双向叠层剪切箱的研制及模型土体振动台试验研究

Development of 2-D laminar shear box and shaking table tests on model soil

在结构–土体动力相互作用试验中,最常用的盛土容器是叠层剪切箱。在总结国内外剪切箱经验的基础上,研制出了刚度可调的二维叠层剪切箱,改进了箱体层间滑动装置。通过地震激励下模型土体试验,验证了该剪切箱很好的解决了单向水平地震输入时的边界效应,研究了土体在地震作用下的位移变化形态和非线性特征,得到了土体剪应力随地震动峰值的变化规律。结果表明:不同高度处土体的位移分布接近第一振型,土体剪应力和剪应力–剪应变滞回曲线的包络面积都随着地震动峰值的增大而增加,但是上下部土体的剪应力增加速率存在明显不同。

The laminar shear box is the most commonly used soil container in shaking table tests for soil-structure dynamic interaction. On the basis of the development experience of the worldwide shear boxes, the two-dimensional laminar shear box with adjustable stiffness is developed, and the interlayered sliding device is improved. Through the shaking table tests on model soil under earthquake, the boundary effect of shear box can be eliminated when the seismic load is applied to only one horizontal direction. The mode of vibration and nonlinear behaviors of soil are studied, and the relationship between soil shear stress and seismic peak is presented. The test results show that the distribution of displacements at different heights of soil is close to the first mode of vibration, and the shear stress of soil and the envelope area of shear stress-strain hysteretic loop increases with the increase of seismic peak, but the increase rate of shear stress at the top and bottom of soil is obviously different.