穿越不良地质段的长距离深埋输水隧洞纵向变形数值分析

Numerical Analysis of Longitudinal Deformation of Long-distance and Deep Buried Water Conveyance Tunnel Passing Through Unfavorable Geological Section

以珠江三角洲水资源配置工程为依托,研究长距离深埋盾构隧洞在穿越不良地质段时衬砌结构的纵向不均匀变形,以保障隧洞施工与运行期的安全稳定。本文采用三维非线性有限单元法对长距离深埋隧洞纵向变形开展研究,精细模拟衬砌接缝以及缝间螺栓,考虑围岩应力的开挖释放,计算复杂地质条件下隧洞衬砌接缝变形与应力状态。研究结果表明:设计参数下,断层破碎带处接缝的最大张开和错台变形量分别为1.065 mm与0.276 mm,螺栓最大拉应力为363.05 MPa,内衬环向拉应力最大值为0.99 MPa,隧洞纵向稳定性满足设计要求;断层破碎带弹性模量的变化对衬砌的纵向变形有较大影响,接缝变形与螺栓应力均随断层模量的减小而显著增加。该结果合理,具有较好的规律性,可为类似工程的设计提供参考。

Based on the water resources allocation project in the Pearl River Delta,this paper studies the longitudinal uneven deformation of the lining structure of long-distance deep buried shield tunnel when crossing the unfavorable geological section,so as to ensure the safety and stability of the tunnel construction and operation period.In this paper,the three-dimensional nonlinear finite element method is used to study the longitudinal deformation of long-distance deep buried tunnel,carefully simulate the lining joint and bolts between joints,consider the excavation release of surrounding rock stress,and calculate the deformation and stress state of tunnel lining joint under complex geological conditions.The results are as follows.Under the design parameters,the maximum opening and dislocation deformation of the joint at the fault fracture zone are 1.065 mm and 0.276 mm respectively.The maximum tensile stress of the bolt is 363.05 MPa,and the maximum circumferential tensile stress of the lining is 0.99 MPa.The longitudinal stability of the tunnel meets the design requirements.The change of elastic modulus of fault fracture zone has a great influence on the longitudinal deformation of lining.The joint deformation and bolt stress increase significantly with the decrease of fault modulus.The results are reasonable and have sound regularity,which can provide a reference for the design of similar projects.