Construction method of cast-in-situ bored pile of existing underground structure

Abstract

The invention provides a cast-in-situ bored pile construction method of an existing underground structure, which comprises the following steps of: digging out covering soil on a top plate of the existing underground structure, and breaking and trepanning at a first preset piling position on the top plate; breaking and trepanning are carried out at a second preset piling position on the bottom plate of the existing underground structure; the pile hole in the bottom plate serves as a first water collecting well for pre-precipitation treatment; according to the hydrogeological condition below the bottom plate, the anti-inrush stability checking calculation is conducted on the underground confined water, the minimum mud specific gravity is determined, and mud is prepared according to the minimum mud specific gravity; and hole drilling, hole cleaning and concrete pouring are carried out. Holes are locally formed in the top plate and the bottom plate of the existing underground structure through the bearing force of the existing underground structure, and the safety risk of dismantling is avoided. And moreover, by taking a pre-precipitation measure before pile foundation construction and adjusting the specific gravity of slurry in the construction process, the problem that the difference between the elevation of the existing underground structure and the elevation of the natural terrace is large, and consequently the influence of underground water on the pile foundation pore-forming quality is large is solved.

Description

technical field [0001] The invention relates to the technical field of pile foundation engineering construction, in particular to a construction method of bored piles with existing underground structures. Background technique [0002] In recent years, with the continuous development of cities, more and more building functions cannot meet the growing urban needs. It is imperative to renovate old buildings in the city. Due to the old structures underground, the construction of pile foundation Large-scale demolition and obstacle removal construction is required. During the demolition process, safety risks are high and the progress is greatly affected. After the demolition is completed, due to the large difference in elevation between the existing underground structure and the natural floor, it is necessary to consider the overall backfilling to ensure the normal construction of the pile foundation. Increased the construction difficulty and construction cost of the old building ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a construction method for bored piles with existing underground structures, which not only avoids the safety risk of dismantling the existing underground structures, speeds up the construction progress, but also solves the problem of the existing underground structures and the natural floor elevation. The difference is large, which leads to the problem that groundwater has a great influence on the quality of pile foundation holes

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