Micromechanical Model for Simulating the Fracture Process of Rock
Micromechanical Model for Simulating the Fracture Process of Rock
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DOI：
10.1007/s00603-003-0014-z
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发表时间：
2004-02
影响因子：
6.2
通讯作者：
Wancheng Zhu;Chun’an Tang
中科院分区：
文献类型：
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作者：
Wancheng Zhu;Chun’an Tang
基于细观层次上岩石非均质性的知识，提出了一种细观力学模型来研究岩石的变形破坏过程。在该数值模型中，假设岩石的材料性质服从威布尔分布，从而在细观层次上考虑了岩石的非均质性。用弹性损伤力学描述细观单元的本构关系，以有限元方法作为基本应力分析工具，以最大拉应变准则和莫尔-库仑准则作为损伤门槛。用一种类似于拖尾裂纹模型的简单方法来跟踪裂纹扩展过程和多个裂纹之间的相互作用。在此基础上，编制了岩石破裂过程分析程序RFPA。详细讨论了数值模型中威布尔分布参数、细观单元本构参数和单元个数等参数对数值模拟结果的影响。结果表明，均质指数是用该模型模拟材料破坏的最重要因素。该模型能够捕捉岩石的完整力学响应，包括与不同加载阶段和加载条件相关的裂纹模式、变形局部化、应力重分布和破坏过程。对不同静载条件下的岩样进行了数值模拟，结果与试验结果吻合较好。
A micromechanical model is proposed to study the deformation and failure process of rock based on knowledge of heterogeneity of rock at the mesoscopic level. In this numerical model, the heterogeneity of rock at the mesoscopic level is considered by assuming the material properties in rock conform to the Weibull distribution. Elastic damage mechanics is used to describe the constitutive law of meso-level elements, the finite element method is employed as the basic stress analysis tool and the maximum tensile strain criterion as well as the Mohr-Coulomb criterion is utilized as the damage threshold. A simple method, similar to a smeared crack model, is used for tracing the crack propagation process and interaction of multiple cracks. Based on this model, a numerical simulation program named Rock Failure Process Analysis Code (RFPA) is developed. The influence of parameters that include the Weibull distribution parameters, constitutive parameters of meso-level elements and number of elements in the numerical model, are discussed in detail. It is shown that the homogeneity index is the most important factor to simulate material failure with this model. This model is able to capture the complete mechanical responses of rock, which includes the crack patterns associated with different loading stages and loading conditions, localization of deformation, stress redistribution and failure process. The numerical simulation of rock specimens under a variety of static loading conditions is presented, and the results compare well with experimental results.