Excavation construction method of subway station open-cut interval foundation pit

Abstract

The invention discloses an excavation construction method of a subway station open-cut interval foundation pit. The excavation construction method comprises the steps that a top foundation pit section is excavated; a concrete support is constructed in the top foundation pit section; the remaining earthwork to be excavated is divided into more than two operation units, each operation unit is divided into a plurality of layers, each layer of earthwork is excavated from one side to the other side or from two sides to the middle part of each operation unit in a segmented manner, a concrete support is constructed after each section of earthwork is excavated, and the excavation of the next layer of earthwork is started after the concrete support reaches the designed strength; after top-layer earthwork of each operation unit is excavated, remaining earthwork is divided into multiple layers to be excavated, each layer of earthwork is excavated from one side to the other side or excavated from the two sides to the middle at the same time, a concrete support is constructed immediately after each layer of earthwork is excavated, and after the concrete support reaches the designed strength, excavation of the next layer of earthwork is started; and until the excavation of the last layer of earthwork is completed. The method is simple in process, easy to implement, short in construction period, low in cost and high in construction quality and safety.

Description

technical field [0001] The invention relates to the technical field of subway construction, in particular to an excavation construction method for a foundation pit in an open-cut section of a subway station. Background technique [0002] During the construction of the subway station, it is first necessary to excavate a foundation pit in the soil. During the excavation of the foundation pit, concrete support needs to be constructed in time with the excavation of the earthwork, and the unsupported exposure time of the side excavation section of the foundation pit enclosure should be reduced as much as possible to control the deformation and stability of the foundation pit project. Most of the existing foundation pit excavation methods adopt the layered excavation method, that is, the soil body of the foundation pit to be excavated is divided into multiple layers, and the excavation is carried out layer by layer from top to bottom. Complete the construction as a whole, or grad...

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Problems solved by technology

Most of the existing foundation pit excavation methods adopt the layered excavation method, that is, the soil body of the foundation pit to be excavated is divided into multiple layers, and the excavation is carried out layer by layer from top to bottom. Complete the construction as a whole, or gradually complete the construction in sections during the excavation of each layer of soil. After the excavation of each layer of soil is completed and the concrete support of this layer reaches the design strength, then follow the same method to excavate the subsequent layers of soil in sequence. In this layer-by-layer excavation method, it takes a certain amount of time to reach the design strength after the construction of each layer of concrete support, and the excavation of the next layer of soil needs to wait until the upper layer of concrete support reaches the design strength before starting, which will prolong the entire excavation process. The construction period of excavation has the defects of low construction efficiency and long time consumption

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