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As-Built CQA Report for the Construction of Area 2A at the Foothill Sanitary Landfill San Joaquin County,California • 2.0 EXCAVATION AND EARTHFILL PLACEMENT 2.1 GENERAL This section presents the field observations made and procedures followed during the CQA activities and the testing performed during earthwork construction. Earthworks activities included: • Excavation of approximately 290,000 cu.yds. of native soil and placement of 34,800 cu.yds. of earthfill to achieve finish grades for the slopes and floor area for the Area 2A liner. • Construct two stormwater basins. • Construct an access road to the cell floor. • Placement of fill to reach liner subgrade for the upper portion of the 3:1 (horizontal:vertical) eastern slope,approximately 24 to 36 feet high. • Excavation to construct the remaining portions of the eastern slope. • Construct the 29 to 32 feet high, 2:1 northern slope that joins the floor of Area 2A with the Area 1 to the north. 2.2 EXCAVATION Excavation of onsite siltstone and sandstone to reach liner subgrade was performed utilizing . CAT 627 scrapers, supported by CAT D6 and D8 bulldozers. The excavated soil was hauled either to adjacent earthfill placement areas or to stockpiles for use as foundation layer and operations soil layer. Excess material was also stockpiled by the Contractor in an area northwest of Basin 1 for use by County's daily cover operations. The CAT D6 bulldozer and CAT 14M motorgraders were used to trim the slopes to grade. 2.3 EARTHFILL Earthfill was placed during the project to construct the western access road embankment, to raise portions of the eastern slope to liner subgrade, and raise the southern portion of the floor to foundation layer subgrade. The materials used for the earthfill were excavated using CAT 627 scrapers from adjacent cut areas. The earthfill was moisture conditioned by a water truck or water pull and compacted with a CAT 825 self-propelled steel wheel compactor. AES CQA Monitors conducted visual observation and testing for earthfill placement to ensure all fill soils were free of organic and other deleterious materials and did not contain materials larger than 3 inches in size. Any unsuitable materials and oversize materials larger than 3 inches were removed. Fill was placed in maximum 8-inch thick loose layers, moisture conditioned to approximately -3 to +3 percent of optimum and compacted to at least 90 percent relative compaction in all areas except in the upper 2.5 feet under the access road pavement which was compacted to at least 95 percent relative compaction. The maximum density used to determine PA14 Projects114-101(SJCDPW North County and Foothillffoothill CQA1Report\Final ReportToothill CQA Rport-Final.docx 9