Foundation pit excavation supporting structure on near end well shield tunnel and construction method of foundation pit excavation supporting structure

Abstract

The invention relates to a foundation pit excavation supporting structure on a near end well shield tunnel and a construction method of the foundation pit excavation supporting structure. The invention aims at providing the foundation pit excavation supporting structure on the near end well shield tunnel and the construction method of the foundation pit excavation supporting structure, the doming deformation of the foundation pit excavation is reduced, and the construction difficulty is reduced. The invention has the technical scheme that according to the foundation pit excavation supporting structure on the near end well shield tunnel and the construction method of the foundation pit excavation supporting structure, an M-shaped reinforcing structure is arranged on the shield tunnel under a planned excavation foundation fit region, the M-shaped reinforcing structure comprises deep layer reinforcing regions positioned between two sides of the tunnel as well as between the tunnels, the top ends of the two adjacent deep layer reinforcing regions are connected through top reinforcing regions above the shield tunnel, rest regions in the foundation range are superficial layer reinforcing regions, drilling cast-in-place piles are constructed in the deep layer reinforcing regions at intervals, the top surfaces of all reinforcing regions are integrally cast with bottom plates, and the edge of the foundation pit is provided with a circle of foundation pit surrounding and protecting structure. The foundation pit excavation supporting structure and the treatment method are applicable to urban underground space building and the node treatment of the near end well shield tunnel.

Description

technical field [0001] The invention relates to an excavation support structure and a construction method for an upper foundation pit excavation of a shield tunnel near the head shaft. It is suitable for the construction of urban underground space and the node processing of the shield tunnel near the head well. Background technique [0002] With the development of my country's urban construction and the increase of public transportation pressure, there will be more and more subway shield tunnels, and more and more new projects will be constructed on the shield tunnels that have been built. [0003] The excavation of the foundation pit will cause the shield tunnel under the foundation pit to bulge upward and deform. In actual engineering, in order to ensure the normal operation of the shield tunnel, the requirements for the deformation of the shield tunnel are very strict. The final absolute displacement of the structure cannot exceed 20mm, the curvature radius of the deform...

AI Technical Summary

Problems solved by technology

[0003] The excavation of the foundation pit will cause the shield tunnel under the foundation pit to bulge upward and deform. In actual engineering, in order to ensure the normal operation of the shield tunnel, the deformation requirements for the shield tunnel are very strict. The final absolute displacement of the structure cannot exceed 20mm, the curvature radius of the deformation curve is not less than 15000m, and the relative bending is not greater than 1 / 2500, which poses a very big challenge to the engineering construction

Especially when the foundation pit is excavated on the shield tunnel near Duantoujing, the construction of this kind of project is particularly difficult due to the large difference in the longitudinal restraint stiffness of the shield tunnel

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