Damping of seismic impact in the hardening soil small model in case of railway subgrade

The problem of modeling the stress-strain state of a railway subgrade taking into account seismic impact is considered.

The aim of this study is to determine the dependence of the stress-strain state of a railway subgrade on damping parameters (the material properties of the damping layer, its thickness, and its location within the subgrade structure).

The principle of numerical modeling of dynamic action using the finite element method is used. Modeling was performed using a generated accelerogram in the Plaxis 2D software package. Distinctive features of a hardening soil model with small-strain stiffness, which affect the completeness of seismic impact modeling on the subgrade, are discussed.

A description of the key parameters of the stress-strain state of a railway embankment under dynamic action adopted in the study is provided. These include horizontal displacements of the top surface of subgrade, settlement after the earthquake, stresses in the slip surface formation zone, and the level of specific dissipated deformation energy during seismic action.

Dynamic calculations of the stress-strain state of a railway embankment during an earthquake were performed using a hardening soil model with small-strain stiffness. The influence of the dynamic characteristics of the modal and hysteresis damping of the embankment soil and damping layer on the stress-strain state parameters of the railway subgrade was determined.

Optimal damping parameters were determined to minimize horizontal displacements and settlement after an earthquake, reduce stress fluctuations in the subgrade, and absorb specific dissipated deformation energy during an earthquake. The selection of optimal parameters was carried out on the basis of a comparison of damping options that differ in the thickness and position of the damping layer (layers) in the embankment structure.

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