长江中下游断裂构造、活动性与防洪的关系

Relation of flood control with fractural structure, and its activity in the middle and lower reach of the Yangtze river

受发育其间的20余条主要断裂和次级断裂活动的影响,长江中下游沿江平原和湖积平原长期沉陷,地势低洼、堤外河床不断淤高,防洪形势显著不利。研究从决定防洪形势的地形地貌、晚更新世晚期以来沉积环境、堤基物质组成和地质结构的断裂及其控制的断块的活动性入手,对长江中下游地区的主要断裂、断裂特征、活动性及其与江湖演变演化、防洪形势的关系进行了研究,进而探讨了中下游防洪对策。

Affected by activities of the over twenty main fractures and sub-fractures, the riparian plains and lacustrine plains in the middle-and lower-stream areas of the Yangtze River have been sinking for a long time, resulting in low-lying topography and riverbed silting-up, which is unfavorable to flood control. Starting with geomorphic features concerning flood control situation, depositional environment, material composition of embankment foundation, structural fractures and activities of fault blocks( since the later period of the late Pleistocene), this paper studies the main fractures, fracture characteristics, activities and their relations to the evolution of rivers and lakes and flood control situation in the middle-and lower-stream areas of the Yangtze River, and also discusses flood control countermeasures.