Mechanical piling method for third level bottom-expanded combined pile body

Abstract

The invention relates to a mechanical pile forming method for there level belled composite pile body, comprising the craft steps that: a, a sinking pipe with a metal pile head is immersed into hardpan to design elevation; b, the metal pile head is taken out; c, a lower base space is processed by a belled device, the sinking pile is drawn upward to setting distance H1, an intermediate base space is processed, the pulverizing soil in the base space is cleaned by drawing out soil device, a prefabricated hollow pile body with an inserted reinforcement arranged at the lower end is run into the sinking pile, the lower base, the intermediate base and the lower pile body are poured by concrete pouring; d, the sinking pile is drawn upward to setting distance H2, an upper base space is processed, the pulverizing soil is fell into the inner of prefabricated hollow pile body, the upper base is poured by concrete pouring; e, an upper prefabricated hollow pile body with an inserted reinforcement arranged at the lower end is run into the sinking pile, the inserted reinforcement is anchored with the upper base; f, the sinking pile is run out, cement slurry is injected into the gaps on the external surface of the pile body. The invention has the advantages of improving the utilization ratio of materials strength and reducing the cost of construction.

Description

technical field [0001] The invention relates to a construction method of building pile foundation engineering, in particular to a pile forming method of a three-stage bottom-expanding combined pile body. It is the preferred construction method for high-rise building multi-level foundation large bearing capacity pile foundation engineering. Background technique [0002] According to the national standard, the whole body is cast-in-place (that is, the pile body is cast-in-place concrete, and the base is also cast-in-place concrete). The maximum diameter ratio of the base of the expanded bottom pile is limited to 3-3.5, while the immersed tube prefabricated steel concrete expanded bottom pile, this kind of pile It is prefabricated concrete for the pile body and cast-in-place concrete for the base. Obviously, the ratio of 3-3.5 is broken, and generally can reach 3.5-5. Although the bearing capacity is greater, it still cannot meet the needs of the project, especially when the di...

AI Technical Summary

Problems solved by technology

These two points are quite unfavorable to multi-bearing plate (multi-level bottom expansion) piles. In other words, it brings two problems. 1) The national building code stipulates that the end bearing of the base of the pile expansion bottom using the positive and negative circulation method The force has to be multiplied by a factor of 0.45, because there is mud and the sediment at the bottom of the pile cannot be cleaned up. (The standard in Zhejiang Province is 0.24 discount). However, the construction conditions cannot be protected. In addition, the positive and negative circulation method works underwater, so the bottom expansion construction cannot be seen, and it is difficult to measure and record. It also often happens that a piece of upper soil falls off when the bottom is expanded underwater. Occurrence, also because the multi-stage piles of the prior art all use cast-in-place concrete for the whole body, and the strength of cast-in-place concrete is not high, and the quality is difficult to guarantee, and the quality is difficult to control when pouring concrete in water, plus multiple bases The bearing capacity of the piles is relatively large, the diameter of the pile body must be made larger due to the above factors, and this kind of multiple bases is most afraid of a large diameter of the pile body. Research and tests have shown that as the diameter of the pile body increases, its bearing capacity will be greatly attenuated.

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