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Home My WebLink AboutFCLWD GOLDEN CURRANT WATER LINE - SPA200002 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT400 N. Link Lane | Fort Collins, Colorado 80524 Telephone: 970-206-9455 Fax: 970-206-9441 GEOTECHNICAL INVESTIGATION GOLDEN CURRANT WATERLINE FORT COLLINS, COLORADO Prepared For: CIVILWORX 4025 Automation Way, Suite B2 Fort Collins, Colorado 80525 Attention: Chris Pletcher, PE Project No. FC08620-125 November 30, 2018 Revised December 12, 2018 CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 TABLE OF CONTENTS SCOPE 1 SUMMARY OF FINDINGS AND CONCLUSIONS 1 SITE CONDITIONS AND PROPOSED CONSTRUCTION 2 INVESTIGATION 2 SUBSURFACE CONDITIONS 3 EXCAVATIONS 4 Bracing 5 DEWATERING 6 PIPE SUPPORT 7 Pipe Bedding 7 Pipe Cover 9 THRUST RESTRAINT 9 TRENCH BACKFILL 10 CORROSION PROTECTION 11 Resistivity 11 Water Soluble Sulfates 12 RESTORATION 12 LIMITATIONS 13 FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 – SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX A – RESULTS OF LABORATORY TESTING CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 1 SCOPE This report presents the results of our Geotechnical Investigation for the planned waterline to connect existing Fort Collins Loveland Water District (FCLWD) water storage tanks west of the Ponds at Overland subdivision to an existing waterline along Overland Trail in Fort Collins, Colorado. This investigation was conducted to evaluate subsurface conditions at the site and provide geotechnical design and construction criteria for the proposed waterline. The proposed scope was described in our Service Agreement (FC-18-0399) dated September 25, 2018. This report includes descriptions of subsurface conditions found in our exploratory borings, our evaluation of the engineering characteristics of the soils and bedrock, our opinions and recommendations regarding design criteria for the trench excavation and other design and construction details influenced by the subsurface conditions. This report was prepared from data developed during field and laboratory investigations, engineering analysis of the field and laboratory data, and our experience with similar projects. SUMMARY OF FINDINGS AND CONCLUSIONS 1. Subsurface conditions encountered in our borings generally consisted of 1 to 19½ feet of sandy clay over weathered and competent claystone bedrock to the depths explored. 2. Groundwater was encountered at 6 to 20 feet in three of the borings. Groundwater will likely have seasonal and yearly fluctuations. Depending on the depth and locations of proposed excavations, dewatering may be required during construction. 3. Thrust restraint can be designed for the passive earth pressure condition using an equivalent fluid pressure of 300 pounds per cubic foot (pcf) and an allowable soil bearing pressure of 2,000 pounds per square foot (psf). Additional recommendations are included in the report. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 2 4. Trenches and excavations should be designed to resist lateral earth pressures. Equivalent fluid densities of 40 pcf for the “active” condition, 55 pcf for the “at rest” condition, and 300 pcf for passive restraint are discussed in the report. Trench excavations may require temporary dewatering prior to or during construction. Dewatering recommendations are presented in this report SITE CONDITIONS AND PROPOSED CONSTRUCTION The project site consists of approximately 5000 feet of potable water line installed to replace an existing line. The new alignment was not finalized at the time of our investigation, but we understand the pipeline will likely be routed south of the existing subdivision. The new line will begin at the existing FCLWD water storage tanks, west of the Ponds at Overland subdivision and approximately 230 feet above the termination of the line at Overland Trail. The waterline is anticipated to consist of PVC joined by fusion or bell and spigot connections with diameters on the order of 20 inches. We anticipate excavations for utility installation will require trench cuts of 4 to 14 feet below existing grade. INVESTIGATION Subsurface conditions at the project site were investigated by drilling four exploratory borings along the proposed alignment of the waterline, as it is understood to be located at the time of this exploration. The approximate boring locations are shown on Figure 1. The borings were drilled using a truck-mounted drill rig equipped with 4-inch diameter, solid-stem augers. Samples were obtained by driving a 2.5-inch diameter California sampler into the soil with blows of a 140-pound hammer falling 30 inches. A representative of CTL|Thompson, Inc. logged the soils and bedrock encountered during drilling and retrieved and transported samples to our laboratory for testing. Summary logs of the borings and the results of field penetration resistance tests are presented on Figure 2. