英文摘要 |
In order to study the behavior of saturated sand, including liquefaction and settlement, under multidirectional earthquake shakings, a physical model test using a large biaxial laminar shear box on the shaking table at the National Center for Research on Earthquake Engineering(NCREE), Taiwan was developed. The specimen of a fine Vietnam silica sand inside the shear box is prepared by the wet sedimentation method from a large pluviation device. Pore pressures and accelerations within the soil, and the displacements and accelerations of the frames at various depths were measured during tests under both one-and multi-dimensional shakings of various amplitudes. It is found that the excess pore water pressures generated during a two-dimensional shaking are substantially higher than those generated under the one-dimensional shaking of the same magnitude of acceleration. The settlement of the sand inside the shear box after each shaking test was also measured and evaluated. The test results showed that significant settlements occurred only when there is liquefaction of the soil and the volumetric strain of the liquefied sand decreases with the relative density of sand. |