Shaking table model test for seismic response of soft soil site

Abstract

Soil sites play a crucial role during earthquakes and serve as conduits for the transmission of seismic effects from the bedrock to urban structures. Analyzing the dynamic response of soil sites to seismic waves is crucial as it presents deeper insights into earthquake damage mechanisms. In this study, we prepared a mixture of sawdust and medium sand with a 1:2.5 mass ratio to model soil samples from a soft soil site in Shanghai. The applicability of the scale-factor equation was verified using resonance column tests. A series of shaking table tests were conducted to simulate free-field site responses based on the dimensions, operating frequencies, and vibration modes of the shaking table at the State Key Laboratory of Disaster Reduction in Civil Engineering at Tongji University. Three different types of earthquake waves were selected as the input motions: TCU003 for far-field long-period seismic waves, TCU068 for near-field pulse-type seismic waves, and the El Centro earthquake wave. The Kramer frequency domain method was used to verify the transfer functions of the site seismic responses. Furthermore, discrepancies in the time–frequency distribution of the soft site responses influenced by various types of earthquake waves were assessed and analyzed. The seismic response characteristics of the soft soil sites under varying input intensities were also analyzed. The findings of this study present valuable reference data for the seismic zoning of soft-soil sites and facilitate the determination of seismic input parameters for engineering structures.