Brisbane, Australia: Slurry Wall Construction and Vacuum Trial Area

Brisbane, Australia: Slurry Wall Construction and Vacuum Trial Area

Project Description

Slurry Wall Dimensions:  1.296 linear meters, 18,544 square meters, reaching depths of 16 meters

Description of Work:

The Port of Brisbane has been expanding their port by dredging up river mud into paddocks.  The material is hydraulically placed into the paddocks and mainly consists of sand and low-strength dredged river mud.  In order to build on the paddocks and expand the port, the ground conditions had to be improved through a vacuum consolidation process.   A complete cell with overlying membrane was created to exclude both air and water from the site so it was able to undergo vacuum consolidation.  To obtain the necessary atmospheric pressure to stabilize and strengthen the ground a slurry wall was installed.  The wall has a plastic liner placed in the zone above the local water table, about 7 meters deep, to prevent air from entering the site as the vacuum is applied.

For the construction effort, Geo-Solutions teamed with an Australian Contractor to install the cutoff wall and vacuum.  Geo-Solutions provided technical assistance services to the contractor.  These services included personnel and specialized equipment.  For the entirety of the project, Geo-Solutions provided a supervisor and a QC specialist to train the labor, supervise the operation of specialty equipment, and to ensure that the project was being completed within the intended specifications.  Specialty equipment that was used includes a long stick attachment, necessary buckets, bentonite mixer, and specialized QC testing equipment.

This wall is the second wall to be installed as part of the Port’s expansion project.  Geo-Solutions successfully installed the first wall in 2007.