摘要
准确定量表征煤或岩石的脆性对有效估测深部工程的开挖效率具有重要意义。层理砂岩在全生命周期演化过程中所受到的应力演化特征必然会伴随有能量演化过程。因此,基于上述能量演化特征,本文提出“三阶段”三轴加卸载应力路径,获得损伤演化规律,并定义了脆性指数BI16。研究结果表明:1)围压可以提高层理砂岩的承载力和塑性变形抵抗能力。此外,加载方式和围压对塑性体积变形的抵抗能力存在显著影响,而倾角对其影响则较小。2)层理砂岩在常规三轴加载条件下的峰前损伤演化过程可划分为三个阶段。同时,层理砂岩在三轴加卸载条件下的峰前损伤演化过程则可划分为四个阶段。3)层理砂岩的整个变形过程会显著影响其脆性,且脆性是动态的、并非恒定的。上述研究结论可为准确估算深地工程的开挖效率提供依据。
Accurately quantitative characterization of brittleness of coal or rocks is important for effective estimation of excavation efficiency in deep engineering.The in-situ stress evolution characteristics of layer sandstone during the whole life-cycle process must be accompanied by the energy evolution process.Therefore,based on the above energy evolution characteristics,a stress path of three-stage triaxial loading and unloading(TLUT)is proposed.Subsequently,the damage evolution law and brittleness index BI16 are obtained and defined.The results show that:1)The confining pressure can enhance bearing capacity and plastic deformation resistance of layer sandstone.The loading way and confining pressure have significant influence on the plastic volumetric deformation resistance,but the inclination angle has little influence.2)The pre-peak damage evolution process under conventional triaxial loading(CTLT)and TLUT can be divided into three stages and four stages,respectively.3)The whole deformation process of layer sandstone can significantly affect its brittleness,which is dynamic and not constant.It can provide a certain basis for the accurate estimation of excavation efficiency in deep engineering.
作者
宋治祥
张俊文
赵善坤
吴少康
孙小岩
董续凯
张杨
SONG Zhi-xiang;ZHANG Jun-wen;ZHAO Shan-kun;WU Shao-kang;SUN Xiao-yan;DONG Xu-kai;ZHANG Yang(School of Energy and Mining Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;Mine Safety Technology Branch of China Coal Research Institute,Beijing 100013,China)
基金
Projects(52034009,51974319)supported by the National Natural Science Foundation of China
Project(2020JCB01)supported by the Yueqi Distinguished Scholar Project of China。
关键词
三轴加卸载
层理砂岩
倾角
损伤
脆性
开挖效率
triaxial loading and unloading
layer sandstone
inclination angle
damage
brittleness
excavation efficiency
作者简介
Corresponding author:张俊文,PhD,Professor,Tel:+86-13681359725,E-mail:zhangjw@cumtb.edu.cn,ORCID:https://orcid.org/0000-0001-6226-1693。
