粉质土海岸微地貌形成及泥沙问题的工程地质分析

ENGINEERING GEOLOGY ANALYSIS ON FORMATION OF MICRO-TOPOGRAPHY AND PROBLEMS OF SEDIMENT MOVEMENT AT SILTY COAST AREAS

通过对渤海湾粉质土海岸中的黄河水下三角洲的塌陷凹坑地貌形成、埕岛海域海底电缆中断、黄骅港外航道泥沙骤淤、东营港航道开挖试验段淤积等问题进行原因分析,结合该类海岸粉质土在波浪作用下的动力特性,认为风暴期间在强烈的波浪循环荷载作用下,粉质土在趋于液状化过程中强度降低,被波浪剪切形成振荡滑动,导致运动泥沙的异常增量。因此,在研究粉质土海岸泥沙运动问题中,应注意考虑由于海底粉质土的工程地质特性而造成的泥沙侵蚀或淤积量的异常变化。

There are many engineering problems at silty coast areas in the Bohai Sea,such as the formation of collapse depressions at the Yellow River subaqueous delta,the breaks of marine cables at the Chengdao sea area,the drastic sand siltation of the open channel of Huanghua harbor,and the sand siltation of the Dongying harbor experimental channel.Based on the cause analysis of these problems and the dynamic characteristics of silty soil under storm waves,we propose that the strength of silty seabed deceases while it is approaching liquefaction due to storm waves,and the seabed is sheared and oscillated under waves,resulting in drastic increase of the mobile sediment.As a result,the influence of engineering geology characteristics of silty soil should be taken into account when we research the problems of sediment movement of silty coast areas.