8204 BEVERLY LN 2025-03-24 - Laserfiche WebLink

City of Everett Property Access Work Plan Sonic drilling uses high frequency vibratory energy to advance a solid steel casing into the soil,with intermittent water injections as needed for lubrication. A sampler attached to the interior of the casing collects a highly disturbed continuous soil sample with each casing segment advance. Soil samples are brought to the surface using a wireline system and extruded into plastic bags for laboratory review and testing. For either method, soil samples will be obtained using Standard Penetration Tests(SPT)at 2'h-or 5-foot intervals to the depth explored.Work activities will be actively managed to minimize work area disturbance. Upon completion of each boring, all material generated during drilling operations will be stored in 55- gallon drums and removed offsite for disposal at a permitted facility by the drill crew. Each boring location will be backfilled according to Washington State Department of Ecology (WA DOE) regulations using bentonite chips or bentonite-grout mixture.The boring location will be patched appropriately with concrete upon r completion. �HOLT � The drill crew will install standpipe piezometer groundwater monitoring wells or PVC seismic downhole testing casings at ,tl selected borings. The PVC casings will be fitted with vibrating s wire piezometers (VWPs)to monitor groundwater levels at if - selected depths. Where these installations occur,the borehole a will be backfilled in accordance with WA DOE regulations and - completed with a flush-mount steel monument set in concrete. sj The flush mount steel monument has a secured lid to allow access for subsequent site visits to collect data. wr Seismic Downhole Testing A few days to few weeks after drilling is complete, seismic downhole testing will be performed at select boring locations. Seismic downhole testing will involve placing traffic control devices to safely park a van or similar vehicle at the boring location for about 0.5 day.The testing method involves lowering a string of instruments attached to an instrument cable down the PVC casing and collecting shear wave velocity data at specified depth intervals. Data is collected in a datalogger for downloading, analyses and reporting. Once data collection has been completed,the vehicle will leave the site and traffic control devices will be removed. Piezometer Monitoring Standpipe piezometer installation locations will be revisited to collect water levels approximately every three months and one or more times to perform hydrogeologic testing. VWP installation locations will be revisited approximately every three months to download groundwater level data. Each subsequent visit will involve placing traffic control devices to safely access the steel monument for up to one hour. Once data collection is completed, traffic control devices will be removed. .15 �� , �• �1, SCHEDULE • Sound Transit has committed to 72 hours notification to the City prior to commencing fieldwork. • Unless other arrangements are made, work will be completed on weekdays(Mon-Fri)during daylight hours(approximately 7am to 5pm) unless otherwise specified. • Geotechnical investigations are typically completed in 3 to 5 days per boring location TRAFFIC CONTROL PLANS Work will be conducted during daylight hours.Traffic control plans have been developed for lane(s)or shoulder closures and are provided in Appendix B.