粉质土底床液化塌陷量形成试验研究

EXPERIMENTAL STUDY ON COLLAPSE DEPTH BY LIQUEFACTION OF THE SILTY SOIL BED

  • 摘要: 黄河三角洲海床沉积物质为粉质土,在大的风暴浪作用下海底浅表粉质土能够发生液化,形成塌陷凹坑。以黄河三角洲粉质土铺设底床,进行液化粉质土形成塌陷的波浪水槽试验,在底床粉粒和砂粒不随水流脱离液化区的前提下,对形成塌陷量的贡献因素进行了分析。根据试验数据,估算了黏粒迁移析出与液化区底床密度增大对液化致塌陷凹坑的贡献度,得出黏粒迁移析出贡献一般大于55%。试验还发现在波浪作用下粉质土液化后黏粒发生迁移,原均质底床黏粒含量在垂向上出现2个分段特点的重新分布,分段点处于水土界面、底床液化最终界面和最大液化界面上,每段以上少下多分布。

     

    Abstract: Silty soil dominates the Yellow River subaqueous delta. Collapse often occurs due to the liquefaction of shallow silty soil under storm wave action. Wave flume experiments have been carried out in order to reveal the contribution factors to the collapse quantity of the liquefied silty soil bed. The soil was taken from the Yellow River. The contributions of clay migration and density increase to the collapses have been estimated. Our data shows that the contribution of clay migration is generally over 55%. The clay content of the originally homogeneous silty soil bed was redistributed and a double-segment structure formed after the liquefaction at the water-soil interface and the final and maximum liquefied interfaces respectively. The clay content increases with the increase in depth in each segment.

     

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