基于数值评价的隧道衬砌裂缝成因分析与维修设计

地下工程衬砌裂缝是隧道工程常见病害之一。由于衬砌裂缝对隧道结构体受力、防排水等安全方面产生不良影响,有必要对裂缝成因加以分析并采取有效措施来降低裂缝对隧道的影响。以四川省某铁路隧道为研究对象,现场调查衬砌裂缝情况,分析隧道边墙纵向开裂原因。采用应力解除法对该隧道进行地应力测试,测点处围岩初始应力处于极高应力状态,分析得出高地应力作用是导致衬砌开裂主要原因。为检验这一推断,采用扩展有限元(XFEM)对该段衬砌结构性能进行数值模拟,根据XFEM得到破坏区域衬砌结构破坏演化、二衬安全系数,模拟结果与实际衬砌损伤形式一致。最后,针对隧道衬砌结构开裂提出一种具体的维修方案,根据数值计算结果及现场施作情况,验证所提维修方法的有效性及安全性。

Reason Analysis and Maintenance Design of Tunnel Lining Crack Based on Numerical Evaluation

Lining cracks in underground engineering are one of the common diseases in tunnel engineering. Due to the adverse effects of lining cracks on the stress, waterproof and drainage of tunnel structure, it is necessary to analyze the causes of cracks and take effective measures to reduce the impact of cracks on the tunnel. A railway tunnel in Sichuan Province is taken as the research object, the lining cracks were investigated on site, and the causes of longitudinal cracking of tunnel sidewall were analyzed. The stress relief method is used to test the ground stress of the tunnel. The initial stress of the surrounding rock at the measuring point is in a high stress state. The analysis shows that the high ground stress is the main reason for lining cracking. In order to test this inference, the extended finite element (XFEM) is used to numerically simulate the performance of the lining structure in this section. According to XFEM, the failure evolution of the lining structure in the failure area and the safety factor of the secondary lining are obtained. The simulation results are consistent with the actual lining damage form. Finally, a specific maintenance scheme is proposed for tunnel lining structure cracking. According to the numerical calculation results and field operation, the effectiveness and safety of the proposed maintenance method are verified.