三轴循环加卸载条件下热损伤石灰岩力学特性演化规律  

Mechanical properties evolution of thermally damaged limestone under triaxial cyclic loading and unloading

作　　者：张晓悟 徐金海[1,2] 孙垒 张皓文 王琪 ZHANG Xiaowu;XU Jinhai;SUN Lei;ZHANG Haowen;WANG Qi(School of Mines,China University of Mining and Technology,Xuzhou 221116,China;State Key Laboratory of Coal Resources and Safe Mining(CUMT),Xuzhou 221116,China)

机构地区：[1]中国矿业大学矿业工程学院,江苏徐州221116 [2]煤炭资源与安全开采国家重点实验室,江苏徐州221116

出　　处：《采矿与岩层控制工程学报》2022年第4期83-94,共12页Journal of Mining and Strata Control Engineering

基　　金：煤炭资源与安全开采国家重点实验室自主研究课题资助项目(SKLCRSM2020X05)。

摘　　要：为了研究循环加卸载条件下岩石力学特性的温度-围压效应,设计了5个温度梯度石灰岩三轴循环加卸载试验,分析了循环加卸载条件下,不同温度、围压对岩石特征力学参数的影响,建立了岩石破坏形式和损伤的评价指标。结果表明:①岩石力学特性表现为围压强化和温度恶化效应,温度和围压越大,岩石峰后应力衰减越迟缓,其所能承受的循环加卸载次数越多,同时塑性变形量越大;②脆度系数越小,岩石延性越强,反之脆性越强,当围压和温度都增加时,岩石破坏形式由脆性破坏向延性破坏转化;③随着循环加卸载次数的增加,岩石损伤变量呈非线性增加,且峰后阶段增加迅速。研究成果可为分析高温条件下岩石稳定性提供参考。To study the temperature-peripheral pressure effects on rock mechanical properties under cyclic loading and unloading,five temperature gradient limestone triaxial compression tests under cyclic loading and unloading were carried out,and the influence of different temperatures and confining pressures on rock characteristic mechanical parameters was analyzed.The evaluation indexes of rock failure form and damage are described.The results show that:①The mechanical properties of rocks are manifested by the effects of confining pressure strengthening and temperature deterioration.The greater the temperature and confining pressure,the post-peak stress decreases slower lead the rock can withstand more number of cyclic loading and unloading and produce with the greater the amount of plastic deformation;②The smaller the brittleness index,the ductility of the rock is stronger.In contrast,the brittleness of rock is stronger.When the confining pressure and temperature increase,the rock failure form changes from brittle failure to ductile failure;③With the increase in the number of cyclic loading and unloading,the rock damage variable increases non-linearly and increases rapidly in the post-peak stage.The research results provide a reference for the stability analysis of surrounding rock under high-temperature conditions.

关 键 词：循环加卸载 力学特征 脆度系数 温度 损伤 

分 类 号：TD353[矿业工程—矿井建设]