Experimental insights into frictional resistance and slip pattern of granite fractures and implications for thermoshearing prediction  

作　　者：Changlun Sun Jeoung Seok Yoon Ki-Bok Min Li Zhuang 

机构地区：[1]School of Mines,Guizhou Institute of Technology,Guiyang,Guizhou 550003,China [2]DynaFrax UG limited,Potsdam 14467,Germany [3]Department of Energy Systems Engineering,Seoul National University,Seoul 08826,Republic of Korea [4]School of Resources and Safety Engineering,Chongqing University,Chongqing 400044,China

出　　处：《Earth Energy Science》2025年第1期22-37,共16页地球能源科学(英文)

基　　金：supported by the International Collaborative Research Program(fundamental research,2021-2023);funded by Korea Institute of Civil Engineering and Building Technology(KICT).

摘　　要：Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior and its influencing factors are important for the long-term performance assessment of DGRs.We designed multistage mechanical(M)shear tests and thermomechanical(TM)shear tests on three 100 mm-cubic granite specimens,each containing a single inclined sawcut fracture with distinct microroughness of 8-15μm.M test results have shown that the static friction coefficient of the granite fracture decreases in proportion to the increase in the logarithm of the loading rate within the range of 1-15 kPa/s.For the given heating and boundary conditions,thermal loading rate,i.e.,thermal stress increment with heating time,is measured to be around 1 kPa/s in the fractured granite.Thermoshearing can be well predicted by the linear Mohr-Coulomb failure envelope deduced from M shear tests employing a loading rate that is comparable with the thermal loading rate.The granite fractures exhibited two distinct slip patterns during the mechanical shearing,i.e.,stick-slip observed in the smooth fracture and stable sliding in the relatively rough surface.In contrast,the mechanical loading rate(1-15 kPa/s)investigated in this study appears to not influence the slip pattern.Unlike those in M shear tests,thermoshearing in both smooth and relatively rough fractures show stable sliding with a very slow peak velocity of around 0.002μm/s.

关 键 词：Granite fracture Frictional resistance Slip pattern Thermoshearing Deep geological repository 

分 类 号：TG1[金属学及工艺—金属学]