结合常德-张家界高速公路某大桥桥基工程,在DSD-160型电磁式振动三轴试验仪上,通过往返加荷三轴试验,对饱和砂土进行了液化试验研究,探讨了基于动三轴液化试验结果判断饱和砂土液化的方法.并尝试了这种室内研究-反应分析的液化可能性估计方法与地震剪应力时程相结合的综合判断方法.在该高速公路大桥桥基的饱和砂土液化评价中,采用这种综合判断方法,对大桥桥基砂土液化进行了判断.在判断场地是否液化后,对其液化危害程度进行了等级划分,给出了该工程场地在未来遭受到不同超越概率下的地震作用时发生液化的危害程度,得到了一些有工程实用意义的结果.
This paper presents test results of sand liquefaction under sinusoid loading at a site of one Changde - Zhangjiajie expressway bridge using the DSD - 160 electric - magnetic vibration triaxial apparatus. A new method for evaluating sand liquefaction based on dynamic triaxial apparatus is proposed in combination with an earthquake shear stress time history method. The results show some clear evidences for the potential sand liquefaction under earthquake ground motion with different exceedance probability. A risk classification is also given. These results not only prove the feasibility of the new approach on evaluation of sand liquefaction, but also help to gain a better understanding of the seismic resistance design before the construction of the bridge.