| Connecting with country's natural scientific fund item and water resources and environmental important experiment item of Shann'xi province, on the basis of large sum of reading about domestic and overseas relative literatures, according to the rainfall data, including per day and per hour rainfall data of 21 years (from 1980 to 2000), the paper analyzed the rainfall characters. Meanwhile, an artificial imitation rainfall system was developed in order to study the characteristics of city underlying surface and make experimental check up about the relative appraising index, on which 200 rainfall experiments are made, analyzing the effect of rainfall intensity to the runoff of underlying surface; the relationship between runoff permeability and unit factor of rainfall intensity and duration; The effect of rainfall intensity, duration, soil moisture content, and temperature to the runoff permeability; The relationship between rainfall quantity and runoff permeability, and make mathematical imitation to the experimental results, to find the mutual-relationships, and make discussion about the differences between equations of fit. At last, on the basis of analyzing the characteristics of rainfall and runoff-producing and flow concentration and taking the example of multiple -underlying surface of Jing Hua School Area and stressed laboratory building materials of hydrology and environment of Shann'xi, and thus rainfall runoff amount in the cultural areas and roof underlying surface are calculated, and utilizing foreground of rainfall are analyzed.According to the rainfall data analysis, equipment development, experimentation investigation, mathematical analysis and the calculation of examples, from which the product and conclusion are made as follow.1. The rainfall amount of Xi'an is 623.96mm on average for many years. Which is often happened in June to October and the rainfall amount per day of the year is below 10mm/d. From the point of view of utilizing surface runoff, the secondary rainfall standard is projected, that is taking the capability of infiltration recovery time of underlying surfaceas the basis of rainfall. Record the falling data of 1313 times during 21 years. Rainfall intensity, frequency, and duration relationship curve of rainstorm was developed in the six period of the city zone in Xi'an, i.e. lh,2h,3h,4h,5h,6h respectively, by adopting the curve method of Pearson type 3 curve, and the rainstorm type which occur only once a year in 12h was developed.2. Design and development of the experimental system of runoff-producing and flow concentration of city underlying surface. In the process of devising rainfall apparatus, the calculative formula of traditional rainfall degree of consistency can't weight the uniformity of rainfall space. The paper suggests the checkup parameter and calculative method used in testing the degree of consistency of the rainfall intensity in rainfall space. Providing the least value of test which as a testing index in the testing of experimental apparatus.3. Based on the requirements of the character of jet nozzle and degree of consistency, jet nozzle and optimized design procedure of water supply branch distribution were devised. And utilized the compatibility of software saw the optimized products. In order to advance the precision of data processing, practical quantity of flow and turnover duration were adopt to calculate the quantity of water of tilting bucket The experiment of character of tipping bucket in the measure and control system shows that the error between the measurement and calculation, (<=0.01) decreased sharply, and the efficiency is promoted greatly.4. As for the three kinds of waterproof underlying surface, when rainfall intensity is strong, the rise process curve will steep in the process of discharge, and also speed of discharge to reach steady will quicker. But it produces little effects on duration of fall. On the same rainfall intensity, speed rate of these three kinds of underlying surface are list as: cement road surfac...
|
PDF Full Text Request