据统计,天井钻机的钻杆断裂多以拉、弯所引起,其原因是扩孔时刀头对钻杆产生拉、弯作用所致,但现行天井钻机设计未体现这一点显然是一种不足。针对这个问题,笔者从钻杆的受力分析出发,推导出它的内力计算式和它在拉、弯变形情况下危险截面上最大拉应力计算式,最后列举算例予以验证。 According to statistics, the drill pipe drill pipe rupture mostly caused by pulling, bending, the reason is that the reamer bit when the drill pipe pull and bend due to the role, but the current design of the boring machine did not reflect this is clearly a lack of . In response to this problem, the author deduces the calculation formula of its internal force and the formula of the maximum tensile stress of the dangerous cross-section under the condition of drawing and bending under the force analysis of the drill pipe. The last listed examples are verified.