关键词: 冻融循环, 含黏粒粉砂, 循环三轴试验, 动剪切模量, 阻尼比

Abstract: To study the dynamic characteristics of saturated silty sand containing clays in frigid zone, cyclic triaxial tests were carried out on the saturated silty sand containing clays from the floodplain of Songhua River. The effects of environmental factors such as freeze-thaw cycle, dynamic stress amplitude, effective confining pressure and load frequency on the dynamic shear modulus and damping ratio of the saturated silty sand were examined. Results demonstrate that the dynamic shear modulus and damping ratio of saturated silty sand, which do not change in a single way in different freeze-thaw cycles, are significantly affected by the freeze-thaw cycle. The dynamic shear modulus of saturated silty sand which does not undergo freeze-thaw cycles increases with the increase of dynamic stress amplitude, effective confining pressure and load frequency, and the damping ratio declines with the rising of dynamic stress amplitude, effective confining pressure and load frequency. Moreover, an empirical formula is proposed to predict the dynamic shear modulus and damping ratio of silty sand under different conditions. The research results offer reference for the stability and safety design of silty sand in subgrade engineering.

Key words: freeze-thaw cycle, silt containing clays, cyclic triaxial test, dynamic shear modulus, damping ratio