岷江下游典型滩群碍航特性及整治研究

Study on the characteristics of navigation-obstructing of typical serial rapids and regulation in the downstream of Minjiang River

山区河流出峡谷进入丘陵地带,河段滩槽交错、多滩并存、上下联动、滩性复杂,一直是我国西南地区航运开发的重点难题。山区河流碍航滩群治理思路和原则尚不明确,以岷江下游新开河滩群为例,分析复杂滩群的碍航特性、水沙特征和河床演变规律,并结合物理模型和平面二维水沙数学模型对整治方案进行计算分析与优化研究。研究结果表明:对于滩群自上而下“急、弯、险、浅”的问题,要各施其策,对于下“浅”问题,需采用整、疏相结合的手段,依托整治建筑物增强浅段水沙动力;对于中“弯、险”问题,需采用整治建筑物调整水流流路,改善水流流态;对于上“急”问题,应重点拓宽航槽以减缓流速。同时在避免下游滩险整治措施对上游滩险的“急、险”有所恶化的基础上,还需综合协调整个滩群的输沙平衡。研究结果可丰富山区河流复杂滩群整治技术,也可为其他滩群治理提供借鉴。

Some sections of mountain rivers have interlocking rapids and troughs,and multiple beaches coexist,and influence each other in rarious complicated ways,which have been the key problems of navigation development in southwest China.To address the problem of unclear ideas and principles for the management of serial rapids in mountain rivers,we analyze the navigation-obstructing characteristics,water and sediment conditions,and evolution of river bed of serial rapids based on the Xinkaihe serial rapids in the lower reaches of the Minjiang River.In addition,calculation analysis and optimization research are carried out by combining the physical model and the two-dimensional flow and sediment mathematical model.The results of the study show that for the problems of“sharp,curved,dangerous and shallow rapids”from upstream to downstream,the regulation scheme should be targeted for each rapid.Firstly,for the problems of“shallow”in the downstream,a combination of“dredging and remediation”should be used to enhance the water-sand dynamics of the shallow section.Secondly,for the problem of“curved and dangerous”,regulating structures should be used to adjust the flow path and improve the flow pattern.Finally,for the problem of“sharp”in the upstream,the focus should be placed on widening the channel and slowing down the flow speed.At the same time,on the basis of avoiding the remediation measures downstream from worsening the“rapid and dangerous”of the upstream rapid,it is also necessary to comprehensively coordinate the sand transport balance of the whole serial rapids.The research results of this paper can enrich the regulation technology of complex serial rapids in mountain rivers,and can also provide a reference for other serial rapids management in China.