Laserfiche WebLink
C <br />W. MICHAEL CARROLL, PE <br />COUNTY OF SAN JOAQUIN DEPARTMENT OF PUBLIC WORKS <br />DECEMBER 22, 2009 <br />earthquake and peak ground acceleration of 0.158. Results are summarized in the revised Table 1, <br />attached. The maximum estimated displacement for all three earthquake events analyzed is about 3.5 <br />inches. <br />[August 31, 2009 Meeting] Check test criteria for the textured HDPE geomembrane/nonwoven <br />geotextile interface of 0.2 in/min strain rate and dry test condition contained in Table 3 of the <br />referenced report. Revise if necessary. <br />The displacement rate of 0.2 inch/minute is the default rate in ASTM D5321 for geosynthetie- <br />geosynthetic direct shear interface testing that does not involve soil or GCL layers. Table 3 has been <br />revised to specify testing in the wet condition with wetting to be performed by spraying water onto the <br />interface before shearing. Industry sources have confirmed that the 0.2 inch/minute displacement rate is <br />typical and acceptable for non -soil interfaces. <br />Also, the test method for the geomembrane-GCL direct shear tests has been changed to ASTM D6243 <br />"Determining the Internal and Interface Shear Resistance of Geosynthetic Clay Liner by the Direct <br />Shear Method." <br />In summary, we believe the analysis indicates the landfill design results instable slopes per California <br />Code of Regulations Title 27 requirements. We appreciate the opportunity to provide continued services <br />on this project. Please call either of the undersigned if you have any questions or comments. <br />Respectfully submitted, <br />Shaw Environmental, Inc. <br />F�OFE <br />'10.38976 Z m <br />Exp, 3` 3 . / / <br />Sj�.� � EO�r1�P <br />Michael Yacyshyn, PE <br />Principal Engineer <br />Fred W. Cope, PE <br />Project Manager <br />Attachments: References <br />Table 1 (Revised), Summary of Static and Seismic Slope Stability Analyses Results <br />Vertical Expansion of North County Recycling Center and Sanitary Landfill <br />Table 3 (Revised), Summary of Internal/Interface Shear Strength and Testing <br />Requirements, Vertical Expansion of North County Recycling Center and <br />Sanitary Landfill <br />Figure A, Liner Failure Envelope for Modules 5-11 <br />Figure B, Liner Failure Envelope for Module 4 <br />PAGE 9 <br />