3821 SHORE AVE 2024-02-28 - Laserfiche WebLink

February 28, 2023 G-5835 3821 —Shore Ave Everett,WA page 9 Retaining Walls Based on our visual reconnaissance, and discussions with you,we understand the proposed ecology block retaining wall will have a maximum height of approximately 4.0 feet and be constructed as a gravity wall. Our recommendations for ecology block retaining wall constriction are provided below. Ecology Block Retaining Walls The retaining wall's design and construction should adhere to all recommendations provided by the block manufacturer in addition to the geotechnical recommendations below, the wall should be constructed on a crushed rock leveling pad that is at least 4 inches thick founded on a suitable subgrade approved by the geotechnical engineer. The retaining wall should have a minimum embedment of 6 inches below grade along the front of the wall. Backfill directly behind the retaining wall should include a minimum 2 feet wide zone of free- draining crushed rock. This backfill should extend upward to near the top of the wall and downward to the base of the wall. We also recommend that a layer of geotextile filter fabric also be laid on the top of the rock if topsoil surfacing wilt be placed behind the walls. These recommendations are illustrated in the attached Plate 4--Ecology Block Wall Drainage. The backfill in areas adjacent to the retaining wall should be compacted with hand held equipment(such as a jumping jack)or with a small vibratory plate compactor(such as a sled compactor or hoe-pack). Heavy compaction machines should not be allowed within horizontal distance to the wall equivalent to one half of the wall height,unless the wall is designed to accommodate the added surcharge. Site Drainage Surface Drainage Water should not be allowed to stand in any area where wall footings are to be constructed. During construction, loose surfaces should be sealed at night by compacting the surface to reduce the potential for moisture infiltration into the soils. Final site grades should direct surface water away from the retaining wall. I GEO Group Northwest, Inc. i i