Research On The Occurrence Mechanism, Evolution Procedure And Prevention Of Joint Tunnel Collapse

Along with the traffic construction in the southwest mountainous areas, highway and railway constructs are inevitable traversing mountainous area,tunnel construction project becomes a key project, and in the process of tunnel construction,often encountered complex geological conditions, and the tunnel collapse may happen in some adverse conditions, since the complicated geological conditions cannot be precisely and comprehensively considered .To avoid the tunnel collapse and to reduce the harm caused by landslides effectively, it is very important to study the occurence and the development of the tunnel collapse. The mechanism of tunnel collapse are various in different geological conditions.On the basis of a systematic summarization of the collapse type as well as the effective factors,the occurence and the development of the global consequent layer and local collapse are numerical simulated, together with the global and consequent layer pre-collapse simulation and treatment result simulation of local collapse, it reveals the the occurence and the development of the different types of the tunnel collapse, gives prominence to the pre-collapse measure in complex geological condition construction.The reliability of the numerical analysis is verified by comparision with the model test study of the consequent layer collapse. The Liujiawan tunnel collapse was prediction analysised by using collapse grey prediction model according to the local monitoring data.This paper theoretically studied the development mechanism of the different types collapse, enriched the theory of the tunnel collapse, summarized effective pre-collapse and treatment for the different types of collapse, has the important guiding sense to the latent collapse tunnel construction.