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 3 The samples were returned to our laboratory for classification and testing, including moisture content and density, Atterberg limits, gradation, swell- consolidation, resistivity and water-soluble sulfates concentration. Additional samples were sent to a third-party soil chemistry laboratory for chloride, pH, redox potential and sulfide testing. Results of laboratory testing are presented in Appendix A. SUBSURFACE CONDITIONS Subsurface conditions encountered in our borings generally consisted of sandy clay with occasional gravel over weathered and competent claystone bedrock with sandstone interbeds to the depths explored. Bedrock was encountered at depths of 1 to 19½ feet. Additional descriptions of the subsurface conditions are presented on our boring logs and in our laboratory testing. Two samples of the sandy clay were tested for engineering index properties. The moisture contents of the samples were 8.3 and 11.6 percent and the dry densities ranged from 131 to 134 pcf. These samples contained 37 and 56 percent clay and silt sized particles. One sample was tested for Atterberg limits, returning a liquid limit of 23 and a plasticity index of 8. Ten samples of the weathered to comparatively unweathered claystone were tested for engineering index properties. The moisture content of the claystone samples ranged from 5.1 percent to 19.7 percent and the dry densities ranged from 111 to 122 pcf. Some of the bedrock was very hard and resulted in sampler refusal in boring TH-3. Four samples of the claystone exhibited swells ranging from 0.9 to 6.1 percent. Swell tests were wetted at confining stresses approximating the overburden of in-situ soils. Potential heave can impart misalignment pipe systems. Precautions may be necessary to avoid pipeline distress. We recommend pipelines and conduits be constructed with added CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 4 flexibility particularly at the connections. The use of short pipe lengths and flexible connections should be considered. The results of the resistivity testing and the tests performed by the third- party laboratory are included in Table A-I. Groundwater was encountered at depths of 6 to 20 feet in our borings during this investigation. Groundwater levels fluctuate seasonally. Dewatering may be necessary depending on the depths of the trench excavations. If improved characterization of groundwater levels is preferred, periodic water measurements would be necessary. We are available to provide additional groundwater monitoring at the existing boring locations, or other areas of interest by performing additional borings. EXCAVATIONS Excavations of 4 to 14 feet are anticipated for the pipeline. We believe the soils and bedrock encountered during this investigation can be excavated with heavy duty excavation equipment. Some of the bedrock is extremely hard and may require specialized equipment, such as single tooth rippers or chipping hammers, to excavate. We recommend the owner and contractor become familiar with applicable local, State and Federal safety regulations, including the current OSHA Excavation and Trench Safety Standards. The contractor should be aware that in no case should slope height, inclinations, excavations or depths including utility trench excavations exceed those specified in local, State and Federal safety regulations. Specifically, the current “OSHA Health and Safety Standards for Excavations” should be followed. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 5 For this site, the overburden soil encountered in our exploratory borings includes sandy clay with occasional gravel. We believe the clays classify as Type B soil, allowing excavation slopes of 1:1 (horizontal:vertical). Where excavation slopes encounter sand and gravels that classify as Type C soils, slopes of 1.5:1 (horizontal:vertical) are appropriate. Competent claystone classifies as type A soil and slopes of ¾:1 (horizontal:vertical) may be used. Weathered bedrock should be classified and excavated as type B soil. If groundwater is encountered and seeps from the slopes, this may require other precautions. Our preliminary soil classification is based on the materials encountered in our exploratory test borings at widely spaced locations. The soil penetrated by the proposed excavation will vary across the site. The contractor’s “responsible person” should evaluate the soil exposed in excavations as part of the contractor’s safety procedures. If an excavation (including a utility trench) is extended to a depth of more than 20 