Model tests on settlement of single pile in loess under long-term axial cyclic loading

The settlement of a single pile under long-term axial cyclic loading is different from that under static loading. To study how the pile-top displacement s and displacement amplitude ρ_c change with the number of cycles and to analyze the development model of pile-top cumulative displacement under cyclic loading, a series of single-pile model tests on loess and saturated loess are performed. It is found that the static bearing capacity of the single pile in saturated loess is much lower than that in loess. The test s-N curve of pile head under cyclic loading in loess and saturated loess can be described by power function. With the same load size, the displacement of the single pile under cyclic loading is lower than that under static loading in loess. The cyclic displacement ratios (ratio of cyclic load displacement to static load displacement) are mostly in the range of 0.6 to 0.8. But the displacement of the single pile under cyclic loading is much higher than that under static loading in saturated loess, and the cyclic displacement ratios will grow with the cyclic loading ratio in a linear rule. The single-pile displacement amplitude under cyclic loading in loess is obviously higher than that in saturated loess, and it is mainly because of the cyclic loading amplitude and soil properties.