The invention discloses a
pile foundation hole forming construction process under the large-particle-size
cobble sandy soil and severe
water seepage geological condition. Holes are formed through a follow-up process that rotary drilling rig drilling is matched with a steel casing. The
pile foundation hole forming construction process comprises the specific construction steps that 1, site formation is conducted, specifically, site formation of a pioneer road and site formation within a construction area range are conducted; 2,
pile position
lofting is conducted, specifically, on the basis of technical disclosure data, surveying and setting out are conducted through a
total station, the specific position of a pile is determined, and a marker is made in the center of the pile in the mode of
coating a short
steel bar with paint; and 3, outer-side steel casing inserting and beating are conducted, specifically, an outer-side steel casing is inserted and beat to the position 4-6 m under the
river bed ground with a crawler crane being matched with a hydraulic vibration hammer, the wall thickness of the outer-side steel casing is not less than 10 mm, and the
diameter of the outer-side steel casing is 40 cm larger than that of the actual drilled pile. According to the pile foundation hole forming construction process under the large-particle-size
cobble sandy soil and severe
water seepage geological condition, the problem that drilling is difficult due to the fact that a rotary drilling rig encounters large-particle-size cobbles during construction is solved, the amount of
drill slag after the holes are formed is decreased, the problem that the holes are not cleaned thoroughly is solved, accordingly, the drilling time is shortened, and the formed hole quality is improved.