Large-scale prefabricated enclosure structure and construction method for deep foundation pit

Abstract

The invention discloses a deep foundation pit large-size prefabricated envelop enclosure and a construction method. The deep foundation pit large-size prefabricated envelop enclosure comprises composite piles, and jet grouting piles or stirring piles located between the adjacent composite piles and engaged with the composite piles. Each composite pile comprises a prefabricated pile, and cement soil arranged on the outer circle of the prefabricated pile in a filling manner, wherein a cylindrical composite pile structure is integrally formed by the cement soil and the prefabricated piles. The envelope enclosure has the double functions of soil blocking and water stopping. The soil blocking function is achieved through the composite piles, holes formed in the composite piles are circular, the prefabricated piles are planted in the holes, and gaps are filled with the cement soil. The water stopping function is achieved in the manner that the cement soil is engaged with the jet grouting piles or the stirring piles between the adjacent composite piles. The prefabricated piles in a pile foundation project are introduced into the envelop enclosure in the deep foundation pit project, displacement piles are changed into low displacement piles, and the applicability of the prefabricated piles to a stratum is improved; the pile manufacturing and pile forming quality is guaranteed, the prefabricated piles can smoothly reach the designed depth, and pile intersecting is avoided; and pile enclosing and water stopping are combined.

Description

technical field [0001] The invention relates to the technical field of construction engineering, in particular to an enclosure structure and a construction method for promoting the development of prefabrication industrialization concepts in the field of deep foundation pit support. Background technique [0002] The enclosure structure of building deep foundation pit engineering generally adopts bored cast-in-situ piles, and rotary grouting piles or mixing piles are used on the outside to stop water. With the gradual development of deep foundation pit engineering in a deep and large direction, the enclosure structure will inevitably develop to a large size. Due to the construction technology itself and the increase in size and depth, the construction quality of the enclosure structure will be poor and the construction speed will be slow. [0003] Prefabricated piles are generally used in construction pile foundation projects. The existing pile sinking techniques are mainly st...

AI Technical Summary

Problems solved by technology

With the gradual development of deep foundation pit engineering in a deep and large direction, the enclosure structure will inevitably develop to a large size. Due to the construction technology itself and the increase in size and depth, the construction quality of the enclosure structure will be poor and the construction speed will be slow.

[0003] Prefabricated piles are generally used in construction pile foundation projects. The existing pile sinking techniques are mainly static pressure and forced hammering. These two techniques are soil-squeezing piles and are not suitable for dense buildings in downtown, adjacent roads and underground pipelines. In areas with many intersections, due to the large displacement of the soil during pile driving, the horizontal displacement and vertical displacement (uplift) of the soil will occur, especially if the pile tip encounters a hard sandwich layer or a round gravel layer during pile driving, it is difficult for the pile tip to enter the design elevation , causing serious damage to piles, delaying construction time and causing economic losses, and seriously affecting the safety of surrounding buildings, roads and structures

[0004] In order to solve this problem, one of the traditional methods is to cut off the pile, that is, to cut off the upper part of the pile when the pile cannot be driven. The stress seriously affects the strength of the pile foundation, and it is difficult to guarantee the quality of the building; the second is to carry out the pilot hole before sinking the pile. Collapsing holes, it is difficult to guarantee the quality of holes

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