关键词: 饱和粉土, 液化, 大型振动台模型试验, CFG桩桩网结构地基, 加速度放大系数

Abstract:

A 1:10 scale shaking table model test was conducted by a large-scale laminar shear box; the test mainly researched on cement fly-ash gravel (CFG) column-net composite foundation, with the saturated silty soil ground of the Beijing-Shanghai High Speed Railway which was treated by CFG column-net. It has been plot that the amplification coefficient distribution of response acceleration under a series of input acceleration seismic loads, and the relation between the series of input accelerations and its corresponding amplification coefficient of response acceleration. The results show that: (1) at less than 0.101g loading acceleration, the response acceleration scarcely enlarge and its nephogram presents a horizontal type distribution; (2) at 0.161g loading acceleration, as a result of liquefaction of soil between piles, the respone acceleration greatly increase; (3) at 0.210g loading acceleration, the response acceleration increase result from liquefaction of soil between piles and shear break of CFG column; (4) at 0.324g, 0.363g loading acceleration, the integral rigidity of foundation decreases greatly, which reduces its capability of the shock transferred and result in the response acceleraton is less than that at the former loading acceleration; (5) during the course of loading acceleration, amplification effect of response acceleration is obvious in silty soil, but not in clay layer.

Key words: saturated silty soil, liquefaction, large-scale shaking table model test, CFG column-net composite foundation, response acceleration amplification coefficient