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Home My WebLink AboutSoils ReportGtech HEPWORTH - PAWLAI< GEOTECHNICAL 11:I .III, I'. t.l.al 1 r lc hi,r,, I1, 1111 quid I, ,, , I 1 11,1,ioN,,,,.1 `1tIt . t ,•I. ,L :Ila l .0. 971: `I 1 i --I -14 SUBSOIL STUDY FOR FOUNDATION DESIGN PROPOSED RESIDENCE PARCEL 1, WINDANCE RANCH COUNTY ROAD 151 GARFIELD COUNTY, COLORADO JOB NO. 112 026A MAY 30, 2012 PREPARED FOR: SHANNON BURKE 347 GLENCOE STREET DENVER, COLORADO 80222 [mini rke(iegnia i Lconi TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY 1 PROPOSED CONSTRUCTION 1 SITE CONDITIONS - 2 - FIELD EXPLORATION 2 - SUBSURFACE CONDITIONS - 3 - FOUNDATION BEARING CONDITIONS - 3 - DESIGN RECOMMENDATIONS - 4 - FOUNDATIONS - 4 - FOUNDATION AND RETAINING WALLS ... - 5 - FLOOR SLABS - 7 - UNDERDRAIN SYSTEM - 7 - SURFACE DRAINAGE - 8 - PERCOLATION TESTING - 9 - LIMITATIONS 9 - FIGURE 1 - LOCATIONS OF EXPLORATORY BORINGS AND PERCOLATION TEST HOLES FIGURE 2 - LOGS OF EXPLORATORY BORINGS FIGURE 3 - LEGEND AND NOTES FIGURES 4 and 5 - SWELL -CONSOLIDATION TEST RESULTS FIGURE 6 - GRADATION TEST RESULTS TABLE 1 - SUMMARY OF LABORATORY TEST RESULTS TABLE 2 - PERCOLATION TEST RESULTS PURPOSE AND SCOPE OF STUDY This report presents the results of a subsoil study for a proposed residence to be located on Parcel 1, Windance Ranch, County Road 151, south of Sweetwater in 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 agreement for geotechnical engineering services to Shannon Burke dated April 20, 2012. 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 determine their classification, compressibility or swell and other engineering characteristics. The results ofthe 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 recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. PROPOSED CONSTRUCTION The residence will be a two story wood frame structure over crawlspace located on the site as shown on Figure 1. The attached garage will have a slab -on -grade floor. Grading for the structure is assumed to be relatively minor with cut depths from about 3 to 5 feet. We assume relatively light foundation loadings, typical ofthe proposed construction. The on-site septic disposal location is planned to the northeast ofthe residence as shown on Figure 1. 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. 112 026A C leStech -2 - SITE CONDITIONS The site is vacant and the ground surface appears mostly natural. The terrain is strongly sloping down to the northeast. Elevation difference across the building site is estimated at about 4 to 5 feet. The site is at the edge of a moderately thick aspen stand with open meadow/pasture to the east in the building area. There is a small irrigation ditch to the west of the building site along the edge ofthe aspen grove that was flowing water at the time of our field exploration, Vegetation consists of grass and weeds. There were scattered partly buried cobbles on the ground surface. Elevation of the site is estimated at about 8,500 feet, FIELD EXPLORATION The field exploration for the project was conducted on May 2, 2012. Two exploratory borings (Borings 1 and 2) were drilled in the general proposed building area at the locations shown on Figure 1 to evaluate the subsurface conditions. Profile Boring 1 and Profile Boring 2 were drilled at the two alternate septic disposal sites. The boring locations were coordinated with Scott Green in the field. 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 1-lepworth-Pawlak Geotechnical, Inc. Sainples of the subsoils were taken with 1% inch and 2 inch I.A. spoon samplers. 