Construction method for building foundation pit enclosure structure with thin-walled cylinder pile as fender post

Abstract

The invention discloses a construction method for a building foundation pit enclosure structure by using a thin-wall tubular pile as an enclosure pile, which comprises the following steps: a, discharging a pile head and mounting an inner steel cylinder template and an outer steel cylinder template; b, downwards pressing the pile head (2); c, welding an embedded piece; d, placing a steel reinforcement cage; e, pouring concrete for the tubular wall (9) of the thin-wall tubular pile; f, filling a core; g, repeating steps a to f to carry out the construction of the next enclosure pile (1); h, pouring a coping beam and an inner support at the elevation place of the coping beam; i, welding a connecting reinforcement (14) on the embedded piece; j, binding an enclosed purlin reinforcement (13) and an inner support reinforcement (16); k, mounting a template; and l, pouring concrete for an enclosed purlin (8) and an inner support (15) at the elevation place of the enclosed purlin. The construction method for the building foundation pit enclosure structure by using the thin-wall tubular pile as the enclosure pile is safe and environment-friendly, has low cost and low waste rate, and can ensure the quality of the enclosure pile.

Description

technical field [0001] The invention relates to a construction method of civil engineering, in particular to a construction method of a building foundation pit enclosure structure using thin-walled cylindrical piles as enclosure piles. Background technique [0002] With the continuous expansion of the use of underground space in buildings, the scale and depth of excavation of foundation pits are also expanding. In order to ensure the safety and economy of foundation pit excavation, the design and construction of the foundation pit enclosure structure have been further paid attention to, and a complete set of technical demonstration, approval and quality management systems have been established in the industry to ensure the engineering quality. At present, the following structures are generally adopted for the enclosure structure of foundation pit excavation in soft soil areas: use bored piles as enclosure piles, set pressure beams on the top of enclosure piles and support (...

AI Technical Summary

Problems solved by technology

[0004] The above construction methods have the following defects: due to the use of bored cast-in-place piles as enclosure piles, a large amount of retaining mud is inevitably needed, and the retaining mud not only pollutes the environment, but also needs to be transported to a specific place for treatment and discharged. The cost of discharge is high, and the energy consumption of drilling is also relatively large; and the mud also has a great impact on the quality of concrete, and the phenomenon of mud inclusion and necking often occurs in the surrounding protection piles, so the quality of the surrounding protection piles is difficult to guarantee; and because The above-mentioned retaining piles have no function and are scrapped after the underground structure of the building of the foundation pit is completed. Therefore, the greater the amount of concrete used for the retaining piles, the higher the excavation cost of the foundation pit and the more serious the waste of materials.

[0005] If the thin-walled tubular piles used as building foundation piles of the prior art are used as the enclosure piles of the foundation pit enclosure structure, the following defects exist: when the strength of the concrete supported in the top beam and the elevation of the top beam reaches the design requirements , when it is necessary to set the purlin and the inner support at the elevation of the purlin, since the thin-walled cylindrical pile is hollow, the local strength at the place where the purlin is set is not enough, and there are potential safety hazards; moreover, the setting of the purlin needs to be cut at the position of the retaining pile The formed concrete is then welded on the exposed reinforcement cage of the enclosure pile and the connecting reinforcement tied with the enclosure reinforcement

However, because the wall and reinforcement cage of thin-walled piles are relatively thin, they are easy to be damaged during concrete excavation, so the quality of the surrounding piles is difficult to guarantee

Therefore, as far as the applicant knows, there is no precedent for the thin-walled tubular piles used as building foundation piles as the enclosure piles of the foundation pit enclosure structure.

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