Abstract
This paper investigates shaking table test (1g) and numerical simulation (fully coupled) of vertically propagating shear waves for saturated soft free field. A large-scale shaking table model test was performed to study seismic response characteristics of saturated soft soil free field. According to test results of seismic response features of free field system in saturated soft soil, the free field nonlinearity fully coupled numerical model of dynamical effective stress of saturated soft soil was established using OpenSEES, based on the u-p formulations of dynamic consolidation equation as well as effective stress solution method for saturated two-phase media. The numerical simulation of the free field seismic response of saturated soft soil under various test conditions was performed and the calculated results were compared with the shaking table test results. The results show the following. (1) With the increase of input ground motion intensity, the characteristic frequency of the saturated soft free ground decreases and the damping ratio increases gradually. (2) The saturated soft soil ground has short period filtering and long period amplification effect on the horizontal input seismic loads. The failure foundation takes on the isolation and shock absorption under strong ground motions. (3) The peak pore pressure ratio of the saturated soft soil ground is located in the shallow buried soil layer, and with the increase of the input ground motion intensity, the advantage of dynamic pore pressure ratio in this area is gradually weakened. (4) The numerical simulation results are consistent with the results of the shaking table test. This fully coupled effective stress numerical method can reasonably simulate the seismic response characteristics of free field in saturated soft soil, which lay the foundation for other more complex parameter extrapolation models of saturated soft soil sites. This research can provide the necessary technical experience for experimental study on non-free field.
Highlights
Soft soil is widely distributed in China
This paper investigates shaking table test (1g) and numerical simulation of vertically propagating shear waves for saturated soft free field
From the research of shaking table test performed, underground structure is mostly embedded in unsaturated soft soil, and the numerical simulation methods are mostly based on the total stress analysis methods
Summary
Soft soil is widely distributed in China. As numerous studies suggest, soft ground can cause greater seismic damage of underground structures. Chen et al [8] (2016) investigate the effect of pulse-like ground motion on a multistory subway station embedded in unsaturated soft soil with a series of shaking table tests. From the research of shaking table test performed, underground structure is mostly embedded in unsaturated soft soil, and the numerical simulation methods are mostly based on the total stress analysis methods. In order to further consider the coupling effect of pore pressure and soil skeleton in the seismic dynamic response analysis of underground structures embedded in soft soil, Zhou et al [13] (2004) carry out soft soil indoor dynamic test and adopted the two-dimensional decoupling finite element effective stress dynamic response analysis based on Hardin dynamic viscoelastic model. The fully coupled effective stress dynamic calculation method should be applied in seismic dynamic response analysis of the underground structure embedded in saturated soft soil ground. The test results are compared with the numerical simulation results to verify the accuracy of this numerical simulation method
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