Anti-floating construction method and structure for earth excavation of subway tunnel foundation pit with shallow earth covering at pit bottom

Abstract

The invention discloses an anti-floating construction method and structure for earth excavation of a subway tunnel foundation pit with shallow earth covering at the pit bottom. The construction methodcomprises the steps that a supporting structure is constructed, and supporting construction is conducted according to foundation pit supporting design requirements; uplift piles are constructed, namely a row of uplift cast-in-place piles are respectively arranged on the outer side of the safety protection line; foundation pit excavation construction is conducted, specifically, foundation pit excavation construction is conducted in a segmented excavation mode; anti-floating plate construction is conducted, specifically, anti-floating plate construction is conducted in a segmented constructionmode; the construction structure comprises uplift piles and an anti-floating plate, the uplift piles are arranged on the two sides of a tunnel in rows, the two rows of uplift piles are arranged outside safety lines on the two sides of the tunnel, and the anti-floating plate is poured at the upper ends of the uplift piles and stretches across the two rows of uplift piles; the anti-floating construction method and structure for earth excavation of a subway tunnel foundation pit with shallow earth covering at the pit bottom have the advantages of being good in anti-floating effect, simple in construction technology, high in construction efficiency, low in construction cost, environmentally friendly and the like, and the advantages which are not achieved in the prior art are achieved.

Description

technical field [0001] The invention relates to the field of building construction, in particular to an anti-floating construction method and structure for earthwork excavation of a foundation pit of an iron tunnel on shallow-covered pit bottom. Background technique [0002] Nowadays, the underground subway lines in large and medium-sized cities in China are densely distributed. In the process of urban construction, various buildings (structures) are often built on the top of subway tunnels. When excavating the underground foundation pit of buildings (structures) , along with the unloading caused by the external movement of the soil at the top of the tunnel, it will cause the change of the stress field of the original soil around the tunnel. When the pressure of the overlying soil on the tunnel is less than the generated buoyancy of the tunnel, it will inevitably cause the upward deformation of the tunnel structure. Subway operation safety poses a major threat. [0003] Usu...

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Problems solved by technology

[0005] In order to overcome the deficiencies in the prior art, the present invention provides an anti-floating construction method and structure for the excavation of the foundation pit of a subway tunnel with shallow overlying soil at the bottom of the pit, which solves the problem that the existing construction methods and construction structures are difficult to meet the floating requirements of the shallow overlying soil on the top of the tunnel. Low efficiency, complex construction process, high construction cost and other technical defects

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