垃圾填埋场污泥坑原位修复工程实践

垃圾填埋场内污泥坑的存在严重影响填埋场竖向扩建和填埋堆高。对某垃圾填埋场内污泥坑进行现场勘察取样、原位测试与室内实验，获得污泥的分层及沿深度变化的物理、力学特性，并针对不同分层的污泥，提出表层垃圾清除、污水抽排、泥水混合污泥土工管袋脱水、流塑、软塑污泥原位固化综合处理方法。对污泥坑抽排污水过程中垃圾堆体边坡进行渗流稳定分析，发现渗滤液水位快速下降将导致污泥坑垃圾边坡滑移失稳，在污泥坑治理过程中应采取相应措施。根据污泥坑上覆80~120 m垃圾堆体沿原位固化污泥滑移稳定分析，获得污泥坑原位固化处理强度指标，不排水抗剪强度Cu为40 kPa。

Practice of in-situ remediation of sludge pits in landfill

Sludge pit in landfills significantly affects vertical expansion and height of landfills. Field sampling, in-situ testing and laboratory testing were performed for sludge pits in a landfill to obtain physical and mechanical characteristics of the stratification and depth change of the sludge. Surface waste removal, sewage pumping, sludge-water mixed sludge tube dewatering, in-situ solidification were proposed for this site. Seepage stability analysis was carried out for the sludge pits during sludge pumping. It was found that rapid decline of leachate level would cause sludge pit slope instability and measures should been taken during the sludge pit treatment. According to the stability analysis of in-situ solidified sludge overlain by 80 to 120 m wastes, the in-situ solidification strength of the sludge pit was obtained, the undrained shear strength should not be less than 40 kPa.