不同边界条件下剪切速率对类岩石节理剪切力学特性的影响  

Effect of shear rate on shear mechanical properties of rock-like joints under different boundary conditions

作　　者：田世轩 郭保华[1,2] 孙杰豪 程坦 TIAN Shi-xuan;GUO Bao-hua;SUN Jie-hao;CHENG Tan(School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo,Henan 454000,China;The Collaborative Innovation Center of Coal Safety Production of Henan Province,Henan Polytechnic University,Jiaozuo,Henan 454000,China)

机构地区：[1]河南理工大学能源科学与工程学院,河南焦作454000 [2]河南理工大学煤炭安全生产河南省协同创新中心,河南焦作454000

出　　处：《岩土力学》2023年第2期541-551,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51904092);河南省高校基本科研业务费专项资金(No.NSFRF180336,No.NSFRF210303);河南省自然科学基金(No.202300410183);河南省高校重点科研项目基金(No.21A440003)。

摘　　要：为研究不同边界条件下剪切速率对岩石节理剪切力学特性的影响,采用RDS-200型岩石节理剪切试验系统对人工浇筑的具有相同节理形貌的不规则水泥节理试样进行了常法向应力和常法向刚度2种边界条件下5种剪切速率的直剪试验。结果表明:(1)常法向应力边界条件下,随剪切速率增大,相同法向应力下的类岩石节理峰前剪切刚度减速增大,峰值剪切强度和残余剪切强度呈对数降低;随剪切速率增大,类岩石节理黏聚力减速增大,内摩擦角呈对数降低。(2)常法向刚度边界条件下,随剪切速率增大,相同法向应力的类岩石节理峰前剪切刚度减速增大,峰值剪切强度呈对数降低,较高法向应力下的残余剪切强度先增大后减小;随剪切速率增大,类岩石节理黏聚力呈对数降低,内摩擦角减速增大。(3)与常法向应力边界条件相比,常法向刚度条件下,节理黏聚力平均增加了115.85%,内摩擦角平均降低了8.44%;相同初始法向应力和剪切速率下,峰前剪切刚度、峰值剪切强度和残余剪切强度分别平均增加了11.96%、19.47%和32.32%,峰值法向位移平均降低了40.12%。该研究结论可为不同剪切速率下地表和地下工程岩体节理的剪切失稳评价提供一定参考。In order to study the effect of shear rate on the shear mechanical properties of rock joints under different boundary conditions,RDS-200 rock joint shear test system was used to carry out direct shear tests with five different shear rates under two boundary conditions including constant normal stress and constant normal stiffness on artificially cast irregular rock-like joints with the same joint morphology.The experimental results are as follows.(1)Under the constant normal stress boundary condition and a same normal stress,the pre-peak shear stiffness of rock-like joints decreases with a decreasing rate,and the peak shear strength and residual shear strength decrease logarithmically with the increase of shear rate;in addition,the cohesion of rock-like joints increases,and the internal friction angle decreases logarithmically with the increase of shear rate.(2)Under the constant normal stiffness boundary condition and a same normal stress,the pre-peak shear stiffness of rock-like joints decreases with a decreasing rate,the peak shear strength decreases logarithmically,and the residual shear strength increases first and then decreases under higher normal stress with an increase of shear rate;moreover,the cohesion of rock-like joints decreases and the internal friction angle increases logarithmically with an increase of shear rate.(3)Compared with the constant normal stress boundary condition,the cohesion force of the rock-like joint increases by 115.85% on average,and the internal friction angle decreases by 8.44% on average under the constant stiffness boundary condition;the pre-peak shear stiffness,the peak shear strength and the residual shear strength of the rock-like joint increase by 11.96%,19.47% and 32.32% on average,respectively,and the peak normal displacement decreases by 40.12% on average under the same initial normal stress and shear rate.The research results can provide some references for the shear instability evaluation of surface and underground engineering rock joints under different shear rates

关 键 词：岩石力学 类岩石节理 剪切速率 常法向应力 常法向刚度 

分 类 号：TU453[建筑科学—岩土工程]