6617 ASSOCIATED BLVD AMAZON Geotech Report 2022-10-25

• • nKLEINFELDER • • • Removal and Replacement with Crushed Rock and Geotextile Fabric: Unstable • subgrade could be over-excavated 12 to 24 inches below existing grade and replaced • with 3/- or 1-inch crushed rock underlain and/or wrapped by geotextile fabric. The • geotextile fabric should consist of a woven geotextile, such as Mirafi HP series or • equivalent. The final depth of removal will depend upon the conditions observed in the field once overexcavation begins. The geotextile fabric should be placed in accordance • with the manufacturer's recommendations. • • Soil Treatment: Unstable subgrade could be stabilized by mixing the upper 12 to • 18 inches of the subgrade with Portland cement, Class C flyash or lime. For estimating • purposes, an application rate of 10 to 12 percent Class C flyash, 3 to 5 percent high calcium quick lime, or 4 to 5 percent Portland Cement may be used. Final application • rates should be determined in the field at the time of construction in consultation with the • geotechnical engineer. Chemical treatment should be performed by a specialty • contractor experienced in this work. Since soil treatment uses the on-site soil, the • expense of importing material can be avoided. • • 4.5.4 Foundation Excavations • Spread Footings • Following excavation to the foundation subgrade elevations, the exposed subgrade should be • observed by a representative of Kleinfelder to evaluate the presence of satisfactory materials at • design elevations. If unsatisfactory material, such as soft or disturbed soil, debris or otherwise • unsuitable soil is present at the base of footing excavations, the unsuitable materials should be • overexcavated and replaced with structural concrete, 2-sack sand-cement slurry, or structural fill • to the depth and extent determined by the geotechnical engineer. As a minimum, the contractor should be prepared to scarify, moisture condition, and re-compact the upper 6 to 8 inches of footing subgrade. • Drilled Piles • The performance and capacities of piles can be influenced significantly by the selected 411 construction methods and procedures used. Construction methods that create large zones of • disturbance around the drilled shafts can lead to lower than expected skin friction due to • excessive stress relief around the shaft length. Drilling of the pile shafts should be accomplished 40 using heavy-duty excavation equipment. • • • 20203884.001A/SEA20R110164 Page 20 of 28 June 1, 2020 ©2020 Kleinfelder • •