关键词: 黏土地层；顶管；开挖面稳定；支护压力；极限分析法；锦江区再生水综合利用工程；成都市

Abstract: The construction of pipe jacking is usually in shallow stratum, often embedded in the clay stratum, so it requires strict control on soil deformation. The determination of the support pressure of the excavation face is a key to the stability of the excavation face and the control of construction deformation. Based on the comprehensive utilization project of reclaimed water in Jinjiang District, Chengdu City, we carried out an in-depth analysis on the on-site monitoring results of slurry pressure. Then, the limit analysis method was used to solve the upper limit solution of the active support pressure on the pipe jacking excavation face in the clay stratum. The influences of different buried depths and different inner diameters on the active support pressure were calculated and analyzed. The results showed that: ① With the increasing of water and soil lateral pressure, the field slurry pressure increased, and to control the construction deformation, the field slurry pressure was 10-20 kPa higher than the water and soil lateral pressure. ② The active support pressure increased with the increasing of buried depth, and the active support pressure ratio decreased, both in a parabolic shape. In detail, the active support pressure increased by 190.2%, and the active support pressure ratio decreased by 17.1%, when the buried depth increased from 2 m to 10 m. ③ The active support pressure and active support pressure ratio all increased with the inner diameter of the pipe jacking in a parabolic shape. When the inner diameter increased from 2.0 m to 3.2 m, the active support pressure and the pressure ratio all increased by 12.9%. The results can provide reference for pipe jacking construction in clay stratum.

Key words: clay stratum；pipe jacking；stability of excavation face；support pressure；limit analysis method；comprehensive utilization project of reclaimed water in Jinjiang District；Chengdu City