| 基于考虑动力本构的连续−非连续方法的单轴压缩岩样开裂过程模拟 |
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| 引用本文： | 王学滨,刘桐辛,白雪元,李继翔.基于考虑动力本构的连续−非连续方法的单轴压缩岩样开裂过程模拟[J].岩土力学,2022,43(10):2911-2922. |
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| 作者姓名： | 王学滨 刘桐辛 白雪元 李继翔 |
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| 作者单位： | 1. 辽宁工程技术大学 计算力学研究所，辽宁 阜新 123000；2. 辽宁工程技术大学 力学与工程学院，辽宁 阜新 123000 |
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| 基金项目： | 国家自然科学基金（No. 52074142） |
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| 摘 要： | 动载作用下岩石的破坏规律研究对于众多地质灾害的机制分析和预防具有重要的理论及实际意义。鉴于数值模拟研究的优势，应大力发展适于岩石动力断裂过程模拟的数值方法。在自主开发的拉格朗日元与离散元耦合连续−非连续方法的基础上，采用朱−王−唐本构模型取代了广义胡克定律，发展了考虑动力本构的连续−非连续方法，其正确性通过模拟不同加载速度时砂岩试样的单轴压缩试验进行了验证。通过统计裂缝区段数目随着岩样的纵向应变的演化规律，并监测岩样左、右对称线上多个测点的最小主应力的演化规律，开展了不同加载速度时单轴压缩花岗岩试样的变形−开裂过程研究，阐明了岩样的开裂机制。研究发现，剪裂缝以雁列式展布，整体上形成剪切带。随着时步数目的增加，各测点的最小主应力均呈波动下降−震荡上升的变化趋势。震荡上升阶段对应岩样的应变软化阶段。测点分离后最小主应力的震荡幅度较大，这是由于节点分离和单元接触激发了较大的应力波。剪切带尖端的最小主应力集中会使测点发生剪切分离。当岩样的三角块向下楔入时，下方测点的应力状态类似于紧凑拉伸试验进而发生拉伸分离。
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| 关 键 词： | 岩石 动力断裂 朱?王?唐本构模型 连续?非连续方法 单轴压缩 剪切带 开裂机制 |
| 收稿时间： | 2021-12-10 |
| 修稿时间： | 2022-07-05 |
Numerical simulation of fracturing processes of rock specimens in uniaxial compression based on the continuum-discontinuum method considering the dynamic constitutive model |
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| WANG Xue-bin,LIU Tong-xin,BAI Xue-yuan,LI Ji-xiang.Numerical simulation of fracturing processes of rock specimens in uniaxial compression based on the continuum-discontinuum method considering the dynamic constitutive model[J].Rock and Soil Mechanics,2022,43(10):2911-2922. |
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| Authors: | WANG Xue-bin LIU Tong-xin BAI Xue-yuan LI Ji-xiang |
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| Institution: | 1. Institute of Computational Mechanics, Liaoning Technical University, Fuxin, Liaoning 123000, China;
2. College of Mechanics and Engineering, Liaoning Technical University, Fuxin, Liaoning 123000, China |
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| Abstract: | It is important to study failures of rocks under dynamic loads for expounding mechanisms of geological disasters and for predicting and preventing these disasters on theoretical and practical aspects. Owing to advantages of numerical simulation, numerical methods applicable to modeling dynamic fracturing processes must be especially emphasized. Based on the combined Lagrangian-discrete element method, a continuum-discontinuum method considering the dynamic constitutive model was presented, in which the Zhu-Wang-Tang constitutive model was used to replace the generalized Hooke law. The continuum-discontinuum method considering the dynamic constitutive model was validated through modeling uniaxially compressive experiments of sandstone rock specimens for different loading velocities. Evolution of the number of crack segments with the longitudinal strain of the rock specimen was investigated, and evolution of the minimum principal stresses of nodes at the longitudinal symmetric line was also monitored. Deformation-fracturing processes of granite specimens for different loading velocities were modeled, and fracturing mechanisms of rock specimens were revealed. The following results were found. Shear bands include en echelon shear cracks. The minimum principal stress of the node exhibits a fluctuant decrease, followed by an increase in the oscillation form. The increasing stage corresponds to the strain-softening stage of the rock specimen. A large oscillatory amplitude of the minimum principal stress is found for the separating node, which is due to the fact that large stress waves are induced by node separations and contact between elements. Shear separations of nodes occur due to concentrations of the minimum principal stresses at the shear band tip. Motion of the triangle wedge of the rock specimen leads to tensile separations of nodes whose stress states are similar to those of the compact tension experiment. |
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| Keywords: | rock dynamic fracturing Zhu-Wang-Tang constitutive model continuum-discontinuum method uniaxial compression shear band fracturing mechanism |
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