Correction and prevention of deviation in impact drilling of cast-in-place pile holes

Abstract:

Although impact drilled cast-in-place piles have wide applicability in all kinds of strata， holes are prone to deviat under complex geological conditions. In view of frequent deviation of holes in the construction of impact drilled cast-in-place piles for a high-rise building， hole deviation in the impact drilling process is comprehensively analyzed and studied. With hole deviation correction and prevention as the subject of study， research was carried out for two specific cases： deflection from solitary stones and dipped hard rock stratum. For solitary stones， the bit， impact stroke and frequency were properly controlled； for dipped hard rock stratum， increase of the thickness of the TC chips was studied for the bit. Field application demonstrated that hole deviation was effectively avoided.