Numerical limit analysis on the seismic bearing capacity of anti-liquefaction ground

Ground solidification technique such as the cement-mixing and permeable-grouting has been developed for the purpose of liquefaction countermeasure in Japan. Although there have been significant advances for ground solidification technique, the anti-liquefaction ground improved by the ground solidification technique shows a large spatial variability in mechanical properties such as shear modulus and liquefaction strength. Since the spatial variability in mechanical properties is expected to induce the spatial locality of liquefaction area in the improved ground, the influence of the spatial locality of liquefaction area on the seismic behavior of improved ground is needed to be clarified. In this paper, the spatial variability of liquefaction strength in the improved ground was expressed on the random theory and then the seismic bearing capacity was analyzed through the Monte Carlo simulation with the numerical limit analysis. As a result of this study, following conclusions were obtained. (1) The seismic bearing capacity of the improved ground decreases as the coefficient of variation of the liquefaction safety factor increases. (2) The volumetric percentage of liquefaction area in the improved ground is one of the influential indexes to estimate the seismic bearing capacity considering the spatial variability of liquefaction strength. Current study suggests that the seismic bearing capacity decreases greatly when the volumetric percentage of liquefaction area is over 5%.