【摘要】 分析了导向钻进法用三翼回拉扩孔钻头在复杂地层条件下的力学性质 ,推导了计算不同岩石的最优切削角公式 ,并得出常见岩石的最优切削角值 ,进一步对回拉扩孔钻头的结构形式提出了优化 ,为导向钻进法回拉扩孔施工达到最优钻进 ,提供了必要的力学计算依据更多还原

【Abstract】 The mechanical characteristics of the three wing back reamer used in guided boring in difficult formation is examined. The formula for calculating the optimum cutting angle in different rocks is deduced with the optimum angle obtained. The structural type of the back reamer is furthur optimized to provide necessary mechanical calculation basis for optimization of back reaming in guideel boring.更多还原