高密度聚乙烯(HDPE)土工膜覆盖层对垃圾填埋体中期稳定性影响分析

Analysis of the Effect of HDPE Geomembrane Cover Layer on the Medium-Term Stability of Landfill Body of Waste Soil

城市垃圾填埋场在填埋和运营过程中,垃圾土的抗剪强度会随着填埋龄期的增长而改变,高密度聚乙烯(HDPE)土工膜作为现代卫生垃圾填埋场的中间覆盖层,其规格参数直接影响着垃圾填埋体的填埋中期稳定。文章对不同填埋龄期的垃圾土和不同类型HDPE土工膜进行界面剪切试验,得到土膜界面抗剪强度参数,再结合数值模拟方法分析HDPE土工膜对分层垃圾填埋体稳定性的影响。结果表明:随着填埋龄期的增加,土膜界面黏聚力呈现出总体下降的趋势,而界面内摩擦角呈现出总体上升的趋势,其中柱点式HDPE土工膜具有更高的界面抗剪强度;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的形成的作用;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。研究结果对垃圾填埋场设计及其安全性评价有重要的指导意义。

In the process of landfill and operation of municipal waste landfill,the shear strength of waste soil will change with the growth of landfill age.The specification parameters of HDPE geomembrane,the middle cover layer of modern sanitary waste landfill,its specification parameters directly affect the mid-term stability of landfill body.Conducting interface shear tests on waste soils of different landfill ages and different types of HDPE geomembranes to obtain soil-membrane interface shear strength parameters,this artical analyzes the influence of HDPE geomembranes on the stability of layered waste landfills by using numerical simulation methods.The results reveal that with the increase of landfill age,the cohesion of soil membrane interface shows an overall downward trend,while the friction angle of interface shows an overall upward trend.Among them,the cylindrical HDPE geomembrane has higher interfacial shear strength;HDPE overburden can delay the penetration of the upper slip surface and block the formation of the slip zone of the lower landfill body;laying HDPE geomembrane can significantly enhance the overall stability of landfill in the middle stage of landfill.The research results have important guiding significance for landfill design and safety evaluation.