5213 GLENWOOD AVE 2017-03-09 - Laserfiche WebLink

Western Geotechnical Consultants, Inc. 4183 Saltsprings Dr., Ferndale,WA 98248 Phone/FAX(360)380-2507 e-mail: western_geo@hotmail.-com April 17. 2015 Mustach.Land Development, LLC B L5 7 P. 0. Box 12176 Mill Creek, WA 98082 cwt.evic ATTN: Mr. John Mustach ( *{ CP Jt14e_ 2$ 2._(76 Re: Revised Report Re-di-Rock Retaining Wail Design 52X.X Glenwood Ave. Property Everett,WA This report presents the results of our engineered design of a Redi-Rock retaining wall for the above referenced property. A geotechnical report for the property was prepared by LIU and Associates, LLC, which was provided to us for review. This report presents the results of our design of both a gravity Redi-Rock wall and a Mechanically Stabilized Earth (MSE) Re-di-Rock retaining wall which will be constructed along the access drive to the building site location on the property. We traveled to the site on November 4, 2014 and met on site with Mr. John Mustach, who will be developing the property. The site is on the east side of Glenwood Avenue with residential development on both the north and south sides, and a wooded aseendin.g slope to the east, The building site has an access road and a cut slope adjacent to the road that is retained partially by a rockery wall located between the lower portion of the access road and the building site. The plan is to build a ready rock retaining wall to the north of the existing rockery wall and the new wall will he up to 23 feet high (exposed height). The majority of the wall is less than 15 feet high. Figure 1 in Appendix A is a topographic site plan showing the existing rockery wall location relative to the proposed Redi Rock wall location. Figures 2 and 3 in Appendix A are cross-sections thru the wall at the locations shown on Figure 1. Geologic Setting The USGS has mapped the surficial soils in the vicinity of the property as Vashon till. The deposits of the Vashon till soil unit were over ridden by glacial ice during the most recent glacial period as the glacier advanced over an eroded, irregular surface of older formations and sediments. This soil unit is composed of a mixture of unsorted clay,silt, sand,gravel, and scattered cobbles and boulders. The Vashon till soil over the top two or three feet is normally weathered to a medium-dense state, and is moderately permeable and compressible. The underlying fresh till soil is very dense and weakly cemented and is of extremely low permeability. There is a cut slope to the east of the access drive and the exposed soils are glacial till.