GeoEngineers Inc 10/9/2017 - Laserfiche WebLink

EXHIBIT A 7400 BLOCK LOWELL-LARIMER ROAD STABILIZATION GEOTECHNICAL SCOPE OF SERVICES INTERIM ACTION RECOMMENDATIONS GEOENGINEERS, INC. GEOENGINEERS FILE NO. 0661-113-00 PROJECT SCOPE We understand that a segment of Lowell-Larimer Road became unstable following excavation at the toe of the roadway embankment in the vicinity of the 7400 Block by the adjacent and downslope property owner while excavating for a drainage ditch. During two site visits, we observed numerous tension cracks in the roadway, settlement of the roadway, and tension cracks to the west of the road in the lawn of the private residence located at 7404 Lowell Larimer Road. The extent of the observed roadway distress is approximately 300 feet long with significant movement and pavement damage occurring over a section about 100 feet long immediately east of the residence located at 7404 Lowell Larimer Road. We also understand that a 30-inch pressurized sanitary sewer line is located below the north-bound lane and an 8-inch water line is located along the south-bound shoulder. Other underground and overhead utilities exist in the area. In addition, several storm water culverts cross the road and discharge onto the slope downslope of the road. The purpose of our geotechnical engineering services is to investigate the cause of the current roadway failure and to evaluate the subsurface soil and groundwater conditions as a basis for establishing geotechnical criteria and recommendations in support of a City of Everett(City) road stabilization project. SERVICES GeoEngineers scope of geotechnical services includes the following tasks: 1. Review available geologic maps and subsurface information, including previous geotechnical reports in the project area. 2. Perform a geologic reconnaissance to evaluate the conditions along the existing slope. This includes photographic documentation and sketching of significant features along the slope and roadway including signs of existing slope movement. 3. Complete a back analysis of the slide to evaluate the slide mechanism and conditions at failure. • Perform slope stability analyses along two cross-sections in critical areas of the roadway failures. • Coordinate cross-section locations with the surveyor who will be hired by the City. • Use the results of the back analysis to evaluate at least two short-term (interim) and long-term slope repair alternatives. Alternatives may include considerations for rock buttress, retaining walls, or other slope repair techniques.