Environmental Impact And Environmental Effect On Reducing Waterlogging Risk And Controlling Overflow Pollution Analysis Of Deep Tunnel Engineering In Wuhan City

As the surface structure of cities has been basically forming, and the underground space of urban road is occupied by a variety of pipeline, it is difficult to further increase the drainage ability of the city, as well as to merge decentralized wastewater treatment plant, and to build giant pipeline of shallow buried in the surface of earth. The experience of drainage pipe network construction abroad shows that Deep drainage tunnel engineering is a better alternative. Domestic is still in its infancy in the aspects of the research and application.In order to reducing the waterlogging risk and controlling the non-point source pollution, as well as moving out and centralizing several specified sewage factory from downtown area of Wuchang district, Wuhan municipal government has been planning the construction of Deep drainage tunnel engineering in hankou and wuchang district. As the particularity of Deep drainage tunnel engineering relative to general municipal facilities, it is necessary to analysis the environmental effect of Deep drainage tunnel engineering in Wuhan. In addition, we should analysis the environmental benefits of Deep drainage tunnel project on reducing the waterlogging risk and controlling the overflow pollution quantitatively.This thesis mainly includes the following several aspects of research work:According to the characteristics of the Deep drainage tunnel engineering in Wuhan, this text has analyzed the various causes of the pollution sources during the construction and operation of the project, such as waste water, waste gas, noise and solid waste, as well as the probable endanger of Deep drainage tunnel engineering on ground buildings, on water loss and soil erosion, and on the social environment. For instance, corresponding environmental protection measures have been raised.Aiming at the luojia road area in wuchang district with serious waterlogging risk, the text has established the urban rainfall runoff model of the pipe network system in this area by using SWMM( the storm water management model) and has localized the parameters of the model and the rainfall pattern. Simulation results show that the planning shallow system in luojia road area can resist diverse duration of rainfall at 5 years return period aswell as 60 minute duration of rainfall at ten years return period without the occurrence of severe waterlogging. After the completion of reconstruction of the planning shallow system, the waterlogging phenomenon in luojia road area has been ameliorated. But it can not resist 180 minute duration of rainfall at ten years return period. If adding Deep drainage tunnel into the reconstructed planning shallow system in luojia road area, the standard of preventing waterlogging in this area would be improved. It could resist 60 minute and 120 minute duration of rainfall at thirty years return period. However, when encounter 180 minute duration of rainfall at thirty years return period, several highlighted waterlogging point have appeared in this area.After localizing the water quality parameters of the urban rainfall runoff model of the district, the text has been calculated the annual proportion of intercepting pollutants and the proportion of pollutant removing at the inflow shaft of the Deep drainage tunnel in luojia road area by simulation of the model. The results show that the best river closure multiple is 3.The text has established the urban rainfall runoff model of the pipe network system in hankou disrict by using SWMM and has localized the parameters of the model and the rainfall pattern. The simulation of the tunnel diameter uses equal value from beginning to end. The text makes change on the diameter of the Deep drainage tunnel in the model, and makes statistics of total waterlogging and several kinds of waterlogging pionts at different duration of rainfall and return periods. The results show that as to the existing shallow system, the best diameter of the Deep drainage tunnel is 8 meter.The text has analyzed the environmental impact of Deep drainage tunnel engineering in Wuhan, and has proposed the method of analysing the efficiency of reducing waterlogging risk, optimization of river closure multiple, and majorization of diameter in Deep drainage tunnel engineering in Wuhan by using SWMM. The research conclusions can be taken as reference to the engineering design.