Laserfiche WebLink
Ms. Kathy Welt <br />March 11, 2010 <br />Page 2 <br />friction angles presented in Figures 2-1 and 2-2. Please review the methodology used to <br />correlate the SPT blow-counts to friction angle, and revise the data as necessary. (It may <br />necessarily follow that the friction angle selected as being representative of the Refuse material <br />for use in the stability modeling will also be changed.) <br />DRMS 10-Mar: MCC's 9 March response provided supplemental reference material on the <br />conversion of LRP SPT blow counts to friction angles. In addition, all inferred friction <br />angle values greater than 45 degrees have been removed from consideration. <br />Please revise Section 2.0 and the pertinent tables and figures in Volume IOC to reflect the <br />modification made to the refuse material friction angle. <br />18. DRMS 24-Feb: Figures 2-3 and 2-4 depict a similar approach, in which undrained shear <br />strength values are correlated with SPT blow counts. I was unable to obtain a copy of the <br />referenced article by Hara and Niwa. In light of the issues raised in the preceding question, <br />please review and confirm or correct the methodology used to determine the undrained shear <br />strength values depicted in Figures 2-3 and 2-4. <br />DRMS 10-Mar: MCC's 9 March response provided supplemental reference material on the <br />conversion of LRP SPT blow counts to cohesion (undrained shear strength). In addition, all <br />inferred undrained shear strength values higher than 6,000 psf were removed from <br />consideration. This change resulted in only a modest decrease to the undrained shear <br />strength used for modeling the undrained stability of the RPE East. <br />Item resolved; no additional response is necessary. <br />19. Inspection of fill during construction is required by 4.09.1(11) and 4.10.2. 1 was unable to <br />locate, in the TR-120 application, a description of field inspection activities and reporting that <br />are proposed for the RPE East. Please incorporate inspection and reporting details into <br />Volume IOC that comply with the requirements of the sections listed above, or reference <br />another place in the Permit where the information may be found. <br />20. A minimum static safety factor of 1.5 is required by 4.10.4(2). The "Permit Design" <br />configuration modeled in Figures 2-9 and 2-10 of the original application resulted in a static <br />Factor of Safety of 1.82 and a seismic Factor of Safety of 1.58. These factors may be reduced <br />slightly by the change in friction angle for the refuse material, but are still likely to exceed the <br />requisite values. Please revise the Permit Design model runs of Figures 2-9 and 2-10 to <br />reflect the change in refuse friction angle derived from the LRP investigation. <br />General Review Comments <br />21. 2.1 - Geotechnical investigation describes the soil and rock borings drilled for the borehole <br />locations for the RPE East investigation are shown on Drawing No. C-02 in Appendix D. For <br />ease of reference, it would be helpful if the same (or a similar) drawing were also included as <br />Figure 1-3. Please add Figure 1-3 to Volume IOC, illustrating the borehole locations for the <br />RPE East geotechnical investigation.