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在大量冻融试验和动三轴试验的基础上,深入研究和分析了经历多次冻融循环后粉砂土动模量和阻尼比的变化规律。研究结果表明:同一动应变水平下,动应力大小与冻融次数、含水率呈负相关性,而与围压、加载频率、压实度呈正相关性;粉砂土的动应力-动应变关系存在明显的非线性,且随动应变水平的提高,动模量成倍减小,而阻尼比则成倍增大;随冻融次数的增加,动模量降低而阻尼比则增大,且经历6次冻融后均趋于稳定,建议将6次冻融后的力学特性作为设计与计算指标;围压和压实度的提高有效增强了土颗粒之间的骨架作用,动模量随围压和压实度的增减而增减,阻尼比则随围压和压实度的增加而降低;含水率的变化对阻尼比的影响不大,而当土样达到饱和状态时,动模量成倍降低;加载频率对阻尼比的影响较大,并随频率的提高而迅速降低。
On the basis of a large number of freeze-thaw experiments and dynamic triaxial tests, the variation regularities of dynamic modulus and damping ratio of silt soil after repeated freeze-thaw cycles were deeply studied and analyzed. The results show that under the same dynamic strain level, the dynamic stress has a negative correlation with the number of freeze-thaw cycles and water cut, but positively with the confining pressure, loading frequency and compaction degree. The dynamic stress-strain relationship of silt sand There is obvious nonlinearity. With the increase of the level of dynamic strain, the dynamic modulus decreases and the damping ratio increases exponentially. With the increase of the number of freeze-thaw cycles, the dynamic modulus decreases and the damping ratio increases, After 6 freeze-thaw cycles, they all tend to be stable. It is suggested that the mechanical properties after 6 freeze-thaw cycles should be used as design and calculation indexes. Increasing confining pressure and compaction can effectively enhance the skeleton effect between soil particles. Pressure and compaction increase or decrease, the damping ratio decreases with the increase of confining pressure and compaction; the change of water content has little effect on the damping ratio, while when the soil sample reaches saturation, The amount of doubled reduction; load frequency on the damping ratio greater impact, and with the frequency increases rapidly reduced.