砂岩三轴循环加卸载变形特性分析及扩容逾渗模型研究  

Percolation modelling of dilation deformation evolution of sandstone under tri-axial cyclic loading-unloading

作　　者：程建超 贾震 侯孟冬 刘升贵[1] 杨欢 刘殷彤 李阳 薛东杰[1,3] CHENG Jianchao;JIA Zhen;HOU Mengdong;LIU Shenggui;YANG Huan;LIU Yintong;LI Yang;XUE Dongjie(School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,National Institute of Clean-and-Low-Carbon Energy,Beijing 102211,China;School of Resources,Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China)

机构地区：[1]中国矿业大学(北京)力学与土木工程学院,北京100083 [2]北京科技大学土木与资源工程学院,北京100083 [3]北京低碳清洁能源研究院煤炭开采水资源保护与利用全国重点实验室,北京102211 [4]湖南科技大学资源环境与安全工程学院,湖南湘潭411201

出　　处：《岩石力学与工程学报》2024年第11期2687-2699,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：煤炭开采水资源保护与利用国家重点实验室开放基金项目(GJNY-20-113-04);中央高校基本科研业务经费重点领域交叉创新项目(JCCXLJ01)。

摘　　要：为研究煤矿地下水库底板在经历干湿循环与采动应力扰动下的力学行为,以砂岩为研究对象,采用MTS815试验机设计干燥和饱和条件下的三轴循环加卸载试验,分析其损伤演化及破坏前后线性-非线性扩容转变过程中的突变行为特征。通过引入基于塑性体积应变定义的损伤变量,建立基于临界指数的逾渗模型,其能够描述非线性体积扩容现象。试验结果表明,在水的作用下,砂岩的脆性变形破坏被抑制,且水化作用对砂岩力学特性的弱化效应与水压有效应力原理体现的增强作用存在竞争关系。通过最大剪胀角将体积扩容划分为裂隙扩展与剪切滑移2个阶段,在干燥条件下,损伤变量在2个阶段的临界点存在突变现象,而饱和条件下则过渡平缓。在裂隙扩展阶段,建立的逾渗模型理论预测与实测数据的高度吻合,验证模型的准确性。在此基础上,结合损伤变量推导了体积应变的逾渗模型。To investigate the mechanical behavior of the underground reservoir's floor in a coal mine subjected to combined dry-saturated cycling and disturbances of mining-induced stress,triaxial cyclic loading-unloading tests of sandstone under dry and saturated conditions are conducted using the MTS815 testing system,to analyze the damage evolution characteristics and the critical jumping behavior from linear to non-linear transition of dilatancy at pre-and post-failure.By introducing a damage variable dependent on the plastic volumetric strain,a critical index-based percolation model is established to describe the nonlinear dilatancy phenomenon.The experimental results show that the brittle behavior of sandstone is weakened by water saturation and a competitive relationship between the water-weakening effect and the hydraulic pressure-strengthening effect is observed.In addition,the maximum dilation angle is suggested as a criterion to divide the dilating deformation into the fracture growth and the shear-induced slippage.The damage variable's evolution of sandstone under dry states also presents a critical jumping phenomenon at the transition boundary between two stages,while under saturation conditions it shows a gradual transition.In the fracture growth stage,the proposed percolation model fits the testing data well,which confirms the validity of proposed percolation model.Moreover,another percolation model to describe the volumetric strain evolution considering the damage variables was also derived.

关 键 词：岩石力学 三轴循环加卸载试验 扩容 剪胀角 损伤 逾渗模型 

分 类 号：TU45[建筑科学—岩土工程]