疲劳-蠕变交互荷载下含软弱夹层空心圆柱花岗岩变形失稳特性试验研究  

Experimental research on deformation and instability characteristics of hollow cylindrical granite with weak interlayers under fatigue-creep loading

作　　者：易雪枫 王宇 李鹏[1,2] 蔡美峰[1,2] YI Xuefeng;WANG Yu;LI Peng;CAI Meifeng(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083 [2]北京科技大学金属矿山高效开采与安全教育部重点实验室,北京100083

出　　处：《岩石力学与工程学报》2024年第11期2766-2780,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52174069);国家重点研发计划资助项目(2018YFC0808402)。

摘　　要：为揭示金属矿深部构造破碎带在疲劳-蠕变交互荷载作用下扰动活化诱发井巷失稳的物理过程及力学响应,制备含有不同软弱夹层倾角的空心圆柱花岗岩试样,采用宏观力学试验和细观CT扫描相结合的手段,研究软弱夹层倾角对组合结构体时效失稳的影响机制。结果表明:(1)组合结构体试样抵抗疲劳-蠕变交互荷载的能力受软弱夹层倾角的影响明显,当软弱夹层倾角为5°,15°,25°和35°时,典型试样破坏时的围压卸载量逐渐减小,分别为11.58,7.49,7.22和5.07 MPa;(2)在疲劳-蠕变交互加载路径下,组合结构体试样的轴向、径向和体积应变以及耗散应变能与加载阶段均服从非线性指数函数关系,但在最后一个疲劳和蠕变加载阶段组合结构体表现出不同的变形和能量演化特征;(3)组合结构体能量耗散表现为岩石基质内部裂纹萌生、扩展和贯通与软弱夹层剪切滑移变形2种形式,软弱夹层与岩石基质的不协调变形导致体积扩容与岩石破裂,随着倾角的增加组合结构体的能量耗散呈现先减小后增加的趋势;(4)CT扫描试验结果表明软弱夹层和孔洞之间破裂面的贯通是导致组合结构体破坏的根本原因,软弱夹层的最终塑性变形量与倾角呈正相关趋势。研究结果对揭示深部构造破碎带井巷围岩大变形灾害的时效扰动机制具有重要的理论意义。To investigate the physical processes and mechanical responses of deep-seated tectonic fragmentation zones in metal mines induced by alternative fatigue-creep loads,hollow cylindrical granite specimens with varying inclinations of weak interlayers were prepared,and the impact of weak interlayer inclinations on the time-dependent instability of the composite structure specimens was investigated by employing a combination of macroscopic mechanical tests and microscopic CT scanning.The findings indicate that:(1)The resistance of composite structure specimens to alternative fatigue-creep loads is significantly influenced by the inclination of weak interlayers.As the inclination of weak interlayers increases from 5°to 35°,the confining pressure unloading at the point of failure gradually decreases,with values of 11.58,7.49,7.22 and 5.07 MPa,respectively.(2)When subjected to the loading path of alternative fatigue and creep,the composite structure specimens exhibit nonlinear,exponential relationships in their axial,radial,and volumetric strains,as well as in dissipated strain energy,with the loading stages.However,during the final loading stage,the composite structure specimens display unique deformation and energy evolution characteristics.(3)The energy dissipation of the composite structure is characterized by the initiation,propagation,and connection of internal cracks in the rock matrix,alongside the shear slip deformation of the weak interlayers.The incompatible deformation between the weak interlayers and the rock matrix leads to volume expansion and rock matrix fracturing.Notably,with the increase in interlayer inclinations,the energy dissipation of the composite structure shows a decreasing-then-increasing trend.(4)CT scanning test results indicate that the connection of failure surfaces between the weak interlayers and cavities is the fundamental cause of failure in the composite structure.The final plastic deformation of the weak interlayers shows a positive correlation with the interlayer inclinations.Thes

关 键 词：岩石力学 软弱夹层 空心圆柱花岗岩 疲劳-蠕变交互荷载 能量耗散 损伤演化 破裂形态 

分 类 号：TU45[建筑科学—岩土工程]