Stability of excavation face in soft soils by roof-box jacking method considering seepage

The roof-box jacking method can significantly reduce the impact of construction on ground traffic. It is suitable for underground engineering under the dense urban space. The limit equilibrium method for the stability of excavation face with pipe curtain considering seepage is proposed by introducing the fitting formula for distribution of water head in front of the excavation face. The new method is verified through finite element simulations of examples and an actual project case. The results by the proposed method are in consistent with those by the finite element simulations, which verifies the rationality and effectiveness of the method. The analysis shows that the seepage has a great influence on the stability of the excavation face with pipe curtain, and the limit support pressure to maintain the stability of the excavation face is much greater than that without considering groundwater. The influences of seepage should be considered in practical projects.