现代黄河水下三角洲土体工程性质及固结沉降特性研究

Engineering Properties and Consolidation Settlement of the Modern Yellow River Subaqueous Delta

现代黄河水下三角洲沉积速度快，具有含水量高、密度低的特点，极易因固结压实产生沉降，从而导致地形变化。本文通过收集位于现代黄河水下三角洲的2个钻孔资料，分析了2个钻孔的工程性质，计算了土体的最终固结沉降量和沉降速率。结果表明，由于黄河改道及钻孔所在位置不同，2个钻孔的10m以浅沉积物有明显的差异，ZK-1的表层沉积物有明显的粗化现象，相应的工程性质也有所差别；根据Terzaghi一维固结理论，计算得到ZK-1和ZK-2孔的最终固结沉降量分别为2．08和1．70m，单位厚度土体的沉降量在0．2～9．6cm／m之间；土体达到稳定状态大约需要15～20a，厚度50m以内土体的平均沉降速率为6．5～8．5cm／a。

In this paper, the consolidation settlement of the Yellow River subaqueous delta was studied based on the drilling data of the Yellow River subaqueous delta and forecasted the final settlement. In result, surface sedi- ments of ZK-1 was significantly coarsen than ZK-2, and correspondingly with varying physical and mechanical properties in different cores. Based on the one-dimensional consolidation theory, 60 m thickness of layer could produce a total of 2.08 m settlement in ZK-1, and 50 m could produce 1.70 m settlement in ZK-2. The consolidation settlement of unit depth was at 0. 2-9. 6 cm/m. The consolidation degree needed about 15-20 years to reach 90% and the average sedimentation rate was at 6. 5-8. 5 cm/a within 50 m layer thickness.