沉积相和深度对第四纪土动剪切模量和阻尼比的影响

发布时间：2018-11-13 15:08

【摘要】：依据苏州第四纪地层特点,使用GCTS循环三轴试验仪对取自典型钻孔剖面100 m以浅的40个原状土样进行了剪应变10~(-5)~10~(-2)量级的动剪切模量和阻尼比试验,研究了土的沉积环境、深度和土类对土体的规准化动剪切模量比G/G_(max)和阻尼比λ的影响。当剪应变g1×10~(-4)时,G/G_(max)折减很小,土体处于非线性弹性状态。沉积相、土层深度和土类对苏州第四纪地层土的G/G_(max),l与g关系曲线的影响有明显差异。相同沉积相的同类土,土层深度越深,G/G_(max)随g增长而衰退越慢,l越小;深度相近的同类土,滨海相土比河泛相土具有更为明显的非线性,而滨海相土的l略高于河泛相土。沉积相相同、深度相近时,粉砂、粉质黏土、黏土的G/G_(max)随g增长而衰退的速率依次减慢;应变水平相同时,粉砂的l最小,粉质黏土的次之,黏土的最大。
[Abstract]:According to the characteristics of the Quaternary strata in Suzhou, the dynamic shear modulus and damping ratio of 40 undisturbed soil samples from a typical borehole section of 100m were tested by using GCTS cyclic triaxial test instrument in the order of 10 ~ (-5) ~ 10 ~ (-2). The effects of sedimentary environment, depth and soil type on the normalized dynamic shear modulus ratio G / G _ (max) and damping ratio 位 of soil were studied. When the shear strain is 1 脳 10 ~ (-4), the G / G _ (max) reduction is very small and the soil is in a nonlinear elastic state. The influence of sedimentary facies, soil depth and soil type on the G / G _ (max), l and g relationship curves of Quaternary stratigraphic soil in Suzhou is obviously different. With the same sedimentary facies, the deeper the soil layer is, the slower the G / G _ (max) decline with g, and the smaller l is. For the similar soils with similar depth, the coastal facies soil has more obvious nonlinearity than the river panfacies soil, while the coastal facies soil is slightly higher than the river panfacies soil. The G / G _ (max) of silty sand, silty clay and clay decreased with the increase of g, while when the strain level was the same, the l of silt was the smallest, that of silty clay was the second, and that of clay was the largest.
【作者单位】：南京工业大学岩土工程研究所;江苏省土木工程防震技术研究中心;江苏省地震局;
【基金】：国家自然科学基金项目(51378258,51438004) 国家科技重大专项(2013ZX06002001-9)
【分类号】：TU43

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