1020 N BROADWAY EVCC STUDENT HOUSING Geotech Report 2022-10-25

Proposal for Geotechnical Engineering Services Proposed Apartments: 1020 North Broadway,Everett,Washington September 27,2017 percent of the maximum dry density, as determined using test method ASTM D-1557. Within 5 feet of the wall,the backfill should be compacted with hand-operated equipment to at least 90 percent of the maximum dry density. 4.5 PERMANENT CUT AND FILL SLOPES Based on the anticipated soil that will be exposed in the planned excavation, we recommend permanent cut and fill slopes be constructed no steeper than 2H:1 V (Horizontal:Vertical). 5.0 EARTHWORK CONSIDERATIONS 5.1 TEMPORARY EXCAVATIONS AND SHORING Temporary excavations should be constructed in accordance with Part N of WAC (Washington Administrative Code) 296-155. The contractor is responsible for maintaining safe excavation slopes and/or shoring. We anticipate the excavation will encounter two to three feet of loose to medium dense fill overlying the medium dense to very dense weathered and un-weathered till consisting of silty sand with gravel. Based on these conditions the building excavation can be accomplished as an open cut with a 1H:1V inclination in the upper 4 feet and 3/4H:1V inclination below 4 feet. An L-shaped footing may be used to conserve space for temporary excavations. Temporary excavations should be evaluated in the field during construction based on actual observed soil conditions. If seepage is encountered, excavation slope inclinations may need to be reduced. During wet weather, the cut slopes may need to be flattened to reduce potential erosion or should be covered with plastic sheeting. If there is not sufficient room to maintain the excavation within the limits of the property, temporary easements may be needed to slope the excavation into the adjoining properties or right-of-ways. If easements cannot be obtained, then temporary shoring may be needed. Temporary shoring options that would be applicable to this project include gravity walls, such as an Ultrablock wall or a cantilevered soldier pile wall with timber lagging. 17-233 1020 North Broadway Page 10 PanGEO,Inc.