垃圾焚烧炉渣在道路基层中的应用实验及数值分析

城市固体垃圾焚烧炉渣作为一种废弃物,具有广阔的资源化利用前景。为研究生活垃圾焚烧炉渣替代部分级配碎石在道路基层中应用的可行性,以焚烧炉渣和石灰岩级配碎石为原料,测试其基本性能。制备不同配合比的水泥稳定炉渣碎石试样,并进行无侧限抗压实验;采用MIDAS/GTS(geo-technical analysis system)对水泥稳定炉渣碎石作为道路基层进行数值模拟,探究在不同工况下路面结构的变形。结果表明:焚烧炉渣吸水率较高而密度较低,压碎值介于30%~45%,大于碎石20%的压碎指标但与海砂相似;且承受结晶压的坚固性良好;水泥稳定炉渣碎石的强度与刚度随着养生龄期的增长而增长,在相同的炉渣与水泥掺量下,原状炉渣试样强度和刚度明显低于同龄期破碎炉渣试样。数值模拟方面,在路面中心处受到轴载时,路面沉降随距路面中心线距离的增大而减小;在承载力满足要求的情况下,道路基层模量不是影响路面沉降的主要因素;增加水泥稳定炉渣碎石基层厚度则可以明显减小路面中心处沉降。

Experimental and Numerical Analysis of Municipal Solid Waste Incineration Bottom Ash used in Road Base

As a by-product from the incineration of municipal solid waste, bottom ash has a broad application prospect of resource utilization. In this study, bottom ash was selected as partial aggregate alternative, and used as road base materials. The cemented aggregate containing bottom ash was evaluated through both experimental and numerical analysis. According to the results, the crushing value of bottom ash with high water absorption and low density is between 30%~45%, more than limestone crushing index but similar to sea sand crushing index. The CBR value is greater than 25% and the bottom ash has good ability to withstand the crystallization pressure. The strength of stabilized aggregate containing bottom ash was found proportional to curing time and influenced by the types of bottom ash. Under the same condition, the strength of simples within original bottom ash was significantly lower than that within cracked bottom ash simples. Subsequently, the finite element calculation results showed that the modulus of the road base is not the main influences on the pavement settlement, under the condition that the bearing capacity meets the requirements. Increasing the thickness of road base containing bottom ash can reduce the settlement at the center of the pavement obviously. When the axle load is applied at the center of the road surface, the settlement of the road decreases with the distance from the centerline of the road surface increasing.