浅滩碍航淤积厚度变化规律初步研究

为定量衡量浅滩碍航程度,提出"碍航淤积厚度"的概念.统计分析表明,对于长江中游多数"洪淤枯冲"的浅滩而言,存在影响浅滩冲淤变化的临界流量区间,上荆江在14 000～18 000 m3/s之间,下荆江在12 000～16 000 m3/s之间,浅滩碍航淤积厚度与冲淤临界流量天数差成反比.河床形态对浅滩碍航淤积厚度的影响,表现在河相系数大、放宽率大和水流动力轴线的弯曲率与河槽的曲率半径不适应而导致航道出浅等方面.

Preliminary study on the variation law of siltation thickness of navigable shoals

In order to measure the degree of the deposition-caused innavigability of shoals quantitatively,"navigation hindering siltation thickness(NHST)" is proposed.Analyses show that for the majority of the Yangtze River′s shallows characterized by "deposition in the flood season and scouring in the dry season",there is a critical flow range: 14,000~18,000 m3/s for the upstream of Jingjiang River and 12,000~16,000 m3/s for the downstream of Jingjiang River.NHST is inversely proportional to the difference of continuous days between erosion critical flow and deposition critical flow.The influence of the river morphology is in the performance of the larger river phase coefficient;the larger widening rate and the maladjustment of radius of curvature between the flow dynamic axis and the river channel lead to the formation of shallows.