Mechanics of Discontinuous Solids for the Safety Evaluation of Nuclear Waste Disposal- Development of Coupled Flow Analysis Method

点击翻译按钮获取中文摘要

Due to the defomiation of sliding opening of joints in fractured rock mass, consequent changes in the flow characteristics of jointed rock mass would be anticipated. The effect of deformation of joints are clarified by newly developed FE analysis method, which enable us to investigate both mechanical and hydraulic property of a joint whose surface geometry is obtained from existing rock joints. In the present study, a number of numerical techniques are employed in order to evaluate the excavation-induced changes in hydraulic properties of jointed rock mass. These are represent by the Micromechanics-Based Continuum (MBC) model analysis (FE excavation analysis in jointed rock mass), FE flow and transport analysis in the dscrete network of joints, and a separate computational module connecting these two techniques which is incorporated to modify initially imposed transmissivity into the excavation-induced ones. The effect of excavation on the hydraulic properties is evaluated by including this excavation-induced transmissivity of individual joints in the FE flow analysis in jointed rock mass. The excavation induced transmissivity of individual joint is calculated by the numerical and analytical techniques developed for flow through a single rock joint. The calculation of the excavation-induced transmissivity involves the distribution of shear displacement and normal stress around the excavation, and implicitly takes into account the effect of surface geometric roughness. Using the proposed model, test simulation for a deep underground repository is performed to illustrate the typical trends predicted in the pesent method.