桩-黄土-结构体系地震动力相互作用的数值分析
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摘要
引入饱和黄土的结构性动力本构模型,结合通用有限元程序建立了桩-土-结构体系的有限元-无限元耦合模型,分别考察了水平地震作用下土体结构性和超孔隙水压力对桩身截面剪应力、水平位移、水平加速度分布的影响。研究表明:结构性、超孔压没有改变桩身各曲线的分布形态,但对其大小有一定的影响。具体表现为:随着土体结构性系数的增大,桩身截面剪应力及桩顶水平位移均先增后降,存在一个峰值点;考虑超孔压时,桩身水平位移最大值、桩截面剪应力最大值和桩身水平加速度最大值都有所增大,其中后两者的分布具有反相关性;不考虑超孔压力的影响总体上是偏于不安全的。
Dynamic structural model of saturated loess was introduced,and combined with the finite element program,the finite-infinite element model of pilesoil-structure system is established to research the influences of structure and super-pore pressure on the system's dynamic characteristics,which include the distributing of pile section's shearing stress,horizontal displacement and acceleration.The results indicate that,two factors don't change their distributing shapes,but have effects on their values.Along with the increase of soil's structure,both of shearing stress and horizontal displacement are increased initially,and then reduced.There has a peak value point.When the super-pore pressure is considered,the maximum of pile's horizontal displacement,shearing stress and horizontal acceleration all have a certain increase,and the latter two ones' distributing is anti-related to each other.On the whole,it is inclined to be unsafe of analysis which is not to consider the super-pore pressure.
Dynamic structural model of saturated loess was introduced,and combined with the finite element program,the finite-infinite element model of pilesoil-structure system is established to research the influences of structure and super-pore pressure on the system's dynamic characteristics,which include the distributing of pile section's shearing stress,horizontal displacement and acceleration.The results indicate that,two factors don't change their distributing shapes,but have effects on their values.Along with the increase of soil's structure,both of shearing stress and horizontal displacement are increased initially,and then reduced.There has a peak value point.When the super-pore pressure is considered,the maximum of pile's horizontal displacement,shearing stress and horizontal acceleration all have a certain increase,and the latter two ones' distributing is anti-related to each other.On the whole,it is inclined to be unsafe of analysis which is not to consider the super-pore pressure.
引文
[1]吴燕开,陈红伟,张志征.饱和黄土的性质与非饱和黄土的流变模型[J].岩土力学,2004,25(7):1143-1146.
[2]陈存礼,高鹏,何军芳.考虑结构性影响的原状黄土等效线性模型[J].岩土工程学报,2007,29(9):1330-1336.
[3]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理试验研究[J].岩土力学,2002,23(4):395-399.
[4]胡伟.饱和黄土动力本构模型及其在桩-土-结构体系地震动力相互作用中的应用[D].西安:西安建筑科技大学,2008.
[5]徐远杰,王观琪,李健,等.在ABAQUS中开发实现Duncan-Chang模型[J].岩土力学,2004,25(7):1032-1036.
[2]陈存礼,高鹏,何军芳.考虑结构性影响的原状黄土等效线性模型[J].岩土工程学报,2007,29(9):1330-1336.
[3]佘跃心,刘汉龙,高玉峰.饱和黄土孔压增长模式与液化机理试验研究[J].岩土力学,2002,23(4):395-399.
[4]胡伟.饱和黄土动力本构模型及其在桩-土-结构体系地震动力相互作用中的应用[D].西安:西安建筑科技大学,2008.
[5]徐远杰,王观琪,李健,等.在ABAQUS中开发实现Duncan-Chang模型[J].岩土力学,2004,25(7):1032-1036.
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