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 ofthe subsoils. Depths at which the samples were taken and the penetration resistance values are shown on the Logs of Exploratory Borings, Figure 2. The samples were returned to our laboratory for review by the project engineer and testing. Job No. 112 026A G tech -.3 - SUBSURFACE CONDITIONS Graphic logs ofthe subsurface conditions encountered at the site are shown on Figure 2. The subsoils encountered in Borings 1 and 2, below about 2 to 2'/z feet of organic topsoil, consisted of sandy to very sandy clay with scattered gravel and cobbles. The clay was stiff to very stiff with depth and extended down to the drilled depths of 31 and 21 feet. The subsoils encountered in Profile Boring 1, below about 11/2 feet of topsoil, consisted of medium dense, clayey to very clayey sandy gravel with cobbles and sandy clay zones that extended down to the drilled depth of 9 feet. The subsoils encountered in Profile Boring 2, below about 2 feet of topsoil, consisted of stiff, sandy clay with scattered gravel and cobbles that extended down to the drilled depth of 9 feet. Laboratory testing performed on samples obtained from the borings included natural moisture content and density, gradation analyses, and Atterberg limits. Results of swell - consolidation testing performed on relatively undisturbed drive samples of the clay soils, presented on Figures 4 and 5, indicate generally moderate compressibility under conditions of light loading and wetting. Two ofthe samples showed a low swell potential when wetted under a constant light surcharge. Results of gradation analyses performed on a small diameter drive sample (minus 11/2 inch fraction) ofthe gravel soils from Profile Boring 1 are shown on Figure 6. The laboratory testing is summarized in Table 1. Free water was encountered in Boring 1 at the time of drilling and when checked 12 days later at depth of about 17 feet. No free water was encountered in Boring 2 or in Profile Borings 1 and 2. The subsoils were moist to very moist becoming wet with depth in Boring 1. FOUNDATION BEARING CONDITIONS Based on the proposed cut depths and the residence location, the sandy clay soils will probably be encountered at subgrade level. Theses soils possess low bearing capacity and low to moderate settlement potential. Spread footings bearing on these soils appear Job No. 112 026A Gtech -4 - feasible for foundation support of the building with some risk of movement. Based on our experience with this type of soil condition, in the area, the low expansion potential encountered in the samples can be neglected in the foundation design, but the exposed bearing soils should be further evaluated at the time of construction. A lower risk foundation with respect to settlement would be to place several feet of structural fill below the spread footings or a relatively deep foundation system such as helical piers or screw piles bearing in suitable soils. Provided below are recommendations for spread footings bearing on the natural soils. If recommendations for spread footings bearing on structural fill or a helical pier or screw pile foundation system are desired, we should be contacted. 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 footings bearing on the natural soils with some risk of movement. The design and construction criteria presented below should be observed for a spread footing foundation system. 1) Footings placed on the undisturbed natural soils should be designed for an allowable bearing pressure of 1,500 psf. Based on experience, we expect movement of footings designed and constructed as discussed in this section will be about 1 to 11/2 inches and probably occur over time. 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. Job No. 112 026A Gaiitech -5 - Placement of foundations at least 48 inches below exterior grade is recommended for this area of Garfield County. 