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With the rapid development of high-speed railway, there must be a large number of tunnels to emerge because of the technical standards for high-speed rail lines (in plane and profile) is much higher than the normal rail. The design of tunnel supporting structure is a very complex task, but the current method is mainly based on engineering analogy, with large-scale development of high-speed railway, the establishment of a scientific and rational design of supporting structure is an imperative task. This paper made the following study on optimization design of high-speed railway tunnel supporting:(1) On the basis of access to a large number of relevant literature, Comprehensive analyze the development of domestic high-speed railway, analysis theory and methods of surrounding rock stability, and theory of the mechanism of tunnel support, using reasonable support theory and research methods of surrounding rock stability, to guide the design of the tunnel support parameters.(2) Based on numerical simulation for the main factors by FLAC3D,analyzed the law between the stability of surrounding rock and the level of physical and mechanical parameters of surrounding rock, the tunnel depth, the lateral pressure coefficient of surrounding rock, the length of bolt, bolt spacing, the thickness of sprayed concrete, to determine the level of the tunnel depth.(3) Using orthogonal design method, design experiment of geological factors (level of physical and mechanical parameters of surrounding rock, the tunnel depth, the lateral pressure coefficient of surrounding rock), supporting factors (length of bolt, bolt spacing, the thickness of shotcrete),got composition and efficient basis sample.(4) Based on the visual analysis and calculation variance analysis of test results, to further determine the main factors affecting stability of surrounding rock, using the least square method, got the optimization value function of support parameters of tunnel.(5) Selected high-speed railway tunnels have been built as project examples and using the formula obtained in this support parameters, got optimize results, then compare the practical engineering design and the optimization one, the two are very close, proved optimal value function of this article has good practicability.
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