Shaking Table Test on a Large Specimen of Mailiao Silty Sand

Based on the results of assessment of various preparation methods, the specimen of the Mailiao silty sand was prepared by the staged sedimentation method in the large biaxial laminar shear box of 1880 x 1880 x 1520 mm (L x W x H) at the National Center for Research on Earthquake Engineering (NCREE). It was found that there is no significant difference of the densities and fines contents of sand at various depths, except a very thin layer (< 1 mm) of soil with a higher fines content at the top of the specimen. The P-wave velocity measurement confirmed the saturation of the silty sand specimen. The relatively low permeability and high compressibility of the Mailiao silty sand resulted in a longer duration of dissipation of generated pore water pressure and a larger volumetric strain after shaking compared with those of the clean Vietnam sand. Sand boils were observed when water rushed out through the thin relatively impervious layer on the surface of the specimen.