植被生长对填埋场三层覆盖系统防渗性能的影响  

EFFECTS OF PLANT GROWTH ON WATER INFILTRATION INTO THREE-LAYER LANDFILL COVER SYSTEM

作　　者：郭浩文 吴宏伟[1] 张琪 陈锐 张彦敏 GUO Haowen;NG Charles Wang Wai;ZHANG Qi;CHEN Rui;ZHANG Yanmin(The Hong Kong University of Science and Technology,Hong Kong 999077,China;Harbin Institute of Technology,Shenzhen 518055,China;Shenzhen Xiaping Env-park,Shenzhen 518001,China)

机构地区：[1]香港科技大学,中国香港999077 [2]哈尔滨工业大学(深圳),深圳518055 [3]深圳下坪环境园,深圳518001

出　　处：《工程地质学报》2022年第5期1731-1743,共13页Journal of Engineering Geology

基　　金：国家自然科学基金(资助号:U20A20320,51778166).

摘　　要：植物已被广泛用于改善岩土设施的服役性能。然而,植物生长对填埋场多层覆盖系统防渗性能的影响尚不清楚。本研究通过在深圳下坪固体废弃物填埋场开展为期两年的现场试验,并利用数值模拟进行对比与参数化分析,旨在量化湿润气候下植物生长对土体水力性质以及三层覆盖系统防渗功能的影响。经研究发现,土体饱和渗透系数(k_(s))随根长密度(RLD)的增加呈线性下降。相比裸露土,植草土k_(s)、入渗量和入渗速率分别降低55%,18%和35%。这导致在现场监测期间植草覆盖系统中维持的吸力明显高于裸露覆盖系统,数值分析与实测结果相一致。然而,百年一遇降雨后两覆盖系统内吸力分布无显著差异。在两年的现场监测中,相比裸露覆盖系统,草类减少累积渗漏量达21%。通过裸露与植草覆盖系统的年均渗漏量均满足美国环保局建议的每年30 mm的设计要求,证明了没有土工膜的三层覆盖系统在湿润气候下的良好防渗性能。Plant has been widely recognized for improving the sustainable performance of geotechnical infrastructures.However,the influences of plant growth on water infiltration into layered landfill cover are still unclear.This study aims to quantify the effects of plant growth on the variations of soil hydraulic properties and water infiltration into a three-layer landfill cover using recycled concrete without geomembrane under humid climates.Full-scale field monitoring was carried out for two years at the Shenzhen Xiaping landfill.Numerical analyses and parametric study were also conducted.The field monitoring results show that saturated water permeability(k_(s)) decreased linearly with the increase of root length density(RLD).Compared with bare soil,the reductions in k_(s) and infiltration rate due to the rise of RLD were up to 55%,18%and 35%,respectively.Consequently,higher matric suctions were preserved in the grassed three-layer landfill cover system compared to the bare one during the field monitoring,which are also support by the numerical results.However,no significant difference in matric suction was observed between the bare and grassed covers under the 100-year return period rainfall.During the two-year monitoring,the occurrence of grass roots resulted in a reduction in cumulative percolation by 21%.They all meet the USEPA recommended criterion of 30 mm·a^(-1).The field monitoring results demonstrate the effectiveness of bare and grassed three-layer cover systems using construction waste without geomembrane in humid climate areas.

关 键 词：三层填埋场覆盖系统 现场试验 植被 非饱和土 再生混凝土骨料 无土工膜 

分 类 号：TU42[建筑科学—岩土工程]