| The change of terrain in mountainous urban area is obviously,which can full use of the terrain height difference as the advantages to organize drainage systems,but also lay out of the drainage system lot of problems,summarize the main problems are the following:(1)Because of the obvious differences between the plains cities,it means that mountain cities are choosing to choose their own drainage pipes in terms of drainage;(2)Due to the geographical collapse of the ground,the drainage system is built on the surface of the drainage system,causing congestion problems in drainage systems.China’s current "outdoor drainage design specifications" provides the maximum design flow rate of metal pipe are 10m/s;will non-metallic pipe are 5 m/s.The maximum design flow rate of such non-metallic pipelines is 5 m/s,which makes the erosion resistance of the new composite pipe not fully utilized,and result a great waste of material.Based on the above,this paper studied selection of drainage pipe and the design parameters of the drainage system by two experiments.After scientific analys is of the test data,the following conclusions are obtained.(1)In the high velocity and small diameter in the mountainous region city should not be used concrete pipe,obtained through the comparison of performance parameters of five kinds of drainage pipes,and pipe in drainage pipeline is greater than 1000 mm to date selection of reinforced concrete pipe.Compared with other kinds of pipes,the price of steel pipe and glass fiber reinforced plastic sand pipe is too high.Double wall corrugated pipe and PE pressure pipe are more suitable for the drainage system of mountainous cities.(2)Under the similar test condition,the wear value of the steel pipe after 1 million revolutions wear is the least,the glass fiber reinforced plastic sand pipe and the double-wall corrugated pipe are the second,the wear value of the reinforced concrete pipe is the biggest,it means anti-scouring ability is the worst;Under the premise of meeting requirements through the linear fitting and interpolation calculation,the maximum design flow rate of the glass fiber reinforced plastic sand inclusion pipe,double wall corrugated pipe and PE pressure pipe are 9.85m/s,9.43m/s and 9.42m/s.(3)PE’s stress drain is closely related to the Flow velocity of the brush and the brush time,which is associated with a linear proportional ratio of the amount of time to the brush.The amount of friction and brush Flow velocity is a two-time ratio;The maximum design Flow velocity for 9.0 m/s during 20 years of the something 400 PE tube is 3.634 mm.Only 40.37 wall wal s are thick;the brush is divided into two phases by the Flow velocity pattern of PE pressure pipes.In the Flow velocity phase of the 1-5 m/s,a rapid decline in the 1-5 m/s a trend of slow rise in the 5-9 m/s.A small stream of 1-3 m/s is a major Flow velocity that causes friction during the actual run.The biggest mountain in the city drainage system design flow research project(project number: 2015-0213 Chongqing city construction planning project of science and Technology)as the basis,for the mountain city drainage pipeline system from the use of the pipe materials,has important practical significance to provide reference for the research results of the optimization of design parameters. |
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