Soft soil subway foundation pit small-size block inner-basin type soil excavation method

Abstract

The invention discloses a soft soil subway foundation pit small-size block inner-basin type soil excavation method. When the middle part of each soil block of a soft soil subway foundation pit is excavated, basin edge wall retaining soils are reserved on the two sides of the middle part, and the width of the reserved basin edge wall retaining soils are determined according to the depth of the softsoil subway foundation pit; when the depth of the soft soil subway foundation pit is less than 10 meters, the width of the reserved basin edge wall retaining soils is 3 to 4 meters; when the depth ofthe soft soil subway foundation pit is 10 to 18 meters, the width of the reserved basin edge wall retaining soils is 4 to 5 meters; and when the depth of the soft soil subway foundation pit is greater than 18 meters, the width of the reserved basin edge wall retaining soils is 5 to 6 meters. According to the soft soil subway foundation pit small-size block inner-basin type soil excavation method,the non-support exposing time of the foundation pit is greatly shortened compared with that of previous excavation methods, and the remarkable effect of restraining deformation of retaining structures is achieved.

Description

technical field [0001] The invention relates to the field of rail transportation in the civil engineering industry, in particular to a pot-type soil excavation method in a small-scale block of an iron foundation pit on soft soil. Background technique [0002] Due to the rheology of soft soil, the excavation process of the subway foundation pit will inevitably cause the deformation of the surrounding strata. How to control the deformation of the foundation pit? The field was gradually extended to other large-scale foundation pit projects, and an earthwork excavation method based on the theory of "time-space effect" was formed. According to the characteristics of the subway foundation pit, the foundation pit excavation method based on the theory of "time and space effect" has been formed. Excavation of traditional subway foundation pit With the development of production technology, the traditional theory has encountered difficulties in practice: [0003] For example, when th...

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Problems solved by technology

In this case, the soil at the point with large deformation is excavated first and the support is erected at the latest, which also makes the deformation of the foundation pit too large

[0006] In addition, for the convenience of excavation and mechanical limitations, when excavating soil on the same cross-section, the root soil should be excavated first, which will easily lead to over-excavation of the soil in the passive area of ​​the enclosure structure and the reduction of soil strength caused by repeated loading and unloading, thus increasing the soil strength. Deformation of the large envelope

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