摘要
为了更加精细的模拟土石混合体宏细观力学特性和变形破坏机制,针对已有三轴试验侧向柔性薄膜边界模拟方法进行改进,提出三维组合墙法实现了柔性薄膜边界的三维离散元模拟。结合已开发的不规则块石和土石混合体三维离散元建模方法建立土石混合体大型三轴数值试样,开展数值试验标定土石混合体数值模型的细观力学参数并与室内试验结果进行了对比验证。深入分析不同含石量下土石混合体的宏细观力学特性和变形破坏机制。结果表明:三维组合墙法原理简单、参数较少、易于实现且应用效果较好;大型三轴试验数值模拟能够较好地再现土石混合体宏观的应力–应变特征、强度特性和破坏模式;随含石量增加,土石混合体的骨架结构效应越来越显著;剪切带内土颗粒旋转量较大而块石颗粒旋转量较小,表明剪切面绕过了较大的块石颗粒。
To precisely simulate the macro and meso mechanical properties and the failure mechanism of soil-rock mixture（SRM）,an improvement on the three-dimensional discrete element（3D DEM） modeling for the flexible membrane boundary method used in the triaxial tests is made with 3D wall-arrangement method. 3D DEM models of SRM to simulate the large-scale triaxial specimens are constructed using the previously developed 3D DEM modeling method for rock blocks and SRM with irregular shapes. The meso-mechanical parameters of numerical SRM specimens are calibrated by large-scale numerical triaxial tests and verified through comparison with laboratory results. The insight into the macro and meso mechanical properties and failure mechanism of SRM are obtained from the detailed simulation of large-scale triaxial tests. The results show that the proposed modeling method for 3D flexible membrane boundary has many advantages, such as fewer parameters,easy to implement and better results. The stress-strain characteristics,strength properties and failure modes of SRM are reproduced nicely with the numerical simulation of large-scale triaxial tests using the generated DEM models. With the increasing of rock block proportion,the skeleton-effect of rock blocks on numerical SRM specimens becomes more and more obvious. The particle rotations of soil matrix are larger while the particle rotations of rock blocks are generally smaller,indicating that the shear planes propagate bypassing the larger rock blocks.
作者
金磊
曾亚武
JIN Lei;ZENG Yawu(School of Civil Engineering and Arehiteeture, Hubei Polytechnic University, Huangshi, Hubei 435003, China;School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2018年第6期1540-1550,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(41272342)
湖北省高等学校优秀中青年科技创新团队计划项目(T201823)
关键词
土力学
土石混合体
三维离散元
柔性薄膜边界
宏细观力学特性
变形破坏机制
精细模拟
soil mechanics
soil-rock mixture
three-dimensional discrete element method
flexible membrane boundary
macro-and meso-mechanical properties
deformation and failure mechanism
refined simulation
