6617 ASSOCIATED BLVD AMAZON Geotech Report 2022-10-25

• • nKLEI NFELDERR aryl .eigntsoulioro. • • Caving of subsurface sandy soils should be anticipated; pockets of sand and gravel may cave during drilling of the pile shafts and temporary steel casing may be needed to stabilize the sides • of the pile shaft. Concrete should be placed immediately after drilling of the hole is complete. • The concrete should be pumped to the bottom of the drilled shaft using a down-hole tremie. If steel casing is used, the casing should be removed as the concrete is placed but the bottom of the casing should be kept at least 5 feet below the top of the concrete. 4i 4.5.5 Structural Fill Material and Compaction Criteria • • Materials placed below pavements or structures should consist of structural fill. The on-site IA soils, minus debris, organic matter, or other deleterious materials may be used as structural fill. • Rock or other soil fragments greater than 3 inches in size should not be used in the fills and • should be disposed of off-site. • • Structural fill soils should be compacted to at least 95 percent of the maximum dry unit weight • (ASTM D1557). The moisture content of the fill should be maintained at or above optimum • during compaction. Fill should be placed in loose horizontal lifts not more than 10 inches thick (loose measurement). Utility trench backfill should be mechanically compacted. Flooding should • not be permitted. • Imported fill, if needed, should consist of granular soils with at least 70 percent passing the • No. 4 sieve and no more than 20 percent passing the No. 200 sieve with soil and rock particles • no larger than 3 inches in diameter. The Plasticity Index (PI) of material should be less than 5. • Imported fill materials must be approved by the geotechnical engineer prior to importing. The • contractor should provide documentation that imported fill is free of hazardous materials, including petroleum or petroleum byproducts, chemicals and harmful minerals. Also, prior to • placing fill, the excavations should be observed by the geotechnical engineer to observe that all ID unsuitable materials have been removed and that the exposed soils are in a firm, unyielding • condition. • 4.5.6 Excavation Characteristics • • The upper soils consist predominantly of silty sand with variable gravel content. Excavations should be excavatable with conventional heavy-duty construction equipment maintained in good • condition. Caving of the sidewalls during excavation in sandy soils may occur depending on • conditions at the time of excavation and should be anticipated by the contractor. • 20203884.001A/SEA20R110164 Page 21 of 28 June 1, 2020 ©2020 Kleinfelder