Method for forming variable-cross-section compaction thread pile and compaction drilling tool

Abstract

The invention provides a method for forming a variable-cross-section compaction thread pile and a compaction drilling tool. The method comprises the following steps: (1) arranging a pile driver in place; (2) forming holes at the upper section of a pile body; (3) axially separating an inner drill stem from an outer drill stem; (4) forming holes at the lower section of the pile body; and (5) lifting and extruding to form the pile. The compaction drilling tool comprises the inner drill stem and the outer drill stem, wherein, the spiral rotary wings of the outer drill stem and the inner drill stem are equipped with reaming heads; the outer drill stem is sheathed outside the inner drill stem; the upper end of the inner drill stem is equipped with an outer spline, the outer drill stem is equipped with an inner spline, the inner spline of the outer drill stem is matched with the outer spline of the inner drill stem, and the circumferential clearance between the outer spline on the upper end of the inner drill stem and the inner spline of the outer drill stem is more than or equal to the width of one spline tooth; and an axial limit block is arranged on the lower end of each tooth of the inner spline of the outer drill stem, and the distance between the axial limit block and an adjacent spline tooth is more than or equal to the width of one spline tooth. The pile body formed by the compaction drilling tool through the method is a variable-cross-section compaction thread pile, and the pile body has the advantage of large bearing capacity.

Description

technical field [0001] The invention relates to a foundation construction technology, in particular to a pile-forming method of a variable cross-section compacted screw thread pile and a compacted drilling tool. Background technique [0002] There are many studies on the treatment of soft soil foundation at home and abroad. At present, the commonly used low-strength concrete piles (CFG piles) are end-bearing friction piles, and most of them are soil-discharging type holes. Since the pile body is in a single column shape, the frictional surface area of ​​the pile body is limited. Certain restrictions, although the strength of the pile body is relatively large, the friction of the soil is not enough, so that the concrete of the pile body cannot fully play its role, so the project cost is high, and the application is also subject to certain limitations. [0003] Since the pile body is extruded and cast, and there are threads around the pile body, the compact threaded pile has a...

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Problems solved by technology

[0006] But the patent No. is the pile-forming method of 200610040028.3 threaded cast-in-place pile for the compact hole-forming drilling tool of 89215780.1 and the patent application number, and the pile body that it makes can only be single columnar, and promptly the section of pile body is constant, and its to improve The bearing capacity of the pile body is not large

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