Abstract:

During the construction of the water conveyance tunnel of “Hongyan River to Shitou River Water Transfer Project” in Shaanxi, China, the smalldiameter telescopic TBM used is jammed. Advance grouting holes are drilled through the cutter head of the TBM and chemical grouting is performed to consolidate the collapse area and the fractured zone so as to release the jammed TBM. The practice shows that the releasing of the jammed TBM described is simple, timesaving and reliable. In the paper, the application of PUR chemical grouting material and silicate modified PUR chemical grouting material is presented. It is proposed that the performance of the grouting materials should be properly adjusted in accordance with the rock mass conditions so as to achieve economic and reliable effect.

Key words: tunneling, smalldiameter telescopic TBM, jamming, jam releasing, PUR, chemical grouting material