| As a kind of typical safety accident, tunnel collapse happens in the tunnel construction process. It not only leads to the delay in carrying out the project, but also the huge loss of property, and even casualties, thus it causes adverse effect on the whole project’s construction. In order to avoid the occurrence of collapse and ensure the safety of tunnel construction, the research, centering on tunnel collapse mechanisms and pre-warning technology, is of great significance.Based on Jiangyuan Ridge highway tunnel in Hunan province which is deep buried and has large cross-section, the paper has derived the scope of tunnel collapse by limit analysis theory, carried out numerical calculation by using FLAC3D software, and set up the deformation prewarning system of highway tunnel collapse based on monitoring data. This paper has mainly completed the following work:(1) The paper has employed the limit analysis upper bound theorem and nonlinear Hoek-Brown criterion to investigate the shape and scope of the collapse in smooth three-centred arch cross-section tunnel. And the analysis of each parameter’s influence on collapse shape and collapse dimension has been done.(2) The analytical solution obtained by limit analysis upper bound theory has been contrasted with previous research findings, numerical results and tunnel collapse examples. Through comparison and analysis, the correctness and validity of the theory were verified.(3) Based on the strength reduction method, the numerical simulation of the tunnel has been carried out. The laws of progressive development of tunnel collapse have been summarized, and the reinforcement effect on preventing tunnel collapse has been investigated.(4) By carrying out statistical analysis for measurement data of a large number of tunnels and introducing the concept of confidence interval, three-level prewarning system of highway tunnel collapse was proposed based on the deformation alarm value and was finally applied to Jiangyuan Ridge tunnel. |
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