Construction method of screw drilling and squeezing cast-in-place pile and combined screw drill

Abstract

The invention discloses a construction method of a screw drilling and squeezing cast-in-place pile. The construction method comprises the following steps: a combined screw drill is rotated clockwise for drilling and squeezing hole forming in advance; after a designed depth is reached, the combined screw drill is enabled to move upwards and rotated clockwise again to squeeze and expand a pile hole;the combined screw drill is screwed upwards, and at the same time, a concrete pump is started to fill the pile hole with a piling material to a preset height; and then a reinforcement cage is implanted. The combined screw drill comprises a spiral drill pipe at the upper part and a screw-type drilling and tunneling head at the lower part, wherein the upper end of the spiral drill pipe is connectedwith a power head; the lower end of the spiral drill pipe is connected with the screw-type drilling and tunneling head at the lower part; the screw-type drilling and tunneling head consists of a drill reducing segment and a drill cutting pick segment; the diameter of the drill reducing segment is gradually reduced from the upper end to the lower end to a certain set diameter; and meanwhile, alloycutting picks are distributed at the end part of the drill cutting pick segment. The screw drilling and squeezing cast-in-place pile constructed by the combined screw drill has the characteristics ofstrong constructability on a hard stratum, high bearing capacity, small sedimentation, good piling quality, lower cost, less energy consumption and the like.

Description

technical field [0001] The invention relates to the field of geotechnical engineering, in particular to a construction method for screw-drilled cast-in-situ piles and a combined screw drill bit. Background technique [0002] In the pile foundation construction of hard ground, pebble gravel and other strata, the traditional construction technology has many shortcomings, such as the limited drilling capacity of bored piles and cannot be driven in; punched cast-in-place piles are easy to collapse holes, and the verticality is difficult to control. The hole-forming effect is very unsatisfactory and the filling coefficient is too large, which affects the quality of the pile and the cost of the pile foundation; screw piles and spiral squeezed soil piles are also difficult to advance due to excessive drilling resistance, insufficient torque of the power head, and deformation of the spiral blades. Affect the life of the pile driver and the construction period of the project. Conte...

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Problems solved by technology

[0002] In the pile foundation construction of hard ground, pebble gravel and other strata, the traditional construction technology has many shortcomings, such as the limited drilling capacity of bored piles and cannot be driven in; punched cast-in-place piles are prone to collapse, and the verticality is difficult to control. The hole-forming effect is not ideal and the filling coefficient is too large, which affects the quality of piles and the cost of pile foundations; screw piles and spiral soil-squeezed cast-in-situ piles are also difficult to advance due to excessive drilling resistance, insufficient torque of the power head, and deformation of the spiral blades. Affect the life of the pile driver and the construction period of the project

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