为研究寒区饱和含黏粒粉砂的动力学特性,对松花江河漫滩饱和含黏粒粉砂土进行循环三轴试验,分析冻融循环、动应力幅值、有效围压、荷载频率等环境因素对饱和粉砂土动剪切模量与阻尼比的影响。结果表明:冻融循环对饱和粉砂土动剪切模量与阻尼比影响显著,表现为在不同冻融次数区间内两者不单一变化;未冻融饱和粉砂土动剪切模量随动应力幅值、有效围压、荷载频率的增大而增大,而阻尼比随动应力幅值、有效围压、荷载频率的增大而减小。并进一步提出了可预测该种土不同工况下动剪切模量与阻尼比的经验公式。研究成果可以为粉砂土在路基工程中的稳定性与安全性设计提供参考。
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.
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
Key words
freeze-thaw cycle /
silt containing clays /
cyclic triaxial test /
dynamic shear modulus /
damping ratio
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基金
中央高校基本科研业务费项目(DL12CB03);黑龙江省自然科学基金项目(E201149)
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