三轴压缩下单裂隙位置对复合岩样力学变形与破坏模式的影响  

Influence of Single Fissure Position on Mechanical Deformation and Failure Modes of Composite Rock Specimens Under Triaxial Compression

作　　者：谢志英[1] 许可 陆逸帆 肖桃李[1] 折海成 赵云峰 XIE Zhiying;XU Ke;LU Yifan;XIAO Taoli;SHE Haicheng;ZHAO Yunfeng(School of Urban Construction,Yangtze University,Jingzhou 434023,Hubei,China;Jingzhou Chengfa Construction Engineering Group Co.,Ltd.,Jingzhou 434023,Hubei,China;Key Laboratory of Reservoir and Dam Safety Ministry of Water Resources,Nanjing 210024,Jiangsu,China)

机构地区：[1]长江大学城市建设学院,湖北荆州434023 [2]荆州市城发建设工程集团有限公司,湖北荆州434023 [3]水利部水库大坝安全重点实验室,江苏南京210024

出　　处：《黄金科学技术》2024年第3期458-469,共12页Gold Science and Technology

基　　金：国家自然科学基金项目“酸雨冻融耦合作用下混凝土灾变破坏的雪崩过程研究”(编号:52204201)资助。

摘　　要：在地下富存裂隙的层状复合岩体中,复杂围压环境和裂隙分布对复合岩体力学性质和损伤破坏具有显著影响。选取由类灰岩和类砂岩组成的含预制单裂隙的复合岩样作为研究对象,通过常规三轴压缩试验,分析不同裂隙位置和围压条件下岩样的力学变形和破坏模式。结果表明:(1)完整复合岩样的强度受砂岩控制,而变形受灰岩限制。(2)随着围压的增加,复合岩样破坏特征由裂隙位置主导转变为由围压主导;复合岩样的体缩受围压的影响,而体胀受裂隙位置的影响。(3)在单轴压缩条件下,裂隙对岩样力学性质的削弱程度最大;当裂隙位于灰岩中时,损伤应力受围压影响最显著,岩样的强度和弹性模量随着裂隙位置的改变(从灰岩、接触面到砂岩)及围压的增加呈现出增加的趋势。(4)灰岩中的裂隙易产生拉伸裂纹,砂岩中的裂隙易产生剪切裂纹;随着围压的增加,复合岩样由拉伸破坏转变为剪切破坏,破坏模式由围压主导。该研究成果对复合岩体工程的安全加固设计具有一定的指导意义。Composite rocks are widely present in underground geotechnical engineering such as tunnel excavation,mining projects,and oil and gas resource extraction.Composite rocks are formed by the layered accumulation of rocks with disparate properties,and are rich in fissures.The intricate features of these fissures,combined with the distribution of stress,collectively influence the stability of composite rocks,making them prone to disasters such as roof collapse,expansion of surrounding rocks,and significant tunnel deformations.Therefore,investigating the mechanical failure mechanisms of composite rocks under different confining pressures and fissure positions is of paramount importance for effectively preventing disasters in underground engineering construction.Based on the above reasons,this study prepared composite rock samples with preexisting fissures,conducted triaxial compression tests by varying the fissure positions,and analyzed and summarized the influence of fissure positions and confining pressure on the mechanical behavior and failure modes of composite rock.The main conclusions are as follows:(1)Limestone exhibits the highest strength,while sandstone undergoes the greatest deformation under compression.The mechanical deformation of the intact composite rock sample falls between sandstone and limestone,with its strength controlled by the sandstone portion and deformation restricted by the limestone portion.(2)Under lower confining pressures,the intact rock sample and the one with fissures in limestone exhibit brittle failure,while the one with fissures in the contact zone and sandstone exhibits ductile failure.With the increasing of confining pressure,rock samples generally exhibit ductile failure,and the dominant factor in the failure characteristics shifts from the fissure position to the confining pressure.The volumetric contraction of the rock sample increases with the rise in confining pressure,and the volumetric expansion is minimal when fissures are in sandstone.Volumetric contraction is influenced by

关 键 词：复合岩样 预制单裂隙 围压 裂隙位置 破坏模式 

分 类 号：TD315[矿业工程—矿井建设]