OAKLAND LINE B TUNNEL SOIL STABILIZATION IMPROVEMENTS TO A PORTION OF LINE B
Advanced Construction Techniques (ACT) was awarded the project to stabilize ground prior to hand mining activities for the lowering of a combined concrete arch and round corrugated metal tunnel.
To accomplish this stabilization a number of grouting techniques were used, including, contact grouting, compensation grouting, and a combination permeation/fracture grouting.
Custom manufactured steel Tube-a-Manchettes (TAM), or sleeve port grout pipes, were hydraulically jacked into place radially along the length of the tunnel to facilitate grouting.
A combination of cement grout and sodium silicate chemical grout were utilized to stabilize the soil surrounding the tunnel segments. To accomplish the chemical grouting, ACT custom built a semi automated sodium silicate batch plant.
Grouting operations were viewed and recorded in real-time. Surface structures were viewed and recorded in real-time for any indication of heaving.
All work was performed under an accelerated schedule and completed on time. All work was performed in a confined space environment.