MATHEMATIC-MECHANIC RESEARCH ON THE INFLUENCE OF THE SHUITIANBA FAULT BY THE STRESS FIELD OF THE THREE-GORGE RESERVOIR

摘要

According to the fundamental theory of Hydraulic Stress Field formed by full-storage reservoir, the math-mechanic model is set up. It shows that there is a certain effect on the Fault with the plane range of 5-6 km along the fault zone. Acted by this hydraulic stress field, both walls of the fault are all in condition of compressive stress. The stress increases with depth from zero on the surface. In view of the relationship of the magnitude of stress with expanding depth of the fault, the stress value on its top and foot walls produced by the hydraulic stress field is far higher than that measured in this area, so that is bearable by the fault. The hydraulic stress field brings about a floating support effect to Shuitianba Fault and surrounding rock where the surface displacement is no more than 10 mm and reduced with the increasing depth. Additionally, the top and foot walls of the fault exist clearly a tendency of displacement discontinuity and compressive deformation. After Three-Gorges Reservoir full storage, it is impossible to cause a moderate strong seismicity by a considerable from Shuitianba Fault under a hydraulic stress field condition to give influence to the Three-Gorges Project.