When the force can not contact drill string with one side of the borehole wall, the stiffness of drill string can influence the contact force.
当外力不足以使钻柱紧贴于井壁的一侧时,钻柱的刚度对钻柱与井壁之间的接触力有影响。
2
Elements of stonework excavation: Use down-hole drill assisted with hammer drill drilling. Control blasting loosely and side slope molding smoothing wall blasting.