房地产建设项目雨水池适宜容积计算模型

Model of calculating suitable volume of rainwater tanks for real estate construction projects

随着城市化进程加快,城市内涝问题越来越突出。为解决因下垫面硬化引起的城市内涝问题,探求建设项目中雨水池容积计算方法。本文以北京市房地产建设项目为研究对象,从北京市1953—2012年降雨数据中选取降雨量最大、平均和最小年的日降雨数据,并拟定中水同时用于绿化和道路浇洒,应用日水量平衡模型方法,对比分析雨水池可利用率和中水补给率变化趋势,综合考虑经济效益因素,确定雨水池适宜容积。应用多项式拟合法,得到雨水池适宜容积简易计算模型。结果表明:随着雨水池容积增加,雨水池可利用率增大(0~1),中水补给率减小(1~0);当雨水池容积增至一定程度,其可利用率与中水补给率的变化趋于平缓;3种年况的雨水池可利用率的关系为最大>平均>最小,中水补给率的关系为最大<平均<最小,为互补趋势;效益费用比随着雨水池容积增大而减小。经验证,模型符合工程建设要求,且具普遍性,可投入应用。为提高模型可靠性,应用时宜将模型计算结果与规范最低建设标准进行校核比对。本研究为今后雨水池设计提供了一种新的快捷简便算法,丰富了设计理论。

[Background] China is on the peak of urbanization.However,with increased hardened proportion and imperfect drainage measures in cities,rainstorms cannot efficiently infiltrated and ultimately resulted in the formation of waterlogging.As the best measure of reducing flood,solving water pollution and shortage,the rainwater tank has been promoted and applied widely.Though rainwater tank was widely used in estate construction projects and was advocated in a larger volume on the principle of none out drainage,few studies had been conducted on it.Otherwise,the design of rainwater tanks in our country is mainly based on the experience formula of foreign countries,or estimated by the annual rainfall.Therefore,a convenient and reliable method for calculating the volume of rainwater tank is very important to the development of the city.[Methods]We took nine construction projects in Beijing as the research site,selecting three kinds of daily rainfall（maximum,average and minimum） from the rainfall data of Beijing during 1953—2012.We assumed recycled rainwater used for both greening and road sprinkling.Applying the method of daily water balance model,we analyzed trends of rainwater tank availability and reclaimed water recharge rate.We suggested an appropriate volume of rainwater tank aftertaking the economy benefits.Applying the method of polynomial fitting,the model of calculating suitable volume of rainwater tanks was obtained.Lastly,we used five construction projects for verification.[Results]With the increasing of rainwater tank volume,rainwater tank availability becomes higher（0-1） and reclaimed water recharge rate becomes lower（1-0）.When rainwater tank volume reaches to a certain level,the tendency of rainwater tank availability and reclaimed water recharge rate become gentle.The rainwater tank availability relationship of three years is maximum yearmean yearminimum year.The reclaimed water recharge rate relationship of three years is maximum yearmean yearminimum year.The trend of rainwater tank availability and reclaimed water recharge rate is complementary.The benefit-cost ratio becomes lower as rainwater tank volume increase.[Conclusions]In this study,we set up a simple and convenient calculation model of volume of the rainwater tank.It can enhance accuracy in practical application by comparing the results of model calculation and the minimum construction standards.We need to strengthen the maintenance and management of the rainwater tanks after completion for increasing revenue by extending service life.The future study of rainwater tanks should be focused on the more abundant data samples,additional safety volume of it,and negative impact of sediment accumulation.