Grounds subjected to cyclic loading, either continuous or fragmentary, widely exist in natural deposits and at reclaimed sites, e.g., induced by traffic loads, earthquakes, and wave-induced loading environments. Assessing the ground deformation under cyclic loading conditions is necessary for proper design and maintenance planning for traffic services. Accordingly, a testing program, in which vertical, horizontal, and shear stresses are automatically controlled, were newly developed in this study to reproduce the actual cyclic traffic load conditions using a hollow-cylindrical torsional shear apparatus.

Estimations based on the results obtained from cyclic triaxial stress conditions were seen to underestimate the ground settlement compared to actual stresses, with combined vertical, horizontal, and shear stresses. Two kinds of vertical strain arose after a certain number of cycles: incremental collapse, in which unstable deformation (failure) is caused, and plastic creep, in which deformation continues to accumulate with the dampened rate (per cycle). The number of cycles of combined vertical, horizontal, and shear stresses necessary to reach a certain vertical strain increased linearly on a logarithmic scale when the magnitude of loading decreased. Moreover, the relationship between vertical strain and excess pore water pressure presented the same trend independent of the magnitude of loading. Practical uses of the obtained results were proposed and discussed.

承受循环载荷的地面，无论是连续的还是碎片的，广泛存在于自然沉积物和开垦场地，例如由交通载荷、地震和波浪引起的载荷环境引起的。评估循环载荷条件下的地面变形对于交通服务的正确设计和维护规划是必要的。因此，本研究中新开发了一个自动控制垂直、水平和剪切应力的测试程序，以使用空心圆柱扭转剪切装置重现实际的循环交通荷载条件。

与实际应力相比，基于从循环三轴应力条件获得的结果进行的估计被视为低估了地面沉降，以及垂直、水平和剪切应力的组合。在一定次数的循环后出现两种垂直应变：增量坍塌，其中引起不稳定变形（失效），以及塑性蠕变，其中变形以阻尼速率（每个循环）继续累积。当载荷大小减小时，达到某个垂直应变所需的组合垂直、水平和剪切应力的循环次数在对数尺度上线性增加。此外，垂直应变和超孔隙水压力之间的关系呈现出与加载大小无关的相同趋势。