Close-to-river submerged tunnel foundation pit excavation support and water precipitation and blocking method and structure

Abstract

The invention discloses a close-to-river submerged tunnel foundation pit excavation support and water precipitation and blocking method and structure. The close-to-river submerged tunnel foundation pit excavation support and water precipitation and blocking method mainly comprises the steps that a tunnel foundation fit adopts stratified and symmetrical unprotected open cut excavation, and slope protection is carried out on a slope of the foundation pit to ensure the stability of the slope of the foundation pit; a water stop curtain is arranged around the foundation pit, and the water stop curtain is formed by the water stop piles interlocking with each other, the foundation pit is closed, the water stop piles enter an impervious layer, and the water seepage of adjacent rivers outside the foundation pit is intercepted; water precipitation wells are longitudinally arranged along both sides of the foundation pit in the water stop curtain to reduce the groundwater level in the foundation pit; penetrating ground intercepting ditches are arranged on the outer periphery of the water stop curtain of the foundation pit for closure to prevent the ground water from entering the foundation pit; and drainage side ditches are arranged on both sides of the bottom of the foundation pit, and water collecting wells are arranged at appropriate intervals to exclude the water accumulated in the bottom of the foundation pit. The close-to-river submerged tunnel foundation pit excavation support and water precipitation and blocking method and structure are simple in construction equipment, the process is mature, the engineering period is shortened, the engineering investment is reduced, the combination of the water stop curtain, the water precipitation wells and the intercepting drainage sideditches is adopted, and the foundation pit has a good water precipitation and blocking effect and high safety guarantee.

Description

technical field [0001] The invention belongs to the technical field of tunnel foundation pits, and in particular relates to a method for excavating and supporting a foundation pit of a subsidence tunnel along a river, as well as a method for lowering and stopping water and its structure. Background technique [0002] Sinking tunnels near rivers generally have large spans, shallow buried depths, complex geological conditions, thick silt and gravel soil layers, and are widely distributed. Difficult to stop water. In order to ensure the quality and safety of the project, it is particularly critical to choose an economical and reasonable foundation pit excavation support and water stop method. [0003] At present, the conventional method of excavation, support and water stop of the foundation pit of the sinking tunnel near the river is: the foundation pit is supported by surrounding row piles and internal supports, combined with the water stop measures of the water stop piles b...

AI Technical Summary

Problems solved by technology

There are obvious problems in this prior art method: the one is that foundation pit earthwork excavation can only be carried out after foundation pit support structure and water stop construction are completed, and the construction period is longer; the other is that support structure and tunnel structure construction have interference, and after construction Part of the supporting structure still needs to be dismantled; third, the amount of supporting work is relatively large and the cost is relatively high

Therefore, existing technical methods are not ideal

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