单齿冲击作用下破岩机制分析

研究牙齿冲击下破岩机制是提高冲旋破岩效率的理论基础，目前对牙齿低速冲击下的岩石力学研究主要集中在仿真和试验，因此，有必要研究牙齿低速冲击下的破岩机制。首先分析了单齿冲击下岩石破碎坑的形貌，提出了分区建立物理模型和力学模型。考虑到单齿冲击的低速条件和岩石围压效应，得到修正的球形空腔膨胀理论，推导了岩石破碎坑的密实区、开裂区、弹性区3个区域的应力与位移解析解。利用Matlab对各区域解析解进行数值求解，得到了围压、质点运动速度以及岩石物理性质参数等对破碎坑各区域无量纲应力和位移变化的影响，采用仿真试验验证结果的正确性。该模型不仅解释了岩石破碎坑的形成，而且也提供了一种分析牙齿冲击破岩力学模型。

Study of rock-breaking mechanism under single-tooth impact

To improve the efficiency of the rotary-percussive drilling, it is necessary to understand the rock-breaking mechanism under tooth impact. Current research efforts in this regard are mainly focused on the numerical or experimental simulations of rock breaking under tooth impact. Thus it is important to investigate the rock-breaking mechanism under tooth impact at low velocity. In this paper, the crushing pit morphology resulting from single-tooth impact is first analyzed; and then the physico-mechanical models are developed for classifying different crushing areas. Considering the low-velocity and confining pressure effects in single-tooth impact, the theory of spherical cavity expansion is revised, from which the stress and strain solutions are obtained in the area around the cracked pit of the rock. Analytical solutions are obtained for different regions using Matlab; and the effects of confining pressure, particle velocity and rock mechanical parameters are analyzed on the dimensionless stress and displacement of the three different regions. The applicability and capability of the proposed model are shown by comparing the numerical results with those yielded from the LS-DYNA code.