冻融循环下木钙协同EICP固化铜污染黄土的耐候性试验研究  

Experimental study on the weathering resistance of copper-contaminated loess solidified by calcium lignosulfonate-assisted EICP under freeze-thaw cycles

作　　者：江世超 刘华[1,2] 阮春发 JIANG Shichao;LIU Hua;RUAN Chunfa(School of Civil Engineering,Xi’an University of Architecture and Technology(XAUAT),Xi’an 710055,China;Key Laboratory of Geotechnical and Underground Space Engineering of Shaanxi Province,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]陕西省岩土与地下空间工程重点实验室,陕西西安710055

出　　处：《冰川冻土》2025年第2期477-489,共13页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(52378367);陕西省自然科学基金项目(2022JM246)资助。

摘　　要：近年来,重金属污染引起土体的力学-水力学参数变化,从而诱发其工程性能劣化,导致岩土工程体的稳定性问题日渐突出。本文基于酶诱导碳酸钙沉淀(EICP)技术联合木钙固化铜污染黄土,通过冻融循环前后的无侧限抗压试验和毒性浸出试验,对中长期的固化效果和耐候性进行评估,并通过SEM试验进行微观分析揭示冻融循环下木钙协同EICP固化铜污染黄土的微观作用机理。试验结果表明:随着EICP掺量逐渐增大,固化土体的无侧限抗压强度随之增大并逐渐稳定。掺入木钙可提升土体的强度,在4%掺量下效果最为显著,当掺量继续增加,土体易形成软弱面从而降低抗压强度;随着冻融循环次数增长,EICP-木钙显著减缓了黄土无侧限抗压强度的衰减。经过9次冻融循环,联合固化土体的强度保持在相对高位,强度损失仅为8.5%,而未固化土、单独EICP和木钙固化土强度则分别衰减41.5%、42.4%和26.4%,说明木钙联合EICP增加了土体的耐候性。在毒性浸出测试中,EICP与木钙的联合固化处理显著降低了不同污染浓度黄土的铜离子浸出量,最高固化率可达79.54%。随着冻融循环次数增加,污染土的固化率逐渐降低,9次冻融循环后,各浓度污染土的联合固化率比单独使用EICP高15%以上。由SEM图像分析得知,木钙在EICP固化过程中不仅提供了物理结构上的增强,还通过促进碳酸钙的均匀沉淀,提升了铜污染土的固化效果和耐候性,展现出其在联合加固机制下的显著优势。本文试验结果可为重金属污染黄土场地的加固修复提供科学依据和数据支撑。In recent years,heavy metal pollution has caused changes in the mechanical and hydraulic parameters of soils,leading to a deterioration in their engineering performance.This,in turn,has raised significant con⁃cerns regarding the stability of geotechnical structures.This paper investigates the combined application of en⁃zyme-induced calcium carbonate precipitation(EICP)and lignin-based calcium solidification(referred to as EICP-lignin)for the remediation of copper-contaminated loess.The long-term curing effects and weather resis⁃tance of the combined treatment are evaluated through unconfined compressive strength(UCS)tests and toxicity leaching tests conducted before and after freeze-thaw cycles.Furthermore,scanning electron microscopy(SEM)is employed for microstructural analysis to explore the microscopic mechanisms underlying the EICP-lig⁃nin solidification of copper-contaminated loess under freeze-thaw conditions.The experimental results indicate that as the EICP dosage increases,the UCS of the treated soil increases and stabilizes over time.The incorpora⁃tion of lignin significantly enhances the soil’s strength,with the most pronounced effect observed at a lignin dos⁃age of 4%.However,when the lignin content is further increased,weak planes may form,leading to a decrease in compressive strength.With an increasing number of freeze-thaw cycles,the EICP-lignin treatment significant⁃ly reduces the deterioration in UCS.After 9 freeze-thaw cycles,the strength of the combined solidified soil re⁃mains at a relatively high level,with a strength loss of only 8.5%.In contrast,the strength of untreated soil,EICP-only solidified soil,and lignin-only solidified soil decreases by 41.5%,42.4%,and 26.4%,respective⁃ly.This demonstrates that lignin combined with EICP enhances the soil’s weather resistance.In the Toxicity Characteristic Leaching Procedure(TCLP)leaching tests,the EICP-lignin combined treatment significantly re⁃duces the copper ion leaching from loess contaminated with various concentrations

关 键 词：冻融循环 木钙 EICP 污染土 

分 类 号：X53[环境科学与工程—环境工程] P642.14[天文地球—工程地质学]