Aspect Consulting LLC 4/11/2017 - Laserfiche WebLink

City of Everett—Water Main Replacement"S" March 10,2017 Project No. 170095 We anticipate the groundwater will be deeper than the proposed trench excavation depth and conventional open-cut installations techniques will be feasible with limited to no dewatering. However,these fine-grained till-like soils are highly moisture sensitive and difficult to reuse as structural backfill. Imported trench zone backfill is likely. This geotechnical study will provide the right information to inform that decision. Proposed Scope of Work The purpose of our geotechnical services is to evaluate subsurface soil and groundwater conditions as a basis for providing geotechnical engineering recommendations in designing and constructing the water main replacement and future sanitary sewer main replacement. Task 1— Literature Review We will review relevant and available geologic maps of the Site area,existing constriction data, and available geotechnical reports in our files and those provided by the City(including from 1928, 1930, and 2016 along Grand Avenue and recent studies north of the Project)for information regarding subsurface conditions. Task 2— Exploration Planning and Permitting We will visit the Site,meet with City staff and the utilities' representatives to discuss the proposed exploration locations, and adjust conflicts based on utility mark-outs.We will then submit an Exploration Program Plan. The plan will describe our rationale for the number of borings and locations and include additional details pertaining to: • Field work and deliverables schedules • Aerial image showing the boring locations and sections of street parking areas that will need to be restricted during explorations • Completed City of Everett PW Site Work/Right-of-Way Permit Applications • Drilling equipment and method(with equipment photos) • Site restoration and borehole completion details • Utility notification tickets • Traffic control plans in accordance with City of Everett Design & Construction Standards Section 700: Traffic Control, for two-lane roadway • Safety plan and emergency response • Contact information for Aspect's key personnel and subcontractors We anticipate portions of street parking will need to be restricted during drilling to reduce impacts to traffic and specifically between Everett Avenue and Hewitt Avenue.The City will be notified in advance with the time and dates and no explorations will be performed less than 48 hours prior to the no parking signage being posted. Task 3— Exploration Program and Soil Testing A local geotechnical driller will be subcontracted to advance 10 borings(up to two full days)along Grand Avenue,providing subsurface data at spacing of approximately 500 feet along the water main. We understand that in some areas of Grand Avenue the sections may consist of asphalt concrete(AC)atop concrete pavement.Prior to drilling the borehole,the pavement will be cored and retained for later inspection.A truck-mounted drill rig will then be used to advance auger Page 2