工业废渣固化淤泥破碎后的压实特性试验研究

Experimental study on compaction characteristics of industrial waste residues solidified sludge after crushing

摘要

针对采用高炉矿渣、电石渣、磷石膏复合固化剂固化后的高含水率淤泥破碎重塑土，通过开展击实试验及无侧限抗压强度试验，研究固化剂掺量和前养护龄期对破碎重塑土压实特性的影响。试验结果表明：固化剂掺量越高，前养护龄期越长，固化淤泥破碎重塑土越难压实，且当固化剂掺量超过150 kg/m³后，前养护龄期对破碎重塑土压实密度的影响十分显著；破碎重塑土的压实密度随破碎前固化淤泥无侧限抗压强度的增大呈先增大再减小的趋势，对应最大压实密度的无侧限抗压强度可作为破碎重塑时机选择的一个参考指标；破碎重塑土的压实特性取决于固化淤泥中自由水和吸附水转化为化合结晶水的量以及破碎土团颗粒之间的摩擦咬合作用；对于工期不紧迫、有足够堆场的工程，建议减少固化剂掺量，延长前养护龄期，而对于工期紧迫的工程，则建议提高固化剂掺量，缩短前养护龄期。

Abstract

For the crushed and remodeled solidified soil(CRS) which is formed by the crushing and compaction of solidified sludge with high water content by using the composite curing agent contained blast furnace slag, carbide slag, and phosphogypsum, the effects of curing agent content and pre-curing age on the compaction characteristics of CRS were investigated through compaction tests and unconfined compressive strength tests. The result show that the CRS is hard to compact as the increase of the curing agent content and the pre-curing time. As the curing agent content is larger than 150 kg/m³, the effect of the pre-curing age on the compaction characteristics of CRS increases significantly. In addition, the compacted density of CRS increases initially and then decreases with the increase of the unconfined compressive strength(UCS) of the solidified sludge without crushing. Thus, there is an optimal UCS corresponding to the maximum compacted density, which can be treated as one of the reference indexes to determine the crushing time. Besides, it is revealed that the compaction characteristics of CRS are greatly influenced by the amount of free water and adsorbed water that converted into the combined crystalline water in the solidified sludge, as well as the frictional action between the crushed particles. Finally, it is recommended to reduce the amount of curing agent and extend the pre-curing age for projects with a long construction period and sufficient yards. In the opposite, it is suggested to increase the amount of curing agent and shorten the pre-curing age for projects with a tight construction period.

关键词

固化淤泥 / 破碎重塑 / 压实特性 / 工业废渣

Key words

sludge solidified soil / crushing and remodelling / compaction characteristics / industrial waste residues

Author summay

王柳江(1985—), 男, 副教授, 博士, 主要从事软土地基电渗加固技术方面的研究工作。E-mail: [e-mail]

基金资助

国家重点研发计划项目(2022YFE0105000)