Pipeline Project | Geotechnical Exploration
Brightwater Conveyance System
 2 EDITED.jpg) |
 1 EDITED.jpg) |
Project Description
King County, Washington, performed a geotechnical exploration program for the Brightwater Conveyance System. The System consisted of influent conveyance lines, effluent conveyance lines, a safety relief point, and a marine outfall for the new Brightwater Treatment Plant. The influent and effluent pipelines consisted of approximately 20 miles of tunnel that reached depths of 600 feet.
The subsurface exploration program consisted of drilling more than 200 borings to depths of 600 feet utilizing several drilling methods, including: open hole mud rotary, auger, RotoSonic, and wireline core drilling. Subsurface conditions within the project area consisted of glacial and non-glacial deposits. Consolidated sediments of fill, alluvium, and recessional deposits were encountered at shallow depths. Below the younger deposits there were several hundred feet of glacially overridden sediments.
Team Members
King County Wastewater Treatment Division, Crux Subsurface Inc.
Crux’s Role
Crux was selected to provide wireline core drilling services on this project, drilling borings to depths of 600 feet. Crux utilized a PQ3 and HQ3 wireline triple-tube coring systems for obtaining core samples in weak soil and glacial deposits. In addition to core sampling, drive and push samples were obtained in the borings. Crux also built custom solid steel liners in one- to three-foot intervals that replaced the split inner liners in the core tubes. Core samples were drilled directly into the steel liners and then capped for lab testing, minimizing sample disturbance.
Artesian conditions, including gases, were present in a majority of the borings. Crux was primarily utilized on borings with the highest propensity of artesian conditions. Crux developed drilling and mud programs that successfully controlled artesian conditions. Vibrating wire piezometers and PVC piezometers were installed in the borings. In selected borings, Crux installed multi-staged vibrating wire piezometers or 2-inch PVC piezometers to depths of 600 feet.
Work was completed along a public right-of-way, on private property and near wetlands. All work was completed with minimal site impact during drilling operations. All drill wastes were disposed of offsite.
To request additional information, please use our Contact Page or call 866-CRUXSUB (866-278-9782).
