黄河三角洲地面沉降机理与海岸防护

Process and Characteristics of Land Subsidence and Its Impact on Coastal Protection in the Yellow River Delta

综述了黄河三角洲地面沉降的研究现状、影响因素、沉降机理及造成的危害,并对减缓地面沉降的方法和海岸防护工程措施等方面进行了讨论。分析显示,受自然和人为因素的影响,黄河三角洲的地面沉降具有显著的时空变异性。影响三角洲地区地面沉降的人为因素主要是地下水抽取和油气开采,但它们引起的地面沉降是区域性的;三角洲松散沉积物的固结压实是三角洲进积过程中地面沉降的主导因素,三角洲软土、黏性土的压缩延迟特征以及河道的频繁摆动致使三角洲的压实沉降过程的时空差异明显,但各个三角洲叶瓣体的平均沉降速率将随时间推移逐年递减。地面沉降将造成或加剧黄河三角洲及沿海地区的区域性洪水灾害、农田和水资源污染、土地排水难度、基础设施受损以及海岸侵蚀等环境问题,需制定有效的地下水资源保护和补救方案,修建防护堤坝等工程是当前行之有效的缓解措施。然而,沿海堤坝等工程建设引起的环境问题与其防护作用目前还存在较大争议,因此,制定有效的海岸防护战略对于应对在海平面上升背景下的三角洲沉降引起的沿海地区环境灾害至关重要。

This study presents a comprehensive review of the land subsidence cause, mechanism, geohazard and methods to mitigate land subsidence and coastal protection works in the Yellow River Delta. The results demonstrate that the land subsidence in the Yellow River Delta has significant temporal and spatial heterogeneity of both subaerial and submarine areas due to influence of natural and anthropogenic factors. The anthropogenic factors affecting land subsidence in the delta region are groundwater extraction and oil and gas exploitation, but the land subsidence caused by them is regional. During the early stages of the development of the active deltaic lobe, the compaction of neritic sediments was the primary contributor to initial subsidence. Furthermore, combined with the relevant sedimentary age and environment determined by previous studies, we found that the spatial variation in compaction-induced subsidence in the subaerial deltaic area over time is closely related to the historical distributions of the river channels in the modern Yellow River Delta. Land subsidence will cause or aggravate the regional flood disaster of Yellow River Delta and its coastal areas, farmland and water pollution, land drainage difficulty, damaged infrastructure and coastal erosion and other environmental problems,needs to make effective protection of groundwater resources and remedy, building levees and other projects is the current effective mitigation measures. However, the environmental problems caused by the construction of coastal breakwater and other projects and their protective effects are still controversial. Therefore, it is of great importance to formulate effective coastal protection strategies to deal with the environmental disasters in coastal areas caused by the subsidence of the delta under the future of sea level rise.