Akkerman News: TBM Provides Versatility in Difficult Ground for Water Conveyance Tunnel in El Paso, Texas
Written By: Nicole McBride
Date: October 18, 2019
The Canal Water Treatment Plant Discharge Transmission Main Project for El Paso Water has been featured in Volume II of Akkerman News. This water resources project addressed potential issues relating to Downtown El Paso’s aging infrastructure. PSC worked alongside BRH Garver as the design lead on the design/build team.
The Robertson Umbenhauer Water Treatment Plant, also known as the Canal Water Treatment Plant, is located between the Rio Grande River and BNSF Railway yard. PSC worked alongside BRH Garver as the design partner on the design/build project team contracted for the Canal Water Treatment Plant Discharge Transmission Main Project. PSC also provided site supervision and contract administration. The project addressed potential issues of Downtown El Paso’s aging infrastructure by replacing existing transmission lines.
The new 48-inch transmission line from the Robertson WTP crosses the BNSF rail yard and Paisano Drive and ties into an existing 48-inch line on San Antonio Avenue in Downtown El Paso. The tunnel casing pipe is 66-inch Permalok steel-casing pipe. The new pipe was installed by an Akkerman tunnel boring machine which El Paso Water, the project owner, nicknamed “Robbie” at the beginning of the project.
The project had several challenges including abandoned utilities in the railyard, sandy ground, and cobbles. The entire project required close coordination with the BNSF rail yard and TxDOT for the staging of equipment, construction of the launch and reception shafts for the TBM, and safety of all those involved.
The use of a TBM rather than a microtunneling system proved to be the optimum method to complete this project. The use of this system contributed to the cost savings of the project, particularly when the obstacle of boulders was discovered in the path of the new tunnel. Additional cost-savings accumulated from the downsizing of the casing diameter from 72 inches to 66 inches and avoidance of deep well dewatering, which reduced settlement risk.