This study was aimed at highlighting the effect of loading frequency on the sand liquefaction response by performing cyclic triaxial tests in both stress-controlled and strain-controlled modes. For the first case, dense (I_Dmat = 0.70) and medium-dense (I_Dmat = 0.55) sand specimens were subjected to alternative and non-alternative axial stresses; whilst dense (I_Dmat = 0.70) sand specimens were subjected to alternative axial strain over a wide range of loading frequencies in the second case. It was experimentally found that in the case of alternative loading for test specimens with I_Dmat = 0.70 in stress-controlled mode, the effect of the loading frequency was not notable for dry sand specimens. In contrast, the effect of the loading frequency was significant for saturated sand specimens in both the loading modes. This was because, upon shearing, transient deformation occurred with the presence of excess pore water pressure, during which the inertia force needed to be taken into account. In the axial direction, the inertia force opposing the external loading certainly increased the liquefaction resistance by suppressing the complete development of the sand liquefaction. As for non-alternative loading in stress-controlled mode for test specimens with I_Dmat = 0.55, the loading frequency played a vital role in pure extensional loading, which could also be logically attributed to the presence of the axial inertia force appearing in the large strain and transient deformation stages. However, the effect of the loading frequency on the compressive pattern was unclear due to the following two reasons: (i) the inertia force in the lateral direction appeared in the form of enhancing lateral confinement, thereby impeding the relative sliding; and (ii) during shearing, the rearrangement of the sand grains occurred in a more stable direction. These two aspects both provided beneficial contribution to sand liquefaction resistance, thereby preventing the occurrence of transient deformation. Under the circumstance, the sand specimens deformed only moderately, thereby eliminating the need to consider the role of the loading frequency.

这项研究旨在通过在应力控制和应变控制模式下进行循环三轴试验来强调加载频率对砂土液化响应的影响。对于第一种情况，致密的（I _Dmat  = 0.70）和中等密度的（I _Dmat  = 0.55）砂试样受到交替的和非交替的轴向应力。而 在第二种情况下，致密的（I _Dmat = 0.70）砂试样在较大的加载频率范围内经受了交替的轴向应变。实验发现，在交替加载I _Dmat的试样的情况下， = 0.70在应力控制模式下，加载频率对干砂样品的影响并不明显。相反，在两种加载模式下，加载频率对饱和砂样的影响都很大。这是因为在剪切时，由于存在多余的孔隙水压力而发生了瞬时变形，在此期间需要考虑惯性力。在轴向上，与外部载荷相反的惯性力通过抑制砂土液化的完全发展而确实增加了液化阻力。对于具有I _Dmat的试样在应力控制模式下的非替代载荷 = 0.55时，加载频率在纯拉伸载荷中起着至关重要的作用，这在逻辑上也可以归因于在大应变和瞬态变形阶段出现的轴向惯性力的存在。然而，由于以下两个原因，加载频率对压缩模式的影响尚不清楚：（i）横向惯性力以增强横向约束的形式出现，从而阻碍了相对滑动；（ii）在剪切过程中，沙粒的重排发生在更稳定的方向上。这两个方面都为抗砂液化提供了有益的贡献，从而防止了瞬时变形的发生。在这种情况下，砂土样本仅发生了中等程度的变形，