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KLE/NFELOER �Bright People.Right Solutions. 5.2.3 Disturbed Soil, Undocumented Fill and Subsurface Obstructions During our field investigation, fill material was encountered withing the upper 3 feet in some of the borings (B-3, B-5, B-6 and B-9). Any existing undocumented fills on site should be over-excavated to firm soil or to depths determined by the geotechnical engineer during construction. Any over- excavation should extend at least 5 feet beyond the perimeter of the proposed structure and 3 feet beyond the perimeter of pavement areas. The exposed subgrades(existing and over-excavated)to receive engineered fills should be proof- rolled with a fully-loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding should be over-excavated to firm, native soil, or to depths determined by the geotechnical engineer during construction. After proof-rolling, the subgrade should be scarified to a depth of 8 inches, moisture conditioned, and compacted as engineered fill. Deleterious materials encountered during over-excavation should be removed, and the excavated materials compacted to the requirements for engineered fill. This proof rolling, over-excavation and recompaction operation would serve to provide a uniform, stable subgrade throughout the development area thereby improving foundation design conditions and reducing settlement potential. The zone of proof rolling, over-excavation and compaction should extend horizontally at least 5 feet outside the perimeter of the proposed structure and at least 3 feet outside the perimeter of pavement areas. All site grading should include a reasonable search to locate soil disturbed by previous activity and abandoned underground structures or existing utilities that may exist within the areas of construction. Any loose or disturbed soils, void spaces made by burrowing animals, or undocumented fill that may be encountered should be over-excavated to expose firm soil, as approved by a representative of Kleinfelder. 5.2.4 Scarification and Compaction In areas requiring placement of fill, it is recommended the fill be placed and compacted as engineered fill. Following site stripping and any required grubbing and/or over-excavation, it is recommended areas to receive engineered fill be scarified to a depth of 8 inches, uniformly moisture conditioned to between about 2 and 4 percentage points above the optimum moisture content and be compacted to at least 90 percent relative compaction, as determined by ASTM D 1557. 20210067.001A/ST020R111447 Page 11 of 37 May 11, 2020 ©2020 Kleinfelder www.kleinfelder.com