Case Studies

Occidental Chemical: Slurry Walls for Groundwater Containment System

Project Summary

Groundwater Containment System Project in Delaware City

As a part of the overall environmental compliance program, a groundwater containment system was constructed around the production facilities of a chemical plant to contain and permit the recovery of historical releases of mercury, volatile organics, and other contaminants. The containment system required a deep cutoff wall around and through existing production facilities, without disturbing continuing operations. In the most congested parts of the site, a Cement-Bentonite (CB) Slurry was used. In the portions of the site contaminated by organics, the levels were unusually high, requiring special measures to even complete the laboratory testing required. Final permeability requirements were 1 x 10-8 m/secin the CB section and 1 x 10-9 m/sec in the SB section.

Geo-Solutions teamed with the owner, engineer and contractor in a design/build effort to build the cutoff wall. In relatively open areas the cutoff wall could be a soil-bentonite (SB) mixture. In more confined areas a cement-bentonite (CB) mixture was used to minimize disturbance to traffic and plant operations. Geo-Solutions performed a laboratory design mix program to design the SB and CB mixtures for impermeability and compatibility with the groundwater. Geo-Solutions also helped the designer to develop quality control requirements and specifications for the work.

One of the numerous pipe bridge crossings
that were accomplished at this site

The site was unusual in the number of difficult services crossings that had to be accomplished. Shown above is the crossing of the main rail lines serving the site. These were back in service within a week of excavating under them, with the soil bentonite wall supporting rail operations. Shown in the photo to the left is one of the numerous pipe bridge crossings that were accomplished at this site.

The picture below shows excavation operations with excavator and clamshell approaching the same pipe bridge.

Excavator and clamshell operations on pipe bridge in Delaware City

For the construction effort, Geo-Solutions provided technical assistance services to the contractor. Geo-Solutions provided specialty equipment including the long stick and long boom (capable of digging 65 ft deep) for the excavator, bentonite and cement-bentonite slurry mixing plants, and the clam bucket for deeper excavations. Geo-Solutions also was responsible for quality control of the work and the operation of key specialty equipment. The project was a success for all parties.

Slurry Wall Dimensions

SB wall: 20,000 sm, 900mm wide, maximum depth of 27 m.
CB wall: 12,000 sm, 750 mm wide, maximum depth of 18 m.

Geo-Solutions Can Help

To download, read, and learn more about the various slurry wall sample specs and technical papers we offer online here at Geo-Solutions.com, click on the links below or to your left:

• Slurry Wall Sample Specs– Geo-Solutions provides slurry wall sample specs which can be modified for real world use on your project. Download sample specification for Slurry Wall Construction.

• Slurry Wall Technical Papers – Browse our library of Slurry Wall Technical Papers.

Call Us Today