黄土地区一种储水-绿化带的开发研究

Study on New Rainwater Collecting System in Loess Area

黄土地区海绵城市建设面临着地表雨水集中入渗过程中可能诱发深层黄土湿陷变形的问题,地表不均匀沉降威胁周边建筑的安全。基于对黄土湿陷问题和海绵城市建设雨洪转换关系的认识,实现城市雨水资源的高效利用,避免城市雨洪诱发的地质灾害,应用海绵城市建设理念,设计出一种适合黄土地区的雨水收集利用系统,利用砂砾石强导水特性进行雨水蓄存和疏导,采用三七灰土和土工膜的低透水特性减少下渗量,实现地表雨水的收集、蓄存、过滤和综合利用,减少汇入城市管网的水量。利用Geo Studio SEEP/W模块验证其可靠性,模拟一次强降雨后12 h和24 h总水头等势线的变化规律,得出雨水可经种植土下渗至储水砂砾石层,在12 h开始积聚,直至24 h雨水依然被三七灰土层和土工膜有效阻隔,表明开发的雨水收集结构能有效实现雨水浅层收集和利用,避免集中入渗引起深层黄土湿陷变形的问题。

The construction of sponge city in loess area faces with the issue of collapsible deformation which may be induced by the infiltra tion of rainwater.Based on the loess collapsibility and the conversion between rain and flood,the efficient utilization of urban rainwater was realized as far as possible to avoid the geological disasters induced by urban rain flood.The idea of sponge city was applied to design a system which suitable for loess area to collect and utilize rainwater.Sand and gravel with strong water conductivity could store and infiltrate rainwa ter,lime soil and geomembrane could prevent rainwater from seeping deeper,so as to realize the collection,storage,filtration and compre hensive utilization of surface rainwater,and reduce the amount of water flowing into the urban drainage network.The change rule of the total head contour at 12 h and 24 h after a heavy rainfall was simulated by the GeoStudio SEEP/W module.The results show that rainwater can in filtrate into the gravel layer through planting soil,and begin to accumulate at 12 h.Until 24 h,rainwater is still effectively blocked by lime soil and geomembrane,indicating that the developed rainwater collection structure can effectively realize the shallow collection and avoid the collapsible deformation of deep loess caused by infiltration.