基于三维多晶离散元柱状节理岩体压缩特性研究  

Study on compression characteristics of columnar jointed rock mass by 3D Voronoi-based discrete element model

作　　者：牛子豪 朱珍德[1,2] 阙相成 卢文斌 NIU Zihao;ZHU Zhende;QUE Xiangcheng;LU Wenbin(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210098,China;Jiangsu Research Center for Geotechnical Engineering Technology,Hohai University,Nanjing,Jiangsu210098,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学江苏省岩土工程技术工程研究中心,江苏南京210098

出　　处：《岩石力学与工程学报》2022年第9期1874-1887,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41831278)。

摘　　要：柱状节理玄武岩在强度和变形模量方面表现出高度的各向异性特征,明确其物理力学特性对工程安全具有重要意义。针对柱状节理岩体自然结构特征,建立包含柱间节理和柱内隐节理双重节理网络的三维Voronoi多面体离散元模型(三维多晶离散元模型);应用该模型探究单轴条件下柱状节理岩体的力学特性及破坏模式;进而开展特定倾角岩体在三向应力条件下的压缩破坏模拟。研究结果表明:数值模拟结果与试验结果吻合度较高,试样表现出3种典型破坏模式;三向应力条件下,应力–应变曲线具有较为明显的阶段性和各向异性,体积应变ε_(V)表现出扩容现象。当ε_(3)方向卸荷后,柱状节理岩体的峰值强度及相应弹性应变量大幅减小,试样的脆性指数大幅增加,破坏模式呈现由卸荷面向中心延伸的脆性破坏,且在能量演化上表现为耗散能占比增加;微裂纹的演化过程反映出柱状节理岩体的劣化过程呈现渐进破坏特征,且中主应力对柱间节理面的滑移破坏有促进作用。Columnar jointed basalt shows highly anisotropic characteristics in strength and deformation modulus,and hence,understanding its physical and mechanical properties is of great significance to engineering safety.According to the natural structural characteristics of columnar jointed rock mass,a three-dimensional polycrystalline discrete element model including double joint networks was established. Using this model,the mechanical properties and failure modes of columnar jointed rock mass under uniaxial conditions were explored. Then,the compression failure simulation of rock mass with specific dip angle under three-dimensional stress conditions was carried out. It is shown that the numerical simulation results are in good agreement with the experimental results,and the samples show three typical failure modes. Under the condition of three-phase stress,the stress-strain curve shows obvious multistage and anisotropy,and the volumetric strain ε_(V) shows dilatancy. After unloading in the ε_(3) direction,the peak strength and corresponding elastic strain of columnar jointed rock mass decrease significantly,while the brittleness index of the specimen increases significantly. The failure mode presents brittle failure extending from the unloading plane to the center,and the proportion of the dissipated energy increases in energy evolution. The evolution process of microcracks reflects that the degradation process of columnar jointed rock mass presents progressive failure characteristics,and the intermediate principal stress has a promoting effect on the slip failure of the inter column joint plane.

关 键 词：岩石力学 柱状节理岩体 Voronoi多面体 各向异性 倾角 破坏模式 

分 类 号：TU45[建筑科学—岩土工程]