排水管网检查井死水区对溶质纵向离散影响综述

Review on influence of dead water zone in inspection shaft of drainage network on pollutants longitudinal dispersion

在排水管网中,下沉式检查井的底部区域或者出现超载情况的平流式检查井,均可为可溶性物质提供滞留死水区,显著改变溶质的输运及混合过程,对其纵向离散有重大影响。综述了排水管网检查井死水区内溶质混合扩散过程的相关理论及模型研究进展,并梳理了相关学者的研究成果,揭示了检查井死水区对溶质纵向离散的影响,详细刻画了超载检查井内死水区对溶质混合扩散的滞留效应,量化了检查井超载深度与直径的比值,并根据不同的水文条件给出了两个水力临界值。针对当前水质模型忽略死水区滞留效应而导致水质预测存在误差的现状,提出了排水系统内溶质输运离散过程精确预测模型进一步研究的重点方向。

In drainage networks,the bottom area of the sinking inspection shaft or the horizontal flow type inspection shaft under overload condition,can provide a stagnant dead water zone for the soluble substance,which significantly changes the transporting and mixing process of the pollutants,and has a significant impact on its longitudinal dispersion.In this paper,we reviewed the related theories and model research progress on pollutants mixing and diffusion process in the dead water area of inspection shafts in drainage networks,and the research results of relevant scholars were sorted out.The influence of the dead water area of an inspection shaft on longitudinal dispersion of the pollutants was revealed.The retention effect of the dead water zone in the overload inspection shaft on the pollutants mixing and diffusion was described in detail.The ratio of depth to diameter of an inspection well was quantified,and two hydraulic thresholds were given according to different hydrological conditions.In view of the current situation that the water quality models ignore the retention effect of dead water zone,which lead to water quality prediction error,key research directions on accurate prediction models for simulating pollutants transport dispersion process in drainage network are put forward.