液化砂土中单桩地震响应振动台试验研究

Shaking table tests for single pile-soil dynamic interaction in liquefied foundation soil

通过小型振动台动力模型试验,观测了饱和砂土中桩-土-结构(PSSI)在模拟地震力作用下的动力响应。结果表明:超静孔隙水压力在振动过程中不断增长,不同深度的土层均达到液化,并且离土面越近越先达到液化;土层的液化伴随着桩侧摩阻力的大大减弱,上部结构物的大部分荷载由桩底较硬持力层土承担,桩基的竖向承载力降低,上部结构的沉降量加大。同时在地震力的作用下PSSI效应加大了底层上部结构的地震反应。本研究加深了对饱和砂土在地震力作用下PSSI效应的理解,有助于建立或优化可液化土中桩基抗震设计方法。

Based on shaking table tests,the dynamic responses of a pile-soil-structure were observed under the simulated earthquake.The test results indicated that the soil with different depth is liquefied with continuous increase in excess pore water pressure within the vibration process,and the top soil firstly reaches liquefaction;pile side friction decreases greatly after the soil is liquefied,the most load of the upper structure is born by the harder stratum at the bottom of the pile,the vertical bearing capacity of the pile foundation drops significantly;the settlement of the upper structure rises;at the same time,PSSI amplifies the seismic response of the bottom super-structure.In this study,the pile-soil-structure dynamic interaction was clarified during soil liquefaction,it was helpful for establishing and optimizing the aseismic design method of pile foundation in liquefied soil.