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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g<1×10~(-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。
According to the characteristics of Quaternary strata in Suzhou, GCTS cyclic triaxial test instrument was used to measure the shear strain of 10 ~ (-5) ~ 10 ~ (-2) of the 40 undisturbed soil samples taken from shallow depth of 100 m from the typical borehole profile The dynamic shear modulus and damping ratio test were used to study the influence of sedimentary environment, depth and normalized dynamic shear modulus ratio (G / G max) and damping ratio λ of soil on soil. When the shear strain is less than 1 × 10 ~ (-4), the G / G_ (max) reduction is very small and the soil is in a nonlinear elastic state. The influence of sedimentary facies, depth of soil layer and soil on G / G_ (max), l and g curves of Quaternary stratigraphy in Suzhou is obviously different. For the same soil with the same sedimentary facies, the deeper the soil depth, the slower the G / G_ (max) growth with g, the smaller the l; the similar soil with similar depths, the more obvious Non-linear, while the coastal facies l slightly higher than the river pan-phase soil. When the sedimentary facies are the same and the depths are similar, the G / G max of silt, silty clay and clay decrease with the increase of g, and the rate of decline declines in turn. At the same strain level, The largest of clay.