A Method for Deformation Estimation of Deep Foundation Pit Enclosure Structure in Soft Soil Strata

Abstract

A method for estimating the deformation of the enclosure structure of deep foundation pits in soft soil layers. Firstly, according to the fitting analysis of the measured curves of the enclosure structure deformation caused by the excavation of a large number of deep foundation pits in soft soil layers, the concept of the stratum loss method is introduced to establish the soft soil layer. Then, referring to the Peck formula, Schmidt formula and triangle settlement formula of shield tunnel ground settlement, it is concluded that the envelope curve area of ​​the surface settlement behind the wall can also be used to obtain the deformation envelope of the enclosure structure. Calculate the envelope area of ​​the surface settlement curve behind the wall B ; Then, according to the previous formulas, the calculation formula for the deformation estimation of the enclosure structure of the deep foundation pit in the soft soil layer is derived; finally, the values ​​of each parameter are substituted into the calculation formula for the deformation estimation of the enclosure structure of the deep foundation pit in the soft soil layer, and the envelope structure can be calculated. Deformation value at any point. The fitting curve of the enclosure structure deformation through the Gaussian function is highly fitted with the measured result curve, and the effect is good.

Description

technical field [0001] The invention relates to the technical field of deep foundation pit engineering, in particular to a method for estimating deformation of a deep foundation pit enclosure structure in soft soil strata. Background technique [0002] With the rapid development of my country's economy, the development of super high-rise buildings and the excavation of subway stations have a greater impact on people, and the number of deep foundation pit projects brought about by this is increasing, and it is moving towards deeper and larger , more complex direction. Since most of the deep foundation pit projects are constructed in the city, the deformation of the foundation pit enclosure structure and the impact on the surrounding environment cannot be ignored. Especially in soft soil areas, the soil has the characteristics of high water content, low strength, low permeability, etc., and the engineering geological and hydrogeological conditions are poor, which increases the...

AI Technical Summary

Problems solved by technology

The limit equilibrium method was proposed in the early stage of foundation pit design. It is simple to calculate and easy to use. It is often used in support structures with insignificant spatial effects, relatively uniform strata, and relatively stable surrounding environments. However, this method does not consider wall deformation and lateral support deformation. Calculating the inclination of the wall through the known earth pressure, the calculation result cannot meet the requirements

When the elastic foundation beam method is used to analyze the deformation of the foundation pit enclosure structure, the calculation mode of the "m" method is clear, the results are more in line with reality, and it is widely used. However, because there are many factors affecting the horizontal resistance coefficient m of the soil, the value of m The requirements are very high; although the finite element numerical simulation calculation method can simulate the entire excavation process of the foundation pit and conduct research on its three-dimensional geometric characteristics, it has high requirements for the selection of different types of soil parameters, and improper parameter selection will lead to calculation Results vary widely

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