4) Continuous foundation walls should be heavily reinforced top and bottom to span local anomalies and better withstand the effects of some differential settlement such as by assuming an unsupported length of at least 14 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) The topsoil and any loose disturbed soils should be rernoved and the footing bearing level extended down to the firm natural soils. Track - mounted equipment should be used where needed to avoid disturbance of the bearing soils. If water seepage is encountered, the footing areas should be dewatered before concrete placement. Soft subgrade areas should be stabilized prior to the footing construction. The stabilization can probably be done by subexcavating 11/2 to 2 feet of the subgrade soils and replacing thele with imported coarse granular soils such as crushed rock. 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 soils. Cantilevered retaining structures which are separate from the building 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 50 pcf for backfill consisting of the on-site soils. The wall backfill should not contain topsoil or oversized rocks. Job No. 112 026A GAZtech -6 - 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 near 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. We suggest imported granular soils for backfilling foundation walls and retaining structures because their use results in lower lateral earth pressures and the backfill will help to improve the subsurface drainage. Subsurface drainage recommendations are discussed in more detail in the "Underdrain System" section of this report. Imported granular wall backfill should contain less than 15% passing the No. 200 sieve and have a maximum size of 6 inches. 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 0.35. Passive pressure of compacted backfill against the sides of the footings can be calculated using an equivalent fluid unit weight of 325 pcf for moist condition. 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 Job No, 112 026A G tech 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 near optimum. FLOOR SLABS The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded slab - on -grade construction. There maybe some risk of slab heave if potentially expansive clay soils underlie the slab and become wetted. We should further evaluate the expansive potential of the slab subgrade at the time of construction to determine if mitigation is needed. 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 minimum 4 inch layer of free -draining gravel should be placed beneath slabs for support and 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 frill can consist of the on-site soils devoid of topsoil and oversized rocks, or a suitable granular material can be imported. LINDERDRAIN SYSTEM Free water was encountered during our exploration below proposed excavation depths but it has been our experience in mountainous areas and where clay soils are present that groundwater level can rise and/or perched groundwater can develop during times of Job No. 112 026A Gtech -8 - 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, crawlspace and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain system. The drain should consist of drainpipe placed in the bottom of the wall backfill and surrounded above the invert Ievel with free -draining granular material. The drain should be placed at each level of excavation and at least 11/2 feet 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 should be separated from the wall backfill with filter fabric such as Mirafz 140N. SURFACE DRAINAGE The following drainage precautions should be observed during construction and maintained at all times after the building has been completed: 1) Inundation ofthe 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% ofthe maximum standard Proctor density in pavement and slab areas and to at Ieast 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 first 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. Job No. 112 026A "gted -9- 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. PERCOLATION TESTING Percolation tests were conducted on May 5, 2012 to evaluate the feasibility of an infiltration septic disposal system at the site. One profile boring (Profile Boring 1) was drilled and four percolation holes (P-1, P-2, P-3 