材料状态对干砂小应变特性的影响

Effects of material state on the small strain behavior of dry sand

利用注能虚拟质量(EIVM)共振柱系统进行了干砂小应变特性试验,研究了有效平均正应力、土样密度、剪应变幅值以及荷载往复次数对剪切模量和阻尼比的影响。试验结果表明,剪切模量随有效平均正应力与土样密度的增加而增加,而阻尼比的变化规律则与之相反,并且有效平均正应力对干砂小应变特性的影响程度比土样密度的影响程度大得多;随着剪应变的增加,剪切模量越来越小,而阻尼比越来越大;荷载往复次数对剪切模量基本没有影响,而对阻尼比有较大影响。

An energy-injecting virtual-mass (EIVM) resonant column system was employed to investigate the small strain behavior of dry sand; and the effects of effective mean normal stress, density of soil samples, amplitude of shear strain, as well as number of loading cycles on shear modulus and damping ratio are studied. The test results show that the shear modulus increases with effective mean normal stress and soil density, while the damping ratio exhibits the opposite response. Moreover, the effects of effective mean normal stress on the small strain behavior of dry sand are more than those of soil density. As the shear strain increases, the shear modulus become smaller; but the damping ratio become larger. The number of loading cycles has no significant effects on shear modulus, but it influences the damping ratio to a quite extent.