Construction technique for pits in foundation-pit support system

Abstract

The invention discloses a construction technique of a pit tangent system in a pit, which includes the following steps of: taking measurement and calculating the intensity, the rigidity, the friction force and the subsidence factor of the tangent system - leveling of ground and measuring paying off - spreading a sand cushion and stow-wood - building a cutting edge and a brickwork base - making and erecting the tangent system - extracting the stow-wood - subsidising excavation to the design depth - injecting a concrete cushion - constructing on the tunnel wall of structural concrete; the tangent system is made and erected by adopting an open caisson. The construction technique has small construction occupying area, the operating space is not influenced by the surrounding environment, and the construction speed is high so as to ensure the soil body at the periphery not to be disturbed, the bearing capacity of the soil body not to be affected and the consumption of templates to be saved; furthermore, the structure has the characteristics of strong integrity, strong rigidity, high bearing capacity, and reducing the influence of the pit construction in the pit on the stability and the deformation of the retaining and protecting for foundation excavation.

Description

technical field

[0001] The invention relates to a construction technology of a pit-in-pit support system. Background technique

[0002] With the development of the construction industry and the comprehensive utilization of land resources, the phenomenon of pit-in-pit construction has become more and more common, especially in deep foundation pits in soft soil, which greatly increases the difficulty of construction support. The traditional techniques of pit-in-pit support are mostly: brick tire formwork, pine piles, steel sheet piles and other support technologies. Difficult or impossible to recycle, poor integrity, low rigidity, low bearing capacity, instability, easy deformation, large footprint, complex construction, and mechanical vibration also affect the support of large foundation pits. Moreover, the pit-in-pit support scheme is often neglected in the design of foundation pit support, and accidents of partial collapse of large foundation pit support due to excavation ...