Under The Condition Of Water Force Coupling Granite Fracture Mechanics And The Permeability Test Research

Underground energy storage, CO₂ geological sequestration, oil gas and mineral mining and underground disposal of high-level radioactive waste rock engineering such as many water related countries all over the world are very concerned about the issue.The granite has a series of characteristics of permeability of small, dense, high strength for nuclear waste, oil, natural gas underground storage.A large number of international scholars to study the mechanical behavior of granite.Due to the excavation and construction of underground rock engineering, the formation of rock excavation disturbed zone, in the formation of tensile cracks of excavation disturbed zone of the near field and far field compressive shear fracture is formed, and the groundwater, high energy and underground disposal of radioactive wastes must consider the seepage- stress interaction process:1)Due to the excavation of underground rock engineering granite area of the rupture process and thus caused the changes of permeability of rock mass and fracture opening;2)Due to the change of groundwater flow field caused by the above process, and the flow field pressure on rock stress, deformation of the reaction.Due to the permeability of complete granite is extremely low, Rock engineering of underground excavation disturbed zone field coupling more prominent characteristics: granite fissure in many field coupling.By the discussion above,Built from the physical and chemical mechanical mechanism can really reflect the excavation disturbed zone of granite fissure seepage flow-stress coupling mechanism analysis of the theoretical model and method is still need to break through the primary subject and key problem.In fact,Excavation disturbed zone of granite fissure seepage flow-stress coupling macro effect has its clear and profound mesoscopic mechanism,Only from the mesoscopic point of view,Analysis of granite tension and shear fracture pressure inside the different mechanism of the seepage flow-stress coupling effect.Establish seepage flow-stress coupling conditions granite fissure mesoscopic- macro scale associated mechanism.Can be established from the physical and chemical mechanics can really reflect the high level radioactive waste disposal granite fissure seepage flow-stress the coupling mechanism of the theoretical model and analysis method.This paper emphatically from the angle of mesoscopic tension and pressure within the shear fracture mechanism of coupled seepage flow- stress were studied. The paper main research work and achievements:1. In the granite triaxial compression test.The experimental results showed that:Granite obviously has some basic mechanical properties of the brittle rock: such as sensitivity to confining pressure, peak intensity failure mode brittle-transformation, transformation of compressed volume deformation, expansion.2. The experimental results showed that:（1） with the increase of hydrostatic pressure, all sample permeability decrease quickly, and then tends to a stable value. This is due to the crack opening decreases with increasing hydrostatic pressure caused; 2) containing tensioning-pressure shear fracture sample permeability decreasing the rate of decrease with the increase of hydrostatic pressure; 3) with the increase of hydrostatic pressure, including tension crack sample permeability decreases at a rate of more than with the decrease of the permeability rate of compression-shear crack sample.3. In order to in-depth analysis including tension and compression shear fracture specimen under the condition of hydrostatic pressure loading different evolution law of permeability shown, conducted with tension- compression-shear fracture surface granite mesoscopic scanning electron microscopy（SEM） test. Results show that the uniaxial compression test of granite fracture surface more smooth; And with the increasing of confining pressure, fracture surface obviously observed increasing pressure type shear fracture, fracture surface is rough. The shear fracture surface tension and pressure, therefore, different mesoscopic structure determines the tension and pressure shear fracture specimens of different permeability evolution.