Deformation estimation method for deep foundation pit support structure in soft soil strata

Abstract

The invention provides a deformation estimation method for a deep foundation pit support structure in soft soil strata. The method comprises steps as follows: firstly, according to fitting analysis for a measured curve of support structure deformation caused by excavation of a large quantity of deep foundation pits in the soft soil strata, a concept of strata loss theory is introduced, and a deformation calculation model for the deep foundation pit support structure in the soft soil strata is constructed; by reference to thoughts of a shield tunnel surface subsidence Peck formula, a Schmidt formula and a triangular subsidence formula, an area of a support structure deformation enveloping curve can be obtained through an area of an enveloping curve of surface subsidence behind a wall, and an area B of the enveloping curve of surface subsidence behind the wall is calculated; a deformation estimation calculation formula for the deep foundation pit support structure in the soft soil strata is derived out according to the former formulae; finally, values of parameters are substituted into the deformation estimation calculation formula for the deep foundation pit support structure in the soft soil strata, and a deformation value of any point of the support structure can be calculated. A fitting curve of deformation of the support structure is highly fitted with a measured result curve by adopting a Gaussian function, 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

Images