4937 SEA BREEZE WAY 2017-01-13 - Laserfiche WebLink

• Geotechnical Engii�eeri��g Evaluation Pepe Retaii�ing Wall Everett, Washington � NGA File No. 916915 April 27, 2015 Page 3 9. Document the results of our findin�s, conclusions, and recommendations in a written geotechnical report � SITE CONDITIONS Surface Conditions The site consists of a rectangular-shaped parcel. The site is currently occupied by an existing abandoned residence on a ilat bench o1-f of the eastern side of Seabreeze Way with an assoicated driveway, concrete walkway, and yard area. The site is bordered to tl�e north and south by vacant wooded lots, to the east by Powder Mill Gulch Creek, and to the west by Seabreeze Way. A failing soldier pile retaining wall is located between the house and a steep slope below, which descends into the creek. The retaining wall is approximately eight feet tall and has been offset up to two feet towards the stream due to its failuee. A long tension crack exists along the wall side of the driveway. A large depression, up to roughly 30 inches deep, extends from the house to the wall and extends the length of the driveway to the southern side of the house. We observed that the sidewalk along the ho�ise in this area was undertnined by several inches. On the southern side of the house, we observed areas of past slope instability including a large tree that was Icanins� towards the ho��se. Several severe cracks werc observed within the garage and lower level of the house, including a crack on the outside in the foundation wall on the southern side of the house. At that tiine, we observed that the roof drains were directed into pipes in the ground and the pipes were outletting on the slopc bclow the wall. We did not� see any other drainage systems such as foundation drains around the peri�r�eter of the house. The ground surface within the vicinity of the existing residence and retaining wall area is relatively flat. The site then slopes steeply down towards the creek and is covered with young to mature trees and vegetation, and also significant fill and debris that was dumped over the walL We did not observe standinQ water within the property during our site visit. Steep slopes are also located on the opposite side of the creek and several slope failures and exposed soil were observed on that side of the creek. The slope on the southern side of the house appears io have eYperienced sliding events in the past, b�it have since been overrun by vegetation. This area appears to be moderately stable but could experience failures as a result of creek action at the tow of the slope. lt was not clear where the property line was in this area, but if any stabilization actions take place, thc lot bo�indary should be established and the work NELSON GEOTECHN/CAL ASSOC/ATES, INC.