feet, it will be necessary to have the side slopes designed by a registered engineer. Vehicles and soil stockpiles should be kept a minimum lateral distance from the crest of the trench slope equal to one- half the trench depth. The exposed slope face should also be protected against the elements. As an alternative to temporary slopes, vertical excavations can be temporarily braced. Bracing Bracing or “trench box” construction may be necessary in order to limit the width of excavations and reduce the amount of surface disturbance. Bracing systems include driven sheet piling, soldier piles and lagging and others. Lateral loading of bracing depends on the depth of excavation, slope of excavation above the bracing, soil stockpiles and other surface loads, hydrostatic pressures, and allowable movement. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 6 For bracing allowed to move enough to mobilize the strength of the soils with associated settlement and cracking of the ground surface, “active” earth pressure conditions are appropriate for design. If movement is not tolerable, “at rest” earth pressures are appropriate. Lateral load can be calculated using an equivalent fluid density of 40 pcf and 55 pcf for “active” and “at rest” conditions, respectively. Hydrostatic pressure and surcharge loads should be accounted for, where applicable. The OSHA construction standard provides recommendations for timber bracing. We are also available to assist further with bracing design if desired. DEWATERING Groundwater was encountered in three of the four borings at depths of 6 to 20 feet. Our experience in this area suggests that groundwater depths can vary with season and, depending on the time of construction, could be higher than measured in our borings. Any excavations deeper than about 6 feet in the areas surrounding boring TH-2 will likely encounter saturated soil and/or groundwater. Excavations within about three feet of the groundwater level should consider temporary dewatering prior to and/or during construction. Dewatering can be accomplished using a series of trenches and sumps and granular materials from which water can be pumped, or by a system of well points. The sumps should be several feet below the bottom of the excavations to pump water down through the soil rather than up through the bottom of the excavation. Pumping water up through the base of the excavation will likely result in destabilization of the base of the excavation. The ground surface surrounding the excavation should be sloped to direct runoff away from the excavation. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 7 For excavations planned several feet below the groundwater level, a series of well points may be needed to effectively dewater the excavation. The contractor should anticipate extensive dewatering and possibly caving soils in excavations below the water table. The design of a well point system will likely require further exploratory drilling and permeability tests both of which were not in the scope of this study. PIPE SUPPORT Typically, the bedding material and the embedment material are the same soil type. A granular soil or gravel material is typically selected. Compaction of very coarse materials and gravels can be difficult or impossible to evaluate with standard methods such as the nuclear density gage. In this situation, an alternate method to evaluate compaction on coarse materials is the Sleeve Method (ASTM D 4564). Consideration should be given to particle size compatibility between the native soils and the bedding and embedment materials. If the particle sizes are sufficiently different, migration or piping of soil around the trench could occur, leading to poor support and even sinkholes. Often this issue is avoided by simply wrapping the bedding/embedment soils with a geotextile to limit particle migration. Pipe Bedding We believe pipe is normally bedded in manufactured granular material in accordance with the pipe manufacturer specifications. We believe that pipe bedding consisting of material that conforms to the “Larimer County Urban Street Standards” or Fort Collins Loveland Water District Standard Construction Specifications requirements will meet typical requirements. We believe angular crushed rock, conforming to CDOT #67 specifications, is usually acceptable CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 8 bedding material. Squeegee or sand can be considered, but issues with compaction below and around the pipe should be considered. Maximum particle size depends on selected piping material according to ASTM and AWWA and should be verified with the pipe manufacturer. We do not recommend the natural soils encountered be used as bedding material. We recommend bedding material, thickness