Laserfiche WebLink
<br />\j <br />EEC Project No. 1082030 <br />ASCI - Turnpike Reservoir <br />May 5, 2008 <br />Page 9 <br />Earth Engineering Consultants, Inc. <br />classified as lean to fat clay, lean clay with sand or sandy lean clay. Any sample having less <br />than 50 percent passing the No. 200 sieve would be classified as a sand or gravel material. <br />Shear Strength Tests <br />The overburden cohesive soils and the underlying bedrock have similar characteristics in <br />comparison with the results of the standard Proctor dry density (ASTM D698). However <br />based on our experience with similar soil and bedrock conditions slight variations would be <br />expected in shear strength design parameters. For the overburden clay soils, we would <br />anticipate an internal friction angle of approximately 15 to 25 degrees, along with a cohesion <br />value ranging from 150 to 250 psf. For the underlying bedrock, we would anticipate an <br />internal friction angle of approximately 20 to 30 degrees along with a cohesion value of <br />approximately 500 psf. Prior to final design, these parameters should be confirmed. Based <br />on the test results and the majority of the underlying bedrock material being used for the <br />earthen liner, a conservative effective stress internal friction angle of 20 degrees along with a <br />cohesion of approximately 200 psf is suggested, for use in the preliminary slope stability <br />analysis. <br />In-Situ Permeability Test Results - Field Packer Tests <br />Field water pressure tests, known as "packer tests" are typically performed in a borehole to <br />evaluate permeability characteristics. Water pressure testing can identify and/or locate potential <br />porous or fractures zones within a rock mass, and also provide quantitative measurements of <br />the capacity of such zones for transmitting water. The collected data can be used to calculate an <br />equivalent coefficient of permeability of the formation within the limits of the test zone. The <br />primary purpose for conducting the field permeability testing procedures for the proposed <br />Turnpike Reservoir was to evaluate the in-situ conductivity and/or water tightness of the <br />undisturbed bedrock and to determine the necessity for an earthen liner. <br />For this feasibility study, within three (3) of the ten (10) borings, packer tests were performed at <br />various intervals and one (1) packer test was conducted within a supplemental boring drilled in