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考虑地铁隧道因初始损伤缺陷长期累积作用对结构所造成的影响,以北京地铁10号线双井站为工程背景,引入相关文献提出的刚度折减理论,探索了对初始损伤缺陷的简化描述;在此基础上利用FLAC 3D有限差分软件,进行了部分嵌入初始损伤缺陷模型的二次程序设计,对含初始缺陷累积效应的地铁隧道在运营动载作用下抗震动力学行为进行了数值仿真研究。结果表明,初始损伤缺陷在长期的累积作用下,对隧道结构的抗震性能有一定的影响;通过分析不同运营阶段的抗震动力响应结果,可以发现随着隧道结构损伤缺陷的不断累积,即刚度的减小,隧道结构中的某些关键控制点,如拱肩、仰拱和拱顶的位移均出现增大的趋势,其应力均表现出不同程度的衰减,且隧道结构周边土体的剪切破坏区域逐渐减小。研究结果对于进一步探索初始损伤缺陷累积作用下隧道结构的灾变机制有重要参考价值。
Considering the influence of long-term cumulative effect of initial damage defects on the structure of subway tunnels, taking Shuangjing Subway Station of Beijing Metro Line 10 as the engineering background, the stiffness reduction theory proposed by relevant literature is introduced to explore the simplified description of the initial damage defects. Based on this, the quadratic program design of partially embedded initial damage defect model is carried out by using FLAC 3D finite difference software. The numerical simulation of the seismic behavior of metro tunnel with cumulative effect of initial defects under operational loading is carried out. The results show that under the long-term cumulative effect of the initial damage, the seismic performance of the tunnel structure is affected to a certain extent. By analyzing the seismic response results of the different operation phases, it can be found that with the continuous accumulation of damage defects of the tunnel structure, ie, the stiffness Decreases, the displacement of some key control points in the tunnel structure such as the spandrel, the inverted arch and the vault all tend to increase, and their stresses show different degrees of attenuation, and the shear of the soil around the tunnel structure Damage to the area gradually reduced. The results are of important reference value for further exploration of the catastrophic mechanism of tunnel structure under the cumulative effect of initial damage defects.