压力舱土体改良对盾构开挖面稳定影响研究

在渗透性大且富含地下水的砂砾地层中进行土压平衡式盾构施工，切削下来的土体具有渗透系数大、流动性差的特点，由于地下水的渗透使压力舱内支护土压力不能有效地施加到开挖面。通过压力舱土体改良技术，降低土体渗透性和提高土体的流动性是改善压力舱土体状态和提高支护土压力的重要措施。利用能够考虑大变形破坏的快速拉格朗日有限差分计算程序研究了压力舱土体改良效果对开挖面稳定性的影响，分析了压力舱土体渗透系数的降低对开挖面支护压力的影响关系，为土压平衡式盾构施工开挖面支护压力的确定提供参考。

Soil conditioning influence on face stability of shield tunnel

EPBM excavates in gravel stratum, whose ground water level is high. The soil excavated in chamber has big permeability coefficients, and is poor in flow ability. It is difficult to apply the support earth pressure to the working face due to the permeation of groundwater. Soil conditioning is a way of adjusting the soil condition in pressure chamber and increasing support earth pressure, which can decrease the permeability and increase the flow ability. The three-dimensional fast Lagrangian differential finite element method which can reflect the large strain of material is utilized to study the contribution of soil conditioning to face stability. The relationship between soil permeability decreasing and support pressures is analyzed. Some results from simulation are given for controlling face pressure.