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C-1980-007 TR-120 <br />PAR Comments - MLT <br />10-Mar-2010 <br />Page 2 of 4 <br />DRMS 10-Mar: a) In their March 9th response, MCC provided "Figure 1 - LRP Soil <br />Boring Locations". Please incorporate this map into the Figures of Volume IOC <br />(suggestion: as Figure 1-4). <br />DRMS 10-Mar: b) Boring Logs, SPT values and laboratory results for the LRP <br />investigation have been provided. Please incorporate the boring logs into Volume IOC <br />- Appendix A. Laboratory test results for the LRP were previously intermingled in <br />Appendix B with results from the RPE East investigation. Please organize the <br />information presented in Appendix B to make it easier to differentiate between the <br />various investigations. <br />2. DRMS 24-Feb: Figure 2-1 depicts friction angles of materials in the LRP plotted as a <br />function of depth. According to Section 2.2.2, the friction angles have been "determined <br />from a blow count correlation developed by Kulhawy and Mayne...". The friction angles <br />so inferred range from 26 to 58 degrees (or 62 degrees, as shown on Figure 2-2). Friction <br />angles greater than 45 degrees are unlikely, even in well-compacted sandy gravels. I <br />reviewed the K and M study (available on the internet), and observed nothing in that <br />report that supports the extremely high friction angles presented in Figures 2-1 and 2-2. <br />Please review the methodology used to correlate the SPT blow-counts to friction angle, <br />and revise the data as necessary. (It may necessarily follow that the friction angle <br />selected as being representative. of the Refuse material for use in the stability modeling <br />will also be changed.) <br />DRMS 10-Mar: MCC's 9 March response provided supplemental reference material <br />on the conversion of LRP SPT blow counts to friction angles. In addition, all inferred <br />friction 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 <br />the modification made to the refuse material friction angle. <br />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 <br />question, please review and confirm or correct the methodology used to determine the <br />undrained shear strength values depicted in Figures 2-3 and 2-4. <br />DBMS 10-Mar: MCC's 9 March response provided supplemental reference material <br />on the conversion of LRP SPT blow counts to cohesion (undrained shear strength). In <br />addition, all inferred undrained shear strength values higher than 6, 000 psf were <br />removed from consideration. This change resulted in only a modest decrease to the <br />undrained shear strength used for modeling the undrained stability of the RPE East. <br />Item resolved, no additional response is necessary.