| With the rapid development of the national economy,China has been increasing the investment in transportation infrastructure construction,the tunnel engineering has become an important part of transportation construction,at the same time,it also brings opportunities and challenges to the construction.Nowadays,the tunnel dynamic information design and construction technology is widely praised,in view of the complexity of the tunnel's underground environment,how to obtain the mechanical parameters of surrounding rock accurately,it is very important to tunnel design,construction and numerical calculation theory of rock mechanics.In order to solve this problem,based on the construction of Shun Shao highway Xiao Qian tunnel as the project support,the site measured data as the basis,combining the orthogonal test and numerical simulation,set up an intelligent displacement back analysis model of BP neural Network,and the surrounding rock mechanics parameters obtained by back analysis are applied to the dynamic simulation of tunnel construction and optimization analysis of excavation methods,which realizes dynamic feedback of information and guidance for tunnel design,construction and monitoring.The main research contents and results are as follows:(1)In view of the importance of monitoring and measuring in the New Austrian Tunneling Method,according to the geological condition and actual engineering situation of the Xiao Qian tunnel,making the monitoring measurement scheme during the tunnel construction,carries on the regression analysis processing to the field displacement monitoring data,predicting the deformation trend of the surrounding rock,the final value of displacement and the time for deformation to stabilize are determined,providing a reasonable support time for second lining,and the construction management control datum of tunnel surrounding rock deformation is established.(2)The numerical model of tunnel is established by the geotechnical engineering finite element software of MIDAS GTS NX,on the basis of the importance and principle of choosing the inverse parameters,based on the principle of orthogonal experimental design and analysis method,the sensitivity of different mechanical parameters to the deformation of surrounding rock was studied by orthogonal numerical test,and the mechanical parameters of the rock to be reversed were determined by considering all factors.(3)Through the optimization and improvement of neural network structure,the BP neural network intelligent Back analysis system is established,the learning and test samples are constructed by orthogonal test and uniform test,the posterior differential method is used to test the predict ability of the network,combining with field monitoring data,the mechanical parameters of surrounding rock are calculated by using MATLAB platform neural network toolbox,simulating calculation by replacing parameters in the model,and compare with the measured displacement,the correctness and feasibility of the inverse analysis method is further verified.(4)The mechanical parameters of surrounding rock are applied to the dynamic simulation analysis of tunnel construction,the deformation law of surrounding rock after tunnel excavation is mainly studied,and the influence of different excavation methods on the stability of surrounding rock is analyzed and compared,which provides guidance and basis for the design,construction and monitoring measurement of tunnel engineering. |
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