Case Studies

Soil-Cement-Bentonite Fill and Cement-Bentonite Slurry Wall Installation Pumping Station Repairs

Project Summary

One of the flood water pumping stations protecting the City of New Westminster, BC suffered serious settlement and emergency repairs were necessary. Geo-Solutions was employed by the City as part of the overall effort to stabilize the pumping station and the adjoining flood dike. First a sheet pile cofferdam was installed around the pumping station and into the Fraiser River and dewatered to permit repairs.

Geo-Solutions teamed with the engineer and a local contractor for a design/build solution to the repairs. Despite wet winter weather the work was completed prior to spring floods, thus ensuring the safety of the city behind the dikes. Geo-Solutions provided the design mix proportions for the CB and SCB based on previous experience.

A new CB (cement-bentonite) cutoff wall was installed through and under the pumping station.. The excavation used a small hydraulic clamshell bucket working inside the confines of the cofferdam. The working platform for the work was about 3 meters below the surface of the river. CB provided a major benefit since construction could be completed in small panels and the hardened CB provided added strength.

After the successful completion of the CB slurry wall, Geo-Solutions was again employed to supervise the construction of an SCB (soil-cement-bentonite) fill to replace the former clay core of the flood dike. Wet weather made conventional compacted clay construction impossible and time was critical. The SCB fill had to be placed in cold, wet winter weather. Local materials were evaluated and a SCB design mix was selected. The SCB was placed in as a semi-fluid in 1 meter high vertical lifts. Each lift was allowed to cure only over night before placing the subsequent lift. The sides of each lift were formed with large concrete blocks. The SCB encased and pumping station and re-established the core of the flood dike. The SCB fill was completed in about 1 week, thus allowing completion of the repairs.

Overall, the project was considered a major success for the general contractor and the owner and allowed completion of the work prior to the start of flood season.

Slurry Wall Dimensions: :4200 sf, maximum depth of 10 meters.
SCB Fill Dimensions: 175 cy, maximum height of 6 meters.

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.

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