and P-4) were excavated at the locations shown on Figure 1. The test holes were hand dug in the bottom of shallow backhoe trenches and soaked with water one day prior to testing. The soils encountered in the percolation holes were more clayey than those encountered in Profile Boring 1 and consisted of sandy clay with scattered gravel and cobbles. The test P-3 location was gravelly and the P-4 location contained minor gravel. No free water was encountered in the profile borings at the time of drilling. The sandy clay soils probably classify as Sandy Clay Loam with variable gravel content as per USDA system. Percolation tests were not requested at the Profile Boring 2 location due to the clay soils with minor gravel content. The percolation test results are presented in Table 2. No test was performed in test hole P-4 due to water still remaining in hole when we returned the next day for the percolation testing. The percolation test results indicate rates of 240, 80 and 60 minutes per inch in tests P-1, P-2 and P-3, respectively. Based on the subsurface conditions encountered and the percolation test results, the tested area is not suitable for a'conventional infiltration septic disposal system. A civil engineer should design the infiltration septic disposal system. Additional percolation testing could be done to locate a more suitable site for subsurface infiltration. 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 Job No. 1!2026A Gtech -10 - 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 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, HEPWORTH - PAWLAK GEfi�ICAL, INC. David A. Young, P. E. Reviewed by: 2-216° Z •r �9 d ICNA LSA y �� Steven L. Pawlak, P. E. DAY/ljg cc: Scott Green Excavating — Scott Green (sgegypsum cr gmail.com) Job No. 112 026A C e<Dtech ariA vecc r 0-11 ENS P ASPEN rl�, GROVE-{' Yhmi EXISTING ACCESS ROAD IRRIGATION DITCH P-1 P 2 P-3 PROFILE BORING 1 • PROPP-4LD LEA FIELD •BORING 2 PROPOSED 55' X32' HOUSE TO COUNTY ROAD 151 PROFILE BORING 2 • PROPOSED WELL PROPOSED ACCESS ROAD Jaw - APPROXIMATE SCALE: 1"=60' 112 026A � H 'stec l HEPWOFTIH-PAWL KGEOTECHNICAL. LOCATIONS OF EXPLORATORY BORINGS AND PERCOLATION TEST HOLES FIGURE 1 DEPTH - FEET 0 5 10 15 20 25 30 35 112 026A BORING 1 12 0 • • • • • • • • • • • • • • • • • • • • • • • 12/12 17/12 1 WC=22.3 DD= 100 14/12 WC=31.7 DD=89 12/12 WC=20.4 DD=103 22/12 20/12 BORING 2 8/12 WC=30.3 DD=91 -200=81 10/6, 30/6 18/12 WC=16.6 DD=111 • • •^ 15/12 / WC=15.4 DD=116 ' r -200=51 • i/I 18/12 PROFILE PROFILE BORING 1 BORING 2 7: o 6/6,20/6 WC=6.7 +4=53 -200=21 12/6,26/6 NOTE: Explanation of symbols is shown on Figure 3. Gtech I IEPWORTH-PAWLAK GEOTECHN1CAI r r • • r r • • • 11 25/12 25/12 LOGS OF EXPLORATORY BORINGS 5 10 15 20 25 30 35 DEPTH - FEET FIGURE 2 LEGEND: • • TOPSOIL; organic silty sandy clay, roots, moist to very moist, dark brown. CLAY (CL); silty, sandy to occasionally very sandy, gravelly with cobble zones, stiff to very stiff with depth, moist to very moist becoming wet with depth in Boring 1, mixed brown, calcareous zones, medium to high plasticity. GRAVEL (GC); with cobbles, clayey to very clayey with sandy, clay zones, medium dense, moist, brown, medium plastic fines. Relatively undisturbed drive sample; 2 -inch I.D. California liner sample. Drive sample; standard penetration test (SPT), 1 3/8 inch I.D. split spoon sample, ASTM D-1586. Drive sample blow count; indicates that 17 blows of 140 pound hammer falling 30 inches were required to drive 1712 the California or SPT sampler 12 inches. 0,12 Free water depth measured in boring and number of days following drilling measurement was taken. Depth at which Boring 1 caved when checked on May 14, 2012. Boring 2 was dry to the drilled depths of 21 feet. NOTES: 1. Exploratory borings were drilled on May 2, 2012 with 4 -inch diameter continuous flight power auger. 2. Locations of exploratory borings were measured approximately by pacing from approximate field staked building corners. 