Abstract:

Backfilling grouting behind the segments is the key technology to ensure the safety and construction quality of the shieldbored tunnel, is the key technology to control the ground settlement, and is closely related to the construction cost. Xiangjiang tunnel on ChangshaZhuzhouXiangtan intercity railway is a large diameter shield bored tunnel crossing waterrich bedrock strata. Due to the big annular space behind the segment rings and the flushing erosion effect of the ground water, the simultaneous grouting carried out cannot achieve the expected result. In the paper, the causes for the problems in the simultaneous grouting are analyzed, and countermeasures including “simultaneous grouting, complementary grouting, secondary consolidation grouting and sealing ring execution” are taken and optimized during the tunneling. In the end, the safety and grouting quality are ensured and the construction cost is effectively reduced. 

Key words: large diameter EPB shield, waterrich bedrock strata, simultaneous grouting, complementary grouting