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Kraus-Anderson Realty Company Project BL-11-01014 March 18, 2011 Page 16 pressures of clay backfill. Backfill placed under foundations for the proposed retaining wall should meet the recommendations provided in Section D.2.c of this report. We recommend that backfill placed under foundations and within the reinforced zones be compacted to a minimum of 98 percent of the soil's maximum dry density(ASTM D 698—Standard Proctor method). We also recommend that fill be placed with within+/-3 percentage points of the soil's optimum moisture content. D.8.d. Wall Lateral Earth Pressures We recommend the following design parameters for clean sand backfill placed behind the modular block wall; a wet unit weight of 120 pounds per cubic foot(PCF), a friction angle of 33 degrees, a sliding coefficient of 0.4,and an equivalent fluid pressure (active conditions) of 35 pounds per square foot per foot of depth.These values should be considered ultimate or nominal and appropriate factors of safety should also be applied. The walls should also be designed to remove water from behind walls using French drains and/or weep holes, or hydrostatic pressures will need to be added to the design pressures. E. Construction Quality Control E.1. Excavation Observations We recommend having a geotechnical engineer observe all excavations related to subgrade preparation and spread footing, slab-on-grade and pavement construction.The purpose of the observations is to evaluate the competence of the geologic materials exposed in the excavations, and the adequacy of required excavation over sizing. E.2. Materials Testing We recommend density tests be taken in excavation backfill and additional required fill placed below spread footings, slab-on-grade construction, beside walls, and below pavements. BRAUN INTERTEC