Upper Bound Analysis And Risk Assessment For Collapse Of Deep Tunnel

Tunnel collapse is a typical accident in the tunnel construction process. It not only leads to the delay in the carrying out the projects, but also the huge loss of property, and even casualties, and might to cause adverse effects on the whole society. For this reason, in order to avoid the occurrence of landslides, the research, centering on the surrounding rock failure and collapse mechanisms of tunnel, is of great significance.Based on the tunnel of Longtou Mount in Guangzhou, which is the deep and large cross-section. The article will derive the scope of the tunnel collapse by limit analysis theory based on numerical software for numerical calculation, and therefore study on the law of landslides development. The thesis mainly completes the following aspects of work:(1)Through reading files and field investigation, this paper classifies landslides into several types and analyzes the main influencing factors attributing to the collapse.The linear and nonlinear Mohr-Coulomb criterions were presented, and the limit analysis theory also was described.(2)The paper has studied on the limit analysis upper bound theorem based on nonlinear Mohr-Coulomb criterion, and deduced the shape and scope of the collapse in rectangular and circular-arc cross section tunnel.And the analysis of each parameter on the influence of surrounding rock failure and landslide scope was been done.(3) The results of limit analysis upper bound theory have been contrasted with landslides examples, numerical results and height of collapse in design code for highway tunnel. Through this method, it can verify the correctness and feasibility of the theory.(4) Through the numerical simulation of the tunnel, the laws of occurence and the development of collapse have been summarized.And by using the fuzzy analytic hierarchy process method, this paper has assessed the collapse risk level of the tunnel.