Examining the seismic behaviour of partially saturated sand using centrifuge shaking table tests

Zitao Zhang,Jun Yan,Hong Cai,Jianzhang Xiao,Jianhui Liang,Yingqi Wei,A Tarantino,E Ibraim

doi:10.1051/e3sconf/20199217002

Zitao Zhang, Jun Yan + Show 6 more

Open Access

https://doi.org/10.1051/e3sconf/20199217002

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Abstract

Similar to fully saturated sand, the partially saturated sand can also liquefy under certain conditions during earthquakes. This study aims to characterize the seismic behaviour of partially saturated sand. Centrifuge shaking table tests were performed using the IWHR horizontal-vertical centrifuge shaker. The experimental results indicate that the liquefaction resistance of the partially saturated sand increases with decreasing the degree of saturation and with increasing the initial effective stress right before shaking. The boundary between the liquefied and un-liquefied sand becomes deeper and deeper during shaking.

Highlights

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The experimental results on the soil water characteristic curve of clean sands similar to the one used in this study demonstrated that the suction value, i.e., is smaller than 4 kPa when the degree of saturation is larger than 50%
Since the seismic behavior is mainly affected by the initial condition in terms of the initial degree of saturation and effective stresses right before shaking, the initial condition is essential for analyzing the seismic behavior during shaking

Summary

Experimental results and discussions

The experimental results on the soil water characteristic curve of clean sands similar to the one used in this study demonstrated that the suction value, i.e., (pore air pressure pa – pore water pressure pw) is smaller than 4 kPa when the degree of saturation is larger than 50%. To ease the discussion, it is assumed that the air and water pressure, i.e., pa and pw, at a given location are identical. The variation in the pore air pressure during shaking can be reflected by the measured pore water pressure as shown later. The initial condition is firstly discussed in the following text, followed by the variations in the excess pore water pressure during shaking

Initial condition right before shaking

Variations in the excess pore water pressure ratio during shaking

Concluding remarks