This paper presented the solution of BHA under large deformation by means of bom-column theory, on the basis of solution of BHA under small deformation, through the developing of theory.

• 本文在求解BHA小变形的纵横弯曲法基础上，经过理论扩展，提出了求解BHA大变形的纵横弯曲法，列出了转盘钻下部钻具组合的三弯矩方程组及钻头侧向力和倾角公式；