关键词: 分级循环荷载, 土工格室, 模型试验, 沉降, 法向累积变形

Abstract: Current research on geocell-reinforced embankments is mainly concerned with the static load condition, and little attention is paid to dynamic loading conditions. To investigate the mechanical property of geocell-reinforced embankment under stepped cyclic loading, a series of model tests is performed, using the loading device of USTX-2000, on geocell reinforced embankment with different reinforced layers, different heights of geocell and different welding distances. The vertical and normal deformations at the slope of embankment are monitored under stepped cyclic loading, and compared with those of the embankment under fixed amplitude cyclic loading and static loading, by which the difference of mechanical properties under different loading schemes are analyzed. It is shown that geocell can significantly increase the capacity of the embankment under stepped cyclic loading condition, and reduce the vertical cumulative settlement. At fixed reinforcement spacings, the reinforcement effect of two or more layers is more significant than that of single layer. Both the increase of the height and the decrease of the welding space of geocell can improve the capacity of the embankment under stepped cyclic loading conditions and reduce the vertical cumulative settlement. Reinforcement can reduce the normal deformation of slope of embankment under stepped cyclic loading. Both the increase of the height and the decrease of the weld space of geocell can reduce the normal accumulated deformation of the top and the middle of slope in the same amplitude of stepped cyclic loading. Under the effect of stepped cyclic loading, when the number of vibration is greater than or equal to 8 000 or the amplitude is greater than or equal to 80 kPa, the vertical cumulative settlement of embankment exceeds the fixed amplitude cyclic loading. When the number of vibration is greater than or equal to 9 000 or the amplitude is greater than or equal to 90 kPa, the normal accumulated deformation of the top of slope exceeds the fixed amplitude cyclic loading. Under stepped cyclic loading, both the vertical cumulative settlement of embankment and the normal accumulated deformation of slope are larger than those under static loading, and the reinforcement can effectively reduce the difference between stepped cyclic loading with static loading in the normal accumulated deformation of slope.

Key words: stepped cyclic loading, geocell, model test, settlement, normal accumulated deformation