循环剪切方向对饱和软黏土动静力特性的影响

发布时间：2018-03-16 06:39

本文选题：土力学　切入点：循环单剪　出处：《岩石力学与工程学报》2015年05期 　论文类型：期刊论文

【摘要】：地震中土层运动是复杂的多维运动,土体遭受水平两方向的剪切作用,两方向剪切在大小和方向上相互耦合。针对上述问题,采用多向循环单剪系统(VDDCSS),研究循环剪切方向和剪应变幅值γ对软黏土剪切过程中剪切模量G和孔压u的影响。试验结果表明:由于土样的各向异性,不同方向的G是不同的;小γ下剪切作用会使下一次其他新方向的G稍微增大;大γ下剪切方向的变化会促进G的衰减(最多为单向剪切G衰减量的1.51倍),也会促进剪切过程中u的增大(最多为单向剪切u增加量的1.67倍);存在一个剪应变特征值γs,即当γ≤γs时,剪切作用会使其他新方向的G稍微增大,反之无此现象;剪切方向对G和u的影响程度随γ的增大而先增后减,剪切方向的变化极大地影响了循环孔压周期幅值uamp的发展;当0.1%γ2.0%时,再固结轴向变形△Hrc/H随γ的增大而增大,剪切方向使△Hrc/H在小γ下达到单向剪切时大γ时的值;当γ≥2.0%时,2种剪切方式下△Hrc/H趋于一致。
[Abstract]:The soil in the earthquake motion is a complex multi-dimensional movement, the soil shear suffered two horizontal directions, two direction shear coupling in magnitude and direction. In view of the above problems, the multiaxial cyclic simple shear system (VDDCSS), cyclic shear direction and shear strain amplitude effect of gamma on shear modulus G and pore pressure of soft clay u in the shearing process research. The experimental results show that the anisotropy of the soil, G in different directions are different; shear small gamma will make the next other new direction of G slightly increased; change of shear direction under G will promote gamma attenuation (up to 1.51 times the one-way shear G attenuation), will also promote the increase in the shear process of U (up to 1.67 times the amount of the increase of u unidirectional shear); there is a characteristic value of shear strain s when gamma = gamma, gamma S, shearing action will make other new direction of G increased slightly, whereas the shear direction; Increase the degree of impact on G and u with gamma and first increased and then decreased, the shear direction changes greatly influence the development of cyclic pore pressure cycle amplitude of uamp; when the 0.1% gamma 2%, reconsolidation of axial deformation of delta Hrc/H increases with the increase of gamma delta Hrc/H, shear direction to unidirectional shear in small gamma when the large gamma value; when gamma = 2%, 2 kinds of shear mode Hrc/H tended to be the same.

【作者单位】：西北农林科技大学水利与建筑工程学院;
【分类号】：TU411

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