含污泥坑生活垃圾填埋场竖向扩容工程稳定沉降分析

Analysis of the stabilization and settlement of vertical expansion project for municipal solid waste landfill with sludge pit

为减少生活垃圾填埋场内污泥坑的存在给填埋场后期竖向扩容工程带来的难度,以辽宁省某含污泥坑生活垃圾填埋场为例,对其竖向扩容工程进行了工艺设计和验证分析。根据工程目标和相关规范,合理确定了扩容后填埋场整体平面布置和填埋堆高等参数,选用原位固化技术对污泥进行了加固处理,并确定了处理后污泥的力学参数设计值。使用Geo-Slope软件,建立了扩容后填埋场堆体边坡的计算模型,并分析和评价了3种不同工况边坡抗滑稳定性的影响。基于理正岩土软件,对填埋场垃圾堆体进行了沉降计算,并根据沉降分析结果进一步确定了防渗系统设计方案。结果表明:污泥坑加固处理后,各工况下的垃圾堆体边坡抗滑稳定安全系数均满足规范要求;固化处理后污泥的相关强度等指标均满足垃圾堆体竖向扩容设计要求;防渗系统最大伸长率为0.4%,满足规范要求;防渗结构中设置了抗沉降加筋层,可抵抗垃圾堆体的不均匀沉降。本研究成果可为国内同类型生活垃圾填埋场的竖向扩容工程工艺设计提供参考和借鉴。

The existing sludge pit in municipal solid waste(MSW)landfill significantly increases the difficulty of the design and construction in its post vertical expansion.In this study,a MSW landfill with sludge pit in Liaoning Province was taken as a case,and the process of its vertical expansion project was designed,verified and analysed.According to the engineering objectives and relevant specifications,the overall layout of the landfill and the engineering parameters(e.g.,landfill height)were reasonably determined.The in-situ solidification technology was selected to treat the sludge,and the design values of mechanical parameters of the treated sludge were determined.The Geo-slope software was used to establish the calculation model of landfill slope stability,and the effects of three different conditions on the slope stability were analysed and evaluated.The settlement of the landfill was calculated based on the Lizheng geotechnical software,and the design scheme of the anti-seepage liner system was determined based on the settlement analysis.The results show that all the safety factors of stability of landfill slope under three conditions met the requirements of the technical code after sludge pit in-situ solidification.The strength and other indexes of the solidified sludge met the design requirements of the landfill vertical expansion.The maximum elongation of the anti-seepage liner system was0.4%,which met the requirements of the specification.The anti-settlement reinforced layer embedded in the anti-seepage structure could resist the uneven settlement of the garbage mount.The research results can provide some references for the technological design of the vertical expansion project of similar domestic MSW landfills.