【摘要】 水平场地地震响应分析是岩土地震工程实践中最重要的问题之一.深圳近年多次经历外围地震引起的小振动,因而研究场地在小震作用下的响应有特殊意义.利用香港科技大学离心机及双向振动台,进行饱和砂土场地的动力模型试验.观测模型在原型峰值加速度为0.07g的小震作用下,加速度、侧向位移、竖向沉降及超静孔压等方面的响应.发现在地震过程中,土体变形较小,超静孔压比也小于0.5,但超静孔压的变化使场地固有频率靠近输入地震波的频率,加速度的放大系数最大可达到3.67.分析结果表明,小震作用下场地虽不大可能发生液化,但在特定情况下,仍可能对上部结构造成破坏.更多还原

【Abstract】 Analysis of response of level ground subjected to earthquake is one of the most important problems in geotechnical engineering practice.Since Shenzhen has been subjected to small vibration several times in recent years,the studies on response of level ground under small earthquakes are of particular interest.In this study,a centrifuge dynamic test was performed on a uniform saturated sand ground model under a small earthquake loading with a peak acceleration of about 0.07 g in the prototype scale.Acceleration,lateral displacement,vertical settlement as well as excess pore pressure were measured during the shaking event.It was observed that the deformation of soil body was small,and the excess pore pressure ratios were less than 0.5.However,the input acceleration was amplified by a factor as large as 3.67 at the ground surface.The phenomenon is associated with a shift of the natural frequency of the sand ground induced by the buildup of excess pore pressure during the earthquake.This study indicates that small earthquake may bring detrimental effect to superstructures,although liquefaction is unlikely to occur.更多还原