Abstract:

During the boring of the running tunnel from Beihuanlu station to Dongfenglu station on Line 2 of Zhengzhou Metro, the cutterhead of the shield is jammed in waterrich fine silty sand strata. Jet grouting with inertia bentonite slurry is carried out to rescue the jammed shield. In the end, the jammed cutterhead is rescued successfully. Conclusions drawn are as follows: 1) On the one hand, the inertia bentonite slurry can cut off the sandy soils on the cutterhead; on the other hand, it can fill and condition the sandy strata around the cutterhead, and in turn can reduce the ground stress on the cutterhead; 2) Due to the application of the jet grouting technology, the rescue of the jammed cutterhead is more efficient and more safe; 3) The mentioned technology is applicable to soft soil strata; 4) The mentioned technology can not only rescue the jammed cutterhead, but also can rescue the jammed shield shell. 

Key words: Zhengzhou Metro, jet grouting, shield, jamming, rescue, waterrich fine silty sand strata