Stability Analysis Of Surrounding Rock On Deep-Buried Tunnel Of Hanjiang-to-Weihe River Water Diversion Project

There are a lot of underground rock engineering and slope engineering in many fields,such as water conservancy and hydropower,railway,highway,mine,national defense,resource reserve,etc.According to incomplete statistics,in recent years,there are more than 500 kilometers of newly built hydraulic tunnels and more than 4000 kilometers of railway and road tunnels.The traditional stability analysis of surrounding rock,whether numerical analysis or theoretical analysis,is a process of positive analysis,which often uses empirical analogy to determine the mechanical parameters of surrounding rock,which has inaccuracy and certain security risks.Therefore,in the actual project,through the back analysis of the monitoring data of the project,the mechanical parameters of the rock mass are obtained,and the stability of the surrounding rock is analyzed.In this paper,based on Deep-buried Tunnel of Hanjiang-to-Weihe River Water Diversion Project,the monitoring data of the actual project site are collected for regression analysis.Combined with the finite element calculation model and BP neural network genetic algorithm intelligent system,the mechanical parameters of the surrounding rock of the tunnel are inverted.Using orthogonal design test and uniform design test,the determined mechanical parameters(elastic modulus,cohesion,internal friction angle)are designed in the initial domain.Multiple groups of parameter samples are taken into the established finite element model,and the training samples and test samples of BP neural network genetic algorithm intelligent system are obtained.Genetic algorithm is used to optimize BP neural network,which is easy to fall intotraining time and local minimum.The results of the finite element model are used as training samples and test samples to build the BP neural network genetic algorithm intelligent system.The optimized mechanical parameters are brought into the finite element model to analyze the stress-strain,displacement deformation and plastic zone before,after and after the excavation of tunnel surrounding rock,so as to achieve the purpose of safety analysis and information construction of surrounding rock stability.The research results have certain reference value for the change of construction method,confirmation and modification of reserved deformation,and change of construction process.