Back-analysis Of Initial Ground Stress Based On ANSYS And Wavelet Neural Network And Rheology Analysis Of Surrounding Rock Of Cave

Along with the continuously quickly development of our country's western region many large projects in the rock body engineering. Such as the exploitation and utilize of resource for western water power, petroleum, coal, the design and the remark of the stabilities in the ground engineering, underground space and the rock slope. All of these need us understand the initial stress value much better. Aiming at the high stress in the Jinping hydroelectric power station, the bury deep of the level and the uprightness is very big. The lithology of the rock is complex and the rupture structure is growth, especially the region belongs to high stress. So it is very important to reasonably evaluate the initial stress. In the high stress the deformation grows with the time. The cave's distortion is also one of the important research problems.The initial stress was calculated a great deal by building the 3D FEM model. We can get the boundary conditions and the mechanics parameters that are relatively adjacent to the realmeasure data. Because wavelet neural network includes two new variables------scale factor anddisplacement factor, the WNN has excellent functional approximation abilities. The WNN that is composed of relatively less series term has often fast functional approximation abilities and has a good predicting precision By sifting out the parameters. Firstly, the almost initial stresses were calculated by using FEM theory : Secondly, the most approximately boundary condition and mechanics parameters can be got by the WNN: Thirdly, the region stress field can be simulated by taking the most approximately boundary condition and mechanics parameters. The simulation results show that the method is high approximation efficiency and feasibility.Finally applying the simulation results to the engineering example, the surrounding rock excavating stability is analyzed by taking rheological model. According to the straight shear test result the time-dependent behavior, the stability and the hole excavating influence each other of the surrounding rock are analyzed by using 3D viscoelastic-plastic numerical method.