Coupled Unsteady Seepage And Stress Fields In Discrete Fracture Rock Mass

Coupled analysis research of unsteady seepage and stress in fractured rock masses is a very valued task for discussion. The seepage in rock mass mainly reflected as fracture flow. With the changing of boundary hydra-head, the width of the fracture increased or reduced, which affects the fracture flow. Conversely, the change of seepage field affects the stress field. The interaction of the two filed is called coupling. On the basis of existing studies in the field of seepage of rock mass both at home and abroad, the thesis has conducted a broad study. The discrete fracture network method is used in seepage field and the FEM is used in stress field, then iterative method is used in the coupling unsteady seepage and stress fields numerical analysis. The paper is written by employing such methods as field observation, model test, theory research and numerical analysis. The main researches as follows:1. Study on the interaction of the seepage and stress on fractured rock mass. Analyzed and used the result on study field of visible rock mass mechanics. Based on study properties of rock mass mechanics, analysis the relationship between stresses and osmotic ratio, and created the model of coupling.2. The discrete fracture network method is used in unsteady seepage field. The programs are made and proved based on the mathematic model of the unsteady seepage in the fracture network to analysis the two example which aperture is the same and different. The distribution of the fracture network in the rock mass is simulated by the Monte-Carlo method.3. Coupled unsteady seepage and stress fields in 2-D and 3-D fracture network rock mass are used different elements to simulation. The programs to analysis unsteady seepage and coupling fields in fracture rock mass are made by the research group.4. Study the interaction of the seepage and stress on the rock mass stability of high dam. The coupling model of unsteady seepage and stress on fractured rock mass are created. Based on the dynamics parameterand the condition of the interaction of the seepage on a project of high dam, analysis coupled unsteady seepage and stress fields on the dam foundation stability. The discrete fracture network method is used in seepage field and the FEM is used in stress field, then iterative method is used in the coupling unsteady seepage and stress fields numerical analysis. The calculation results indicated that, considered the coupling the hydraulic head in the fracture rock mass is lower than unconsidered the coupling. Especially in the unsteady case, the hysteresis of the seepage head distribution is more obvious than the steady case.