A bonded-particle model for rock
A bonded-particle model for rock
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DOI：
10.1016/j.ijrmms.2004.09.011
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发表时间：
2004-12-01
影响因子：
7.2
通讯作者：
Cundall, PA
中科院分区：
文献类型：
--
作者：
Potyondy, DO;Cundall, PA
本文提出了一种岩石数值模型，其中岩石由非均匀圆形或球形颗粒的紧密堆积所表示，这些颗粒在它们的接触点处粘结在一起，其力学行为用离散单元法模拟，使用二维和三维不连续程序PFC2D和PFC3D。微观性能包括颗粒和粘结剂的刚度和强度参数。损坏明确地表示为断裂的键。当施加载荷时，其形成并结合成宏观裂缝。该模型再现了岩石的弹性破裂、声发射、损伤累积、材料各向异性、滞后、膨胀等特性。峰后软化和强度随着约束而增加。这些行为是模型的涌现性质，它们来自一组相对简单的微观性质。本文介绍了表征邦纳湖花岗岩的物质、成因过程和显微特征。该模型的行为描述为二维和三维双轴。三轴试验和巴西试验以及在最大压应力区域形成崩落缺口的二维隧道模拟。的微观性能，包括粒度的敏感性，进行了研究。粒子大小不是一个自由的参数，只控制分辨率：相反。它影响断裂韧性，从而影响损伤过程（例如切口形成），其中损伤定位在经受延伸载荷的宏观断裂尖端。(C)2004 Elsevier Ltd.保留所有权利。
A numerical model for rock is proposed in which the rock is represented by a dense packing of non-uniformized circular or spherical particles that are bonded together at their contact points and whose mechanical behavior is simulated by the distinct-element method Using the two- and three-dimensional discontinuum programs PFC2D and PFC3D. The microproperties consist of stiffness and strength parameters for the particles and the bonds. Damage is represented explicitly as broken bonds. which form, and coalesce into macroscopic fractures when load is applied. The model reproduces many features of rock behavior includinq elasticity fracturing, acoustic emission, damage accumulation producing material anisotropy, hysteresis, dilation. post-peak softening and strength increase with confinement. These behaviors are emergent properties of the model that arise from a relatively simple Set of microproperties. A material-,genesis procedure and microproperties to represent Lac du Bonnet granite are presented. The behaviour of this model is described for two- and three-dimensional biaxial. triaxial and Brazilian tests and for two-dimensional tunnel simulations in which breakout notches form in the region of maximum compressive stress. The sensitivity of the to microproperties, including particle size, is investigated. Particle size is not a free paranieter that only controls resolution: instead. it affects the fracture toughness and thereby influences damage processes (such as notch formation) in which damage localizes at macrofracture tips experiencing extensile loading. (C) 2004 Elsevier Ltd. All rights reserved.