芮大虎, 姚为峰, 聂文君,等.开放-单向冻结模式下固化铅镉污染土毒性浸出试验[J].河南理工大学学报（自然科学版）,2026,45(1):189-196.

RUI D H, YAO W F, NIE W J, et al.Toxicity leaching test of solidified Pb-Cd contaminated soil under an open-unidirectional freezing condition[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(1):189-196.

开放-单向冻结模式下固化铅镉污染土毒性浸出试验

芮大虎1,2, 姚为峰1, 聂文君1, 张军1,2, 潘卫东3

1.河南理工大学 土木工程学院，河南 焦作  454000；2.中国科学院 西北生态环境资源研究院 冻土工程国家重点实验室，甘肃 兰州  730000；3.郑州地铁集团有限公司，河南 郑州  450003

摘要: 目的 为了评估开放-单向冻结模式下固化重金属污染土浸出特性，开展开放-单向冻结模式下固化铅镉污染土毒性浸出试验研究。 方法 本文采用活性MgO-粉煤灰固化/稳定化铅镉复合污染土，进行开放（外界补水）和封闭（无外界补水）单向冻结模式下的冻融循环试验及其毒性浸出试验。通过扫描电镜的方法，进一步探究冻融循环作用对固化/稳定化铅镉复合污染土浸出特性的劣化机理。 结果 结果表明，不同冻结模式下固化/稳定化铅镉污染土的冻胀量及其Pb、Cd浸出质量浓度规律为：开放-单向冻结组>封闭-单向冻结组>恒温-冻结组。11次冻融循环后，相较未掺入固化剂的开放-单向冻结组，掺入固化剂的封闭-单向冻结组和开放-单向冻结组的冻胀量分别减小38%，83%。且开放-单向冻结组的Pb和Cd浸出质量浓度为5.62，1.09 mg/L，分别是封闭-单向冻结组的1.99，1.58倍，恒温-冻结组的5.21，2.53倍，超出国家土壤标准限值。 结论 冻融循环作用会导致固化污染土中的水化产物含量减少，同时使土体内部孔隙增大，这一过程显著劣化了MgO-粉煤灰对污染土中Pb、Cd的固化效果。其中开放-单向冻结模式下劣化效应更为显著。研究结果可为丰富和完善季节性冻土区浅埋地下水环境污染土固化/稳定化工艺设计和长期稳定性评价提供借鉴和参考。

关键词:开放-单向冻结;固化/稳定化;重金属污染土;浸出特性;劣化机理

doi:10.16186/j.cnki.1673-9787.2024010004

基金项目:国家自然科学基金资助项目（U2004181）；中国科学院西北生态环境资源研究院冻土工程国家重点实验室开放基金资助项目（SKLFSE20191702）；河南省科技攻关计划项目（192102310503）

收稿日期:2024/01/02

修回日期:2024/03/22

出版日期:2025-12-03

Toxicity leaching test of solidified Pb-Cd contaminated soil under an open-unidirectional freezing condition

Rui Dahu1,2, Yao Weifeng1, Nie Wenjun1, Zhang Jun1,2, Pan Weidong3

1.School of Civil Engineering， Henan Polytechnic University， Jiaozuo  454000， Henan， China；2.State Key Laboratory of Frozen Soil Engineering， Northwest Institute of Eco-Environment and Resources， Chinese Academy of Sciences， Lanzhou  730000， Gansu， China；3.Zhengzhou Metro Group Co.， Ltd.， Zhengzhou  450003， Henan， China

Abstract: Objectives This study aims to evaluate the leaching characteristics of solidified heavy metal-contaminated soil under an open-unidirectional freezing condition in the shallow groundwater environment of seasonally frozen regions. Methods Active magnesium oxide （MgO） and fly ash were used to solidify/stabilize Pb-Cd composite contaminated soil. Freeze-thaw cycle tests and leaching toxicity  tests were conducted under two unidirectional freezing conditions： open （with external water replenishment） and closed （without external water replenishment）.  Scanning electron microscopy （SEM） was employed to investigate the deterioration mechanism of freeze-thaw cycles on the leaching characteristics of the solidified/stabilized Pb-Cd contaminated soil. Results The results showed that under different freezing conditions， the frost heave and the leaching concentrations of Pb and Cd followed the same trend： open-unidirectional freezing > closed unidirectional freezing > constant temperature freezing. After 11 freeze-thaw cycles， compared with the open-unidirectional freezing group without stabilizer， the frost heave of the closed unidirectional freezing group and the open-unidirectional freezing group with stabilizer decreased by 38% and 83%， respectively. The leaching concentrations of Pb and Cd in the open-unidirectional freezing group with stabilizer were 5.62 mg/L and 1.09 mg/L， which were 1.99 and 1.58 times those of the closed unidirectional freezing group， and 5.21 and 2.53 times those of the constant temperature freezing group， exceeding the limits specified in the national soil quality standards. Conclusions Freeze-thaw cycles reduced the content of hydration products and increased internal pore development within the solidified soil， thereby significantly weakening the immobilization effect of MgO-fly ash on Pb and Cd. The deterioration effect was more pronounced under the open-unidirectional freezing condition. These findings provide references for improving the design of solidification/stabilization processes and evaluating the long-term stability of contaminated soil in shallow groundwater environments of seasonally frozen regions.

Key words:open-unidirectional freezing;solidification/stabilization;heavy metal-contaminated soil;leaching characteristic;degradation mechanism