and compaction meet current City of Fort Collins specifications and be confirmed with the pipe manufacturer. Recent research (primarily for rigid pipe) has shown placement of pipe bedding in a looser state (for example 85 percent proctor) will result in a more uniform stress distribution along the bottom of the pipe. The looser bedding appears to allow enough movement of the pipe to develop support pressure in the haunch area. Typically, this results in a reduction of stress concentrations and damage to the pipe. However, not all municipal guidelines allow this method. Embedment height is generally specified by the pipe manufacturer. However, at a minimum, rigid pipe should be provided an embedment of 0.37 times the outside diameter of the pipe and flexible pipe should be provided 0.7 times the outside diameter of the pipe. Embedment soils should be placed in thin, compacted lifts and placed equally on both sides of the pipe to prevent pipe displacement. Particular care should be given to ensure soil in the haunch area of the pipe is properly compacted. Compaction effort should be monitored around thin wall or flexible pipe to limit elongation of the pipe section due to lateral pressure. Interior bracing may be considered for flexible pipe to limit deflection or elongation during backfill. Groundwater barriers should be constructed in tandem with the pipeline to prevent the bedding from becoming a conduit for subsurface water. According to the FCLWD Standard Construction Specifications (Rev. 2.0 June, 2010) the CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 9 groundwater barriers should be 4 to 8 feet long, keyed 1 foot into the trench bottom and walls, extend up to the transition from bedding to on-site materials, and be placed at a spacing no greater than 400 feet. Pipe Cover Appropriate cushion zone above the pipe should be provided with proper maximum particle sizes to limit damage to the pipe from backfill compaction. A minimum of 12 inches of soil cover should be provided above pipes prior to initiating compaction efforts. Thin wall or flexible pipes may require thicker cover. THRUST RESTRAINT Thrust restraint at bends, valves and other discontinuities in the pipeline can be provided by either thrust blocks or by frictional restraint of the pipe in the soil. Frictional restraint requires the use of restrained joints for the length of pipe necessary to obtain the necessary friction force and sufficient pipe and fitting strength to support the thrust forces. The friction developed between piping and soil is dependent on soil type, or embedment soil type, if different, and pipe material type. The coefficient of friction of a pipe in soil is typically 0.25 to 0.5 for most soil conditions. We recommend the use of a coefficient of friction of 0.35 for the native sandy clays at this site. If embedment soils are imported, an appropriate value should be used. This value should be further reduced for smooth pipe (ex. PVC), for smooth corrosion coatings or if the pipe is encased in polyethylene. For PVC, we recommend a maximum friction coefficient of 0.25 be used for typical bedding materials. Mechanical pipe restraints will increase the effective friction due to passive soil bearing of the restraint. Thrust blocks should bear against undisturbed soil at least 3 feet below the ground surface. For thrust restraint, passive earth pressure theory is CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 10 applicable. We suggest assuming an equivalent fluid density of 300 pcf and an allowable soil bearing pressure of 2,000 psf to calculate soils resistance for the “passive” earth pressure condition. TRENCH BACKFILL Trench backfill placed at the site should be placed in thin lifts and observed by a representative of CTL|Thompson, Inc. All compacted fill should be expected to undergo some amount of future settlement. Deeper areas of fill should be expected to exhibit higher amounts of settlement. Increased compactive effort will help to reduce the potential amount of settlement below pavements and other structures. Settlements of up to 1 to 2 percent should be expected. Guidelines for compaction of fill is presented below in Table A. TABLE A FILL COMPACTION AND MOISTURE REQUIREMENTS Soil Type Depth from Final Grade (feet) Moisture Requirement (% from optimum) Density Requirement Clay 0 to 15 feet -2 to +2 95% of ASTM D 698 Sand -2 to +2 95% of ASTM D 698 Clay Greater than 15 feet -2 to +1 98% of ASTM D 698 Sand -2 to +1 95% of ASTM D 1557 Compaction of trench backfill can have a significant effect on the life and serviceability of pavements or other structures sensitive to movement that are constructed above the pipeline. We recommend trench backfill below paved areas be placed in thin, loose lifts, moisture