Abstract:
Damage dealt with by some recent major earthquakes has raised concerns among the geotechnical engineering community to delve more into the area of soil liquefaction. As part of a PEER-funded project, a large-scale shake table test on a laminar soil box was carried out at the University of California, San Diego, to investigate the effect of liquefaction-induced ground motion on a shallow foundation. In this study, a 2D numerical finite difference simulation of the baseline test was conducted in FLAC using the PM4Sand plasticity model. Some general behavior of sand layers during liquefaction including generation of excess pore water pressure, total head distribution and flow pattern in the soil, development of shear and volumetric strain, and their relative contribution to the total settlement were investigated. While developing the model, both glued and unbound types of interfaces between foundation-soil were tried and the model with glued interface yielded better prediction. Average final foundation and free-field settlements are captured to be 22.14 cm [measured value is 22.4 cm] and 12.13 cm (heave) [measured value is 2 cm (heave)] respectively. The shear strain appears to govern the total settlement during seismic excitation compared to volumetric strain, during strong ground motion, while the latter becomes more apparent after ground motion subsides.