Study on the influencing factors of the dynamic response of underground structures based on a viscoelastic-plastic model

Zhai Yafei; Song Zhiyu; Tian Zhifeng; Jin Junchao; Liu Guangkun

doi:10.16186/j.cnki.1673-9787.2024010018

Abstract：Objectives Under strong seismic excitation,soil often exhibits pronounced nonlinear dynamic characteristics,which can exacerbate damage to embedded structures.Methods To investigate the seismic input method that accounts for the nonlinear behavior of layered soils and the influencing factors affecting the dynamic response of underground structures,a modeling approach was developed to simulate seismic motions in layered soils.This approach enables iterative updating of material parameters at various soil depths,thereby reflecting the spatial distribution characteristics of real soil properties.For the dynamic analysis of soil-structure systems,an equivalent linear soil model was nested within the Mohr-Coulomb model to establish a viscoelastic-plastic model.A complete seismic response analysis procedure for a lay-ered soil-structure system considering soil nonlinearity was proposed.Using a specific engineering case,a nonlinear seismic response analysis was conducted to examine the effects of burial depth and soil param-eters on the seismic performance of underground structures.Results The results indicate that,under com-bined static and dynamic loads,the relative displacement difference between the top and bottom of the structure decreases with increasing burial depth.Under identical burial conditions,dynamic bending mo-ments induced by seismic loading contribute more significantly to the overall structural response than shear forces.Moreover,when the surface acceleration time history remains constant,the internal force response of the structure decreases as the soil shear modulus increases.Conclusions For double-layer underground structures,seismic actions cause greater shear and bending moment responses in the upper-layer central columns,which should be carefully considered in seismic design.In soft-soil environments,attention should be paid to the dynamic bending moment response,and effective reinforcement measures should be implemented.