Abstract
Input of sinusoidal excitation with specified frequency is an optimal way to capture the mechanism of soil-tunnel interaction. Focusing on the relationship between the frequency of input sinusoidal motions and the dynamic response of a system, this study carried out a series of shaking table tests on both a free-field model and soil–tunnel model in the background of the tunnel in soft ground. To detect the detailed deformation of segmental linings, a refined lining ring of the model tunnel was developed, and the stiffness ratio between the soil and tunnel was verified. Seven sinusoidal excitations were designated to cover the fundamental frequency of the model ground, with the input of transverse direction. Effects of frequency of sinusoidal excitations on soil-tunnel interaction can be evaluated by the detailed responses of segmental linings, such as cross-sectional deformations, extension/closure of longitudinal joints, dynamic normal earth pressures, and dynamic strains of segments. Results shows that the differences of the acceleration responses, on the respects of waveform, phase, and peak, between the upper soil layer and the lower soil layer are obviously increasing with the input frequency increasing. The presence of the tunnel induces a relatively high effect on acceleration responses of the ground within excitation frequency varying from 9 to 17 Hz. The maximum responses of the tunnel are highly influenced by both the fundamental frequency of the model ground and lower frequency of excitations.
Highlights
Published: 31 May 2021The seismic performance of tunnels in soft ground has attracted the attention of researchers worldwide
Focusing on the relationship between the frequency of input sinusoidal motions and the dynamic response of a system, this paper recounts a series of shaking table tests carried out on both a free-field model and soil–tunnel model
In order to study the relationship between dynamic responses of segmental tunnel and input motions conveniently, sinusoidal wave was introduced as the input motion in this paper
Summary
The seismic performance of tunnels in soft ground has attracted the attention of researchers worldwide. Cilingir and Madabhushi [4] studied the dynamic responses of a tunnel under sinusoidal excitations of frequencies from 40 to 60 Hz, by means of a centrifuge test and numerical analysis. In this investigation, uniformed tunnels with a square section and circular section were modeled at a scale of 1:50 and were imbedded in sandy ground. Focusing on the relationship between the frequency of input sinusoidal motions and the dynamic response of a system, this paper recounts a series of shaking table tests carried out on both a free-field model and soil–tunnel model. The relationship between sinusoidal excitations and maximum tunnel responses was concluded
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