Transport of leachate through vertical curtain grouting in landfills
垃圾填埋场渗滤液穿过垂直防渗帷幕的渗漏分析

Vertical curtain grouting is often constructed to prevent contamination of ground water by landfill leachate. The leachate water levels in landfills in southern China are generally high, however, and contaminants in such a landfill may leak through the vertical curtain grouting and give rise to environmental problems. The Qizishan landfill in Suzhou was taken as an example to investigate leakage of leachate through the vertical curtain grouting. The influence of advection, diffusion and adsorption on transport of contaminants was analyzed and the influence of permeability and depth of the curtain grouting on leakage were analyzed The results show that advection plays a key role when the leachate water level is high. It takes 19.5a for the contaminants in the landfill to transport through the curtain grouting in the present conditions. The contaminated zone is mainly located in the silty clay beneath the waste, consistent with field investigations. If the permeability of the vertical curtain grouting reaches 10-7cm·s-1, leakage through the curtain grouting will not occur before stabilization of the landfill. But the leakage time will be shorten to 7a if the depth of the vertical curtain grouting is inadequate. Permeability and depth of the curtain grouting are critical to transport of leachate.