胖头泡蓄滞洪区老龙口分洪闸泄洪能力分析

Analysis of flood discharging capacity of Laolongkou flood-diversion sluice at Pangtoupao flood retarding basin

胖头泡蓄滞洪区位于哈尔滨市上游嫩江干流、松花江干流及第二松花江交汇处,可减轻三江洪水对哈尔滨市的防洪压力。采用数学模型计算和实体模型试验相结合的方法研究老龙口分洪闸的泄流能力及其影响因素,数学模型主要用于分析嫩江干流河道的冲淤演变及水位变化,同时为实体模型提供上下游边界条件;实体模型用于研究不同方案下分洪闸的过流能力。结果表明,老龙口分洪闸的泄流能力主要取决于嫩江干流水位和分洪通道的水位,而且对二者水位差的变化非常敏感。分洪闸过流能力的影响因素主要包括嫩江干流河道冲淤变化、分洪流量、洪水类型及行洪流路走向等。嫩江干流河道冲淤变化幅度很小,对干流水位基本不产生影响;分洪流量对嫩江干流水位影响比较明显,最大分洪流量时水位降幅达0.70m。嫩江干流与第二松花江共发型洪水分洪对蓄滞洪区水位的减小幅度大于嫩江干流型洪水;蓄滞洪区内地形地貌复杂,不同分洪通道对分洪闸闸下水位影响显著,是泄洪闸过流能力的关键影响因素。因此,在蓄滞洪区内设置能快速分散蓄滞洪水的分洪通道非常必要。

Lying at the junction of the Nenjiang River, the Songhua River and the second Songhua River, situated at the upstream of Harbin city, the Pangtoupao flood retarding basin plays a key role in alleviating the Harbin city flood pressure. The flood discharging capacity and its influencing factors of the Laolongkou flood diversion sluice are studied by the mathematical model calculation and physical model tests in this research. The mathematical model is applied to analyzing the evolution of the channel erosion or deposition and the variations in the water level of the Nenjiang River, and giving the import and export boundary conditions for the physical model. And the physical model is applied to studying the discharging capacity of the flood-diversion sluice under different given schemes. The analysis results show that the discharging capacity of the Laolongkou flood diversion sluice mainly depends on the water levels of both the Nenjiang River and the diversion channel, and is very sensitive to their changes. The influencing factors of the flood discharging capacity of the sluice mainly include the changes of erosion or deposition of the Nenjiang main stream, the flood diversion discharge, the flood type, and the direction of the diversion channel, etc. Specifically, as for as the Nenjiang water level concerned, the variation of scouring and silting in the main stream of the Nenjiang is very small, and has little effect on the water level of the main stream. The influences of the flood diversion discharge on the water level of the main stream of the Nenjiang River are more obvious, and the water level drops to 0.70 m during the maximum flood diversion discharge. As for as the Pangtoupao basin water level, the influence from the type of the simultaneous flood originates from the Nenjiang River, and the second Songhua River is greater than the flood singly originating from the Nenjiang River. Owing to the complex topography in the flood retarding basin, the different flood diversion channels have significant and different impacts on the water level of the flood diversion sluice, which is the key factor affecting the flood discharging capacity of the sluice. Therefore, it is very necessary to set up flood diversion channels in the flood retarding basin for rapid dispersion of flood.