5034 OCEAN AVE Geotech Report 2022-10-25

51xx Ocean Avenue (Parcel#00571700100100) November 1, 2017 Everett, Washington Project#17110 structural fill. In areas that will provide structural support, any existing fill soils or loose soils should be removed and replaced with structural fill as described below, or the fill soils should be mitigated as described in later sections. Structural Fill Structural fill is defined as non-organic soil, placed in horizontal loose lifts, with each lift being compacted to at least 95 percent of the maximum dry density, using the modified Proctor test (ASTM: D1557) as the standard. Prior to placing any structural fill,the exposed soils must either be undisturbed or be compacted to a dense, non-yielding condition and be approved for structural fill placement. In the case of utility trench filling,the backfill should be placed and compacted in accordance with the applicable municipal or utility company standards. Fill soils should be predominantly free of organics and other deleterious material and should be appropriately moisture conditioned when placed and compacted. Placement and compaction of the structural fill should be monitored by a competent field technician. In situ density testing should be performed during fill placement to verify proper compaction of the fill soil. A sample of the planned structural fill soil will need to be available at least 48 hours prior to compaction verification testing for laboratory analysis. If structural fill is used to raise the foundation bearing elevation,the downslope toe of the structural fill body must be keyed into the existing native sediments. The keyway will help prevent a plane of weakness between the new fill and the native sediments and reduce the potential for lateral translation. The size and location of the keyway can be determined in the field at the time of construction and should be reviewed by South Fork Geosciences prior to placing structural fill. The perimeter of the new fill should be benched into the temporary cut slopes during the placement and compaction of the structural fill. Temporary Slopes Temporary cut slopes will be necessary to allow the installation of the foundations and for utility installation. Temporary cut slopes should be limited to 1.5H:1V in any fill soils and to %H:1V in the native transition bed sediments. Stability of the cut slopes is the responsibility of the on-site contractor and a safe work environment should be maintained at all times. A trench shield or trench box should be used to install all utilities over 4 feet in depth or the sides of trenches and excavations should be sloped back per OSHA/WISHA standards. Permanent Slopes As a standard of practice, permanent cut slopes in the native sediments and slopes in structural fill soils should be limited to a maximum of 2H:1V and landscape fill slopes comprised of organic rich soil or non-structurally compacted mineral soil should be limited to 3H:1V. Foundations Spread footings may be used for building support when founded on medium dense native soils, or approved structural fill soils. We recommend that an allowable bearing pressure of 2,000 SOUTH FORK GEOSCIENCES, PLLC Page 5 PO Box 1275 NORTH BEND,WA 98045 425-831-2023 I ANDREW@SFGEO.COM •