Study On Diagnosis Technology Of Typical "Causes" Of Urban Drainage Pipe Network In Dongxihu District Wuhan

Due to the complex layout,various forms and hidden engineering characteristics of urban drainage network,a large number of mixed connections,breakage,overflow,siltation,infiltration into the flow and other problems,which seriously affects the normal operation of urban drainage system and the daily life of residents.How to obtain the operation of drainage network in an efficient,accurate and low-cost way is a difficult problem to be solved in the process of diagnosing the "cause" of urban drainage network.In this paper,by studying the relationship between the typical "causes" of drainage network and water quality,we obtain a typical "causes" of urban drainage network diagnosis technology,and apply the technology to the diagnosis of the drainage network in East-West Lake,Wuhan City,specifically as follows.In this paper,based on the relationship between the typical "causes" of pipe network and the water quality of pipe network,a four-step diagnostic technique of typical "causes" of urban drainage pipe network is derived,which consists of monitoring area/section identification,monitoring point deployment,data acquisition and diagnostic analysis,and result verification.Firstly,the four aspects of monitoring area/segment identification and point placement are investigated,including the principle of monitoring point placement,monitoring index,monitoring frequency,data analysis and calibration,etc.;secondly,the simultaneous monitoring with interdigitated flow meters coupled with ultraviolet spectral sensors is adopted to obtain flow,level,flow rate and chemical oxygen demand data of the drainage network to meet the typical"cause of disease" of urban drainage network."diagnostic needs;secondly,a variety of analysis methods are combined to carry out diagnostic analysis of pipe network etiology traceability,pipeline siltation risk assessment,and pipe network infiltration and flow diagnosis methods,such as water quality monitoring data and traceability method,siltation risk coefficient method,water quality balance method,etc.;finally,according to the site situation,the flexible use of pipeline closed-circuit television detection system,periscope,sonar imaging and other technologies to verify Diagnostic results.In this paper,the typical "cause" diagnosis technique of urban drainage network is applied to the East-West Lake area of Wuhan City,and it is found that 13 points in the area have mixed connection problems;5 points have infiltration and inflow problems.In-depth analysis found that the mixing problem was concentrated in 3 points in the East-West Lake Wastewater Treatment Plant area,3 points in the Xindou area and 3points in the Xin’andu area.Siltation risk assessment found that Xin’andu area and East-West Lake sewage treatment plant area is very high risk,and the new ditch area sixteen branch ditch area also has some risk.There are three sources of regional infiltration flow: sewage source,rainfall source and river water backflow source.A total of six points of infiltration in the new ditch area are mainly low concentration sewage,and the spinning new road area is mainly dry weather sewage.The rainfall inflow rate of the two points in the new ditch area is the most serious,accounting for 87.32% and83.0% respectively,while the rainfall inflow rate in other areas is lighter.Among them,the Xinandu area and the new ditch area both have 1 point with river water inflow and infiltration problems,and the average values of inflow and infiltration ratio are 20.8%and 20.4% respectively.Take the pipeline closed-circuit television detection system auxiliary pipeline internal detection technology for verification,mixed connection,siltation and infiltration into the flow detection results are consistent with the water quality synchronous monitoring and diagnostic analysis results.