Construction Numerical Simulation Of Cavern Group In Underground Hydropower House

With the development of the engineering technology, great and rapid progress inunderground engineering has been achieved, which expands the survival space of humanbeing. People can be able to make use of the resource. The development of undergroundengineerings increase quickly both in number and scale, some century and large hydrolic andhydropower engineering has been in construction, which is marked by the design of large orhuge cavern group, the excavation work of cavern group disturb initial state of rock mass,From comparation of stability, safety and the technique economies analysis, it is necessary tocarry on the construction numerical simulation.This paper takes ANSYS as preprocess platform to generate the finite element meshdividing, t use data preprocess programme that designed by the author is adopted to changeANSYS file format to FLAC^3D file format, FLAC^3D is taken as calculation platform tosimulate excavation work of cavem group.An improved simple and effective method for generation of the initial stress field isintroduced by using FLAC^3D and its embedded programming language: FISH, the FISHprogramme is taken to process the stress components of finite difference zones in order toreach equilibrium of calculation, some internal commands are executived to changethe constitutive relationships of difference zones to simulate the dispute of initial stress field.Base on characteristic distribution of initial stress field, the three-dimensional nonlinear backanalytical numerical analysis model is built up and the fault and major joint cranny issimulated. Back analysis method is adopted to get different side pressure coefficients by theimproved neural network method. Direct computations based on FLAC^3D are performed tocheck the back analysis results by measured principal stresses of some specific points, theback analysis result of initial stress field is used to the following trial calculation ofmechanical rock masse parameters.Based on the construction procedure and measured data, the first excavation issimulated to get the rock masse parameters by trial calculations, and the parameters is takeninto the next excavation calculation, and the accuracy of rock masse parameters is checked bymonitoring values of embedded multiple-point extensometers and statistics analysis, theanalysis show the rock masse parameters are reasonable With the initial stress field and parameters from back analysis and trial calculations, thestability of the rock mass is simulated by construction procedure, the change of displacement,plastic zones, stress field and axial force of prestress anchor rope is analyzed, and some usefulconclusions are given as a reference for the engineering practice.