Study On Effects Of Water-rock Interaction On The Shear Behavior Of Granite Joints

The construction requirements of high-level nuclear waste disposal repository are more and more urgent with the rapidly development of nuclear power in China.However,the long-term stability and safety problems of surrounding rock engineering have attracted wide attention due to the harmfulness of high radioactive waste.The water-rock interaction is one of the most active factors affecting the safety and stability of a rock engineering.The research on the damage effect of water-rock interaction on rock mass is becoming more and more important.Therefore,it is of great significance to study the effect of water-rock interaction on the mechanical properties of surrounding rock of high-level radioactive waste disposal reservoir.This thesis mainly studied the effect of water-rock interaction on the stability and safety of a rock mass engineering.The shear behavior of granite joints under the action of water-rock interaction and other different factors was studied and discussed combining test and numerical simulation.The following three tests were conducted:(1)Beishan granite at three different water-bearing states,dry,surface wet and saturated for 3 days;(2)Hunan granite was treated with different temperature levels;(3)Hunan granite was treated with different soaking time.The influence of water-rock interaction and other different factors on the shear behavior of granite were analyzed.In addition,this thesis introduced two weaken coefficient(and).and represent reduction rates of the uniaxial compressive strength and basic frictionangle in the analysis model,respectively.On the basis of the wear process of joint roughness coefficient of regression models,the numerical simulation study on the weakening evolution of rock joint roughness under the influence of water is carried out.At the same time,the verification of model and analysis of examples were carried out.According to the results of the above tests and numerical simulations,the following conclusions are drawn:(1)The uniaxial compressive strength and the basic friction angle of the saturated granite were significantly decrease compared with the dry and surface wet states.Because the water act as a lubrication lead to a trend of monotonic decrease in the shear strength of granite from dry state to wet state of joint surface to saturated state together.(2)The shear properties of rock are related to normal stress,soaking temperature and soaking time.With the increase of soaking temperature and soaking time,the peak and residual shear strength of the rock will decrease monotonously,and the degree of reduction is positively correlated with the normal stress.(3)The shear strength of rock is related to surface geometry.The larger the value of geometric parameter,the greater the shear strength value is.