【摘要】 为了研究地震作用下群桩–土–结构的相互作用规律,采用量纲分析方法,设计了群桩–柱墩模型振动台试验,通过输入幅值为0.15g和0.5g的El Cenro地震波,探讨了地基加速度反应、桩–柱墩加速度反应和孔隙水压力反应的规律。试验结果表明:①小震输入下,地基动力变形的线性特征较突出,主要表现为对地震波的动力放大作用,且加速度反应自下而上逐渐增大;大震输入下,地基动力变形表现出明显的非线性,加速度反应规律不单一;②桩–柱墩加速度反应主要集中在低频段,反应规律复杂;③埋深和桩距对地基孔隙水压力变化影响较大,且随埋深减小,孔压减小,孔压比增大,同时随桩距减小,孔压增大,以致在桩周形成一定的孔压梯度。振动台试验能很好地再现天然地震作用的宏观现象,是研究液化场地桩–土–结构动力相互作用反应规律的一种很好的手段。更多还原

【Abstract】 In order to study the laws of pile group-soil-structure interaction under seismic actions,dimensional analytical method is used to design the pile group-pier model shaking table tests.Then foundation acceleration response,pile-pier acceleration response and the law of pore water pressure response are discussed by inputting El Cenro seismic waves with amplitude of 0.15g and 0.5g respectively.The test results indicate that(1) when small earthquake is input,linear characteristics of foundation dynamic deformation are evident,mainly reflecting the dynamic amplification effect on seismic waves and the gradual increase of acceleration response from bottom to top;when large earthquake is input,dynamic deformation of the foundation shows obvious non-linearity and the laws of acceleration response are diverse;(2) pile-pier acceleration response mainly concentrates in low-frequency band with complicated laws;(3) buried depth and pile spacing impact greatly on the variations of pore water pressure of the foundation,also,the pore pressure decreases while pore pressure ratio increases with the reduction of buried depth,and the pore pressure grows with the reduction of pile spacing,which causes a certain degree of pore water pressure gradient around the pile.Shaking table tests can reproduce the macroscopic phenomena of natural earthquake action well and are a good approach to study the pile-soil-structure dynamic interaction laws on liquefied ground.更多还原