Pressure compensation type foundation pit supporting structure and construction method

Abstract

The invention relates to a pressure compensation type foundation pit supporting structure and a construction method. The pressure compensation type foundation pit supporting structure is characterized in that a multi-cavity back-pressure bag composed of a plurality of continuous airtight cavities is arranged on the base foundation supporting side; a bag top beam and a bag bottom beam connected with the bag in an airtight manner are arranged on the top and at the bottom of the multi-cavity back-pressure bag respectively; the bag top beam and the bag bottom beam are connected with a transverse counterforce structure and a vertical counterforce structure respectively; transverse counterforce beams and vertical counterforce beams are arranged at partitions of the airtight cavities; transverse reinforcement bodies are arranged at the crossed parts of the transverse counterforce beams and the vertical counterforce beams; cavity pressurizing pipes and cavity grouting pipes are arranged in the cavities of the multi-cavity back-pressure bag; and a tension steering structure is arranged between the transverse counterforce structure and the side wall of a foundation pit. According to the pressure compensation type foundation pit supporting structure, the change of the stress state of a soil body due to excavation of the foundation pit can be avoided, in addition, an airtight seeping-preventing structure can be formed on the supporting side, and deformation of the soil body on the outer side can be dynamically controlled. The invention further provides the construction method for the pressure compensation type foundation pit supporting structure.

Description

technical field [0001] The invention relates to a foundation pit support structure and a construction method, in particular to a pressure-compensated foundation pit support structure that can effectively prevent soil stress release, groundwater level reduction, and adjacent building deformation during foundation pit soil excavation and construction methods. It belongs to the field of foundation pit engineering and is suitable for foundation pit support engineering, especially for foundation pit engineering with high groundwater level, poor geological conditions, and strict deformation control of adjacent buildings. Background technique [0002] Foundation pit support is a support, reinforcement and protection measure taken at the side wall of the foundation pit to ensure the construction of underground structures and the surrounding environment of the foundation pit. It has been widely used in building foundation construction in my country. At the same time, with the develo...

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Problems solved by technology

[0006] It is undeniable that the existing foundation pit support structure has achieved good engineering benefits under suitable working conditions, but there are still some deficiencies, mainly reflected in: the cement-soil wall involves large-volume concrete pouring, the construction quality is not easy to control, and the wall Temperature shrinkage and deformation cracks are prone to occur, and leakage problems are prone to occur when the groundwater level is high; the wall rigidity of the row of piles or the underground diaphragm wall support structure is small, and the internal force and deformation of the wall body are significantly different at different depths, so it is difficult to effectively control the damage of buildings around the foundation pit. Deformation; the surrounding buildings of the soil nail wall support structure have a large amount of deformation and are prone to seepage problems

A soil-nail retaining pile + water-stop support pile row structure has considered the waterproof problem of the side wall of the foundation pit, but the structure's ability to resist lateral deformation is weak; a foundation pit support structure of an underground diaphragm wall is easily damaged at the joints. Leakage problems occur, and the cost of structural support is high

It is worth noting that the existing foundation pit support is mostly passive support, which cannot effectively control the release of soil stress on the side wall of the foundation pit, and it is difficult to fundamentally solve the problems of soil settlement and building deformation around the foundation pit

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