相对密实度及激振频率对可液化场地动力响应特性影响数值模拟研究

Study on Influences of Relative Compaction and Excitation Frequency on Characteristics of Dynamic Response of Liquefiable Site

基于Finn孔压模型,探讨相对密实度和激振频率对可液化场地动力特性的影响。研究结果表明:相对密实度小的场地最大超静孔压比更大,松散场地振动时需要耗散的能量大于密实场地;场地响应加速度放大系数与相对密实度呈线性正相关;液化后的松散场地对加速度有隔振作用,密实场地会放大加速度;埋深越大的砂土所受围压越大,砂土结构越不易破坏,液化程度越小;输入自由场地的激振频率越大,响应加速度放大系数越小,场地越不易液化。

Based on Finn pore pressure model,the influences of dynamic characteristics of relative compaction and excitation frequency on the liquefiable site were discussed.The result of the research shows that the site in less relative compaction is of greater maximum excess pore pressure ratio,in case of vibration,the loose site requires to consume more energy than compacted site;the response acceleration amplification coefficient of the site is linearly correlated with relative compaction;after liquefaction,the loose site has vibration isolation effect on the acceleration,and the compacted site may amplify the acceleration;more deeply the sandy soil is buried,the greater confining pressure it bears,thus the sandy soil structure is more difficult to be damaged with less degree of liquefaction;the greater excitation frequency input to the free site,the less response acceleration amplification coefficient,then the site is more difficult to be liquefied.