Advanced Earth Sciences professionals provided geotechnical design and construction quality assurance services for the geotechnical characterization of the landfill site and design and construction of Phases I, II and IV of the landfill.

Design services included design of the clay-geosynthetic composite liner system, leachate collection and removal system (LCRS), and subsurface barrier for leachate collection. Design of the composite liner system involved two- and three-dimensional slope stability analyses of 440-foot high landfill face and geosynthetic-soil interface testing in 12 x 12 inch direct shear equipment. Clay liner suitability was evaluated by laboratory triaxial permeability tests and sealed double-ring infiltrometer tests.

Construction quality assurance services (CQA) were provided for 3 phases as separate projects, including Phase I, Phase II and Phase IV. Phase I included placement of 45,000 cu. yds. of clay liner and 1.5 million sq. ft. of 80-mil, textured HDPE; Phase II included placement of 45,000 cu. yds. of clay liner and 1.4 million sq. ft. of HDPE, and Phase IV included placement of 75,000 cu. yds. of clay liner, 2.0 million sq. ft. of HDPE and GCL on sideslopes.

Phases I and II were constructed in accordance with Title 23, Chapter 15 of California Code of Regulations, requiring a clay liner permeability of 1.0 x 10-6 cm/sec. Phase IV was constructed in accordance with Subtitle D which requires a clay liner permeability of 1.0 x 10-7 cm/sec and with GCL on sideslopes. The CQA services also included observation and testing during processing activities for over 300,000 cubic yards of clay liner construction, including construction of four test pads, testing of 7 million cu. yds. of compacted fill and construction of surface drainage structures.