| A lot of large-scale underground projects have appeared in recent years, for instance such a lot of fields as the tunnel , railway , highway , mine , water and electricity , national defense , urban subway and urban construction ,etc. The surge shaft of FUTANG power station originally in the geological condition complicatedly, and internal diameter and depth are relatively heavy, known as the first well of Asia. as a underground structure ,which is different from the ground structure, security and stability of analyzing and studying the underground structure not merely relate to structure, still closely related with the environment around - the geological condition of the project (natural rock body) and construction course, namely the stability of the country rock influences the security of the underground structure greatly. So correct stability analysis is the assurance that is designed and constructs safely. Underground structures calculate development of theory have a history of over one hundred years already, it has already presented a large number of analysis rock project stability methods in rock mechanics now. No matter which kind of methods, need the mechanics parameter of introduction country rock at first but Because of natural rock complexity , body of itself, and survey technological restriction of means live at present, make mechanics of country rock parameter difficult to confirm , it is difficult to judge security of project.With the development of information science, against to is it solve this problemget the new thinking out of to give analytical method, in this paper, utilizes on-the-spot monitoring data and identification of systems method to confirm the material parameter of the country rock. Then carry on finite element analysis, to confirm the excavation stability of the project on this basis. Combine the finite element method and neural network method together to solve large-scale rock soil project safe analysis of performance to use for; it is a main achievement of this paper. Summarize concretely:(1) Set up surge shaft three-dimensional finite element model, combine on-the-spot monitoring data judge the feasibility of calculating model. To adopt is even to design by thought of law, choose different material parameter of (Elastic mould E and passion ration) to do finite element analyze, to receive the back-analysis data.(2) Carry on the country rock parameter back analysis in MATLAB artificial neural network: Have set up the back-analysis neural network elastic model. This model has reflected the relation of shining upon between the mechanics parameter of country rock and rock body displacement, adopt the momentum gradient descent method to study the parameter space and search for and seek excellently the overall situation in rock physical power. Perform result is it indicate network model this have better prediction precision to measure, mechanics parameter of country rock is performed instead to suitable for the Geotechnical Engineering.(3) Utilize neural network back analysis country rock material parameter that receive, is it set up three-dimensional finite element model to simulation excavate course to, research the stability surge shaft of excavated, result show: because the shaft well excavate section to be very big , high and steep slope have behind the well to transfer well to transfer originally, it is asymmetric to live in the topography, Stress and displacement of the surge shaft distribute more complicated of country rock. Generally, present the middle heavy, upper and lower department less distribution law. By behind slope side rock pinch, the surge shaft has trend moving outside mountain. Can be judged through intensity criterion and norm, the structure is steady.(4) Compare with reconnaissance and survey data, result show , combineneural network back-analysis method and finite-element method, used in the large-scale underground project structure analysis that has calculating amount few high in precision , with high efficiency characteristics. So calculation model in this paper put forward can use for underground design of project that similar to and of the construction. |
