Construction method of vibration pressing type special-shaped multi-head bottom expanding pile

Abstract

The invention discloses a construction method of a vibration pressing type special-shaped multi-head bottom expanding pile. The method comprises the steps that a, a sinking pipe is subject to vibration pressing, and a pile hole is formed; b, an inner casing pipe is pulled up, concrete is poured in, forced extrusion is carried out, an outer casing pipe is pulled up synchronously, and an expansion head is formed; c, after first-time bottom expanding, a pile driver is adopted to synchronously sink the inner casing pipe and the outer casing pipe, forced concrete extrusion is carried out again, second-time bottom expanding is carried out, and a final pile bottom expansion head is formed; d, after second-time bottom expanding construction is finished, the inner casing pipe is pulled up, concretefor forming a pile main body of the pile body is poured into the outer casing pipe, the pile driver is adopted to carry out sinking pipe vibration pressing on the inner casing pipe, the outer casingpipe is pulled up synchronously, concrete is extruded, and the pile main body is formed; e, when the pile main body is constructed to the preset position, the concrete on the preset position is subject to forced vibration pressing, and the pile main body is subject to radial expansion; f, after the pile main body expansion head is formed, concrete is poured into the outer casing pipe, the sinkingpipe is subject to vibration pressing, concrete is extruded, and the pile main body is formed; g, a steel reinforcement cage is inserted in the concrete.

Description

technical field [0001] The invention relates to a construction method for a pile body of a building foundation, in particular to a construction method for a vibration pressure type special-shaped multi-head expanded bottom pile. Background technique [0002] The single pile bearing capacity of the pile body of the building foundation is mainly determined by the end resistance of the pile bottom and the frictional resistance of the pile body. No matter increasing one or both of the two forces, the single pile bearing capacity can be improved. Chinese patent document CN2023233935U discloses a cast-in-situ concrete large-diameter hollow five-star pile and its special construction equipment. The frictional resistance of the pile body is improved by reducing the volume of the pile body and increasing the surface area of ​​the pile body. Cylindrical hollow casing with five-star cross-section, and vibratory hammer equipment for immersed tubes. Although using this set of equipment ...

AI Technical Summary

Problems solved by technology

Although this patent document discloses a relatively wide prefabricated reinforced concrete pile point, it is prefabricated, and the pullout resistance of the pile body is insufficient after being driven into the soil. In addition, a Y-shaped plastic sleeve with threads is arranged inside the pile body The pipe is connected with the outer sleeve so that the injected concrete can be better combined with the Y-shaped plastic sleeve, so as to be integrated with the prefabricated reinforced concrete pile tip at the bottom to improve the pullout resistance of the pile body. However, this patent In the literature, the cement soil on the outside of the pile body finally forms a cylindrical pile body, so the friction resistance of the pile body has not been improved.

In addition, there are some defects in the molds and equipment used to make the special-shaped piles for the above two patent documents. For example, the mold used to make the five-star shaped pile body disclosed in the patent document CN2023233935U is a uniform five-star-shaped columnar sleeve in cross section. Tube, this kind of casing needs another inner casing that also has a five-star shape and its structure is matched with it. Due to the relative rotation and side collision between the pipes, the damage to the casing is relatively large

The special-shaped pile disclosed in the Chinese patent document CN103485334B is too complicated for making special-shaped piles with expanded bottoms, and the manufacturing steps are relatively cumbersome, and the final pile resistance and pile bearing capacity are not good enough

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