岩石三轴压缩峰后曲线与抗剪强度参数关系探讨  

Discussion on Relationship between Post-Peak Curves and Shear Strength Parameters of Rock Subjected to Triaxial Compression

作　　者：张骞[1] 李术才[1] 李利平[1] 张乾青[1,2] 

机构地区：[1]山东大学岩土与结构工程研究中心,济南250061 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《地下空间与工程学报》2015年第3期642-646,657,共6页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金重点资助项目(51139004);国家自然科学基金资助项目(51009085);中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金项目(SKLGDUEK1210)

摘　　要：对岩样在常规三轴压缩下应力应变曲线特别是峰后强度变化曲线进行深入分析,通过分段函数和双曲函数建立峰后强度参数随软化参数变化的规律,给出了花岗岩常规三轴状态下峰后应力应变关系式的具体求法,并发现岩石粘聚力和摩擦角可用岩石峰值强度和残余强度结合破坏角近似描述,因此,提出一种较简便的计算岩石黏聚力和摩擦角的近似方法。对多组花岗岩试样进行三轴压缩试验,利用不同围压下应力应变曲线,求得内摩擦角φ和黏聚力c,将后者结果与前者对比可知:(1)该函数可近似的描述岩石峰后的应力应变关系和软化规律;(2)在围压的许可范围内,利用花岗岩三轴压缩强度峰后曲线求得的粘聚力和摩擦角可作为岩石的抗剪强度参数的近似值。上述方法可在一定程度上反映岩石力学三轴试验中常出现剪切破坏的物理意义,并对实际工程和试验提供借鉴。An analysis on the stress-strain curve of rock specimen under conventional triaxial compression（ especially the curve of post-peak strength） is progressed to establish the change rules of post-peak strength parameters along with softening parameters by piecewise function and hyperbolic function,and the method of solving expression of post-peak curve under conventional triaxial condition is obtained. It is found that the post-peak curve of triaxial compression test is interrelated to the cohesion and internal friction angle,so an approximate method to easily calculate the cohesion and internal friction angle is proposed in this paper. With the triaxial compression tests on groups of granite,the cohesion c and internal friction angle φ are obtained by using peak shearing strengths under various confining pressures. The comparison of calculation results with test data shows that：（ 1） the functions adopted in paper can approximately describe the post-peak stress-strain relationship and softening rules;（ 2） within the allowed scope of confining pressures,the cohesion and internal friction angle calculated from post-peak curves can be seen as approximate value of the rock shear strength parameters. The above methods can reflect the physical meaning of shear failure in the triaxial compression test of the rock to some extent,and provide reference for actual projects and similar tests.

关 键 词：花岗岩 三轴压缩试验 峰后曲线 黏聚力 内摩擦角 

分 类 号：TU458[建筑科学—岩土工程]