Tunnel projects often entail the use of some type of excavation support, groundwater cutoff,  seepage mitigation, or ground improvement to facilitate excavation activities via tunnel boring machine (TBM) or cut and cover methods.

Reinforced slurry diaphragm walls can be used as support for excavation for underground structures such as cut-and-cover stations along a tunnel alignment, TBM launch and retrieval shafts, CSO storage tanks, and influent pump station shafts. For deep tunnel access shafts in particular, where the bedrock is also far below the ground surface and groundwater inflow is significant, the use of slurry diaphragm walls is often the most cost effective means of earth support and water resistant performance.

In addition to slurry walls, Bencor has also constructed jet grouted bottom plugs to reduce water infiltration, provided pre-treatment grouting to minimize water and gas inflow during shaft construction, and installed anchors from the bottom of the completed structure to resist hydrostatic uplift forces.