Analysis And Research On The Design Scheme Of Self Pressurized Water Transmission Pipe Network In Xinjiang Large And Medium Irrigation Area

Self pressurized water transmission pipe network project is a water conveyance project with great high efficiency,energy saving and water saving potential for development.It is the first choice for the current water conveyance project of irrigated area in Xinjiang.However,there are large quantities,high investment and certain requirements for natural geographical conditions and engineering safety of the engineering.The water source is the surface water containing the sand which is to be treated for the water quality.There is a certain distance between the water source and the irrigation area and the engineering design is complicated.The maximization of the appropriate design scheme makes full use of the favorable factors to avoid weakening the adverse factors.Therefore,studying the design scheme of self pressure water conveyance pipeline network is very significant for reducing investment cost,improving engineering safety,reducing engineering construction difficulty and good engineering operation.The significance of the research on the self pressurized water transmission pipe network project and the overseas and domestic research status are expounded in this paper.And taking the actual engineering of self pressure water conveyance network in typical large and medium-sized irrigation areas of Xinjiang as an example,the corresponding achievements and theories are obtained.The contents and results of the study are as follows:(1)Considering the terrain conditions,engineering economy,construction difficulty and other factors,through the analysis of the original data of the actual engineering,we find the principle of line selection and pipe network layout,and four layout forms of the common terrain.The corner of the bend pipe should be avoided by the hydraulic calculation.(2)Through the analysis of the method of determining the minimum pipe diameter by economic flow velocity and flow,we concluded that the large and medium diameter pipes of the self pressurized water pipeline network in Xinjiang are generally glass tubes considering by the properties of common pipes,investment,operation,transportation,safety,installation,maintenance and other factors.And the best applicable environment and filter selection methods of different filters are obtained through quantitative analysis of common filters.(3)The calculation method of the head loss of the self pressurized water transmission pipe network and the calculation method of the joint pressure are obtained on the basis of the original data of the actual project.In the analysis of water hammer,the mechanism of water hammer is analyzed,and the calculation method of common water hammer is analyzed.The method of water hammer calculation and water hammer protection for self pressure water delivery network is obtained.(4)Under the premise of ensuring the normal operation of the planned irrigation area,a variety of decompression schemes can be carried out by preliminary presupposition,and the problem of comparing and studying the ten engineering indexes and four working criteria of the pipe network under the different decompression schemes is studied by the comparison of the selection problem of the pressure relief scheme of the self pressurized water pipeline network.Based on the four criteria of the economy,security,functional and adaptability,the project are quantitatively studied.According to the importance of the four criteria in the project,the proportion of the four engineering criteria must be divided,and the respective engineering indicators which affect the four engineering criteria are determined according to the corresponding criteria.Then the influence degree of the item is divided into proportion weight,and some qualitative indexes are assigned to special value,and the non dimensional treatment of the benefit type and the cost type is carried out in different methods.Finally,the target value is calculated by the calculation of the proportion weight,and the best design scheme for the pressure reduction of the self pressurized water transmission pipe network is obtained.The method of non dimensional treatment of the benefit and cost index is obtained,and the final comparison target items are compared with the larger and more superior,and the original qualitative comparison analysis is converted into a quantitative comparison and analysis.(5)Combining the acquired theory,the detailed analysis and research on the design of the pipe network selection,pipe network layout,bend corner design,pipe material selection,filter selection,pipe network hydraulic calculation,pressure reduction scheme comparison and water hammer calculation are carried out respectively.The emphasis is on the comparison and selection of the decompression scheme.