关键词: 软土地层, 矩形顶管, Mindlin解, 随机介质理论, 地表隆沉

Abstract: Accurately predicting and timely controlling the ground surface upheaval and settlement induced by rectangular pipe jacking in soft ground will effectively reduce the impacts on the adjacent constructed facilities. In this paper an analytical method for ground surface upheaval and settlement induced by rectangular pipe jacking is derived by combining Mindlin’s solutions and stochastic medium theory. The proposed method considers total influences of the additional excavation pressure due to the squeezing effect of cutter-head, softening and non-uniform distributed shield skin-soil frictions in soft soils, thixotropic mud affected friction resistances between pipe segments and surrounding soils, additional grouting pressure and soil loss considering convergence mode of excavation face. The predictions given by the proposed method are in good agreement with measurements from three field cases, indicating that the proposed can reasonably predict the ground upheaval and settlement caused by the rectangular pipe jacking in soft ground. It is also found that upheaval of ground surface is observed in front of the excavation face. As the excavation face moves away, the effects of fiction resistances and grouting pressure on the ground surface deformation gradually reduce and the ground surface settlement is mainly caused due to the soil loss. Moreover, the ground surface settlement is dominantly influenced by the convergence mode of excavation face.

Key words: soft soil stratum, rectangular pipe jacking, Mindlin’s solution, stochastic medium theory, ground surface upheaval and settlement