JZUS - Journal of Zhejiang University SCIENCE

Journal of Zhejiang University SCIENCE A 2019 Vol.20 No.1 P.1-9

Effects of vegetation type on water infiltration in a three-layer cover system using recycled concrete

Author(s): Charles W.W. Ng, Bang-wen Lu, Jun-jun Ni, Yun-min Chen, Rui Chen, Hao-wen Guo
Affiliation(s): Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China; more
Corresponding email(s): jniaa@connect.ust.hk
Key Words: Recycled concrete, Soil suction, Three-layer landfill cover, Vegetation, Water content

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Abstract: To promote environmental sustainability, recycled construction concrete is suggested for civil infrastructure works. The aim of this study was to investigate the effects of vegetation type on water infiltration under extreme rainfall conditions in a proposed three-layer landfill cover system containing recycled concrete. Three soil columns, namely bare, covered with shrub (Schefflera arboricola), and covered with grass (Cynodon dactylon), were subjected to ponding tests. Each column was compacted with a bottom layer of silty soil, an intermediate layer of coarse recycled concrete aggregate, and an upper layer of fine recycled concrete aggregate. Water breakthrough occurred only in the bare cover system after 48 h of ponding, equivalent to a rainfall return period of greater than 1000 years in Hong Kong. Under the vegetated covers, suction maintained in the bottom silty soil layer was higher than under the bare cover by 49–52 kPa and hence no percolation was observed after 48 h of ponding. Comparing the two vegetated cover systems, suction maintained under the shrub cover was 2–12 kPa higher (2%–8% lower volumetric water content) than that under the grassed cover in the layers of recycled concrete. This implies that shrub cover can be more effective than grass cover in reducing water infiltration in humid climates.

植物种类对由建筑垃圾构筑而成的三层土覆盖层系统防渗特性的影响研究

目的:为提高资源重复利用率,建筑垃圾常常被回收、粉碎并重新应用在土木工程建设中. 本文旨在将回收建筑垃圾骨料应用于三层土覆盖层系统,并研究植物对其防渗特性的影响.
创新点:1. 提出一种由建筑垃圾构筑而成的三层土覆盖层系统; 2. 对比灌木、草以及裸土3种工况下该覆盖层的防渗特性.
方法:1. 采用一维土柱渗透试验研究由建筑垃圾构筑而成的三层土覆盖层系统的防渗特性. 2. 分别模拟灌木、草和裸土3种植被覆盖情况. 3. 移栽植物并养护,而后进行降雨试验,对比3种植被覆盖层的吸力响应及水分渗入.
结论:1. 在干旱条件下,蒸腾作用的大小顺序为:灌木>草>裸土,因为植物可以将更多的水分从覆盖层中释放到大气中; 2. 在极端降雨条件下,相比裸土覆盖层,植被覆盖层可以更好地保持吸力并阻止渗滤液的产生,且灌木比草效果更佳; 3. 在极端降雨条件下,由建筑垃圾构筑而成的植被型三层土覆盖系统是一种理想覆盖层,可以在湿润地区有效防止雨水下渗而进入垃圾体.
关键词：回收骨料; 吸力; 三层土覆盖系统; 植物种类; 土壤含水率

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植物种类对由建筑垃圾构筑而成的三层土覆盖层系统防渗特性的影响研究

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