3.. Elevations of exploratory borings were not measured and the logs of exploratory borings are drawn to depth. 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. No free water was encountered in Boring 2. 7. Laboratory Testing Results: WC = Water Content (% ) DD = Dry Density ( pct ) +4 — Percent retained on the No. 4 sieve -200 = Percent passing No. 200 sieve 112 026A ,Gtech HEPWORTH•PAWLAK GEOTECHNICAL LEGEND AND NOTES FIGURE 3 COMPRESSION - EXPANSION (% ) COMPRESSION - EXPANSION (% ) 1 0 1 2 3 4 1 0 1 2 3 4 01 0 10 10 APPLIED PRESSURE (ksf ) 100 Moisture Content = 22.3 percent Dry Density = 100 pcf Sample of: Sandy Clay From: Boring 1 at 5 Feet Moisture Content = 31.7 percent Dry Density = 89 pcf Sample of: Sandy Clay From: Boring 1 at 10 Feet °N\N.\\\,0 Expansion upon wetting , 01 0 10 10 APPLIED PRESSURE (ksf ) 100 APPLIED PRESSURE (ksf ) 0 112 026A C;',1(5 -tech tii:r.1m,,IP;IfFAWlr.r:;nu atrj,c.AL SWELL -CONSOLIDATION TEST RESULTS FIGURE 4 Moisture Content = 31.7 percent Dry Density = 89 pcf Sample of: Sandy Clay From: Boring 1 at 10 Feet Expansion upon wetting 1 1 0 10 10 APPLIED PRESSURE (ksf ) 0 112 026A C;',1(5 -tech tii:r.1m,,IP;IfFAWlr.r:;nu atrj,c.AL SWELL -CONSOLIDATION TEST RESULTS FIGURE 4 COMPRESSION - EXPANSION (% ) COMPRESSION (% ) 1 0 1 2 3 4 0 1 2 3 4 5 0.1 0 10 10 APPLIED PRESSURE ( ksf ) 100 Moisture Content = 30.3 percent Dry Density = 91 pcf Sample of: Sandy Clay From: Baring 2 at 2 Feet Moisture Content = 16.6 Dry Density = 111 Sample of: Sandy Clay From: Boring 2 at 10 Feet percent pcf • • I • C\ Expansion • upon wetting Compression upon wetting 0.1 0 10 10 APPLIED PRESSURE ( ksf ) 100 112 026A APPLIED PRESSURE ( ksf ) GeStech HEPWORTH-PAWLAK GEOTECHNIGA9. SWELL -CONSOLIDATION TEST RESULTS 0 FIGURE 5 Moisture Content = 16.6 Dry Density = 111 Sample of: Sandy Clay From: Boring 2 at 10 Feet percent pcf • • Compression upon wetting 1 1 0 10 1C 112 026A APPLIED PRESSURE ( ksf ) GeStech HEPWORTH-PAWLAK GEOTECHNIGA9. SWELL -CONSOLIDATION TEST RESULTS 0 FIGURE 5 PERCENT RETAINED HYDROMETER ANALYSIS SIEVE ANALYSIS TIME READINGS 24NR. 7NR 45 MIN. 15 MIN, 60MIN, 1911119. 4 MIN. 1 M114. # 0 10 20 30 40 50 60 70 60 90 100 .001 .002 .005 .009 .019 .037 .074 .150 .300 .600 1 10 2.30 4.75 0 5 125 19.0 #100 U.S. STANDARD SERIES #50 #30 0 1 #4 310' CLEAR SOUARE OPENINGS 3!4' 1 112' 3' 5 6 B' DIAMETER OF PARTICLES IN MILLIMETERS 100 90 60 70 60 50 40 30 20 10 0 37.5 762 l27152 203 CLAY TO SILT 5A1413 GRAVEL FINE MEDIUM COARSE FINE COARSE C060LES Gravel 53 % Sample of: Clayey Sandy Gravel Sand 26 % Silt and Clay 21 % From: Profile Boring 1 at 2 1/2 Feet PERCENT PASSING 112 026A c�tecn HEPWORTH•PAWLAK GEOTECHNICAL GRADATION TEST RESULTS FIGURE 6 HEPWORTH-PAWLAK GEOTECHNICAL, INC. TABLE 1 SUMMARY OF LABORATORY TEST RESULTS Job No. 112 026A SAMPLE LOCATION NATURAL MOISTURE CONTENT (%) NATURAL DRY DENSITY(ado) (pcf) GRADATION PERCENT PASSING N0.200 SIEVE ATTERBERG LIMITS AASHTO CLASSIFICATION SOIL OR BEDROCK TYPE BORING DEPTH (ft) GRAVEL SAND (,f0} LIQUID LIMIT PLASTIC INDEX 1 5 22.3 100 Sandy Clay 10 31.7 89 Sandy Clay 15 20.4 103 Sandy Clay with Gravel 2 2 30.3 91 Sandy Clay 10 16.6 111 Sandy Clay 15 15.4 116 51 Very Sandy Clay Profile Boring 1 21/2 6.7 Clayey Sandy Gravel HEPWORTH-PAWLAK GEOTECHNICAL, INC. TABLE 2 PERCOLATION TEST RESULTS JOB NO. 112 026A 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 24 10 71/4 71/4 0� 240 71/4 71 118 71/ 71 0 71/ 7% 0 71 71/ 0 7% 7% 0 7 7 % 7 7 0 P-2 30 10 61/4 6' 0 80 61/ 611 % 6% 53/ % 5 555/ '/ g1/4 5% 5% % 53/ 5' % 51/ 5! % 51 5 1/ P-3 20 10 4% 41/4 a 60 41/ 41/ 0 41/ 4' ' 41% 3% 1/ 3' 35 1/4 35/ 31/ % 31 3% % 3%/ 314 1/4 Note: Percolation test holes were hand dug in the bottom of backhoe trenches and soaked on May 4, 2012. Percolation tests were conducted on May 5, 2012. The average percolation rates were based on the last three readings of each test. 615-1 'Apm t It ShE CA g tg fgs E erg 5y