耦合质量对饱和黏弹性土中桩纵向振动的影响分析

Effect Analysis of Coupling Mass on Longitudinal Vibrations of Pile in Saturated Viscoelastic Soil

基于Biot理论,在频率域内研究了考虑质量耦合效应的饱和黏弹性土中桩的纵向耦合振动特性.采用Novak薄层法得到了饱和黏弹性土的位移、应力等的解析表达式.将桩视为Euler-Bernoulli杆,给出了饱和黏弹性土中端承桩纵向振动的动力方程.根据桩土连续性条件,得到了桩顶的复刚度表达式.与Novak解进行了对比,并考察了饱和土和桩各参数对桩顶动态刚度因子和等效阻尼的影响.结果表明:耦合质量项对桩顶复刚度有较大影响;桩土模量比对桩纵向振动特性的影响与桩长径比的取值有关.

Based on the Biot＇ s theory, the longitudinal coupled vibration of pile in the saturated viscoelastic soil with mass-coupling effect was investigated in the frequency domain. By utilizing the Novak＇ s method, the analytical expressions of the displacement and stress of the saturated viscoelastic soil were received. The pile was treated as the Euler-Bernoulli rod. The dynamic equation of the end-bearing pile in the saturated viscoelastic soil was established. By the continuity conditions of pile and soil, the solution for complex stiffness of the pile top was obtained. Compared with the Novak＇ s solution, the dynamic stiffness factor and the equivalent damping were analyzed for different parameters of the soil and pile. It is shown that the coupling mass has great influences on the complex stiffness of pile top ; the influ- ences of modulus ratio of pile and soil on the longitudinal vibration of pile with respect to the value of length-diameter.