箱涵清淤及泥处理利用典型实例研究

雨水箱涵作为城市排水管网的干管,由于长期运行,其内部出现了严重淤积,堵塞管网。如何对箱涵进行清淤、清淤后的泥如何处理和利用是许多城市目前正面临的难题。以湖北省武汉市光谷管网及渠道清淤混错接改造工程为典型案例,研究泥处理过程中泥的物理和化学性质的变化规律,同时对泥饼的力学性质进行分析。基于对泥性质的分析,梳理了该典型工程在清淤及泥处理利用中存在的关键问题:人工清淤危险低效;工艺适合大方量快速施工工况,存在泥处理过程效率低、沉淀池浓缩效果差、板框机未能充分发挥效力问题;未进行施工尾水的处理,泥饼Zn含量超标,属于污染土,外包处理可能造成二次污染。这些问题也是我国城市管网清淤工程中普遍存在的问题,通过对上述问题的梳理能够为箱涵清淤工程提供指导及借鉴。

Box Culvert Dredging and Mud Treatment and Utilization:A Case Study

As the trunk main of urban drainage network,stormwater box culvert has been seriously silted and blocked during long-term operation.How to dredge the box culvert,treat and use the mud after dredging is a difficult problem that many cities are currently facing.Variations in physical and chemical properties of mud during treatment in a typical reconstruction project in Wuhan Optical Valley,Hubei Province were investigated,and the mechanical properties of mud cake were also analyzed.Based on the analysis of mud properties,the key problems existing in the dredging and mud treatment and utilization of this typical project were summarized as follows:artificial dredging was dangerous and inefficient;the process was suitable for large earthwork and rapid construction conditions,but there were some problems such as low efficiency of mud treatment process,poor concentration performance of sedimentation tank,and failure of plate and frame machine to give full play to its effectiveness;the tail water of construction was not treated,Zn content of the mud cake exceeded the standard,and outsourcing treatment of this contaminated soil might cause secondary pollution.These are also common problems in Chinese urban network dredging project,and guidance and reference for box culvert dredging project are provided through summarizing the problems.