利用英国WFI生产的WF25735循环单剪试验系统，完成了一系列不同含水率重塑砂土在不同剪应变条件下的循环剪切试验，分析了不同剪应变条件下含水率的变化对非饱和砂土动力特性的影响规律。试验结果表明：动剪模量Gd/Gdmax-?归一化数值，在大应变下存在一个临界含水率11.2%，低于临界含水率时，Gd/Gdmax随含水率的增大而增大，高于临界含水率时，随着含水率的增大，Gd/Gdmax逐渐减小。骨架曲线存在一个相同的临界含水率，当低于该临界含水率时，随着含水率的增大，骨架曲线呈缓慢增大趋势，在含水率为11.2%处达到峰值；当高于该临界含水率时，随着含水率的增大，骨架曲线下降比较剧烈，且出现软化现象，从骨架曲线可以进一步解释Gd/Gdmax-?散点图的变化趋势。对阻尼比D/Dmax-?进行归一化数值，在较大正应力下，D/Dmax随着剪应变的增大而增大。非饱和砂土的滞回耗能随着剪应变的增大而增大；随着含水率的增大，存在一个临界含水率，滞回耗能曲线呈现先增大后下降的趋势，且临界含水率随着正应力的增大出现了偏移。

A series of cyclic shear test on remolded unsaturated sandy soil with different water contents was performed using the cyclic simple shear test apparatus WFI25735. The effect of water content variation on dynamic properties of unsaturated sandy soil is examined at different shear strains. The experimental results show that there exists a critical moisture content of 11.2% corresponding to the normalized value of dynamic shear modulus Gd/Gdmax-? at large strain. When the water content is lower than critical moisture content, the value of Gd/Gdmax increases with the water content, and when the water content becomes higher than the critical moisture content, it decreases gradually with the increase of water content. The same critical water content can be found on the skeleton curve. When the water content is lower than the critical water content, the skeleton curve goes up slowly, and reaches a peak value at 11.2% water content. The skeleton curve decreases sharply with the increase of the water content when the water content is higher than the critical water content, and the strain softening appears, which can further explain the scatter diagram changing trend of Gd/Gdmax-?. At relatively high stress, the normalized damping ratio D/Dmax increases as the shear strain increases. The hysteretic energy dissipation of unsaturated sandy soil increases with the increase of the shear strain. As the water content increases, there exists a critical water content. The hysteretic energy curve shows a trend of first increasing and then decreasing and the critical water content can shift as the normal stress increases.