Excavated soil body stability analysis method using deformation quantity as instability criterion

Abstract

The invention discloses an excavated soil body stability analysis method using deformation quantity as an instability criterion. The excavated soil body stability analysis method comprises the following steps that 1, a soil body elastoplastic constitutive model capable of reflecting a stress deformation law of an excavation slope soil body is established, the relation between position displacement deformation amounts of typical characteristic points of an excavation slope and the internal stability of the excavation slope is determined through calculation and analysis of finite elements; 2, the reliability is verified by adopting a traditional limit equilibrium method; 3, normalization processing is conducted on the position displacement deformation amounts of the typical characteristic points of the excavation slope to obtain normalized deformation parameters, and the relation between the normalized deformation parameters and the internal stability of the excavation slope is established; 4, field monitoring of the actual deformation amount of the excavation slope is performed, and the internal stability of the excavation slope is determined and monitored according to the relation. Stress deformation analysis is conducted on the slope by adopting a finite element shear strength reduction method, and the deformation amount of the slope is related with the stability of the slope after being subjected to normalization processing.

Description

technical field [0001] The present invention relates to a method for analyzing the stability of excavated soil, in particular to a method for analyzing the stability of excavated soil with deformation as the criterion of instability, belonging to the stability of soil slopes in geotechnical engineering, especially excavated slopes Fields of application of stability analysis. Background technique [0002] The importance of excavating slopes The soil deformation and damage caused by excavation widely exist in water conservancy, civil engineering, transportation, municipal and other engineering constructions, and have been widely concerned by academic and engineering circles. Using the finite element method to analyze the stability of the excavated soil, first of all, it is necessary to develop a soil constitutive model of the excavation stress path under the real stress state; The whole process should be described reasonably; finally, a simple and reliable instability criteri...

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Problems solved by technology

The first two instability criteria are proposed based on the development law of the internal stress and strain of the slope, while the third criterion is proposed based on the external characteristics of the slope. With the decrease of the internal friction angle and cohesion, the slope A plastic zone appears inside, and the slope begins to produce a certain amount of internal deformation gradually. With the development of the plastic zone, the slope deformation gradually accumulates, and finally the plastic zone is completely penetrated, and the slope will slide along the plastic development zone, showing as characteristic points Displacement mutation, at this time, the calculation convergence condition cannot be satisfied

[0005] Although the mechanical properties of soil have been simulated and studied through true triaxial tests, as an unconventional indoor test method under complex stress conditions, there are few systematic test methods, and there are a few existing ones. True triaxial test methods also focus on the study of soil strength characteristics under different three-dimensional stress conditions, and there are few studies on the relationship between stress and strain. To carry out the numerical analysis of stress and deformation, it is necessary to carry out the true triaxial test of the stress path under the complex stress condition in line with the engineering reality according to the corresponding indoor true triaxial stress path test method, in order to understand the anisotropic stress-strain relationship of the soil under the complex stress state. make a reasonable description

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