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长期往复荷载作用下,饱和软黏土强度和刚度的衰减是近海桩基础设计必须考虑的,利用带弯曲元的循环三轴仪对原状饱和软黏土进行了一系列等向固结和非等向固结条件下不排水单调和循环加载三轴试验,并在循环加载过程中通过弯曲元测试土体剪切波速。试验结果表明,在相同的固结条件下,随循环次数的增加和动应力比的提高土体的强度和刚度衰减显著;在相同动应力比作用下较小的有效固结应力和偏压固结减缓了土体刚度的弱化。已有的相对偏应力水平参数不能反映不同固结条件下近海饱和软黏土强度和刚度循环弱化特性,为此引入了动偏应力水平参数,考虑了有效固结应力、固结静偏应力、动偏应力的相互影响,利用动偏应力水平对饱和软黏土的强度和刚度循环弱化特性进行描述。
Under long-term cyclic loading, the attenuation of strength and stiffness of saturated soft clay must be considered in offshore pile foundation design. A series of isotropic consolidation and non-isotropic solidification of intact saturated soft clay Under undrained monotonous and cyclic loading triaxial tests, the soil shear wave velocity was tested by bending element during cyclic loading. The experimental results show that under the same consolidation conditions, the strength and stiffness of the soil decrease significantly with the increase of the number of cycles and the increase of dynamic stress ratio. The smaller effective consolidation stress and bias pressure under the same dynamic stress ratio The knot slows down the weakening of soil stiffness. The existing relative deviatoric stress level parameters can not reflect the cyclic weakening characteristics of strength and stiffness of offshore saturated soft clay under different consolidation conditions. Therefore, the parameters of deviatoric stress level are introduced to consider the effective consolidation stress, consolidation static deviatoric stress, Deviatoric stress, the cyclic weakening characteristics of the strength and stiffness of saturated soft clay are described by using the level of deviatoric stress.