摘要
为防止支护工程中锚索在剪切荷载下过早发生破断,一种将C型钢管与锚索进行组合的管索组合结构被提出,该结构抗剪增强机制尚未完全揭示。利用ABAQUS软件建立管索组合结构的非线性有限元精细化模型,锚索钢绞线采用七股实际结构模型,并考虑各个组成部分的接触、失效等相互作用,对管索组合结构抗剪机制进行研究。结果表明:剪切初期,管索组合结构在剪切面位置剪力和对称分布弯矩作用下形成“S”形态弯曲及对称塑性铰,其后变形以塑性铰向远离剪切面方向扩展与中间段锚索的拉伸为主,最终管索组合结构失效原因为锚索以拉伸破断为主的拉剪复合破坏;随剪切荷载的增加,C型管在锚索弯曲变形范围内逐渐闭合,与锚索共同受力,增强整体结构抗弯刚度,C型管两端部发生开缝张开与整体扭转,与C型管中间段闭合变形相协调,C型管能够使结构与试块接触压力分布更为均匀,改善受力条件;试块界面局部混凝土处于三轴受压状态,随剪切荷载增加,试块内部形成逐渐扩大的承压区域,局部混凝土破碎失效,混凝土逐步破碎失效过程与管索组合结构塑性铰的扩展同步发生。
In order to prevent premature breakage of anchor cables under shear loads in support engineering,a structure named Anchor Cable with C-shaped tube(ACC)was proposed,which combines a C-shaped steel tube with anchor cables.Shear strengthening mechanism of this structure has not yet been fully revealed.A nonlinear finite element refined model of the ACC was established using ABAQUS software.The actual model of the seven-strand structure was adopted for the anchor cable,and shear resistance mechanism of ACC was studied considering the contact,failure,and other interactions of each component.The results show that in the initial stage of shearing,ACC forms an“S”shape of bending and symmetrical plastic hinge under the action of shear force at the shear plane and symmetrically distributed bending moment.Afterwards,the deformation is mainly caused by extension of the plastic hinge away from the shear plane and the stretching of the middle part of the anchor cable.Finally,the failure reason of ACC is the tensile-shear composite failure of the anchor cable,which is mainly tensile fracture.With the increase of the shear load,the C-shaped tube gradually closes within the bending range of the anchor cable,and works together with the anchor cable to enhance the overall bending stiffness of the structure.The slit opening and overall torsion of both ends of C-shaped tube are coordinated with the closure deformation of its middle part.C-shaped tube can make the distribution of the contact pressure more uniform between the structure and the concrete blocks,improving stress conditions.Partial concrete located at the interface of blocks is in a triaxial compression state.With the increase of the shear load,the bearing area gradually expands inside the concrete blocks,and the progressive failure of concrete occurs synchronously with the expansion of plastic hinge of ACC.
作者
单仁亮
宋威
张书鹏
刘帅
梁俊奇
SHAN Renliang;SONG Wei;ZHANG Shupeng;LIU Shuai;LIANG Junqi(School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;North Blasting Technology Co.,Ltd.,Beijing 100097,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第7期1561-1579,共19页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(52274148)。
关键词
岩石力学
双剪试验
预应力锚索
数值模拟
塑性铰
破断机制
rock mechanics
double shear test
prestressed anchor cable
numerical simulation
plastic hinge
breaking mechanism
