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Abstract: Generally, landfill caps are covered with plants to prevent erosion and maintain a natural environment attractive to birds and other wildlife. Plants extract moisture from landfill cover soils during transpiration, and increase soil matric suction, consequently reducing water permeability and influencing the performance of the landfill cover during wetting. However, the effects of plants on suction distribution during drying and their consequent effect on the performance of a landfill cover system during wetting have not been investigated thoroughly. In this study, two soil column tests (one planted with the shrub Schefflera arboricola and the other one bare) were carried out to investigate the effects of shrub on 1D suction distribution in a three-layer landfill cover system during drying and wetting, and on the effectiveness of the landfill cover system in preventing water infiltration upon wetting. Despite the planted column having a higher infiltration rate, the shrub enhanced the effectiveness of the three-layer landfill cover system in preventing water percolation because of its higher induced suction from drying, leading to a higher water storage capacity.

This paper presented the effects of shrub on the suction distribution in a three-layer landfill cover during drying and wetting, and examined the effectiveness of such a system to prevent water infiltration upon wetting via soil column testing. Novelty of this study lied on the plants' hydraulic effects on three-layer system. In general the paper was well-written.

灌木对三层填埋场覆盖系统一维吸力分布和水分入渗的影响

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