The Research On Selection Of Indoor And Outdoor Storm Sewer System Design Return Period About The Building

Human activity has caused increasingly prominent on urban hydrological environment problem. At the same time, in recent years, with the speeding up of urbanization, urban population has expanded, in order to satisfy the increasingly dense population demand business, entertainment, life, all kinds of super-large buildings rise from the ground, city building impervious area has increased dramatically, which also led to the urban areas, and great changes have been taken place in hydrologic and hydraulic characteristics,all of these have a huge impact on the frequency of local rainfall and rainfall runoff.At present, for the designing of these super-large building’s indoor and outdoor sewer system, according to the current <pecification for design of building water supply and drainage>(GB50015-2003,09edition) and<outdoor drainage design specification>(GB50016-2011), indoor sewer system design return period values bigger than outdoor sewer system design return period, resulting in the flooding of the buildings Chambers and the surrounding.This article research object hankou north farmers markets it covers an area of20hectares, total construction area of310471m2. Its indoor sewer system design return period is10a, outdoor rainwater sewer system design return period is la, first,set up the area of SWMM model, select la,3a,10a design rainfall for CHM, through the model simulation, proved current sewer system running safely and reliably on the1a design rainfall, but when the design rainfall is10a, the study area flooding seriously. Based on the research of the simulated data, and find out the system bottleneck, at the same time in order to ensure that water does not diffuse into the indoor, suggest adding0.3m indoors’elevation.Based on the analysis comparison of pressure flow and gravity flow indoor calculation method of rainwater pipe network system, discusses the pressure flow system raise the necessity of the design return period, and points out the gravity flow system method to calculate the rainwater hopper drainage ability and drainage of the stand pipe flow, specification provides design parameters bore a larger margin. By comparing the economic selection of indoor pipeline network rainwater design return period P=5, used on an area of3root DN100riser scheme is optimal.Through the comparing of the home and abroad Normative, suggest outdoor sewer system design return period should be appropriately increased, the selection of the following groups of multiple current outdoor sewer system design standards for comparison:(1) P1=10a, P2=5a;(2)P1=5a, P2=5a;(3) P1=5a, P2=2a.Corresponding model is established, through the model simulation, found that the above three kinds of scheme system can better running at the20years of rain. Through economic analysis and comparison, put forward the P1=5a, P2=2a is the best solution.