This is a great video showing the application of ground freezing to deep excavations in unstable soil and high groundwater table. It’s also a nice overview of the reason the Hetch Hetchy project was undertaken, to replace aging San Francisco Bay area water supply infrastructure that would not survive a major earthquake on the Hayward Fault or San Andreas Fault. I tried to find the name of the ground freezing contractor…I think it was SoilFreeze based on a quick shot of a logo on some equipment. Can anyone confirm? The vertical access shaft being constructed in Newark will be where the TBM will be disassembled and removed.
Source: ASCE SmartBrief