基于颗粒离散元模型的花岗岩压缩试验模拟研究

发布时间：2019-07-01 16:14

【摘要】：基于颗粒流理论,以黄岛国家石油储备库地下洞库的花岗岩室内试验测试为背景,借助PFC2D(particle flow code)的黏结颗粒模型(bonded particle model,BPM)建立双轴压缩模型。以花岗岩室内试验的宏观力学参数和破坏形态为参照,通过"试错法"得出黏结颗粒模型相对应的细观物理力学性质参数。模拟试验的弹性模量、泊松比与室内试验值吻合较好,BPM模型由于选用圆形颗粒导致黏聚力和内摩擦角与室内试验值相比有一定偏差。模拟试验与室内试验的试件破坏形态均以单斜面剪切破坏为主。采用校准的细观物理力学性质参数,应用BPM模型再现花岗岩压缩试验全过程,深入分析微裂纹萌生演化及能量变化规律。研究表明,压缩过程中岩石试件内裂纹扩展主要经历平稳发展-急剧增加-平稳发展3个阶段;变形过程中,花岗岩试件边界能、应变能、黏结能、摩擦能及动能在各个阶段的变化很好地解释花岗岩受力破坏的细观力学机制。
[Abstract]:Based on the theory of particle flow, a biaxial compression model is established with the help of PFC2D (particle flow code) 's bonded particle model (bonded particle model,BPM, which is based on the granite laboratory test of Huangdao National Petroleum Reserve Underground Cave. Based on the macroscopic mechanical parameters and failure form of granite laboratory test, the meso-physical and mechanical parameters corresponding to the bonded particle model are obtained by "trial and error method". The elastic modulus and Poisson's ratio of the simulated test are in good agreement with the laboratory test values. The cohesion and internal friction angle of the BPM model are deviated from the laboratory test values due to the selection of circular particles. The failure mode of simulated test and laboratory test is mainly monoclinic shear failure. Using the calibrated meso-physical and mechanical properties parameters, the BPM model is used to reproduce the whole process of granite compression test, and the evolution of microcrack initiation and the law of energy change are deeply analyzed. The results show that the crack propagation in rock specimens mainly goes through three stages: steady development, sharp increase and steady development, and the changes of boundary energy, strain energy, bonding energy, friction energy and kinetic energy of granite specimens in each stage explain the meso-mechanical mechanism of granite failure.
【作者单位】：山东科技大学矿山灾害预防控制省部共建国家重点实验室培育基地;山东科技大学山东省土木工程防灾减灾重点实验室;山东大学岩土与结构工程研究中心;
【基金】：国家自然科学基金资助(No.51279097,No.51379117) 国家重点基础研究发展规划(973计划)(No.2012CB723104) 山东省教育厅高等学校科技计划项目(No.J11LE03,No.J10LE08)
【分类号】：TU45

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