Abstract:

The rules and mechanism of ground settlement induced by steel piperoof jacking in ultrashallow covered soft ground of improvement project on Tianlin Road in Shanghai are studied. And then the developments of primary settlement, cumulative settlement and postconstruction settlement of ground are analyzed by field test. Finally, the ground settlement rules under different working conditions are studied. The study results show that: (1) The maximum ground surface settlement after field test is 9.8 mm; the construction of pipe roof group has a cumulative effect on ground surface settlement. (2) The ground uplift occurs in the latter half when single pipe jacking, which is within accuracy range. (3) The change of soil settlement in the range of steel pipe roof burial depth above pipe roof is obvious; the postconstruction settlement of sequential pipe is much larger; and by adopting hole sealing measures, the ground loss can be reduced effectively.

Key words: soft ground, pipe roof method, cumulative settlement, postconstruction settlement, field test