Abstract: UDEC discrete element method can simulate the actual tunnel collapse to a large extent by the cyclic iterative calculation of the large deformation motion of the block. Taking Ziyin tunnel collapse accident as the engineering background, the collapse process of the tunnel was simulated by UDEC discrete element method, and the correctness of the UDEC discrete element method to simulate the tunnel collapse was verified by comparing with the actual collapse situation. The collapse process of tunnel with different buried depth, different rock mass structure and different surrounding rock grade was simulated by UDEC discrete element method, and the collapse characteristics of tunnel were analyzed. The results show that the buried depth mainly affects the range of vault collapse and the rock mass structure (such as joint fissure) has a greater influence on the form of collapse; the surrounding rock parameters also affect the range and the form of collapse.

Key words: tunnel engineering, UDEC discrete element, soft rock tunnel, collapse characteristics, stability of surrounding rock

摘要： UDEC离散元法通过对块体大变形运动进行循环迭代计算，可以较大程度的模拟隧道实际塌方情况。以子尹隧道塌方事故为工程背景，采用UDEC法对 该隧道塌方过程进行模拟，通过与实际塌方情况的对比，验证了UDEC离散元法模拟隧道塌方的正确性；通过UDEC离散元法分别模拟了不同埋深、不同岩体 结构和不同围岩级别的隧道塌方过程，分析了隧道塌方特征。研究表明：埋深主要影响拱顶塌方的范围；岩体结构(如节理裂隙)较大程度的影响塌方的形 式；围岩参数同时影响塌方范围和塌方形式。

关键词: 隧道工程, UDEC离散元, 软岩隧道, 塌方特征, 围岩稳定性