自进式旋转钻头钻孔修复运动方程及关键参数研究

Study on motion equations and technical parameters of borehole restoration for self-propelling drill

针对自进式旋转钻头依据钻孔修复理论计算长钻孔修孔参数误差大的问题,基于变质量牛顿定律,建立钻孔修复运动方程,得到修复长度和水力参数、钻孔参数、管道参数之间的关系,开展系统阻力测试试验,明确钻孔长度、角度、返水和运动速度对综合摩擦系数k的影响,修正运动方程,通过自进式旋转钻头修孔试验,验证运动方程。结果表明:综合摩擦系数k是运动方程的关键参数;自进式旋转钻头运动过程中,系统阻力随着修复距离增加呈线性增加;返水对钻头和高压软管产生阻力,导致综合摩擦系数k增大;钻头和高压软管在仰孔中运动时,重力的分力成为阻力;钻孔角度和射流压力增加均能导致返水流速增加,使综合摩擦系数k增加;综合摩擦系数k理论值需要用系数0.8进行修正;修正后的运动方程可以较为准确地计算自进式旋转钻头的最大修复距离,修复距离104.7 m时理论值与试验值误差为5.7 m,验证了自进式旋转钻头钻孔修复技术在长钻孔中应用的可行性。

To address the problem of large error in the calculation of long hole restoration parameters for existing self-propelled rotary drill hole restore theory,a borehole restoration equation of motion was establised based on Newton’s law of variable mass,and the relationship between restoration length and hydraulic pa-rameters,borehole parameters and pipe parameters was derived.System resistance test experiments were car-ried out,the effects of borehole length,angle,return water and movement speed on the integrated friction co-efficient k were clarified.The equation of motion was revised and validated through self-propelling drill bore-hole restoration experiments.The results showed that:The integrated friction coefficient k was the key pa-rameter of the equations of motion;The system resistance linearly increased with increasing restoration dis-tance during the movement of the self-propelling drill;Return water created resistance to the drill and high pressure hose,resulting in an increase in the integrated friction coefficient k;As the drill and high-pressure hose moved through the upward borehole,the component force of gravity became the resistance;The in-crease in the angle of the borehole and jet pressure could lead to an increase in the return water flow rate,resulting in an increase in the integrated friction coefficient k;The theoretical value of the integrated fric-tion coefficient k needed to be corrected by a factor of 0.8;The modified equation of motion allowed for a more accurate calculation of the maximum restore distance of a self-propelling drill,the error between the theoretical and experimental values was 5.7 m at a restoration distance of 104.7 m,which verified the feasi-bility of applying the borehole restoration for self-propelling drill technology in long boreholes.