内水渗漏软化基底对盾构隧洞衬砌管片受力性能的影响分析

水工盾构隧洞在运行过程中存在内水渗漏导致基底软化的风险，基底软化将对隧洞管片受力变形产生影响。依托实际水工盾构隧洞工程，构建了由管片、灌浆体和围岩组成的三维有限元数值模型，针对Ⅴ类围岩条件下因渗漏导致基底均匀和不均匀软化的状况，研究了管片的受力性能变化规律。结果表明：在内外荷载作用下，管片的环向应力、竖向位移和定位销应力均随基底软化深度的增加而增大，均匀软化条件下仰拱管片出现峰值为1.88 MPa的拉应力，存在管片开裂风险；基底软化导致定位销应力增大，而管片竖向位移的变化幅度较小。研究成果可为水工盾构隧洞的安全运行监测提供科学依据。

Bearing performance of shield tunnel lining segments affected by softened base due to internal water leakage

There is a risk of foundation softening caused by internal water leakage during the operation of hydraulic shield tunnels, which will affect the loading capacity and deformation of lining segments. Based on an engineering hydraulic shield tunnel, a three-dimensional finite element numerical model of tunnel segments, peastone grouting and surrounding rock was built to analyze the variation of bearing performance of lining segments under uniform and non-uniform softened base caused by internal water leakage with class-V surrounding rock. Results show that under the actions of internal and external loads, the circumferential stress, vertical displacement of segments and the stress of assembling pin increase with the increase of the softening depth of the base. The peak tensile stress of the invert segment is 1.88 MPa under uniform softening condition, which increases the risk of segment cracking. The base softening leads to the increase of the peak stresses of the assembling pins, but only has a slight influence on the vertical displacement of the segments. The research can provide a technical basis for the safe operation monitoring of hydraulic shield tunnels.