Planning of the San Francisco Public Utilities Commission's Channel Tunnel

摘要

The proposed Channel Tunnel is a critical component of the San Francisco Public Utilities Commission's Central Bayside System Improvements Project (CBSIP), which is a key element of a $6.9-billion Sewer System Improvement Program to upgrade their aging and seismically vulnerable wastewater facilities. The tunnel will provide gravity conveyance and storage of combined sewage flows from the northeast sector of San Francisco to the Southeast Water Pollution Control Plant for treatment. The tunnel will be approximately 1.7 miles long and 24 feet in internal diameter. It will utilize a single-pass precast concrete segmental lining system. Tunneling challenges include excavating with pressurized face TBM technology through highly variable ground conditions including Franciscan Complex (rock and melange), clayey/silty sands, stiff to hard clay (Old Bay Clay) and mixed-face conditions.