Assessment of seismic response of a soil layer with the oscillating inclusions

• Date: 2020
• Main Authors: Kendzera, O.V., Mykulyak, S.V., Semenova, Yu.V., Skurativska, I.A., Skurativskyi, S.I.
• Format: Article
• Language: English
• Published: S. Subbotin Institute of Geophysics of the NAS of Ukraine 2020
• Subjects: amplitude-frequency characteristics; resonant phenomena; models of heterogeneous media; ground response modeling to seismic load
• Online Access: https://journals.uran.ua/geofizicheskiy/article/view/210669
• Journal Title: Geofizicheskiy Zhurnal

The results of modern studies of the earthquakes impact indicate that the soil layers located under buildings and structures can significantly transform the seismic wave passing through their thickness and have a catastrophic effect on these objects. Hence, the study of wave processes in soil massifs is extremely important and relevant. It is known that soils are characterized by significant heterogeneity, which affects the spectral characteristics of seismic waves, so this should be taken into account when analyzing wave fields in the soil layers. In this paper, it is proposed to describe the dynamics of an inhomogeneous soil massif within the model of an elastic continuum with oscillating non-interacting dissipative inclusions. To examine vibrations in the layer of finite thickness with a free surface and harmonic perturbation applied to its lower edge, it is formulated the boundary value problem for the equations of medium’s motion. Based on the solution of this problem, the influence of inclusions on the characteristics of waves is analyzed. It is found out that the natural frequency of inclusions significantly affects the transfer function, which characterizes the amplification of the displacements on the free surface relative to the displacements at the lower boundary of the layer, i. e. when the natural frequency of inclusions increases, near the leading resonant peak additional resonant frequency appears, while for high frequencies a degeneration of resonant frequencies is observed. In the case when the natural frequencies of the inclusions have a non-discrete distribution with two separate frequencies, the effect of the inclusions is manifested at low-frequency oscillations, and in the high-frequency region only the resonant amplitude decreases. The approach, which uses the model with oscillating inclusions to the analysis of layer response to seismic disturbances, is promising for seismic design and construction.