东兴场隧道水平岩层变形破坏机制的物理模拟研究

Study on the Physical Modeling of the Deformation Mechanism When Excavating a Tunnel

在对东兴场隧道断面围岩的物质组成、结构特征分析的基础上,定性分析其变形、破坏成因机制,选择合理的相似比,并以Ⅰ—Ⅰ'断面为实例建立地质模型进行物理模拟。根据岩层层面及节理产状将其层面共分为11层,以模型架固定边框为约束简化实际边界条件,采用底摩擦试验方法对隧道开挖后围岩变形各阶段进行模拟,由此得出该隧道开挖后围岩的变形过程分为弯曲内鼓—拉裂—折断塌落3个阶段,其结果与现场定性判断相吻合。

First this paper introduced the principle of the experimental method of basal contact friction and then focusing on the Dongxingchang tunnel wall rock-section, analyzed the material composition and the structural characteristics of the surrounding rock. It has also analyzed qualitatively the mechanism for the deformation, established a geological model taking the example of the Ⅰ - Ⅰ cross-section and carried on a physical modeling by choosing a reasonable similar rate. The rock strata are divided into 11 layers according to its terrane and joint attitude, and the actual boundary conditions are simplified by the model frame. The basal contact friction experiment is adopted to simulate surrounding rock＇s deformation in all phases after excavating the tunnel, thus we can get that the deformation is divided into three phases： incurvate-ripping-collapse. This result is totally coincided with the qualitative judgment on site.