Моделирование сейсмического воздействия на земляное полотно с демпфирующим слоем. Сравнение аналитического и конечно-элементного методов

Abstract

The mathematical modeling of seismic impact on the railway subgrade has been considered. While modeling used the coefficients of horizontal and vertical ground accelerations, regulated by building codes, and the generated accelerogram. Analyzing the stability and stress-strain state of the subgrade during an earthquake reduires calculations carried out in the GEO5 «Slope Stability» and GEO5 FEM software packages. The convergence of the results has been assessed. The most unfavorable combination of directions of seismic impact components has been determined, and a conclusion has been made about their influence on the calculation results. The values of the stability coefficient for the embankment, the magnitude of stresses and deformations in the structure of the subgrade and foundation have been given for various parameters of the design scheme and for different earthquake intensities. The results of the analysis allow to estimate the correctness of the reflection of the picture of the stress-strain state of the embankment has been assessed. The necessity and effectiveness of using the finite element method for calculating the stress-strain state of a soil structure taking into account seismic effects is substantiated. The nature of the influence of the physical and mechanical characteristics of the roadbed structure on its stability and stress-strain state during an earthquake has been determined. The author made some calculations of a structure with a damping layer introduced into the structure to reduce the negative impact of seismicity. The dependences of the stability coefficient, stresses and deformations in the roadbed on damping parameters have been determined. The possibility of increasing stability, reducing stresses and reducing deformations of the subgrade under seismic influences using a damping layer or using soil with certain physical and mechanical characteristics as a material for embankment has been established.