2008-09-16_PERMIT FILE - C1982056A

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Index Properties: In order to identify soils and classify them into categories of similar engineering properties, the Unified Soil Classification System {ASTM D-24$7) was used. This system is based on index property tests, including the determination of natural water content (ASTM D-2216), liquid limits (ASTM D-423}, plastic limits (ASTM D-424) and grain size distribution (ASTM D-422). Results of the moisture content, dry density, Atterberg limits, and percent of soil passing the U.S. No. 4 and No. 200 sieves are presented in the attached Tables 1 and 2. Moisture-Density Relationships: Composite samples of the proposed fill materials obtained from the proposed borrow area and a composite sample of the overburden soils obtained from the embankment area were remolded in accordance with ASTM D-698/AASHTO T-99 to determine the maximum standard Proctor density and optimum moisture content of these materials. The standard Proctor test results are shown in Figures #9 through #11. Unconfined Compressive and Tri-axial Shear Stren ths: Uni-axial, unconfined compressive strength testing was conducted on remolded samples of the proposed borrow materials and relatively undisturbed samples of the natural overburden soils and underlying bedrock materials. Each sample was prepared by cutting the end of the specimen parallel to each other and at right angles to the longitudinal axis of the core. Load was applied continuously and without shock to produce a constant rate of deformation while the test was performed. Results of the uniaxial, unconfined compressive strength testing are discussed later in this report and are summarized in the attached Tables 1 and 2. Tri-axial shear strength tests of the overburden soils in the embankment area were conducted to assist in the assessment of the stability of these materials. Knight Piesold Laboratories conducted the tri-axial shear testing and the results of these tests are presented in Appendix A. Falling Head Permeabili Tests: Falling head permeability tests were conducted to determine the permeability of the natural in-situ clays, as well as the permeability of the remolded clays obtained from the borrow area. These test results are presented in Appendix B. Pinhole Dispersion Tests: Pinhole dispersion tests {ASTM D 4647) were also conducted by Knight Piesold on samples of the proposed embankment fill materials and underlying natural clays to evaluate the dispersive nature of the fine grained soils. These test results are presented in Appendix C. Subsurface Conditions The subsurface conditions encountered across the site were variable and generally consisted of a layer of topsoil and organic materials overlying natural clays that extended tv depths ranging from 5 to 13 feet beneath the existing ground surface. The clays were underlain by claystone-shale bedrock materials that extended to the maximum depth investigated, 25 feet. A layer of sands and clays was encountered below the clays and on top of the bedrock materials in one of the test holes (#4) at a depth of 13 to 17 feet beneath the existing ground surface. Outlined below are more specific descriptions of the overburden soils and bedrock materials encountered at the site. C7 Job Number: 07-7556 NWCC, Jnc. Page G