Adjustable multiple coil extruding and expanding drilling tool

Abstract

The invention relates to an adjustable multiple coil extruding and expanding drilling tool, comprising a hollow connecting rod, the lower part of the lateral wall of the connecting rod is provided with a helical blade, the bottom end of the connecting rod is provided with a drill, the connecting rod is coaxially connected with a plurality of helical extruding expanding bodies, the helical extruding expanding body is arranged between the helical blades, the margin of the cross section of each helical extruding expanding body is helical line, maximum outer diameter and minimum outer diameter ofeach helical extruding expanding body are respectively constant or increased from bottom to top, and the maximum outer diameter of each helical extruding expanding body is equal to or less than the outer diameter of the helical blade. The invention aims at providing an adjustable multiple coil extruding and expanding drilling tool which can penetrate thick hard clay or dense sand soil layer, avoid collapse when drilling into finished hole in high ground eater level and high hydrodynamic pressure stratum and can implement complete extruding soil or partial extruding soil type cast-in-place pile through multiple stage extruding and expanding at different depths by freely adjusting the position of multi-stage extruding expanding body according to longitudinal distribution of stratum.

Description

technical field [0001] The invention relates to an adjustable multi-stage spiral extruding and expanding drilling tool applied in the field of civil engineering. Background technique [0002] In the field of pile foundations in civil engineering, modern pile foundations can be divided into three categories: non-squeeze piles, partially squeezed piles and fully squeezed piles according to the influence of pile formation methods on the stratum. At present, the long spiral cast-in-situ pile CFA pile commonly used at home and abroad is a non-squeezing soil pile, which has the characteristics of simple construction, fast speed, no vibration, low noise, etc., and has been widely used in pile foundation engineering, foundation treatment, foundation pit support and other fields. application. However, CFA piles have problems such as low bearing capacity, excavation, and environmental pollution. In recent years, the field of geotechnical engineering has been devoting itself to the d...

AI Technical Summary

Problems solved by technology

For example, for half-screw piles or full-thread piles, in order to realize that the pile body has 2 / 3 or full pile length threads, complex synchronous techniques and techniques must be used during pile construction; since most construction strata have distribution uncertainties Due to the non-uniformity of the soil properties, it is difficult to ensure the instantaneous synchronization of the pile thread generation process, resulting in some or all pile threads not being formed according to the design requirements

However, the short-screw soil-squeezing cast-in-place pile is finally formed into a cylindrical complete soil-squeeze pile by applying torque in the same direction, which does not require synchronization technology; Due to the large amount of soil squeezed, it cannot effectively pass through the thicker hard clay layer or dense sand layer, which affects the depth of the pile.

In addition, because the diameter of the connecting drill pipe on the upper part of the short helical extruded drill bit and the half-screw drill tool is smaller than the diameter of the pile hole, it is easy to cause the hole to collapse in the soft clay and sandy soil layers with high groundwater level or high dynamic water pressure. The frictional resistance on the side of the pile is reduced, which limits the application range of short spiral piles and semi-screw piles

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