中文摘要：

为探讨结构性软土的动力特性及微观机理，对结构性软土在交通荷载作用下的孔径分布特征进行了分析。通过固结试验确定了结构性软土的前期固结压力和结构屈服压力，利用这些值进行了不同围压、不同振动频率以及不同动应力比下的动三轴试验和压汞研究。结果表明：结构性软土存在一个振动频率门槛值和一个随固结压力值变化的临界动应力比，相应振动门槛值的孔径分布特征转折点为0．3μm；振动频率大于门槛值时，频率对孔径累积分布曲线的影响可忽略；根据分形理论，结构性软土具有3个分形的无标度区，根据这一特点确定了团粒内孔径和团粒间孔径之间的分界尺寸为0．5μm，同时给出了新的孔径界限标准。

英文摘要：

In order to discuss the dynamic characteristics and microscopic mechanism of the structural soft soil, authors analyzed pore size distribution features of structural soft soil under traffic loading. The pre-consolidation pressure and the structure yield pressure were determined by consolidation test. Using these values, the dynamic tri-axial test and mercury intrusion test under different pressures, different vibration frequencies and different dynamic stress ratios were made. Result shows that there is a threshold value of vibration frequency and a critical dynamic stress ratio changing with consolidation pressure for structural soft soil under traffic loading. The pore size of the turning-point is 0. 3μm, and the influence of the vibration frequency can be ignored when the vibration frequency value is bigger than the threshold value. Three non-scale zones are found in the structural soft soil by fractal theory, and the demarcation point between intra-aggregate pore and extra-aggregate pore is 0.5 μm, meanwhile the new limited standard is proposed.