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~~~. <br />SMITH WILLIAMS CONSULTANTS, INC. <br />Project: CCBV Phase 5 VLF Job No. 1125 <br />Calculation Title: <br />VLF Foundation Settlement Under 800 it <br />Pre ared B : JFL Date: Februa 22 2008 <br />Checked B : DTW Date: March 14 2008 <br />OBJECTIVE: <br />Assess the foundation settlement and potential strain of geomembrane as the ore height is increased <br />from 590 feet to 800 feet. <br />METHOD: <br />Use PLAXIS, atwo-dimensional finite element program to assess foundation stress and strains <br />under the 800 ft ore height. <br />Apply the model to across-section that cuts through the Phase I VLF and PSSA, where the ore <br />height reaches 800 feet (see attached drawing, Phase I Section). This section also cuts across the <br />Phase I and Phase IV edge of liner, which include the anchor trenches. The plan and cross-section <br />are presented in Figure 1. <br />ASSUMPTIONS: <br /> <br />• Bedrock is typically less than 20 feet from surface based on numerous geotechnical field <br />investigations. To be conservative, place bedrock surface 50 feet below the liner which will <br />result in more settlement than actual. Use finished grade topography for the top of <br />geomembrane surface elevations. <br />• The material between the bedrock and the VLF is structural fill. <br />• Given the scale of the model, the geomembrane liner cannot be modeled explicitly; however <br />the liner strains can be estimated using the strains within the structural fill (e.g. the <br />geomembrane liner does not contribute to the strength of the foundation). The structural fill <br />is modeled as alinear-elastic soil. The parameters of the soil were based on test data, and <br />have the following properties: <br />Pro Valve <br />Unit Wt. 120 cf <br />Elastic Modulus 835,000 psf (This represents a stiff soil based on <br />data presented in Bowles, 1982. Actual test data <br />indicates that the elastic modulus ranges from <br />700 750 sf to 960 300 s . <br />Friction An le 32 de rees <br />Cohesion 0 sf conservative <br />• The ore on the liner was modeled as aMohr-Coulomb material with a friction angle of 40 <br />degrees, with zero cohesion. The unit weight of the ore was set to 118 pcf, which equivalent <br />