摘要
固废堆场封场土质覆盖层由天然非胀缩土料组成,其造价及后期维护费用明显低于传统覆盖层,是填埋场封场覆盖的理想型式。采用基于非等温多孔介质中水热耦合运移控制方程的软件,考虑外界气候条件、地表蒸发作用、植被蒸腾作用,建立土质覆盖层–植被–大气相互作用数值模型,针对中国湿润气候区典型城市长期实测气象条件,系统分析了不同结构型式土质覆盖层的性状。分析结果表明,毛细阻滞型覆盖层可把水分阻滞在根系生长层,便于植被蒸腾作用的提取,其性能优于单一土层型覆盖层。土质覆盖层内水分的排出主要依靠植被蒸腾和地表蒸发,二者与植被特征相关,植被条件越好则腾发总量越大;根系生长区内的含水率变化幅度大于其它区域。在本文气候条件下,选择厚度为1.4 m的毛细阻滞型覆盖层并结合一定植被条件可防止产生深层渗漏。
The alternative earthen final covers （AEFCs） are constructed with relatively non-plastic soils with greater durability and lower cost and require relatively lower post-closure maintenance than conventional covers, so they are good choices for the final closure of landfills. A numerical model that can describe the interactions among earthen final cover, vegetation and atmosphere is developed based on the non-isothermal flow equation considering the thermal moisture coupling. It takes the meteorological condition, the evaporation from the ground surface and the transpiration of the vegetation into account. The performance of AEFCs in humid areas in China is investigated. The numerical results show that the capillary barrier cover can limit downward movement of water and the water is stored in the root zone layer. The capillary barrier cover performs better than the monolithic cover. The transpiration and the evaporation drain most of the water out of the cover and the evapotranspiration increases as the vegetation grows well. Capillary bairrier cover with 1.4 m in thickness and certain vegetation can prevent the deep percolation under the climatic condition considered in the study.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2012年第10期1812-1818,共7页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(50878194)
973计划课题(2012CB719805)
