摘要
锚固节理岩体的剪切特性对于岩体工程稳定性控制设计至关重要。开展一系列不同恒定法向刚度(CNS)边界条件下锚固和无锚固类岩石材料粗糙节理剪切试验,研究CNS边界条件对锚固节理剪切力学特性以及节理面剪切破坏、锚杆剪切变形破断和锚杆破断剪切位移特征的影响。结果表明:峰前阶段法向刚度对剪切应力第一峰值Tp的影响不明显;峰后阶段剪切应力–剪切位移曲线在法向刚度小于3 GPa/m时呈位移软化特征、等于3 GPa/m时趋近于水平、等于5GPa/m时呈位移硬化特征,随着法向刚度的增加锚杆破断剪切应力Tf会显著提高;锚杆破断后阶段剪切应力–剪切位移曲线呈台阶式下沉。锚固节理的Tp和Tf都高于无锚固节理,法向刚度超过3GPa/m后锚固作用可抵消因节理面磨损导致的剪切强度损失。剪切应力第一峰值提升的剪切强度T1随法向刚度和JRC的增大呈增大趋势,而锚杆破断提升剪切强度T2随法向刚度增大呈减小趋势、随JRC增大呈增大趋势。节理面的破坏范围随法向刚度增大而增大,锚杆孔壁椭圆形破坏范围随法向刚度增大而减小。锚杆剪切后呈现"Z"字型变形特征,随法向刚度增加锚杆破断形式由拉伸破坏到弯曲破坏再到剪切破坏转换。锚杆破断剪切位移在法向刚度为0~1 GPa/m阶段呈增大趋势,1~5 GPa/m阶段呈持续减小趋势。
Understanding the shear behavior of bolted rock joints is crucial to designing of geotechnical projects that include discontinuities. The effects of constant normal stiffness(CNS) boundary conditions on shear characteristics of bolted rock joints were investigated through shear tests on bolted rock joints and non-bolted rock joints under different CNS boundary conditions. The results show that,at the pre peak stage,the effect of the normal stiffness on the first peak value of the shear stress(Tp) is not obvious. At the post peak stage, the shear stress-shear displacement curve respectively shows displacement softening characteristic,stability characteristic,and displacement hardening characteristic when the normal stiffness is less than 3 GPa/m,equal to 3 GPa/m and equal to 5 GPa/m, and the shear stress of bolt broken(Tf) increases significantly with increasing the normal stiffness. At the bolt broken stage,the shear stress-shear displacement shows step subsidence. The Tp and Tf of bolted joints are both higher than those of non-bolted joints. When the normal stiffness exceeds 3 GPa/m,the shear strength loss caused by joint wear can be counteracted by bolting. The first peak value increment of the shear stress(T1) increases with increasing the normal stiffness and JRC,while the shear stress increment of bolt broken(T2) decreases with increasing the normal stiffness and increases with increasing JRC. The failure range of the joint surface increases with increasing the normal stiffness,and the elliptical failure range of the bolt hole wall decreases with increasing the normal stiffness. The deformation of the bolt shows a shape of"Z"after shearing,and the failure mode of the bolt changes from tensile failure to bending failure and then to shear failure as the normal stiffness increases. The breaking shear displacement of the bolt tends to increase as the normal stiffness ranging from 0 to 1 GPa/m and decreases continuously as the normal stiffness varying from 1 to 5 GPa/m.
作者
蒋宇静
张孙豪
栾恒杰
王长盛
文志杰
王冬
韩伟
JIANG Yujing;ZHANG Sunhao;LUAN Hengjie;WANG Changsheng;WEN Zhijie;WANG Dong;HAN Wei(College of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;Graduate School of Engineering,Nagasaki University,Nagasaki 852–8521,Japan)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2021年第4期663-675,共13页
Chinese Journal of Rock Mechanics and Engineering
基金
山东省自然科学基金资助项目(ZR2019BEE065)
国家自然科学基金资助项目(51379117)。
关键词
岩石力学
锚固节理
剪切特性
节理粗糙度
恒定法向刚度
边界条件
rock mechanics
bolted rock joint
shear characteristics
joint roughness coefficient
constant normal stiffness
boundary conditions
作者简介
蒋宇静(1962-),男,1993年于日本国立九州大学土木工程专业获博士学位,现任教授,主要从事岩石力学方面的研究工作。E-mail:jiang@nagasaki-u.ac.jp;通讯作者:栾恒杰(1989-),男,博士,现任讲师、硕士生导师。E-mail:luanjie0330@126.com。
