Hard Rock Tunnel Rehabilitation: Small Demonstration Project Informs Design of Complete Tunnel Rehabilitation Project

摘要

San Francisco Public Utility Commission is currently designing an extensive $143 million rehabilitation and repair project for the Mountain Tunnel, scheduled to begin construction in 2020. A $5.9 million interim repair contract was undertaken in 2018/2019 to perform portions of work and provide a demonstration of the project elements. The interim repairs, performed during a 60-day shutdown, included repairs to defective sections of tunnel liner, contact grouting, and invert paving. This paper discusses lessons learned from the design and construction of the interim repairs contract and how these elements will be implemented in the larger Mountain Tunnel Improvements Project.