Abstract:

The tunnel crossing underneath Zhongzhou Avenue in Zhengzhou has such features as superlarge crosssection, shallow cover, 4 parallel tunnel tubes and small spacing between the tunnel tubes, therefore there is great difficulty in the settlement control. Countermeasures, including simultaneous grouting, secondary grouting, ground conditioning, muck discharge control, soil carrying prevention, control of 6 cutter heads, blind area treatment and backward movement prevention are taken to control the ground settlement. In the end, the settlement is well controlled. The practice shows that the countermeasures taken are feasible and effective.

Key words: superlarge rectangular crosssection pipejacking machine, settlement control, tunneling underneath existing urban road, small spacing, control of 6 cutter heads, shallow soil cover