Method for controlling deformation of tunnel outside foundation pit

Abstract

The invention discloses a method for controlling deformation of a tunnel outside a foundation pit. The method comprises the steps that a designing method of a rigidity-flexibility combined segmented blocking barrier system is adopted, and designing parameters of the barrier system are determined according to the foundation pit excavation depth H, the clear distance D between the tunnel and a foundation pit enclosure structure and the buried depth S of the tunnel center; and the blocking barrier system is divided into flexible segments and rigid segments in the up-down direction, reinforced concrete cast-in-situ bored piles are combined with sand piles to serve as a main body structure of the blocking barrier system, up-down rigid and flexible segmented construction is adopted, and the rigid segments adopt the reinforced concrete cast-in-situ bored piles, and the flexible segments adopt the sand piles. According to the method, the positions of demarcation points of the flexible segmentsand the rigid segments are arranged in a deep soil body outside the pit, the deep rigid segments can fully exert the 'blocking effect' on the tunnel outside the pit, meanwhile, the 'traction effect'on tunnel deformation is reduced by the flexible segments, deep deformation of the soil body in an active area is effectively controlled, and meanwhile, through cooperation of a sleeve valve pipe active grouting technology, the deformation control effect of the blocking barrier system on the existing tunnel outside the pit is improved.

Description

technical field [0001] The invention belongs to the technical field of foundation and foundation engineering construction, and in particular relates to an engineering method for controlling deformation of tunnels adjacent to foundation pits. Background technique [0002] With the construction and operation of a large number of urban subways, it has become an unavoidable problem to control the deformation impact of foundation pits on existing tunnels when foundation pits are constructed adjacent to existing subway tunnels. The tunnel adjacent to the foundation pit will undergo coordinated deformation with the soil in the active area under the action of excavation and unloading. If the design and construction are improper, excessive tunnel deformation will be caused, which will seriously threaten its operation safety. [0003] Urban subway tunnels are often highly sensitive to deformation, which makes mm-level deformation control an inevitable requirement. The traditional met...

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Problems solved by technology

[0004] In order to solve the problems existing in the prior art, the present invention provides a method for controlling the deformation of the tunnel outside the foundation pit, which solves the problem in the prior art that the deformation of the existing tunnel outside the pit cannot be effectively controlled by the isolated row of piles

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