衬砌裂缝对隧道结构影响的数值模拟研究

Numerical Study on the Influence of Lining Cracking on the Tunnel Lining

以厦门第二西通道上跨地铁1号线项目为背景,采用FLAC3D有限差分计算软件,并借鉴结构力学中位移法的思路,建立带裂缝衬砌结构的三维数值模型,模拟在隧道变形模式中衬砌裂缝宽度发展规律,并与实测数据对比,验证模拟方法的合理性。同时设计数值实验,研究不同裂缝深度与环向长度对衬砌截面的影响规律。结果表明:与现场实测结果相比,数值计算结果偏大,但是两者的变化规律一致,基本验证了计算模型与模拟方法的合理性;裂缝深度与环向长度的增长会引起拉应变区的裂缝宽度累计变化量增加,导致裂缝处截面轴向应力与钢筋轴向应力增大,其中裂缝深度的影响程度更大。该研究对相似的工程应用具有一定的参考价值。

This paper presents a case history of the second-west Xiamen subway project of the upper-span Subway Line No.1.A three-dimensional numerical model of the lining structure with cracks is established by using the FLAC3D finite difference software and the displacement method in the structural mechanics.The development of the lining crack width in the tunnel deformation modes is simulated.The feasibility of the simulation method is verified by comparing with the measured data.At the same time,numerical experiments are designed to study the influence of the different crack depth and the circumferential length on the lining section.The results show that,compared with the measured results,the numerical results are larger,but their changing rules are consistent,which basically verifies the feasibility of the analytical model and the simulation method.The increase of the cracking depth and the circumferential length will lead to the increase of the cumulative variation of the cracking width in tensile strain zone,and lead to the increase of axial stress at the crack section and the axial stress of reinforcement,in which the effect of cracking depth is more significant.