高密度聚乙烯土工膜对分层垃圾填埋体渐进滑移的稳定性影响分析

Stability analysis of high-density polyethylene geomembrane on gradual slip of layered landfill bodies

对不同填埋龄期的MSW和不同类型HDPE土工膜进行土-膜界面剪切试验,再结合数值模拟方法,分析不同类型HDPE土工膜对分层MSW填埋体渐进破坏的稳定性影响。结果表明,随着填埋龄期的增加,土-膜界面粘聚力呈现出总体下降的趋势,而土-膜界面内摩擦角呈现出总体上升的趋势;填埋体边坡呈现出推移式逐层级渐进破坏的滑坡特征,HDPE覆盖层起到了延缓上层滑移面的贯通,并阻断下方填埋体滑裂带形成的作用;布设HDPE土工膜能显著增强填埋体在填埋中期的整体稳定性。此外,柱点类型HDPE土工膜具有更高的土-膜界面抗剪强度,减小填埋体滑移破坏的影响效果更好。研究结果为HDPE土工膜作为中间覆盖层的选用,提供试验依据和可靠的模拟理论分析。

In this study,soil-membrane interface shear tests were conducted on MSW of different landfill ages and different types of HDPE geomembranes,and then combined with numerical simulation methods to analyze the stability effects of different types of HDPE geomembranes on the progressive damage of layered MSW landfills.The results show that,as the age of landfill increases,the cohesive force of soil-membrane interface shows an overall decreasing trend,while the internal friction angle of soil-membrane interface shows an overall increasing trend;the slope of landfill body shows the characteristics of slippery slope with gradual destruction layer by layer,and the HDPE cover layer plays the role of delaying the penetration of the upper slip surface and blocking the formation of slippery fracture zone of the landfill body below;the deployment of HDPE geomembrane can significantly enhance the overall stability of the landfill body in the middle of the landfill.In addition,the HDPE geomembrane of column point type has higher shear strength at the soil-membrane interface,which is more effective in reducing the effect of landfill slip damage.The results of the study provide the experimental basis and reliable simulation theoretical analysis for the selection of HDPE geomembrane as an intermediate cover layer.