conditioned to between plus or minus 2 percent of optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698). We recommend that, if CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 11 used, claystone backfill should not be placed within 2 feet below pavement, sidewalk or curb and gutter subgrades. Bedrock used as backfill should be broken down to a soil before being used as compacted backfill. Other on-site soils that are free of organics, debris and rock fragments larger than 3 inches in diameter are suitable for placement as trench backfill. Fill placed at the site in non-paved areas, should be compacted to at least 90 percent of standard Proctor maximum dry density (ASTM D 698) at a moisture content plus or minus 2 percent of optimum. Fill not meeting the moisture requirement should be considered unacceptable. Drying of soil or addition of water may be required depending on the source of the fill material. Bedrock used as backfill should be broken down to a soil, with maximum particle size of 3 inches or less, before being used as compacted backfill. We recommend the claystone bedrock not be used as a fill material where it will support overlying improvements. Other on-site soils that are free of organics, debris and rock fragments larger than 3 inches in diameter are suitable for placement as trench backfill. CORROSION PROTECTION As a part of our laboratory program, corrosion testing was performed to provide guidance in material selection for the pipeline. Testing included chloride, pH, redox potential, sulfide, and resistivity testing. Table A-I provides results from the corrosion testing. Resistivity Soil resistivity is a primary factor in the evaluation of corrosion potential for pipelines. Laboratory resistivity testing was performed on a composite sample consisting of materials from anticipated depths across all borings. The testing CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 12 was conducted at a representative field moisture and repeated after inundation. The results of were 1210 ohm-cm and 790 ohm-cm respectively. If further resistivity testing is desired, we should be contacted to perform field resistivity testing along the proposed alignment. Water Soluble Sulfates Concrete that comes into contact with soils can be subject to sulfate attack. We measured water-soluble sulfate concentrations in four samples from this site. Concentrations were measured between less than 0.01 percent 0.15 percent, with one sample having a sulfate concentration between 0.1 and 0.2 percent. Water-soluble sulfate concentrations between 0.1 and 0.2 percent indicate Class 1 exposure to sulfate attack, according to the American Concrete Institute (ACI). ACI indicates adequate sulfate resistance can be achieved by using Type II cement with a water-to-cementitious material ratio of 0.50 or less. ACI also indicates concrete in Class 1 exposure environments should have a minimum compressive strength of 4000 psi. In our experience, superficial damage may occur to the exposed surfaces of highly permeable concrete, even though sulfate levels are relatively low. To control this risk and to resist freeze- thaw deterioration, the water-to-cementitious material ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drainage or high water tables. Concrete should be air entrained. RESTORATION Any pavements, sidewalks, curb and gutter, or other structures disturbed during construction should be replaced in accordance with Larimer County Urban Street Standards and the City of Fort Collins requirements. Pavement repairs should meet, or exceed, existing pavement thickness in the area of construction. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 13 Areas outside pavements should be graded following backfill to follow the contours and merge with adjacent terrain without noticeable breaks. Grading should be arranged to produce a reasonably smooth, well-drained finish with minimal erosion. LIMITATIONS Our borings were spaced to obtain a reasonably accurate characterization of subsurface conditions. Variations in the subsurface conditions not indicated by our borings are always possible. Placement and compaction of fill, backfill, subgrade and pavements should be observed and tested by a representative of our firm during construction. We believe this investigation was conducted with that level of skill and care normally used by geologists and geotechnical engineers practicing in this area at this time. No warranty, express or implied, is made. If we can be of further service in discussing the contents of this report or in the analyses of the influence of the subsurface conditions on design of the structures, please contact the undersigned. CTL|THOMPSON, INC. Taylor H. Ray R. B. “Chip” Leadbetter, III