摘要
将桩周土体视为粘弹性介质,利用分数导数粘弹性模型描述土体的力学特性,在Novak平面应变假定的基础上,借助于势函数并考虑土体边界条件求得了分数导数微分算子描述的粘弹性土层水平位移的衰减函数以及分数导数粘弹性土层的刚度和阻尼系数。利用Winkler动力弹簧-阻尼器模型模拟桩-土之间的动力相互作用,并在此基础上利用初始参数法求解了分数导数粘弹性土层中桩-桩水平动力相互作用和群桩的水平振动问题。以数值算例的形式讨论了分数导数微分算子的阶数和土体的模型参数对分数导数微分算子描述的粘弹性土层水平位移的衰减函数和群桩的水平动力阻抗的影响。研究表明:分数导数微分算子的阶数对土层水平位移的衰减函数的影响与桩间距和荷载方向角有关;分数导数粘弹性土中群桩的动力阻抗可以退化到经典粘弹性和弹性情况;分数导数微分算子的阶数和土体模型参数对群桩水平动力阻抗有较大影响。
The soil around piles is regarded as viscoelastic medium and the mechanical properties are described by fractional viscoelastic model. Based on the Novak plane strain hypothesis, the attenuation function of horizontal displacement and the stiffness and damping coefficient of the soil layer described by fractional viscoelastic model were obtained by potential functions and boundary conditions. The pile-soil dynamic interaction was modeled by Winkler dynamic elastic-damping model, the pile to pile dynamic interaction and horizontal vibration of the pile groups in the soil described by fractional derivative viscoelastic model were solved by initial parameter method. The influence of the order of fractional derivative and model parameter of soil on the pile to pile dynamic interaction and horizontal dynamic impedance of pile groups was investigated through numerical examples. The result indicates that the influence of the order of fractional derivative on the attenuation function of horizontal displacement is related to the pile space and load direction angle; in studying the horizontal dynamic impedance of pile groups, the soil model can be simplified to the cases of classic viscoelastic and elastic; the order of fractional derivative and the model parameter of soil have great effect on the lateral dynamic impedance of the pile groups.
出处
《工程力学》
EI
CSCD
北大核心
2012年第6期160-168,共9页
Engineering Mechanics
基金
国家自然科学基金项目(10872124)
河南省科技计划立项项目(122300410308)
河南省教育厅自然科学研究计划项目(2011A1301001)
关键词
粘弹性
分数导数
动力相互作用
水平振动
势函数
VlSCOelsatlc
fractlonal derivative
dynamic interaction
horizontal dynamic
potentml tunct^ons
