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利用空心圆柱扭剪仪模拟斜入射地震波作用形成的斜椭圆应力路径,对比研究了等向固结条件下饱和福建标准松砂在循环斜椭圆、圆形、扭剪、三轴路径下的动力特性。试验研究表明:土体循环孔压发展存在陡升型和陡降型两种模式;圆形路径下累积孔压增长速率最快,循环扭剪最小;归一化孔压与斜椭圆的倾角无关,但受斜椭圆长短轴比及动应力比影响。砂土的不排水动强度与动应力路径密切相关,循环扭剪和循环三轴最大,循环斜椭圆次之,圆形路径最小。地震波从特定角度入射时,形成近似圆形路径,若只将地震波视为垂直入射的S波,将高估地基土体抗液化强度。
The diagonal elliptical stress path formed by the oblique incident seismic wave was simulated by a hollow cylindrical torsion shear tester. The dynamic characteristics of the saturated Fujian loose sand under cyclic inclined elliptical, circular, torsional shear and triaxial paths under isotropic consolidation were compared. . The experimental results show that there are two kinds of modes of steep rise and steep drop in soil circulation pore pressure. The cumulative pore pressure increases fastest under circular path and has the least cyclic torsional shear. The normalized pore pressure has nothing to do with the inclination of oblique ellipse , But by the oblique ellipse long axis ratio and dynamic stress ratio. The undrained dynamic strength of sandy soil is closely related to the dynamic stress path. The cyclic torsional shear and the cyclic triaxial maximum are the largest, followed by the circular oblique ellipse, and the circular path is the smallest. When a seismic wave is incident from a certain angle, an approximate circular path is formed. If only seismic waves are regarded as S waves incident perpendicularly, the anti-liquefaction strength of the ground-based soil will be overestimated.