砂岩峰后蠕变失稳特性试验研究  

Experimental study on post-peak creep instability characteristics of sandstone

作　　者：李树清[1,2,3] 刘圣 袁越[1,2,3] 姚晓旭 晏钰童[1,2,3] LI Shu-qing;LIU Sheng;YUAN Yue;YAO Xiao-xu;YAN Yu-tong(Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,Hunan University of Science and Technology,Xiangtan 411201,China;Hunan Provincial Key Laboratory of Safety Minning Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan 411201,China;School of Resources,Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]湖南科技大学南方煤矿瓦斯与顶板灾害预防控制安全生产重点实验室,湖南湘潭411201 [2]湖南科技大学煤矿安全开采技术湖南省重点实验室,湖南湘潭411201 [3]湖南科技大学资源环境与安全工程学院,湖南湘潭411201

出　　处：《实验力学》2018年第6期893-901,共9页Journal of Experimental Mechanics

基　　金：国家自然科学基金资助项目(51374104);湖南省自然科学基金资助项目(2015JJ2058);安全生产重特大事故防治关键技术科技项目(hunan-0004-2017AQ);湖南省教育厅一般科研项目(15C0551)

摘　　要：为揭示岩石峰后蠕变失稳特性,利用MTS815电液伺服岩石力学试验系统,对红砂岩进行了峰后蠕变试验,采用线性回归的方法估算了蠕变失稳时间,探讨了损伤、初始围压以及围压增量对峰后蠕变特性的影响规律:结果表明:随着损伤的加大,蠕变变形速率增大,蠕变失稳时间缩短。同一围压下,各级应力水平下蠕变量随应力水平的增大而增大,且服从指数函数关系。增大初始围压,各级应力水平下的蠕变变形速率均有一定程度的降低,且对等速蠕变阶段蠕变速率的影响较加速蠕变阶段蠕变速率大,蠕变失稳时间延长。施加围压增量,大大减小了蠕变变形速率,促使了加速蠕变阶段向等速蠕变阶段转化,明显延长了蠕变失稳时间,减小了蠕变形变量。研究结果为工程围岩的长期稳定性分析提供了参考依据。In order to reveal the post-peak creep instability characteristics of rock,the post-peak creep experiment of red sandstone was carried out by using the MTS815 electro-hydraulic servo rock mechanics experimental system,and the creep instability time was estimated by the linear regression method.The influence of damage,initial confining pressure and confining pressure increment on postpeak creep characteristics were explored.Results show that with the increase of damage,the creep deformation rate increases and the creep instability time is shortened.Under the same confining pressure,the creep values at different stress level increase with the increase of stress level,and obey exponential function relation.With the increase of initial confining pressure,the creep deformation rate decreases to a certain extent at all stress levels,and its effect on creep velocity for creep on constant velocity stage is larger than that for creep on accelerated stage,which results in the delay of creep instability time.The increment of confining pressure greatly reduces creep deformation rate, accelerates the transformation from accelerated creep stage to constant velocity creep stage, significantly prolongs the time of creep instability and reduces creep deformation quantity.Above results provide a reference for the long-term stability analysis of the engineering surrounding rocks.

关 键 词：岩石力学 峰后蠕变 损伤岩样 初始围压 围压增量 蠕变失稳 

分 类 号：TU452[建筑科学—岩土工程]