931 BROADWAY SEPA 016 - 008 - TEUTSCH PARTNERS Geotech Report 2025-04-14

Geotechnical Report Proposed Student Housing: 931 Broadway Street, Everett, Washington December 8, 2015 6.0 EARTHWORK CONSIDERATIONS 6.1 MATERIAL REUSE The on-site soils are moisture sensitive, and will become disturbed and soft when exposed to inclement weather conditions. We do not recommend reusing the on-site soils as structural fill. If it is planned to use the on-site soils in non-structural areas, the excavated soils should be stockpiled and protected with plastic sheeting to prevent it from becoming saturated by precipitation or runoff. 6.2 STRUCTURAL FILL AND COMPACTION Structural fill should consist of imported, free draining granular material or a soil meeting the requirements of Gravel Borrow as defined in Section 9-03.14(1) of the WSDOT Standard Specifications.for Road, Bridge, and Municipal Construction (WSDOT 2014). Structural fill should be properly moisture conditioned, placed in loose, horizontal lifts less than 8 to 12 inches in thickness, and compacted to at least 95 percent maximum density, determined using ASTM D-1557 (Modified Proctor). The procedure to achieve proper density of a compacted fill depends on the size and type of compacting equipment, the number of passes, thickness of the lifts being compacted, and certain soil properties. If the excavation to be backfilled is constricted and limits the use of heavy equipment, smaller equipment can be used, but the lift thickness will need to be reduced to achieve the required relative compaction. Generally, loosely compacted soils are a result of poor construction technique or improper moisture content. Soils with high fines contents are particularly susceptible to becoming too wet and coarse-grained materials easily become too dry, for proper compaction. Silty or clayey soils with a moisture content too high for adequate compaction should be dried as necessary, or moisture conditioned by mixing with drier materials, or other methods. 6.3 WET WEATHER CONSTRUCTION General recommendations relative to earthwork performed in wet weather or in wet conditions are presented below. The following procedures are best management practices recommended for use in wet weather construction: 15-275 931 Broadway,Everett Page /3 cY PanGEO, Inc.