基于文克勒模型的饱和土中单桩对瑞利波动力响应研究

The single pile response to Rayleigh wave in saturated soils

基于Boit饱和多孔介质理论,采用文克勒地基梁模型,研究了表面透水的饱和土介质中顶部固接的桩对瑞利波的横向响应。分别计算了软土和硬土两种情况下不同深度桩的响应、饱和土的孔隙率对桩响应的影响、土介质相对刚度对桩响应的影响、fc-z空间桩响应的分布、桩顶约束条件的影响,并与桩顶自由的结果进行了比较。结果表明,饱和土介质中桩对瑞利波的横向响应受波的频率、土介质性质、桩土刚度比、桩顶约束条件等因素的影响。整体来看,瑞利波对桩的横向影响自上而下大致呈衰减趋势,在地表处影响最大;瑞利波对桩的影响深度随频率的降低而扩大;桩、土之间的水平相对位移幅度与土的孔隙率、相对刚度比均呈正相关关系;同频率下,相对软土地基来说硬土地基中桩受瑞利波的影响较深;顶部固接比顶部自由的桩对瑞利波的响应小。计算结果对工程抗震设计具有参考价值。

Based on Boit's theory of saturated porous medium,the pile lateral responses under Rayleigh wave are studied.The Winkler foundation beam model is adopted and the pile top is fixed in non-watertight saturated soil on surface.The following cases are studied:①pile responses in soft and hard soil in different depth;② pile responses influenced by saturated soil porosity;③pile responses influenced by relative rigidity of soil medium;④pile responses distribution in fc～z space,⑤the effects of constrain conditions,and the results are compared to the results of top free pile.The Results indicate that:the pile lateral responses under Rayleigh wave are affected by frequency,characters of soil medium,pile-soil rigidity ratio and constrain conditions of pile top.Generally,the influence of Rayleigh wave to pile lateral movement appears a descend tendency from top to bottom,and the maximum value appears on the surface;the influencing depth of Rayleigh wave to pile extends when frequency decrease;the relative lateral displacement between pile and soil assumes positive correlativity with porosity and relativity rigidity ratio;under the same frequency,the Rayleigh wave influence on pile in the hard soil is deeper than that in soft soil.;the responses are smaller when the top is consolidated than that is free.The results are useful to engineering anti-seismic design.