中国石油大学学报（自然科学版）2017，Vol.41Issue(1)：90-95,6.DOI:10.3969/j.issn.1673-5005.2017.01.011
楔形钻齿作用下岩石破碎及微观劣化过程
Numerical simulation of rock breaking and microscopic deterioration under wedge-shaped drill bit teeth
摘要
Abstract
Theoretical analysis and numerical simulation were conducted in this study to investigate the propagation of radial and lateral cracks during rock breaking using wedge-shaped drilling bit teeth.The formulas for calculating the radial and lateral crack limitation lengths and the optimal space width were derived,in which the effects of hydraulic pressure and lateral pressure were considered based on the experimental research of Marshall,and the effects of hydraulic pressure,lateral pressure and space width on crack propagation were analyzed.A discrete element method (PFC2D) was used to simulate the indentation process of the drilling bit teeth.The results show that,with the indenter penetrating into rock,the sub-vertical cracks can be formed from the damaged zone and it will extend to bottom edge of the rock at last.The initiation and propagation of the sub-vertical cracks are mainly driven by the tensile contact forces.The development of sub-vertical cracks and the damaged rock zone can be restrained with lateral pressure increasing,and the increase of the lateral pressure can lead to an increase in the critical penetration depth,while the size of the damaged zone decreases and its shape flattens.The development of the sub-vertical cracks and the damaged zone can be promoted with the increase of the hydraulic pressure.A reasonable space width of the bit teeth is beneficial to rock fragmentation,which can improve the efficiency of rock breaking.关键词
楔形钻齿/侵入/岩石破碎/裂纹扩展Key words
wedge-shaped bit teeth/indentation/rock breaking/crack propagation分类
能源科技引用本文复制引用
祝效华,刘伟吉..楔形钻齿作用下岩石破碎及微观劣化过程[J].中国石油大学学报（自然科学版）,2017,41(1):90-95,6.基金项目
国家自然科学基金项目(51674214) （51674214）
四川省科技计划国际合作计划项目(2016HH0008) （2016HH0008）
四川省青年科技创新研究团队项目(2014TD0025) （2014TD0025）
