The Research On Rheological Model Of Complex Dam Rock Mass With Coupled Stress And Seepage Field And Its Application

With the fast economic development and rising energy demand, China put forward in the positive development of hydroelectric, nuclear and other advanced utilization of renewable energy in the energy structure adjustment and optimization proposals. Therefore, it is still the target for the next five-year plan to accelerate the construction of hydropower development and construction. The target will bring the increasing number of rock engineering projects. As the basis of engineering construction, slope and rock engineering geology of the medium, the mechanical properties of rock mass are directly affect the safety of the project. One of the most important mechanical properties is elasticity and plasticity, and time-dependent characteristics, the rheological property. Seepage is an important factor in the mechanical properties of rock creep. Especially the rock mass of hydropower project and long tunnel surrounding rock stay in the state of surrounded by water in the long-term. The tunnel excavation disturbance will cause the original rock burst and increasing the exposed area of rock mass, which leads to the increase of the rock mass seepage path, weakening the rock property. Along with the growth of the time rock instability phenomena may occur and cause major accidents. Therefore, research on rheological model for the complex dam rock under the coupled stress and seepage field conditions have great realistic meaning and social significance and engineering application value for the operation of the long-term stability of high arch dams.Hard brittle rock as the main research object, the diabase was selected. Based on the triaxial compression test and triaxial creep test data, the experimental study and theoretical analysis and numerical simulation method are used to analysis the rheological effect under the coupled stress and seepage field conditions. The main contents of this thesis contain the following aspects:(1) Choosing the diabase of Dagangshan hydropower station dam rock, the triaxial compression test and triaxial creep test were taken. Through the analysis of the experimental data, the initial damage thresholds are obtained. The damage model is established. The model was verified with two types of rock test data.(2) Based on the test data proposes the nonlinear visco-elasto-plasic mixed elements rheological model. This model can describe the accelerated creep stage. Combining the damage model of triaxial compression test, the rheological damage model is established. Validated by the test data, the results show that the calculated value of the model was consistent with the test results and illustrates the rationality of the model.(3) The stress seepage coupled rheological model is established. With C++and fish language programming secondary development of finite difference software, the nonlinear visco-elasto-plastic mixed elements rheological model was embedded in software. Comparison between the user-defined model and the software own model, the results show that the user-defined model can describe the practical creep process.(4) In view of the non-Darcy seepage effect of practical engineering rock in fissure medium or rock mass with more fractures, the Newtonian fluid in such media linear stability problem was developed. Based on normal modes analysis theoretically gives the whole control system dynamic response of different seepage parameters, when the pressure and velocity field under steady state disturbed and destroyed. Then this thesis discusses the value of Darcy deviation factor’s influence on the system stability.(5) Considering the different degree of fractures in rock mass, the dual-porosity medium model was used to establish the rheological model under stress seepage coupled field. The finite element calculation and calculation format and solving method of the model were studied in this paper. Using the finite element software gives the model numerical simulation.(6) Using the rheological model of hard brittle rock, Dagangshan hydropower station excavation and rheological numerical calculation of slope in dam zone was simulated.