徐州市棠张镇饱和粉土液化性能试验研究

Experimental study on liquefaction behavior of saturated silt in Tangzhang Town, Xuzhou City

徐州市棠张镇高速铁路路基的粉土粘粒含量少于1.5%、粉粒含量约为80%,在强烈地震作用下存在着液化可能性,为了分析该路基粉土的液化特性,进行了多组振动三轴液化试验。对试验结果进行分析发现,该地区的粉土振动孔压发展模式与Seed提出的用反正弦三角函数拟合的砂土振动孔压发展模式不同,可以用双曲线进行拟合。采用最大往返剪切作用面上的应力条件确定了该地区的孔压发展模式的拟合参数,为该地区粉土地震液化动力计算分析提供了所需的地震孔隙水压力增长模型。同时,本文指出粉土的密度和结构是振动孔压发展的重要影响因素。

The grain of clay content is less than 1.5% and the grain of fine content is approximately equal to 80% in the saturated silt of the roadbed of railroad in Tangzhang town, Xuzhou city. The silt may be liquefied under strong earthquake. To analyze the liquefaction behavior of the silt, many sets of tests were carried out with dynamic triaxial apparatus. Through the analysis of these test results, the following conclusionsare drawn. First, the development of dynamic pore water in silt differs from that in sand suggested by Seed and fitted with arcsine function. The development of pore pressure can be fitted by hyperbola. The fitting coefficients are determined with dynamic shear stress condition on the largest reciprocal acting surface. Second, the density and consruction of silt are importanteffective factors of development of dynamic pore pressure of silt.