4800 DOGWOOD DR Geotech Report 2022-10-25

Subsurface Exploration, Geologic Hazards, View Ridge Community Church Addition and Geotechnical Engineering Report Everett, Washington Design Recommendations 10.0 STRUCTURAL FILL All references to structural fill in this report refer to subgrade preparation, fill type and placement, and compaction of materials, as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. Any existing site soils containing organics or debris should be stripped from all areas to receive structural fill. The existing grade should then be compacted to a firm and non -yielding condition. If a firm subgrade cannot be obtained, the yielding soil should either be removed and/or an engineering stabilization fabric placed over the area prior to filling. All applications of stabilization fabric should be placed in accordance with the manufacturer's specifications. It may also be possible to utilize a layer of rock spalls to provide a firm base for structural fills depending on the field conditions and planned use of the area to be filled. The use of stabilization fabric and rock should be evaluated by Associated Earth Sciences, Inc.'s (AESI's) field engineer on a case -by -case basis. After recompaction or remediation of the exposed ground is approved, structural fill may be placed as required to attain desired grades. Structural fill is defined as non -organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts, with each lift being compacted to at least 95 percent of the modified Proctor maximum density using American Society for Testing and Materials (ASTM) D-1557 as the standard. Maximum particle size for structural fill should typically be kept less than the lift thickness. However, occasional larger rocks may be placed provided that they are isolated in occurrence and do not create voids in the fill. Rocks larger than 12 inches in diameter should be kept out of the upper 4 feet of all structural fills. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture -sensitive. Use of moisture -sensitive soil in structural fills should be limited to favorable dry weather conditions. The advance outwash sediments contain low to moderate amounts of silt and are considered slightly to moderately moisture -sensitive. Based on the field moisture contents, the near -surface native soils appear to be below optimum moisture content for compaction and may need moisture -conditioning if reused for structural fill. If structural fill is to be placed during wet weather and proper compaction cannot be obtained with the on -site soils, a select material consisting of a clean, free -draining gravel and/or sand should be used. Free -draining fill consists of non -organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction. August 29, 2016 ASSOCIATED EARTH SCIENCES, INC. SKC/Id-KE160351A2-Projects�20160351JKE�WP Page 11