黏弹性地基中基于虚土桩模型的桩顶纵向振动阻抗研究  

Vertical dynamic impedance of pile embedded in viscoelastic soil based on fictitious soil pile model

作　　者：吴文兵[1] 蒋国盛[1] 邓国栋[2] 谢邦华[1] 

机构地区：[1]中国地质大学(武汉)工程学院,武汉430074 [2]中南大学土木工程学院,长沙410075

出　　处：《振动与冲击》2015年第7期192-198,202,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金青年项目(51309207);中国博士后科学基金特别资助项目(2013T60759);中国博士后科学基金面上项目(2012M521495);中央高校基本科研业务贵专项资金-摇篮计划(CUGL150411)

摘　　要：基于虚土桩模型,对均质黏弹性地基中桩土纵向耦合振动问题进行了研究。首先,假定桩侧土为各向同性的线性黏弹性材料,并考虑土体的竖向波动效应,结合Euler-Bernoulli杆件理论,建立了桩土纵向耦合振动的定解问题;其次,采用分离变量法求解桩侧土纵向振动的控制方程,得到了桩侧土与桩身接触面上的剪切动刚度,将所得的剪切动刚度代入到桩身振动控制方程,采用Laplace变换技术,进一步求得了任意荷载作用下桩顶纵向振动阻抗的解析解。基于所得解,详细讨论了不同桩身设计参数时桩端土厚度对桩顶纵向振动阻抗的影响。最后,将虚土桩模型与其他桩端土支承模型进行了对比研究,结果表明,对虚土桩模型选用合适的材料参数和桩端土厚度,其得到的桩端支承复刚度值介于现有多种模型的计算值之间。Based on fictitious soil pile model, the vertical dynamic response of pile embedded in homogeneous viscoelastic soil was investigated. Assuming the surrounding soil of pile to be isotropic viscoelastic material and considering its vertical wave effect, the definite problem of soil-pile system subjected to arbitrary dynamic force was established based on the Euler-Bernoulli rod theory. The shear dynamic stiffness at the interface of soil and pile was derived by means of separation of variables to solve the governing equation of surrounding soil. Substituting the shear dynamic stiffness acquired into the governing equation of pile, the analytical solution of vertical dynamic impedance was deduced by virtue of Laplace transform technique. Based on the obtained solution, the influence of depth of pile end soil on the vertical dynamic impedance was studied in detail with different design parameters of pile. Constrast analysis was made between the fictitious soil pile model and other pile end soil supporting models. It is shown that the complex supporting stiffness calculated by fictitious soil pile model is in the middle of the supporting stiffnesses calculated by other existing models if adopting appropriate material parameters and proper depth of pile end soil in the fictitious soil pile model.

关 键 词：虚土桩模型 纵向振动阻抗 黏弹性地基 竖向波动效应 LAPLACE变换 解析解 

分 类 号：TU435[建筑科学—岩土工程]