Particle simulation of spontaneous crack generation problems in large‐scale quasi‐static systems
Particle simulation of spontaneous crack generation problems in large‐scale quasi‐static systems
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DOI：
10.1002/nme.1851
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发表时间：
2007-03
影响因子：
2.9
通讯作者：
Chong-bin Zhao;B. Hobbs;A. Ord;P. Hornby;S. Peng;Liang-ming Liu
中科院分区：
文献类型：
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作者：
Chong-bin Zhao;B. Hobbs;A. Ord;P. Hornby;S. Peng;Liang-ming Liu
为了将离散元方法的应用范围从实验室尺度扩展到诸如地质尺度这样的大尺度，我们需要处理一个与模拟大尺度准静态系统中的自发裂纹产生问题相关的高级问题。针对这一方向，本文详细讨论了影响准静态系统粒子模拟结果质量的三个重要模拟问题。第一个模拟问题是如何根据测得的岩石宏观力学性质确定颗粒的颗粒尺度力学性质。第二个模拟问题是，在准静态问题的粒子模拟中使用的是虚拟时间，而不是物理时间。第三个模拟问题是，离散单元法中使用的常规加载程序在概念上是不准确的，至少从力传播的角度来看是这样。提出了一种新的加载程序来解决由第三次仿真问题引起的概念问题。拟议的加载程序包括两种主要类型的时间段：加载时间段和冻结期。使用所提出的加载过程，可以在一定程度上解决由第一个问题引起的参数选择问题。由于第二个问题是一个固有的问题，强烈建议对至少两个具有相同几何形状但不同最小颗粒尺寸的不同模型进行颗粒尺寸敏感性分析，以确认大规模准静态系统的颗粒模拟结果。相关的模拟结果证明了所提出的加载方法在处理大型准静态地质系统中自发裂纹产生问题时的有效性和正确性。版权所有©2006 John Wiley&Sons，Ltd.
To extend the application range of the distinct element method from a laboratory scale into a large scale such as a geological scale, we need to deal with an upscale issue associated with simulating spontaneous crack generation problems in large‐scale quasi‐static systems. Toward this direction, three important simulation issues, which may affect the quality of the particle simulation results of a quasi‐static system, have been addressed in details in this paper. The first simulation issue is how to determine the particle‐scale mechanical properties of a particle from the measured macroscopic mechanical properties of rocks. The second simulation issue is that the fictitious time, rather than the physical time, is used in the particle simulation of a quasi‐static problem. The third simulation issue is that the conventional loading procedure used in the distinct element method is conceptually inaccurate, at least from the force propagation point of view. A new loading procedure is proposed to solve the conceptual problem resulting from the third simulation issue. The proposed loading procedure is comprised of two main types of periods, a loading period and a frozen period. Using the proposed loading procedure, the parameter selection problem stemming from the first issue can be somewhat solved. Since the second issue is an inherent one, it is strongly recommended that a particle‐size sensitivity analysis of at least two different models, which have the same geometry but different smallest particle sizes, be carried out to confirm the particle simulation result of a large‐scale quasi‐static system. The related simulation results have demonstrated the usefulness and correctness of the proposed loading procedure for dealing with spontaneous crack generation problems in large‐scale quasi‐static geological systems. Copyright © 2006 John Wiley & Sons, Ltd.