旋挖钻机截齿的破岩机理及优化研究

旋挖钻机成孔的显著优势备受关注，但实际钻孔很难达到理想的破岩效果，揭示复杂地层赋存环境的钻头破岩机理是关键。文中基于Boussinesq问题的求解，得到动力头压力和扭矩作用于截齿时的岩石受力及位移，推导截齿破岩时的侵入力及切削力表达式。建立单截齿破岩的三维数值模型，获得钻头钻进中截齿的侵入力及切削力变化规律，对比理论结果以验证数值模型的可行性。基于旋挖钻机双截齿破岩过程的数值模拟，分析钻进中的岩体力学响应及裂纹演化以揭示截齿的破岩机理，探讨不同截齿布置的旋挖钻机破岩力特征，阐明截齿倾角或偏斜角增大都将不同程度地改变破岩力大小。进一步分析截齿布置方式与不同类型地层组合的破岩效率，结果表明，截齿倾角或截齿偏斜角或截齿间距相等时，由软到硬地层的破碎比功逐渐增大，且钻进某一地层的破碎比功先减小后增大，存在最优的截齿布置使得钻进效率最高。研究成果可为旋挖钻机截齿设计的优化和破岩效率的提高提供理论依据。

Fragmentation mechanism and optimization of the picks in rotary drilling gig

The significant advantages of the rotary drilling rig for boring have attracted increasing attention. However, achieving ideal fragmentation efficiency in practical drilling remains challenging. Therefore, it is crucial to understand the fragmentation mechanism in the stratum environment. By solving the Boussinesq problem, the force and displacement exerted on the picks by the power head, as well as the penetrating force and cutting force under picks fragmentation conditions, have been determined. Additionally, a 3-Dimension numerical model for a single pick has been proposed to analyze the variation in penetrating force and cutting force. The results have been calibrated with theory to validate their reliability. Furthermore, a numerical simulation involving two picks has been conducted to describe the mechanical response and cracking evolution, thus revealing the mechanism of the pick fragmentation. In addition, the fragmentation forces exerted by picks with different arrangements have been extensively discussed, highlighting that the pick inclination or deviation angle has a significant impact on fragmentation force. Finally, the fragmentation efficiency with considering the picks arrangement in different strata has been thoroughly investigated. The findings demonstrate that specific work increases as the machine drills from soft to hard formations, while maintaining the same pick inclination, deviation angle or spacing. Furthermore, the corresponding value firstly decreases, then increases for a given stratum, indicating that the optimized arrangement of picks yields the highest efficiency. These achievements provides theoretical support for the optimization of picks and improvement of fragmentation efficiency.