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~ ' SECTIONTHREE L~ ~ ~ l~ ~ ~ ~ ~ Background Information to 12 inches. Split spoon samples were collected and placed in sealed plastic bags and the lower solid brass liner from each California sampler drive was capped and sealed for later laboratory tests. The field-measured (uncorrected) blow counts are presented in Appendix F. The borings were completed as open-well piezometers to provide monitoring of water levels through the north and south embankments in the seepage areas. Each piezometer consists of 2- inch diameter flush-threaded Schedule 40 PVC pipe. The PVC was machine-slotted from the bottom of each boring to about 5 feet below the ground surface solid to the surface. A 20-foot layer of C-33 silica sand was used to fill the annular space between the PVC and boring wall, starting at the bottom of the boring. A 5-foot bentonite plug was placed above the sand pack and, if necessary, drill cuttings were used to fil~ the hole to ground surface. Surface completion at each hole consisted of cutting the PVC flush to the ground su~face and placing a concrete pad surrounding a bolted metal case protecting the well. Most of the material encountered in the test holes above the claystone/shale bedrock foundation consisted of soft to hard, slightly sandy to sandy, silty to very silty, moderate to high plasticity embankinent clay (CL, CH) in various shades of beige, yellow, brown and gray. An isolated layer of inedium dense, gravelly (fine-grained), slightly silty, clayey (modcra#e to high plasticity) medium- to coarse-grained sand (SP-SC), with a pinkish-beige color, was encountered in test hole DH 1 between 19 and 24 feet, approximately. A third material was encountered in borings DH3 and DH4 consisting of a soft to medium, sandy, moderately plastic, pinkish-beige clay (CL). The observed foundation consisted of weathered shale and claystone. Samples selected for testing were submitted to Advanced Terra Testing, Inc. in Lakewood, Colorado. The laboratory program was designed to classify the soils, chazacterize the strength properties of the materials, and confirm abservations made in the field. Laboratory tests included gradation and hydrometer analyses, water content and dry unit weight measurements, Atterberg limits, and isotropically consolidated undrained triaxial compression tests (CIU') with pore pressure measurements. Results of the tests are presented in Appendix F and are discussed in more detail below. Figure 2, presented in Appendix F, presents summary logs for URS' artd Smith's field investigation programs. UR,,S 3-7