Project Construction Model And Standard Of Subsurface Pipe Drainage In Southern China

Sub-drain pipe drainage is technical measures making use of dark and ditch to get rid of extra water in the fields. Compared with gutter drainage, it can decrease cultivated land occupation, improve land utilization rate, increase control area of the open trench and is beneficial to mechanical tillage without grass and collapse problem. It also takes advantages of easy management, labor saving, which is with few earthwork and easy for mechanical operation, etc. In south China, there are more people and less land, the economics are advanced with good technical conditions but few managers. The promotion of sub-drain pipe drainage technology can effectively improve the present situation of irrigation and water conservancy.In this paper, the research and application situation of sub-drain pipe drainage at home and abroad were reviewed. Combination method of comparative analysis, theoretical analysis and empirical analysis was taken to research the suitability evaluation, engineering layout, engineering construction standard and optimization of drainage project planning and design, the main results were as follows:(1) Through systematic research of sub-drain pipe drainage works in south China, appropriate contestant factors were selected, and then graded and evaluated with exponential numbers. Delphi method was adopted to determine the weight of the evaluation factors and to assess suitability grades, eventually to establish sub-drain pipe drainage engineering suitability evaluation index system in south China. Combined with project cases, to evaluate weather sub-drain pipe drainage works was suitable for development in a certain area.(2) Through influence factor analysis of sub-drain pipe drainage system’s composition and layout pattern and study of construction type region, the sub-drain pipe drainage layout mode of different areas in south China was determined.(3) By the construction of engineering construction standards for sub-drain pipe drainage system, the project construction standards such as drainage technology standards, farmland flood control standards, grid field standard, Suction piping construction standards, Collecting piping construction standards, auxiliary projects construction standards, vented area projects construction standards and drainage project management standards that were suitable for sub-drain pipe drainage in south China were researched.(4) Through study of sub-drain pipe’s material, filter, depth and spacing, diameter, slope and the auxiliary projects, sub-drain pipe drainage project investment estimation model was established with the target of minimum cost of per unit area. Mathematical programming method was adopted to determine the optimal space and depth for sub-drain pipe drainage system.The results of this paper can deepen the understanding of sub-drain pipe drainage technology, and provide scientific basis for regulating technology activities, promoting technical promotion and regional water conservancy modernization.