垃圾腐殖土固化回填可行性试验研究

Experimental study on the feasibility of solidified humus soil in landfill as backfill materials

垃圾填埋场腐殖土的资源化利用是影响垃圾填埋场开挖的可行性和经济性的关键要素,固化/稳定化处理垃圾填埋场腐殖土具有较好的工程应用前景。选取普通硅酸盐水泥(ordinary Portland cement,简称OPC)、硫铝酸盐水泥(sulphoaluminate cement,简称SAC)以及自制的水泥-矿渣基固化剂(OPC-ground granulated blast furnace slag,简称OG)和氧化镁-矿渣基固化剂(Mg O-ground granulated blast furnace slag,简称MG),开展了腐殖土固化体的强度、渗透、浸出和耐久特性研究。结果表明:腐殖土在固化处理后抗压强度显著提升,在10%及15%固化剂掺量下,SAC固化腐殖土的抗压强度最高;在20%掺量下则OPC固化土及OG固化土的强度相对更优,而MG固化土强度发展均不理想。增加固化剂掺量能有效降低有机质对固化效果的影响,综合经济性考虑建议选择15%掺量。在15%掺量下,除OPC固化土无法满足重金属元素As浸出浓度限值要求外,SAC、OG、MG固化土的各项重金属浸出浓度均可满足《地下水质量标准》(GB/T 14848―93)中IV类水质标准要求。在耐久性方面,OG固化土抗干湿循环及冻融循环均表现最优,SAC固化土抗干湿循环性能较差,但抗冻性能表现优于OPC固化土。以上试验结果初步验证了垃圾腐殖土固化体作为回填使用的可行性,为其资源化利用提供了理论及参数支持。

The utilization of humus soil is a crucial factor influencing the feasibility and cost-effectiveness of landfill excavation.Solidification/stabilization technology holds promising engineering applications for humus soil treatment.In this study,four types of curing agents including ordinary Portland cement(OPC),sulphoaluminate cement(SAC),cement-slag mixture(OG),and magnesium oxide-slag binder(MG),were chosen for a systematic investigation of the evolution of engineering properties,permeability,leaching characteristics,and durability of solidified humus soils.The results indicate a significant enhancement in compressive strength of solidified humus soils,with SAC treatment exhibiting the highest compressive strength at 10%and 15%dosages,while OPC and OG solidified humus soils show higher strength at 20%.Additionally,the strength development of MG solidified soils is lower compared to other solidified soils.Increasing the dosage of curing agents can effectively counteract the inhibitory effect of organic matter in soil,with 15%being an appropriate dosage for both engineering and economic considerations.At a 15%dosage,solidified humus soil can meet the regulatory limit for Class IV water quality,except for OPC treatment,which is ineffective for As immobilization.Regarding durability,OG solidified humus soil exhibits the highest resistance to dry-wet and freeze-thaw cycles,while SAC solidified soil shows the weakest resistance to dry-wet cycles but superior frost resistance performance to OPC.Consequently,solidified humus soils can serve as filling materials in landfills and subbase materials in road engineering,offering theoretical and parameter support for the resource utilization of humus soils in landfills.