Excavation method for deep and big foundation pit in long-distance crossing field for shallow-buried subway

Abstract

The invention discloses an excavation method for a deep and big foundation pit in a long-distance crossing field for a shallow-buried subway. The excavation method includes a first step of arranging separating walls, and dividing the foundation pit into a big foundation pit away from a subway tunnel and a small foundation pit adjacent to the subway tunnel, a second step of adopting a reinforcing mode that super-deep stirring piles are combined with chemical churning piles in the small foundation pile, a third step of arranging a row of tying piles on two sides of existing ground walls of the subway tunnel and enabling the tying piles to be in rigid connection with the existing ground walls of the subway tunnel, a fourth step of arranging a plurality of precipitation wells which also serve as recharge wells in the small foundation pit, a fifth step of excavating the foundation pits, firstly excavating the big foundation pit and then excavating the small foundation pit, a sixth step of using reinforced concrete to support the big foundation pit, using the reinforced concrete to support a first support of the small foundation pit, and using steel to support the rest of the supports, and a seventh step of monitoring the operation of the subway tunnel, and using the precipitation wells to take corresponding precipitation recharge and load limiting measures according to tunnel deformation. The excavation method greatly reduces upheaval and deformation of the foundation pits, and severely controls the deformation on the periphery caused by excavation of the foundation pits.

Description

technical field [0001] The invention relates to a method for excavating a foundation pit, in particular to a method for excavating a deep and large foundation pit in a long-distance crossing site of a shallow-buried subway. Background technique [0002] With the development of urban construction, the urban rail transit network is gradually completed and perfected, and the subway line often becomes a golden area for the development of commercial and residential buildings, which promotes the increasing scale of underground space development. Therefore, more and more foundation pit projects are located in On or on both sides of subway tunnels that have been in operation, especially when there is a small distance between them, or even exposed subway stations or tunnels. The construction of these large-scale deep foundation pits will inevitably cause the movement of the surrounding strata, resulting in the deformation of the subway tunnel, and even pose a serious threat to the sa...

AI Technical Summary

Problems solved by technology

[0008] The present invention aims at the deficiencies in the above-mentioned existing foundation pit excavation technology in the construction technology adjacent to the running subway, in order to meet the needs of new foundation pit excavation on both sides of the running subway tunnel, and solve the deformation caused by the traditional foundation pit excavation method that cannot meet the needs of the operation. A new method of foundation pit excavation is proposed

Images