(2.天津大学岩土工程研究所, 天津 300072)
【摘要】通过k0固结不排水动三轴试验, 研究了初始有效平均应力、初始剪应力以及振动应力历史对k0固结饱和黏土动剪模量和阻尼比的影响。结果表明, 可以将振动累积应变作为反映振动应力历史影响的状态参数;将同一状态参数下的动剪模量表示为随动剪应变的变化关系可以反映初始剪应力对动剪模量和阻尼比的影响;依据不同状态参数对应的最大动剪模量确定规一化动剪模量随动剪应变的变化关系可以反映初始有效平均应力的影响。初始有效平均应力、初始剪应力以及振动应力历史对阻尼比随振动剪应变的变化关系影响较小, 可以认为阻尼比随振动剪应变有唯一变化关系。因此, 通过一个固结压力下的一组振动三轴试验, 结合一个试样在不同振动累积应变与不同初始有效平均应力下的多级振动三轴试验, 就可以建立反映初始有效平均应力、静偏应力与振动应力历史影响的k0固结饱和粘土动剪模量与阻尼比变化关系。
【基金资助】 国家自然科学基金项目 (51579174) ;
Dynamic shear modulus and damping ratio of k0 consolidated saturated clays
(2.Geotechnical Engineering Institute of Tianjin University, Tianjin, China 300072)
【Abstract】Influences of the initial average effective stress, the initial shear stress and the dynamic stress history on the dynamic shear modulus and the damping ratio of k0 consolidated saturated clays are studied by dynamic triaxial tests. The following conclusions are obtained. The dynamic accumulative strain can be used as a state parameter to describe the influence of the dynamic stress history on the dynamic shear modulus. The influences of the initial shear stress on the dynamic shear modulus and the damping ratio can be described by expressing the dynamic shear modulus and the damping ratio as variations with the dynamic shear strain. The influence of the initial average effective stress can be considered by normalizing the relationship between the dynamic shear modulus and the dynamic shear strain by using the maximum shear modulus associated with the relationship. Because effects of the initial average effective stress, the initial shear stress and the dynamic stress history on the variation of the damping ratio with the dynamic shear strain are not obvious, it is considered that the damping ratio is only related with the dynamic shear strain. Therefore, variation relationship of the dynamic shear modulus and the damping ratio with the initial average effective stress, the initial shear stress, the dynamic stress history and the dynamic shear strain can be determined by a group of dynamic triaxial tests under a consolidation confining pressure and multi-stages dynamic triaixial test of a sample under different confining pressure.
【Keywords】 cyclic shear modulus; damping ratio; k0 consolidated clay; dynamic constitutive relationship; dynamic triaxial tests;
【Funds】 National Natural Science Foundation of China (51579174) ;
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