ABSTRACT
Current methodologies to assess liquefaction risk and estimate induced settlement are based on a free-field data. The possible influence of the structures founded on top is neglected. Additionally, earthquake loading is commonly considered as an undrained load. Therefore, settlement results from a post-shaking particle rearrangement due to pore-pressure dissipation and transfer of load from the liquid phase to the solid phase. Recent researches have shown that these assumptions can lead to a misleading settlement estimation. A partially-drained scenario of earthquake loading has been proposed as a more accurate approach. However, only a few laboratory tests have been conducted to study the accuracy of free-field approach and partially-drained nature of the earthquake load. This study reports preliminary results from five centrifuge tests conducted in the Japanese Institute of Occupational Safety and Health (JNIOSH). Configurations of stand-alone and two adjacent rigid blocks with different mass were studied. A harmonic load of 1 Hz and a maximum amplitude of 0.2 g (prototype scale) was applied. A free-field test was also conducted. The measurements showed a significant influence of the bearing pressure on the total settlement. Additionally, settlement showed two components (during and after the shaking) supporting the partially-drained nature of the earthquake load.
