摘要
基于大量动三轴试验,针对滨海新区结构性软土,研究了其动应力-应变、动模量和阻尼比变化规律,并对振动波型、加荷频率以及固结应力比等影响因素进行了深入的研究,得出了如下的结论:振动波型对于结构性软土的动应力-应变类型影响不大,但是最大动弹模量Edmax和动剪切模量Gdmax的相差可达2.5倍左右;结构性软土具有明显的频率效应和门槛振动频率;半正弦波型条件下,当围压小于结构屈服压力时,最大动弹模量Ed随固结比的增加而递减,超过某一应变幅值时,最大动弹模量Ed将随着固结比的增加而减小;偏压状态下,低应变条件下固结比越大,阻尼比越大,当应变值超过0.004以后,随应变值的不断增大,固结比越大,阻尼比反而越小。所得出的结论对工程应用具有一定的指导意义。
Based on a lot of dynamic triaxial tests, the variation laws of dynamic stress-strain, dynamic elastic modulus and damping ratio of structural soft soils were studied; meanwhile, the influences of vibration wave, frequency and consolidation ratio were investigated. It is concluded that the influence of vibration wave on the type of dynamic stress-strain is not evident; the value between the maximum dynamic modulus Edmax and dynamic shear modulus Gdmax is 2.5 times or so. The effect of frequency on the structural soft soil is evident; and there is a threshold vibration frequency. The maximum dynamic modulus Edmax decreases with the consolidation ratio increasing as the confining pressure is less than structural yield pressure; and when strain exceeds a certain value, the maximum dynamic modulus Ed decreases with the consolidation ratio increasing. At a lower strain and deviatoric pressure, the higher the consolidation ratio is, the larger the damping ratio is; and when strain exceeds 0.004, the consolidation ratio increases, meanwhile the damping ratio decreases as the strain value increases. The conclusions can provide a useful guidance for the engineering application.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2009年第12期3788-3792,共5页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.50508021)
天津市科技创新专项资金项目(No.07FDZDSF02100-02)
关键词
结构性软土
动三轴试验
本构关系
交通荷载
动模量
阻尼比
structural soft soil
dynamic triaxial test
constitutive relation
traffic loading
dynamic elastic modulus
damping ratio
