循环荷载下平面变形超固结软土蠕变特征试验研究

Experimental study on plane creep of overconsolidated clay under cyclic loading

采用原状试样试验研究平面变形超固结软土在循环荷载下的变形特征。研究表明,静力荷载试验应力状态平面变形条件下,正常固结和超固结软黏土以固结变形为主要特征。循环荷载试验应力状态平面变形条件下,正常固结和超固结软黏土以剪切变形为主要特征,超固结软土侧向变形小于正常固结软土。饱和软黏土试样在循环荷载作用初期孔隙水压力不显示波动特征,总体趋势为累计增大到峰值后连续下降,与静荷载作用下的孔压变化特征类似。循环荷载长时间作用后,孔隙压力呈现波动特征,波动峰值随时间逐渐减小,衰减过程与应力状态和应力历史有关。

The experiment on the plane creep of overconsolidated clay under cyclic loading is studied by using undisturbed samples. The results show that the consolidation deformation is the main characteristic of the normally consolidated and overconsolidated clay under static loading and plane creeping. The shear deformation is the main characteristic of the normally consolidated and overconsolidated clay under cyclic loading and plane creeping. The lateral deformation of the overconsolidated soft clay is less than that of the normally consolidated soft clay. The pore water pressure of saturated soft clay samples does not fluctuate at the initial stage of cyclic loading. The general trend is that the pore water pressure increases to the peak value and then decreases continuously, which is similar to the variation characteristics of pore water pressure under static loading. After cyclic loading for a long time, the pore pressure presents a fluctuating feature. The peak value of fluctuation decreases with time. The attenuation process is related to stress state and stress history.