波浪作用下黄河口粉土液化与“铁板砂”形成机制的模拟试验研究

通过室内水槽试验，观测波浪作用下土体产生的振荡现象，分析土体内孔隙水压力的变化及波浪作用后土体强度变化特征，研究了波浪荷载作用下黄河口粉土粒径粗化和“铁板砂”的形成过程。试验及讨论结果表明：在波浪作用下上层粉土体大部分时间处于液化状态；由液化土形成的振荡土层与下部土层之间形成“W”型的滑动面，振荡土层的厚度随着波浪作用时间的增加而变小；细粒物质从振荡土层中的骨架中脱离进入水体中，并在土体表层形成一层以黏粒为主的絮凝状沉积物，其厚度随波浪作用时间的增加而增加，在土体停止振荡前达到最大值；土体液化是“铁板砂”形成的必要条件，而波浪引起的液化土体振荡则使“铁板砂”的形成成为可能。

Study of liquefaction of silty soil and mechanism of development of hard layer under wave actions at Yellow River Estuary

Experiments are conducted in a wave flume to study liquefaction of silty soil and development of hard layer under wave actions at the Yellow River Estuary. Results indicate that under wave actions superficial silty soil is in liquefaction for most of the times, which leads to a W-shaped sliding interface between the oscillatory layer and the underlying layer; with the passage of time, thickness of the oscillatory layer decreases while that of plume-like sediments increases till the oscillation is stopped. Therefore, the liquefaction of silty soil is the prerequisite for the development of hard layer, while the oscillation of liquefied soil body due to wave actions makes possible the development of hard layer.