建筑物下珊瑚砂地基动力响应振动台模型试验研究

随着岛礁建设的快速发展,珊瑚砂地基抗震安全尤为重要。为揭示珊瑚砂地基和建筑物地震响应特性,开展了地震动作用下不同密实度的可液化珊瑚砂地基上3层框架结构的振动台模型试验,对孔隙水压力、加速度、位移和动应变等动力响应进行测试和分析,并与可液化石英砂场地进行对比。结果表明,相同相对密实度和相近颗粒级配下,珊瑚砂场地相比石英砂场地更难以液化。两种砂场地液化程度均随埋深增大而减小,随与建筑物距离增大而增大。液化后的珊瑚砂场地模型地基相比石英砂场地仍然具有一定的剪切传递能力,这种差异随地基埋深的增加逐渐减弱。珊瑚砂场地液化后建筑物倾斜度、最终沉降和立柱动应变相比石英砂场地均较小。不同相对密实度的珊瑚砂与石英砂场地液化性能存在一定的差异。

Shaking table tests on dynamic response of coral sand foundation under buildings

With the rapid development of coral island construction, the seismic safety of coral sand foundation is particularly important. To reveal the seismic response characteristics of coral sand foundation and buildings, the shaking table tests on a three-story frame structure on liquefiable coral sand are carried out. The pore pressure, acceleration, displacement and strain are tested for different relative densities of model foundation. The test results are compared with those of the liquefiable quartz sand. The results show that the coral sand is more difficult to be liquefied than the quartz sand under the same relative density and similar particle-size distribution. The liquefaction degree of the two kinds of sand decreases with the increase of foundation depth, and increases with the distance from the buildings. Compared with the quartz sand, the liquefied coral sand model foundation still has some shear transfer capacity, while this difference gradually weakens with the increase of foundation depth. The inclination, final settlement and column strain of the model buildings on the coral sand foundation are smaller than those on the quartz sand foundation. The liquefaction properties of coral sand with different relative densities are different.