Construction method for underground diaphragm wall of deep foundation pit for subway station in collapsible loess areas

Abstract

The invention discloses a construction method for an underground diaphragm wall of a deep foundation pit for a subway station in collapsible loess areas. The constructed station deep foundation pit for the subway station is divided into an upper-part foundation pit and a lower-part foundation pit from top to bottom; the building enclosure of the lower-part foundation pit is the underground diaphragm wall; and the upper-part foundation pit is a foundation pit formed by slope excavation. The construction method disclosed by the invention has the following steps of: (1) construction for upper-part foundation pit slope excavation and foundation pit slope reinforcement; (2) construction for lower-part foundation pit building enclosure: surveying and paying off, guide wall construction and underground diaphragm wall construction; and (3) construction for cap beam, and then carrying out excavation on the lower-part foundation pit through combining a well-point dewatering construction method and arranging a bracing system in the excavated lower-part foundation pit. The construction method disclosed by the invention has the advantages of reasonable design, simplicity and convenience for construction, safety and reliability for construction and good construction effect, high construction quality and capability of effectively solving the practical problems, such as high difficulty for construction, complicated construction procedure, difficulty for ensuring the construction quality of deep foundation pits and the like, in a process of constructing the deep foundation pits for subway stations in the collapsible loess areas.

Description

technical field [0001] The invention belongs to the technical field of deep foundation pit construction of subway stations in collapsible loess areas, and in particular relates to a construction method for underground diaphragm walls of deep foundation pits of subway stations in collapsible loess areas. Background technique [0002] Collapsible loess generally refers to unsaturated, unstable soil that, under a certain pressure, undergoes significant subsidence when exposed to water. Due to the above-mentioned characteristics of collapsible loess, it will bring different degrees of damage to structures, causing large-scale settlement, cracking and tilting of lines and bridge structures, seriously affecting the safety and use of lines, bridges and culverts. When building construction in the collapsible loess area of ​​Northwest my country, the foundation treatment of structures is particularly important. Nowadays, in the actual construction process, the foundation constructio...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a construction method for the underground diaphragm wall of the deep foundation pit of the subway station in the collapsible loess area, which is reasonable in design, simple in construction, safe and reliable in the construction process and excellent in construction effect. Good, high construction quality, can effectively solve practical problems in the construction of deep foundation pits of subway stations in collapsible loess areas, such as difficult construction, complicated construction steps, and difficulty in guaranteeing the construction quality of deep foundation pits

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