Movable support based on development of underground space above subway and construction method thereof

Abstract

The invention relates to a movable support system arranged at the beam end of a supporting beam on a subway protective pile, a prestressed beam type underpinning structure and a foundation pit supporting structure based on development of an underground space above a subway and a construction method thereof. The movable support system comprises a plurality of underpinning piles and underpinning beams, wherein the underpinning piles and the underpinning beams are arranged in an abutting mode in sequence, and the underpinning beams are slidably connected with the underpinning piles. One side of each underpinning pile is provided with a pile body guard wall filled with concrete. A U-shaped waist beam arranged horizontally is embedded in each pile body guard wall. The end of each underpinning beam is arranged in an opening of the corresponding U-shaped waist beam. A gap is reserved between the end of each underpinning beam and a corresponding web plate. The construction method comprises thefollowing steps of S1, construction of the underpinning piles; S2, construction of movable supports; S3, construction of a floor transformational structure; S4, construction of the underpinning beams; S5, prestressed tensioning of a floor; and direct pouring of the underpinning beams into the basement floor. The movable support system and the construction method thereof have the effect that the underpinning beams have displacement as a result of prestressed tensioning and cannot forcibly drive the underpinning pile to have displacement.

Description

technical field [0001] The invention relates to the technical field of space development above a subway, in particular to a movable support based on the development of an underground space above a subway and a construction method thereof. Background technique [0002] At present, when excavating the foundation pit above the subway tunnel, it is generally necessary to set up underpinning beams above the subway tunnel, and set up underpinning piles to carry the underpinning beams outside the sideline of the subway tunnel. The load of the building above the subway tunnel The underpinning beam is transferred to the underpinning pile, so that the existing load above the subway tunnel is transferred to the bottom of the subway tunnel, which plays a protective role in the subway tunnel. [0003] The underpinning piles on both sides of the subway tunnel are generally at least 30m apart, and the cross-sectional height of the underpinning beam is relatively high, requiring constructio...

AI Technical Summary

Problems solved by technology

[0004] In the pile foundation underpinning project, in order to ensure that the underpinning beam has sufficient strength and rigidity, the design unit often enhances the crack resistance by bidirectionally prestressing the underpinning beam. After pulling, there will be a large horizontal displacement, so that the underpinning beam forcibly drives the underpinning pile fixed with it, causing the underpinning pile to be pulled to cause displacement or the connection between the underpinning pile and the underpinning beam to break, and the construction hidden danger is great

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