Construction method for grouting cast-in-place pile after dry drilling, soil squeezing and hole forming in hard stratum

Abstract

The invention discloses a construction method for grouting a cast-in-place pile after dry drilling, soil squeezing and hole forming in a hard stratum. The construction method comprises the following steps: 1) moving a machine and positioning; (2) forward rotation, soil squeezing and downward drilling are conducted, specifically, a pile machine rotates forward, a drill bit cuts a hard stratum, cut muck is squeezed towards the periphery of a pile through a screw drill rod, and a small part of muck returns upwards out of the ground; (3) drilling to the elevation of a final hole; (4) pile core concrete is pumped and poured to the bottom of the hole by 1.5-2.5 m, after the final hole standard is met, concrete pumping operation is started to the bottom of the pile, and the pile is rotated forwards and lifted upwards by 1.5-2.5 m at a constant speed while concrete is pumped to the bottom of the pile; (5) forward rotation is conducted, downward re-drilling is conducted by 1.5 m to 2.5 m, and the final hole elevation is reached; according to the cast-in-place pile construction method, the problem that pile forming is difficult in a hard stratum is solved, the vertical compression resistance static load force of a single cast-in-place pile is large, and the occupancy rate of pile body completeness is high.

Description

technical field [0001] The invention relates to the technical field of construction piling, in particular to a construction method of grouting and pouring piles after dry drilling and squeezing soil in hard strata to form holes. Background technique [0002] Definition of hard stratum: 1) sandy pebble layer and gravel layer with heavy conical dynamic penetrating strokes greater than 10 in medium-dense or dense state; 2) cohesive soil in hard state with standard penetration strokes greater than 30 Weathered sandy cohesive soil, the core is soil-like or fragmented; 3) The hard rock strongly weathered formation with a standard penetration blow count greater than 50 blows, the core is massive; 4) The uniaxial saturated compressive strength is greater than 15MPa Moderately weathered soft rock formations. The pile side and pile tip bearing capacity of the above hard ground is extremely high. [0003] In recent years, with the continuous development of the economy and the large-s...

AI Technical Summary

Problems solved by technology

It is not a big problem to match the drilling speed and running speed in general cohesive soil, but for hard formations, it is difficult to match the running speed and rotation speed, that is, it is impossible to achieve pile side threading.

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