摘要
通过k_0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k_0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k_0固结饱和粘土动剪模量与阻尼比变化关系。
Effects of the initial effective mean stress,the initial shear stress and the cyclic stress history on the cyclic shear modulus and the damping ratio of k0 consolidated saturated clays are studied by cyclic triaxial tests.Following conclusions are obtained.The cyclic accumulative strain can be used as a state parameter to describe effect of the cyclic stress history on the cyclic shear modulus.The effects of the initial shear stress on the cyclic shear modulus and the damping ratio can be described by expressing the cyclic shear modulus and the damping ratio as variations with the cyclic shear strain.The effect of the initial effective mean stress can be considered by normali- zing the relationship between the cyclic shear modulus and the cyclic shear strain using the maximum shear modulus associated with the relationship.Because effects of the initial effective mean stress,the initial shear stress and the cyclic stress history on the variation of the damping ratio with the cyclic shear strain are not obvious,it is consid- ered that the damping ratio is only related with the cyclic shear strain.Therefore,variations of the cyclic shear modulus and the damping ratio with the initial effective mean stress,the initial shear stress,the cyclic stress history and the cyclic shear strain can be 'determined by a group of cyclic triaxial tests under a consolidation confining pressure and multi-stages cyclic-triaixial test of a specimen under different confining pressure.
作者
王建华
杨腾
WANG Jianhua;YANG Teng(State Key Laboratory of Hydraulic Engineering Simulation and Safety of Tianjin University,Tianjin 300072,China;Geotechnical Engineering Institute of Tianjin University,Tianjin 300072,China)
出处
《自然灾害学报》
CSCD
北大核心
2018年第6期1-9,共9页
Journal of Natural Disasters
基金
国家自然科学基金项目(51579174)~~
关键词
动剪模量
阻尼比
k0固结黏土
动本构关系
动三轴试验
cyclic shear modulus
damping ratio
k0 consolidated clay
cyclic constitutive relationship
cyclic triaxial tests
