长江口深水航道回淤强度与潮汐动力相关性分析

Analysis of relationships between backsilting and hydrodynamics in deepwater navigation channel of the Yangtze River estuary

长江口12.5 m深水航道的回淤监测资料表明,航道回淤强度大小和潮汐动力强弱存在较好的负相关关系,即大潮-中潮-小潮过程(动力减弱期),北槽实测回淤强度大;而小潮-中潮-大潮过程(动力增强期),北槽回淤强度则变小,目前的疏浚工程仅考虑大通流量的影响而忽略了外海潮汐的贡献,疏浚强度的安排明显与回淤强度不匹配。根据疏浚强度、回淤强度、潮汐动力间的相关关系来看,未来可深入研究长江口北槽深水航道潮汐动力过程和疏浚安排对回淤强度的影响,探索"疏浚-回淤"与"大通流量-外海潮汐"间的制衡关系,以及该关系对航道的宏观、微观冲淤环境的影响,这样才有利于寻找出一套较为合理的疏浚力量配置管理原则,有利于最大限度地提高疏浚效率,为长江口深水航道疏浚资源的优化配置及航道减淤提供新的思考空间。

According to in-situ measurement data of the 12.5 m deepwater navigation channel （DNC） of the Yangtze River estuary, the baeksilting intensity is highly dependent on the variation of tide types. It means that from the neap tide to the spring tide, the hydrodynamic condition becomes stronger, and the sedimentation in the channel decreases respectively; and from the spring tide to the neap tide, the sedimentation is increasing with the tide energy reduction. But the current dredging management only takes account of the influence of freshwater inflow, so the relation of dredging and backsihing intensity is very poor. According to the intensity of dredging, and the correlation between backsihing intensity and tidal hydrodynamics, in the future, the study of the impacts of the tidal dynamic process combined with the dredging arrangement for the north deepwater navigation channel of the Yangtze River estuary upon the backsihing intensity can be carried out, and the relationships between ＂dredging versus baeksilting＂ and ＂freshwater inflow versus tidal forcing＂ and their influences on macro and micro erosion- deposition environments can be explored, so as to find out a reasonable dredging power allocation management principle, to maximize the dredging efficiency, and to provide a new thinking space for the optimal allocation of the deepwater channel dredging resources and waterway sedimentation reduction.