天然气工业2026，Vol.46Issue(1)：105-115,11.DOI:10.3787/j.issn.1000-0976.2026.01.010
多齿重载冲击下花岗岩裂纹萌生—扩展机理及布齿建议
Mechanisms of crack initiation and propagation in granite under multi-tooth heavy-load impact and recommendations for tooth layout
摘要
Abstract
Impact drilling is currently one of the most effective methods for improving the rate of penetration(ROP)in hard rock formations.The bit tooth layout is an important research direction,while no clear understanding has been obtained on the effects of tooth parameters on the initiation,propagation and coalescence of internal rock fractures and rock-breaking efficiency under heavy-load impact.This paper systematically investigates the effects of tooth diameter,tooth spacing,confining pressure,impact energy and tooth distribution pattern on rock crack initiation,propagation and coalescence through laboratory dual-tooth impact experiments and numerical simulations under conditions with/without confining pressure.The following results are obtained.First,a reasonable tooth spacing plays a key role in exciting the cracks between impact craters and promoting their propagation and coalescence.Under the condition without confining pressure,the critical tooth spacings for crack coalescence at single-tooth impact energies of 50 J and 75 J are 20.46 mm and 28.40 mm,respectively.Second,confining pressure enhances the independence between adjacent impact craters,significantly inhibiting the crack propagation and coalescence.At a tooth spacing of 20.46 mm and a single-tooth impact energy of 75 J,crack coalescence becomes unattainable under the confining pressures exceeding 30 MPa.Third,as the single-tooth impact energy increases,tooth diameter and impact energy alternately serve as the dominant factor influencing the critical tooth spacing for crack coalescence.With increasing tooth diameter,the primary factor controlling the variation trend of rock-breaking specific energy gradually shifts from tooth spacing to tooth diameter.Fourth,among different impact tooth distribution patterns,regular quadrilateral pattern yields the optimal rock crack propagation and coalescence effect,followed by regular triangular,regular pentagonal,and regular hexagonal patterns.In conclusion,this research is of important significance to deeply understanding the interaction mechanisms between impact teeth and the mechanisms of rock crack propagation and coalescence,provides a theoretical basis and design references for optimal tooth layout of impact drill bits under heavy-load impact,and offers theoretical guidance value for ROP improvement in deep strata.关键词
重载冲击/冲击破岩/花岗岩/多齿冲击/裂纹贯通/裂纹扩展/临界齿距/钻头布齿Key words
Heavy-load impact/Impact rock-breaking/Granite/Multi-tooth impact/Crack coalescence/Crack propagation/Critical tooth spacing/Bit tooth layout分类
能源科技引用本文复制引用
祝效华,程飞龙,石昌帅,刘伟吉..多齿重载冲击下花岗岩裂纹萌生—扩展机理及布齿建议[J].天然气工业,2026,46(1):105-115,11.基金项目
国家自然科学基金杰出青年基金项目"钻井提速理论与方法"(编号:52225401). （编号:52225401）
