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为了研究了循环动应力、初始静偏应力、固结比、振动频率共同作用对软黏土累积塑性应变的影响,以天津滨海新区临港工业区的浅海-滨海相软黏土为研究对象,利用GCTS循环扭剪三轴仪对其进行一系列循环三轴试验。试验结果表明,循环动应力增加、振动频率降低,能加快软化指数的衰减速率;初始静偏应力和固结比的增加,可提高软黏土抵抗循环动荷载的能力,减缓软化指数的衰减速率。综合考虑以上4种因素对软化指数随累积塑性应变发展变化的影响,总结得到了不同影响因素下软化指数与累积塑性应变之间的经验公式。结合以往学者对软化指数和循环荷载振动次数的相关性研究,以软化指数为桥梁,最终建立了针对天津滨海软黏土累积塑性应变的增长模型,并对模型的适用性进行了验证。
In order to study the effect of cyclic dynamic stress, initial static deviatoric stress, consolidation ratio and vibration frequency on the cumulative plastic strain of soft clay, taking shallow sea-coastal soft clay in Lingang Industrial Zone of Binhai New Area as an example, GCTS Cyclic torsion triaxial device to carry out a series of cyclic three-axis test. The experimental results show that cyclic dynamic stress increases and vibration frequency decreases, which can accelerate the decay rate of softening index. The initial static deviatoric stress and consolidation ratio increase the ability of soft clay to resist cyclic dynamic load and slow down the decay rate of softening index. Considering the above four factors on the softening index with the cumulative plastic strain development and changes, summed up the different factors under the influence of the softening index and the cumulative plastic strain between empirical formula. Combined with the previous studies on the correlation between the softening index and the number of cycles of cyclic loading, using the softening index as the bridge, the cumulative plastic strain growth model of coastal soft clay in Tianjin was established and the applicability of the model was verified.