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应用FLAC3D作自由场典型液化数值模拟试验、刚性结构对液化场影响试验、液化场浅埋地下结构动力特性试验、弹性场浅埋地下结构动力特征比对试验。试验结果再一次揭示了砂土液化典型特性:体积压缩积累增大,有效应力降低,超静孔隙水压升高。试验证实了液化的隔振作用:砂土在液化状态不能传递剪力,其加速度、速度、位移振幅显著衰减。试验得出:刚性结构有抑制周围土液化的作用。计算结果表明,液化场中浅埋地下结构的加速度反应比弹性场要小,但液化场中结构的应力应变却比弹性场大。在场地基底水平振动荷载作用下,弹性场浅埋地下结构的受力变形特点以剪切型变形为主,液化场浅埋地下结构受力变形特点以对称弯曲型变形为主。
FLAC3D was used to simulate the free-field typical liquefaction, the influence of rigid structure on liquefaction field, the dynamic behavior of shallow underground structure of liquefaction field, and the comparison of dynamic characteristics of shallow-buried subsurface structure in elastic field. The test results once again reveal the typical characteristics of sand liquefaction: volumetric compression accumulation increases, the effective stress decreases, excess pore water pressure increases. The test confirmed the vibration isolation effect of liquefaction: the sand can not transmit shear force in liquefaction state, and its acceleration, velocity and displacement amplitude attenuate significantly. The experiment shows that the rigid structure can restrain the liquefaction of surrounding soil. The calculated results show that the acceleration response of shallow subsurface structures in liquefaction field is smaller than the elastic field, but the stress-strain of the structure in liquefaction field is larger than the elastic field. Under horizontal ground motions, the shear deformation of the shallow subsurface structure with elastic field is dominated by shear deformation, and the deformation of the shallow subsurface structure of the liquefaction field is dominated by the symmetrical bending deformation.