Central Water Integration Pipeline Segment 5-1

The Central Water Integration Pipeline Segment 5-1 helps meet the City of San Antonio's water needs for their anticipated 60-year growth. The project comprised five distinct worksites within a densely populated urban landscape: one within a residential neighborhood and across from an elementary school, another in a church parking lot adjacent to a major highway, a third in a carwash parking lot next to a significant roadway, and two sites within the right of way of an urban area.

Strategic roadheader excavation techniques played a pivotal role in different project phases. Initially, the team used roadheaders to create two separate 200-foot-long Tunnel Boring Machine (TBM) starter tunnels, providing the necessary space for TBM construction. These roadheaders were also instrumental in excavating tail tunnels, extending the track length to accommodate the efficient hoisting of full muck trains from the shaft. In the following phase, Atkinson utilized a roadheader to facilitate the disassembly of the TBM in the 550-foot-long Reach 1 Recovery tunnel.

To excavate shafts, the project team primarily used mechanical breakers. However, the rock strength was at the higher end of the provided range and posed a noteworthy challenge. In response, Atkinson completed a prompt submission and approval process within a remarkable 1.5 weeks, which allowed for the implementation of drill and blast methods. This adaptive approach ensured the timely completion of the excavation work. The team carried out the comprehensive project tasks, including shaft excavation, tunnel construction, initial support installation, tie-in, and the construction of supporting structures, with precision and effectiveness.