基于正反向直剪试验的岩石节理JRC值计算研究  

Study on calculation of rock joint JRC value based on forward and reverse direct shear tests

作　　者：肖维民 刘伟超 朱占元 XIAO Weimin;LIU Weichao;ZHU Zhanyuan(School of Civil Engineering,Sichuan Agricultural University,Dujiangyan,Sichuan 611830,China;Sichuan Higher Education Engineering Research Center for Disaster Prevention and Mitigation of Village Construction,Dujiangyan,Sichuan 611830,China)

机构地区：[1]四川农业大学土木工程学院,四川都江堰611830 [2]村镇建设防灾减灾四川省高等学校工程研究中心,四川都江堰611830

出　　处：《岩石力学与工程学报》2021年第S02期3098-3106,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41877195,41502242)。

摘　　要：剖面线JRC值是利用Barton的JRC-JCS抗剪强度模型估算岩石节理抗剪强度的关键参数,目前关于岩石节理剖面线JRC定量计算的研究成果非常丰富,但是考虑剪切方向影响的岩石节理JRC值计算研究还较为欠缺。为此,在对10条Barton标准剖面线进行精细数字化处理获得其二维坐标数据的基础上,考虑剪切方向影响,计算剖面线坡度均方根一阶导数Z_(2)*值,同时,开展具有Barton标准剖面线形貌特征的人工模拟岩石节理试件正反向直剪试验,在此基础上利用正反向直剪试验,反算JRC值和对应的剖面线Z_(2)*值,通过回归分析,建立考虑剪切方向的岩石节理剖面线JRC值对数和幂指数经验计算公式,并将经验公式JRC计算值与直剪试验反算JRC值进行比较,结果表明,幂指数关系式更适合计算正向剪切下的岩石节理剖面线JRC值,而对数关系式更适合计算反向剪切下的岩石节理剖面线JRC值。JRC is a key parameter to predict the shear strength of rock joint by using Barton's JRC-JCS model.Although there are massive researches on methods for calculating JRC of a rock joint profile,few researches had been reported on the calculation of rock joint JRC value by considering shear direction.Herein,based on the 2D coordinate data of Barton's ten standard profiles derived from fine digitization process,firstly the root mean square of the first derivative of the profileZ_(2)^(*)was calculated by consideration of shear direction.Meanwhile,forward and reverses direct shear tests were performed on artificial rock joint specimens which were of the same topography of Barton's standard profiles.Then non-linear regression analyses were performed between JRC and Z_(2)^(*)which were respectively derived from back-calculation of forward and reverses direct shear test results and 2D coordinate data of standard profiles,from which empirical logarithmic and exponential expressions were obtained for determining the JRC value of rock joint profile considering shear direction.Furthermore,the predictions of JRC values derived from the above-mentioned empirical logarithmic and exponential expressions were compared with these back-calculated from forward and reverses direct shear tests.From the comparisons,it showed that the empirical exponential expression was more suitable for calculating the JRC of rock joint profile in forward direct shear tests,while the empirical logarithmic expression was more suitable for reverse direct shear tests condition.

关 键 词：岩石力学 岩石节理 节理粗糙度系数JRC 正反向直剪试验 

分 类 号：TU45[建筑科学—岩土工程]