高应力下花岗岩抗剪强度参数特征试验研究  

Experimental study on characteristics of shear strength parameter of granite under high stress

作　　者：周朝兰 李斌[1,2] 许梦国[2] ZHOU Chaolan;LI Bin;XU Mengguo(School of Environment and Resource,Southwest University of Science and Technology,Mianyang Sichuan 621010,China;School of Resource and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]西南科技大学环境与资源学院,四川绵阳621010 [2]武汉科技大学资源与环境工程学院,武汉430081

出　　处：《有色金属（矿山部分）》2020年第2期58-63,共6页NONFERROUS METALS(Mining Section）

基　　金：国家自然科学基金资助项目(51904248);四川省教育厅科研项目(18ZB0598);四川省大学生创新创业训练计划资助项目(S201910619016)。

摘　　要：为促进深部矿产资源的安全高效开采,基于取自程潮铁矿西区-395 m水平的主要围岩花岗岩的试件,通过伺服试验系统开展高应力下的常规三轴压缩强度试验,研究花岗岩的破坏、强度和参数特征。研究结果表明:1)随着围压的增加,花岗岩的破坏形式由剪切破坏逐渐向剪切劈裂复合型破坏转变,破坏形态由单一破坏断面逐渐转变为多破坏断面,破坏断裂角逐渐减小。2)花岗岩的三轴强度和抗剪强度与围压的关系在低围压下基本均呈线性,在高围压下则均呈上凸的非线性。3)花岗岩抗剪强度参数具有明显的围压效应特征,具体表现为凝聚力和内摩擦角随着围压的增加分别呈逐渐增大和减小的趋势。结合Hoek-Brown准则对瞬态抗剪强度参数的确定进行了初探,结果表明参数推导值的变化趋势符合参数试验规律,但推导值与试验值存在一定的差异,说明Hoek-Brown准则在表征高应力下岩石三轴强度的非线性上仍存在局限,有待进一步研究。To promote the safe and efficient exploitation of deep mineral resources,according to the granite samples from-395 m elevation in Chengchao iron mine,the conventional triaxial compression test under high stress was carried out through the servo-controlled testing machine,and the failure,strength and parameters characteristics of granite were studied.Results indicated that:1)with the increase of confining pressure,the failure form of granite gradually changed from shear failure to shear and splitting composite failure.The failure form gradually changed from single failure section to multiple failure sections,and the failure fracture angle gradually decreased.2)The relationship between triaxial strength of granite and confining pressure as well as the relationship between shear strength and confining pressure both were linear at low confining pressure and nonlinear at high confining pressure.3)The shear strength parameters of granite exhibited the characteristic of confining pressure effect.The cohesion and internal friction angle increased and decreased with the increase of confining pressure,respectively.Meanwhile,the determination of instantaneous shear strength parameters was preliminarily studied.The result showed that the variation trend of the derived value of parameters conformed to that of the test values.However,there are some differences between the derived values and test values,indicating that the Hoek-Brown criterion still has limitations in characterizing the nonlinearity of rock triaxial strength under high stress,which needs further study.

关 键 词：高应力 三轴压缩 强度特征 抗剪强度参数 非线性 

分 类 号：TD313[矿业工程—矿井建设]