固化市政污泥作为填埋场覆土的强度特性

Strength characteristics of solidified municipal sludge as landfill cover

为解决大量弃置的市政污泥和垃圾焚烧飞灰占用填埋场空间、影响周边环境、造成资源浪费的问题,采用垃圾焚烧飞灰替代部分水泥对市政污泥进行改性固化,将固化市政污泥用作填埋场覆土材料。考虑真实的填埋场环境,通过无侧限抗压强度和直剪试验,分析在标准条件、水下条件以及干湿循环作用下,飞灰替代率为0~80%的固化污泥的强度特性变化规律。研究结果表明:随着飞灰替代率的增加,固化污泥的强度降低,且逐渐由脆性向塑性转变,28d抗压强度均可达50kPa;在水下养护条件下,垃圾焚烧飞灰能够提高固化污泥后期强度。研究结论为分析含垃圾焚烧飞灰的固化污泥作为填埋场覆土材料的可能性提供参考。

In order to solve the problems that a large number of abandoned municipal sludge and waste incineration fly ash occupy landfill space,affect the surrounding environment and cause resource waste,the waste incineration fly ash is used to replace part of the cement to solidify municipal sludge,and the solidified municipal sludge is used as the covering material of landfill.Considering the real landfill environment,the unconfined compressive strength and shear strength tests were carried out to analyze the change rule of strength characteristics of solidified sludge with 0~80%fly ash replacement rate under standard conditions,underwater conditions and dry-wet cycle.The results show that with the increase of fly ash replacement rate,the strength of solidified sludge decreases,and gradually changes from brittle to plastic,and the 28d compressive strength can reach 50 kPa.Under the condition of underwater curing,the strength of solidified sludge in later stage can be significantly improved by waste incineration fly ash.The research conclusions provide a reference for analyzing the possibility of solidified sludge containing waste incineration fly ash as the covering material of landfill.