Numerical Analysis Of Seepage-Stress Coupling In Fractured Rock Mass And Its Application In Engineering

The scale of civil engineering is increasing with the rapid development of national economy. The deformation and stability in dynamic equilibrium system of engineering rock interaction between seepage and stress are common problems many engineering principles faced. Statistics show that, groundwater seepage forces are responsible to above 95%of rock slope failures. 60%of the mine disasters are related to the action of groundwater. 30%～40 %of dam failures are caused by percolation. So, fractured rock coupling analysis between seepage and stress or strain is a significant but complicated subject. In recent years, coupling research, between seepage and stress or strain, has been one of the hot issues widely focused in the field of rock mechanics.Cubic law described the fluid flow in fracture is based upon parallel plane joint model. Based on rock hydraulic mechanics, in the thesis, unsteady flow in single joint and non-parallel wedge-shaped joint fluid flow equations are established. The shear formula in single fissure seepage system applied on fracture faces is presented and formed. Some mathematical models of seepage and mechanic analysis in fractured rock mass are summarized. Finite Element Analysis simulation equations of non-double porosity model-equivalent continuum media model and discrete fracture network model are established,furthermore, a coupling model integrated with the merits of two models mentioned above is presented.Coupling research between seepage and stress, assuming the anisotropic rock mass as equivalent continuum media, is achieved through iterative method. First, stress and seepage force on each node of model can be got after computation without reference to coupling. Second, mechanical analysis is carried out with seepage forces got from seepage analysis and applied on nodes at the same time. Third, conductivity of seepage field becomes explicit according to coupling relationship function. Last, iterate the analysis what have done above until the results come to convergence.The stress and displacement formulas of pressure tunnel surrounding rock are established, which is based on principle of elastic theory. These formulas under seepage are also established.Then, the formulas of coupling seepage and stress and the differential solutions are established. In engineering applications, coupling analysis between seepage and stress of the gravity dam foundation and rock slope are done through commercial finite element software.