Staff Geotechnical Engineer Senior Geotechnical Engineer THR:RBL TH-2 TH-1 TH-3 Water Storage Facility South Overland Trail Golden Currant Blvd. TH-4 LEGEND: INDICATES APPROXIMATE LOCATION OF EXPLORATORY BORING TH-1 W. DRAKE RD. W. PROSPECT RD. GOLDEN W. ELIZABETH RD. CURRANT BLVD. SITE TAFT HILL RD. S. OVERLAND TRAIL FIGURE 1 Locations of Exploratory Borings CIVILWORX GOLDEN CURRANT WATERLINE CTL I T PROJECT NO. FC08620-125 0 200' 400' APPROXIMATE SCALE: 1"=400' VICINITY MAP FT. COLLINS, CO NOT TO SCALE 0 5 10 15 20 25 30 35 40 0 5 10 15 20 25 30 35 40 42/12 35/12 18/12 20/12 47/12 50/12 WC=8.3 DD=131 -200=56 SS=<0.01 WC=11.6 DD=134 LL=23 PI=8 -200=37 WC=13.8 DD=121 SW=0.9 WC=8.3 DD=131 -200=56 SS=<0.01 WC=11.6 DD=134 LL=23 PI=8 -200=37 WC=13.8 DD=121 SW=0.9 TH-1 El. 5125.2 31/12 26/12 34/12 50/12 50/11 WC=14.7 DD=115 LL=62 PI=41 -200=96 WC=19.7 DD=111 SW=5.2 Sample of CLAYSTONE, SANDY DRY UNIT WEIGHT= 121 PCF From TH - 1 AT 19 FEET MOISTURE CONTENT= 13.8 % CIVILWORX GOLDEN CURRANT WATERLINE CTL | T PROJECT NO. FC08620-125 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-1 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAYSTONE, WEATHERED DRY UNIT WEIGHT= 111 PCF From TH - 2 AT 9 FEET MOISTURE CONTENT= 19.7 % CIVILWORX GOLDEN CURRANT WATERLINE CTL | T PROJECT NO. FC08620-125 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-2 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAYSTONE, SANDY DRY UNIT WEIGHT= 122 PCF From TH - 3 AT 9 FEET MOISTURE CONTENT= 11.4 % CIVILWORX GOLDEN CURRANT WATERLINE CTL | T PROJECT NO. FC08620-125 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-3 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 Sample of CLAYSTONE, SANDY DRY UNIT WEIGHT= 121 PCF From TH - 4 AT 14 FEET MOISTURE CONTENT= 16.7 % CIVILWORX GOLDEN CURRANT WATERLINE CTL | T PROJECT NO. FC08620-125 APPLIED PRESSURE - KSF COMPRESSION % EXPANSION Swell Consolidation Test Results FIGURE A-4 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 EXPANSION UNDER CONSTANT PRESSURE DUE TO WETTING 0.1 1.0 10 100 PASSING WATER- WATER- pH MOISTURE DRY LIQUID PLASTICITY APPLIED NO. 200 SOLUBLE SOLUBLE REDOX SULFIDES DISTILLED FIELD DEPTH CONTENT DENSITY LIMIT INDEX SWELL* PRESSURE SIEVE SULFATES CHOLRIDES POTENTIAL WATER MOISTURE SATURATED BORING (FEET) (%) (PCF) (%) (PSF) (%) (%) (%) (mV) SOLUTION (OHM-CM) (OHM-CM) DESCRIPTION S-1 BULK 18.0 116 1210 790 CLAY, SANDY (CL) TH-1 4 8.3 131 56 <0.01 CLAY, SANDY (CL) TH-1 9 0.0176 258 POSITIVE 7.6 CLAY, SANDY (CL) TH-1 14 11.6 134 23 8 37 GRAVEL, CLAYEY (GC) TH-1 19 13.8 121 0.9 2,400 CLAYSTONE, SANDY TH-2 4 14.7 115 62 41 96 CLAYSTONE, WEATHERED TH-2 9 19.7 111 5.2 1,100 0.15 CLAYSTONE, WEATHERED TH-2 14 0.0089 267 POSITIVE 7.6 CLAYSTONE, SANDY TH-3 2 5.1 32 11 40 SANDSTONE, CLAYEY TH-3 4 0.0002 274 POSITIVE 7.3 CLAYSTONE, SANDY TH-3 9 11.4 122 6.1 1,100 <0.01 CLAYSTONE, SANDY TH-4 9 0.0003 270 POSITIVE 7.9 CLAYSTONE, WEATHERED TH-4 14 16.7 121 3.2 1,800 0.08 CLAYSTONE, SANDY TH-4 19 14.9 45 24 96 CLAYSTONE, SANDY SWELL TEST RESULTS* TABLE A-I SUMMARY OF LABORATORY TESTING ATTERBERG LIMITS RESISTIVITY Page 1 of 1 * NEGATIVE VALUE INDICATES COMPRESSION. CIVILWORX GOLDEN CURRANT WATERLINE CTL|T PROJECT NO. FC08620-125 SS=0.150 WC=14.7 DD=115 LL=62 PI=41 -200=96 WC=19.7 DD=111 SW=5.2 SS=0.150 TH-2 El. 5128.1 50/6 50/5 50/3 50/1 50/0 50/0 WC=5.1 LL=32 PI=11 -200=40 WC=11.4 DD=122 SW=6.1 SS=<0.01 WC=5.1 LL=32 PI=11 -200=40 WC=11.4 DD=122 SW=6.1 SS=<0.01 TH-3 El. 5174.1 9/12 31/12 50/11 50/5 50/9 WC=16.7 DD=121 SW=3.2 SS=0.080 WC=14.9 LL=45 PI=24 -200=96 WC=16.7 DD=121 SW=3.2 SS=0.080 WC=14.9 LL=45 PI=24 -200=96 TH-4 El. 5213.7 DEPTH - FEET DRIVE SAMPLE. THE SYMBOL 42/12 INDICATES 42 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. 1. NOTES: THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. WATER LEVEL MEASURED SEVERAL DAYS AFTER DRILLING. WEATHERED CLAYSTONE, SANDY, MOIST TO WET, MEDIUM HARD, BROWN, GRAY, RUST 3. LEGEND: CLAY, SANDY, WITH OCCASIONAL GRAVEL, CLAYEY, MOIST TO WET, STIFF TO VERY STIFF, BROWN, TAN, REDDISH BROWN, YELLOW BROWN (CL, GC) CLAYSTONE, SANDY, WITH OCCASIONAL SANDSTONE, CLAYEY INTERBEDS, MOIST TO WET, HARD TO VERY HARD, BROWN, GRAY, RUST DEPTH - FEET Summary Logs of Exploratory Borings THE BORINGS WERE DRILLED ON NOVEMBER 8, 2018 USING 4-INCH DIAMETER CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG. FIGURE 2 WC DD SW -200 LL PI UC SS - - - - - - - - INDICATES MOISTURE CONTENT (%). INDICATES DRY DENSITY (PCF). INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%). INDICATES PASSING NO. 200 SIEVE (%). INDICATES LIQUID LIMIT. INDICATES PLASTICITY INDEX. INDICATES UNCONFINED COMPRESSIVE STRENGTH (PSF). INDICATES SOLUBLE SULFATE CONTENT (%). 2. CIVILWORX GOLDEN CURRANT WATERLINE CTL | T PROJECT NO. FC08620-125