Abstract:

A branch tunnel with large slope a water diversion project in Xinjiang is constructed by open TBM. During tunneling, a large fault structural fracture zone is encountered and collapse occurs; and the TBM cutterhead is buried by the collapse of tunnel face and the shield is pressed by the broken body and jammed. In order to release the TBM safely and rapidly, advanced forecasting method is adopted to ascertain the geological situation ahead, and the support of constructed section is strengthened. And then the chemical grouting material with large mobility, early strength and high strength is used to carry out consolidation grouting to consolidate soils above and ahead of shield, so as to remove the loose ballast around the cutterhead and shield. After that the cutterhead can drive slowly and move forward, which finally releases the TBM safely. By adopting the above methods, the TBM can be smoothly released and further shortened the jamreleasing time.

Key words: water diversion tunnel, fault fracture zone, open TBM, TBM jamming, jam releasing, consolidation grouting