The Study At Computer Modeling For A Reformed Pipe Network In Changsha With SWMM And Infoworks CS Model

The high-ranked culvert buried under the Nanhu road in Yuhua District is themain drainage network of the south of the upper zone of the Nanjiao Park Area. Thepresent situation of the network is that the culverts (4x3boxes) are lying alongXueyuan Road and Shuichang Road and outlet’s elevation are about25.01m. Thereare3overflow wells existing on the Xueyuan Road, Nanhu road status and theirelevations are34.27m,34.2m,32.89m, respectively. Unfortunately, with the levelof Xiangjiang River in the reservoir area rise to29.84m, the high-ranked culverts’outlet will be submerged and the level of received water of those two outlets will beat a constant level of29.81m and29.84m. The original free flow in the pipe networkculvert changes into a submerged flow, due to its culvert bottom elevation below thenormal water level, which will lead to the present network overflow especially whenit rain in those areas. If this problem cannot be solved, we do believe that thisoverflowing condition will inevitably lead to a great economic loss.Taking the particularity of this pipe network hydraulic condition and the specialrequirements of this project into account, in order to provide some technical supportsfor decision making, this thesis combines domestic and international experience toengineering practice and precedent by using computer models to evaluate submergednetwork system under the Nanhu Road. InfoWorks CS and SWMM modeling wereused to assess the transformation of the culvert under different conditions of fluidbefore and after the reformed project.Considering the selection of the modeling, InfoWorks CS was used to stimulatethe present flow condition because its hydraulic simulation can precisely fit theproject in the actual calculated value. SWMM was used to model the reformedcondition by using its rain gauge function which was used to assess thetransformation culvert flow situation. Through the use of the advantages of twodifferent models of simulation, we can more accurately get the actual engineeringsimulation results and to provide technical support based on the transformation ofdesign for pipe culverts. The SWMM pre-simulation in Changsha rainfall Line, ismore precise than stimulated by InfoWorks CS.The results showed that, with the Xiangjiang River water level rise, the presentthe pipe network system cannot meet the city’s normal drainage requirements. According to the results of the InfoWorks CS, it is easily to find out that about5-7inspection wells will over-load under the present network condition. The reformproject of the existing pipe network can effectively increase the water capacity of thestorm sewer system and also can reduce the original competent segment conveyanceload. However, the water level elevation may accumulate the sedimentation of sewagein the submerged pipes, resulting in blockage of the pipe network. It is advised thatwe should strengthen the ability of dredging even the pipeline has been reformed.