摘要
采用Kelvin模型模拟饱和土体和桩的相对滑移,在频率域内研究了饱和黏弹性土层中端承桩的扭转耦合振动.饱和土体的力学行为利用Biot模型描述.将土骨架视为具有分数阶导数本构的黏弹性体,采用Novak薄层法,得到了桩扭转振动时饱和黏弹性土层的动力阻抗.利用Euler-Bernoulli杆模型模拟桩的力学行为,给出了饱和分数导数黏弹性土层中端承桩扭转振动的分析方法和桩顶动力复刚度的解析表达式.在此基础上,分别对以下几个方面进行了对比分析:经典弹性模型、分数导数黏弹性模型和标准线性固体模型的结果;三维模型和薄层法的结果;桩土界面有无相对滑移的结果.考察了分数导数模型参数、饱和土和桩各参数对桩顶刚度因子和等效阻尼的影响.结果表明:在高频处完全接触条件下桩顶刚度因子和等效阻尼的振幅小于滑移条件下;随着阶数和材料参数比的增加,桩顶刚度因子和等效阻尼都有所减小.
The imperfect contact between saturated soil and pile was considered by the Kelvin model.The torsional coupled vibration of an end-bearing pile in saturated viscoelastic soil was investigated in frequency domain.Biot＇s theory was used to describe saturated soil.The soil skeleton was treated as a viscoelastic medium with fractional derivative constitutive relation. The dynamic impedance of the saturated viscoelastic soil to torsional vibration of the pile was obtained by the Novak＇s layer method.The mechanical behavior of the pile was simulated by the Euler-Bernoulli rod model.The analysis method for the torsional vibration of an end-bearing pile in saturated fractional derivative viscoelastic soil was presented,and the analytical expression of the dynamic complex stiffness at the pile top was obtained.On this basis,the results of classic elastic,fractional derivative viscoelastic and standard linear solid model, the results of three-dimensional model and Novak＇s layer method,the results of with or without the perfect contact between pile and soil were respectively compared and analyzed.The influences of the parameters of fractional derivative model,saturated soil and pile on the dynamic stiffness factor and equivalent damping of the pile top were analyzed.The results show that the amplitudes of stiffness factor and equivalent damping at the pile top for the perfect contact condition are less than those for the imperfect contact condition at high frequencies.The stiffness factor and equivalent damping at the pile top decrease as the order and the ratio of material parameter increase.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2013年第12期2146-2152,共7页
Journal of Zhejiang University：Engineering Science
基金
浙江省自然科学基金资助项目(LY12E09006)
浙江省公益技术研究社会发展项目(2013C33G2110023)
关键词
饱和黏弹性土
端承桩
扭转振动
接触模型
分数导数
saturated viscoelastic soil
end-bearing pile
torsional vibration
contact model
fractional derivative
