为了研究不同形式的循环荷载作用下珠三角地区饱和软粘土动力特性的差异，对饱和软粘土分别进行循环压缩荷载试验与循环拉-压荷载试验。研究结果表明：饱和软粘土在循环压缩荷载作用下的临界循环应力比要较循环拉-压荷载下的大得多。循环压缩荷载下饱和软粘土轴向应变的累积效应更显著，而循环拉-压荷载下孔隙水压力的累积效应更明显。在循环压缩荷载作用下，饱和软粘土轴向累积应变发展的规律与累积孔隙水压力发展的规律相似；在循环拉-压荷载作用下，饱和软粘土破坏前的轴向应变均较小且没有明显的先兆，具有突然破坏的特征，与动应变不同，孔压随振次不断上升，不具有在土结构破坏时突然变化的特征。
Abstract
In order to study the distinction in dynamic characteristics of saturated soft clay under different cyclic loading, a series of undrained cyclic triaxial tests were performed on the Pearl River Delta saturated soft clay under one-way cyclic loading or tow-way cyclic loading. The results of tests indicate that：(a)The critical dynamic stress ratio under one-way cyclic loading is much bigger than that under tow-way cyclic loading. (b)The accumulation of axial strain under one-way cyclic loading is more obvious than that under tow-way cyclic loading, but the accumulation of axial strain under one-way cyclic loading is less obvious than that under tow-way cyclic loading. (c)Under one-way cyclic loading, the development of accumulative axial strain is similar with that of accumulative pore pressure. (d) Under tow-way cyclic loading, the accumulation of axial strain is little before soil is destroyed and the development curve of accumulative axial strain has characteristic of collapse. On the contrary, the pore pressure increases quickly with cyclic times until soil is destroyed and the development curve of accumulative pore pressure has characteristic of collapse.
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