Despite working through one of Portland’s rainiest winters to date, AEC crews successfully completed the capping of a large slurry wall along Portland’s Willamette River.
The Owner and Engineer designed an approximate 16,000 vertical square ft. soil bentonite slurry wall to be installed along the western most side of the property in an effort to alleviate potentially contaminated groundwater from entering the river. We were proud to partner with DeWind One-Pass Trenching, LLC. whose unique technology for barrier wall installation proved to be the best method for this project given its ability to substantially decrease the overall project schedule and install the wall more efficiently near the shoreline.
The overall scope of the project called for DeWind to construct a 553 ft. long groundwater barrier wall of bentonite clay material utilizing their proprietary “mix-in-place” method. As DeWind’s subcontractor, AEC provided local resources and construction support activities including installation of erosion and sediment controls, site surveying, excavation of contaminated material, collecting, hauling and disposing of liquids, debris and spoils off site, installation of the groundwater barrier wall cap, and the decommissioning and abandonment of six monitoring wells.
After installation of the wall, AEC installed a 6 in. deep x 10 ft. wide surface of dense graded aggregate (DGA) over a 5 ft. wide x 2 ft. deep clay cap. Due to record-breaking rainfall in December and the resulting saturated soil conditions, AEC proposed an alternate cap process of installing DGA a full 2.5 ft in depth, underlain by HDPE geomembrane and geotextile material to better protect the groundwater barrier wall.
A big CONGRATULATIONS to the crew for doing such a terrific job.