The Application of Improved Steiner Tree for Household Connection Piping in Sewerage System

• Main Authors: Hsin-Ho Weng, 翁新賀
• Other Authors: Machine Hsie
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/86599993715069079261

碩士 === 國立中興大學 === 土木工程學系所 === 98 === Sewage construction is one of the indications of city modernization; how to elevate sewage construction rate has even long been considered the emphasis of regional policy. When sewage pipeline is designed, though population of local area, growth rate, the number of needed manhole cover and exact locations are always investigated, underground pipeline network should be included based on the local geography. However, current construction units usually carry out constructions based on regional point-to-point minimum distance – without considering a bigger picture, that is, the optimum evaluation of an integral pipeline network. Although some literatures targeted at this problem and offered solutions, however, its samples didn’t take into account local geographical alignment and arrangements and thus can be hardly applied to practice. For instance, The direction of flow alters only when a pipeline is installed at intersections; pipeline placement shouldn’t be overlapped or interrupted by other existent pipes and public construction. Only when these preconditions are followed can public projects be applied to construction practice. In addition, manhole covers in the past were always installed at intersections on account of arrangement and construction convenience, and thus in turn caused lots of unnecessary expenses. In this study, Steiner Tree was applied to connect the manhole cover network. Through intersection as a turning point, sewage flow is redirected to main pipeline. This integral network can be seen as a multi-points to multi-points network to optimize choices of manhole cover placement and intersections. Accordingly, all of the possible choices were variables and binary programming was implemented to compute optimal system arrangement with minimum distance. This arrangement was finally put into hydraulic-related constraints function. This can allow the optimum system arrangement matches features of our initial system arrangement in flow volume, flow velocity, elevation and gravity flow. The mathematic model suggested by this study can be used to promptly locate the optimal pipeline network and to evaluate its hydraulic features – in the hope of minimizing the cost of sewage construction network ultimately. Finally, a built case was empirically analyzed. The results showed that the distance of arrangement of this study was shorter than the existent arrangement, which suggests that this model can be used to effectively locate the optimum of manhole cover arrangement and hydraulic features.