a Mita .: C • 1 IS SI aa SI- ---Sw s. .. -SIM - S S 10 Sir 1 SW a a Mal S at SI - a����� .SI I MOM S SIX — SION :-SII SINS -- ---- ala sass wams --- .s— .� SI SI a--VSS ---- IS S ----v SI SI SS a - IS Sin MI111111•1011IN at --- IMS Ilortala all MUM -! Vaal - P 80 80 100 —�-- .600 1.18 2.38 4.75 9.5 37.5 762 127 62 203 .001 .002 .005 .009 .019 .037 .074 .150 .900 DIAMETER OF PARTICLES IN MILLIMETERS, 0.9 CNYTO ELT 1 FINE 1 1CDW IOONSE I FIW O T cam 1 COMES GRAVEL 58 % SAND 28 % SILT AND CLAY 14 % LIQUID LIMIT % PLASTICITY INDEX % SAMPLE OF: Clayey Sandy Gravel FROM: Boring 2 at 15 Feet 70 60 50 40 30 20 10 0 110 360A Ge'~ arch H EP W ORT WPwwwc GEOTECHNICAL GRADATION TEST RESULTS Figure 6 gimmiaThr HTDROINETFA ANAL IS • SIEVE ANALYSIS 224pII��p4� 77R�pR TIME READINGS U3. STANDARD SERIES 1 CLEAR SQUARE OPENINGS 045MIN.15 MM. 80MIN19MIN.4 MIN. 1 MIN. 41200 4100 460 030 418 48 44 3/8' 3/4' 11(7 3' 5.6' 8' 100 10 20 30 40 60 60 70 80 90 100 SIM - �a��� w •� — �A� S— -- �� �N —rte MI� Or 1/8M C� Oilr ._ Ala PIM _•Ore MI MIMI --- MI ANS Matey MONIMI oMPIIII mita INN r/mIll• MIK =MO 1111111111111 limmi MIEEM NSA Mil=1,AME nom 01 IiIMA Mr Al Mi num --- ---- � r—vim-- .— Self amp — •�. • �— CI.. a MrMv� v.v •••••Or� .— Ian/ Miami klialM SOM. 11M.111.1 MbasiaiM/ iorasisempa INS v anal .001 .002 .005 .009 .019 .037 .074 .150 .300 .600 1.18 2.36 4.75 9.5 19.0 37.5 76.2 152 203 12.5 127 CIA? BST DIAMETER OF PARTICLES IN MI WMETERS SIND I %tree 1 FRE 1 maul !alum IM,COMsE Swwl. MEDIUM 1VEL Unca COBBLES 90 80 70 60 50 40 30 20 10 0 RCENT PASS , t GRAVEL 2 % SAND 38 % SILT 42 % CLAY 18 % LIQUID LIMIT % PLASTICITY INDEX % USDA SOIL TYPE: Loam FROM: Profile Boring at 2 z and 5 Feet Combined 110 360A I Gatech Hepworth—NW& 0eotechnle4l USDA GRADATION TEST RESULTS I Figure _ 7 Job No. 110 360A of Sandy Clay U p' 4.T Sandy Clay Clayey Sandy (ravel 11 re U A s UNCONFINED COMPRESSIVE Sf REN II4 (PSF) � °a a O v 18 PanyAN z r�-4 W GRADATION v N tn e ( d' � !-I !-Ig ZOM O 103 ~ 0 1--11-I qM WF' o zE 8 O N O)o0 Ol01 O OG qyg g r ,„ o9, 'n to n N t d -HE .t t N U 2 N M o p Al HEPWORTH-PAWLAK GEOTECHNICAL, INC. TABLE 2 PERCOLATION TEST RESULTS JOB NO. 110 360A HOLE NO. HOLE DEPTH (INCHES) LENGTH OF INTERVAL (MIN) WATER DEPTH AT START OF INTERVAL (INCHES) WATER DEPTH AT END OF INTERVAL (INCHES) DROP IN WATER LEVEL (INCHES) AVERAGE PERCOLATION RATE (MIN./INCH) P 1 31 15 13 11 2 11 9 3/4 1 1/4 9 3/4 9 3/4 9 81/4 3/4 30/1 81/4 71/2 3/4 71/2 7 1/2 7 61/2 1/2 61/2 6 1/2 P2 41 15 181/4 16 21/4 20/1 16 143/4 11/4 143/4 131/2 11/4 13 1/2 12 1/2 1 12 1/2 11 1/2 1 11 1/2 103/4 3/4 103/4 10 3/4 10 91/4 3/4 P3 52 15 161/2 12 41/2 20/1 12 10 2 10 9 1 9 8 1 8 7 1/4 • 3/4 71/4 6 1/2 3/4 61/2 53/4 3/4 53/4 5 3/4 Note: Perco ation test holes were soaked on November 1, 2010. Percolation tests were conducted on November 2, 2010. The holes were protected from freezing with foam insulation. The average percolation rates were based on the last three readings of each test.