Discrete element modeling of tool-rock interaction I: rock cutting
Discrete element modeling of tool-rock interaction I: rock cutting
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DOI：
10.1002/nag.2113
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发表时间：
2013-09-01
影响因子：
4
通讯作者：
Detournay, E.
中科院分区：
文献类型：
--
作者：
Huang, H.;Lecampion, B.;Detournay, E.
根据工具相对于岩石表面的运动方向，工具-岩石相互作用过程可分为压痕或切割过程。由压痕或刀具在岩石中引起的破坏模式可以是延展性的和/或脆性的。延性模式与损伤带的发展有关，而脆性模式与宏观裂纹的扩展有关。这是两篇系列论文的第一部分，这两篇论文涉及到基于离散元方法的切割和压痕过程的分析。本文采用数值模拟的方法，模拟了随着切割深度的增加，材料从韧性失效模式向脆性失效模式转变的过程，并通过实验观察到了这一过程。数值结果表明，控制失效模式转变的临界切割深度d(*)与特征长度=(K-IC/sigma(C))(2)有关，其中K-IC表示材料的韧性，sigma(C)表示其无侧限抗压强度。在延性破坏模式下，还研究了切削面与岩石之间摩擦接触的性质。结果表明，总切削力的倾角是由刀具前方的多向流动机构控制的，这与间歇性地附着在刀具上的失效材料楔形的形成有关。因此，总切削力的倾角随切割器的前角而变化，不能被认为是切割器与岩石之间界面摩擦的内在量度。版权所有(C)2012 John Wiley&Sons，Ltd.
Tool-rock interaction processes can be classified as indentation or cutting depending on the direction of motion of the tool with respect to the rock surface. The modes of failure induced in the rock by an indenting or a cutting tool can be ductile and/or brittle. The ductile mode is associated with the development of a damage zone, whereas the brittle mode involves the growth of macrocracks. This is the first part of a series of two papers concerned with an analysis of the cutting and the indentation processes based on using the discrete element method. In this paper, numerical simulations of the cutting process are conducted to reproduce the transition from a ductile to a brittle failure mode with increasing depth of cut, which is observed in experiments. The numerical results provide evidence that the critical depth of cut d(*) controlling the failure mode transition is related to the characteristic length =(K-Ic/sigma(c))(2) with K-Ic denoting the material toughness and sigma(c) its unconfined compressive strength. The nature of frictional contact between the cutter face and the rock in the ductile failure mode is also examined. It is shown that the inclination of the total cutting force is controlled by a multi-directional flow mechanism ahead of the cutter that is related to the formation of a wedge of failed material, intermittently adhering to the cutter. As a result, the inclination of the total cutting force varies with the rake angle of the cutter and cannot be considered an intrinsic measure of the interfacial friction between the cutter and the rock. Copyright (c) 2012 John Wiley & Sons, Ltd.