Experimental study on the evolution of engineering properties of old clay under acid pollution

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Nov.2025, Vol.48 No.11: 1549-1555

DOI: 10.3969/j.issn.1003-5060.2025.11.017

Authors

CHEN Xiaochuan $ ^{1} $, ZHANG Zhenhua $ ^{2} $, GUO Yang $ ^{1} $, XI Banglu $ ^{2} $, ZHANG Jun $ ^{1} $, YUE Tengsheng $ ^{1} $

(1. Anhui Provincial Key Laboratory of Building Earthquake Disaster Mitigation and Green Operations, Anhui Institute of Building Research and Design, Hefei 230031, China; 2. School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China)

Abstract and Keywords

Abstract: In order to explore the evolution law of engineering properties of old clay under acid pollution, three acidic solutions with different pH values were prepared to carry out continuous soaking test on old clay, and then the laboratory soil tests such as specific gravity, free expansion rate, direct shear, liquid-plastic limit, and particle size analysis were conducted systematically. The microstructure and material composition of soil were analyzed by scanning electron microscope (SEM) and X-ray diffractometer (XRD), and the evolution law of engineering properties of old clay under acid pollution was studied from a microscopic perspective. The test results show that under the immersion of acid solution, the internal minerals of old clay continue to dissolve, the soil particle size decreases, the specific surface area increases, the microstructures become loose and broken, the specific gravity, cohesion, compression modulus, and liquid-plastic limit decrease, the internal friction angle basically remains unchanged, and the free expansion rate and permeability coefficient are improved. Based on the test results, the evolution mechanism of engineering properties of old clay under acid pollution is discussed, and a mathematical model is established to describe the variation rates of engineering properties indicators (shear strength, compression modulus, permeability coefficient, and free expansion rate) of old clay.

Keywords: old clay; engineering properties; acid pollution; evolution law

作者信息

陈小川 $ ^{1} $，张振华 $ ^{2} $，郭杨 $ ^{1} $，奚邦禄 $ ^{2} $，张骏 $ ^{1} $，乐腾胜 $ ^{1} $

（1. 安徽省建筑科学研究设计院安徽省建筑抗震减灾与绿色运维重点实验室，安徽合肥 230031；2. 合肥工业大学土木与水利工程学院，安徽合肥 230009）

摘要和关键词

摘要: 为探究酸污染下老黏土的工程特性演变规律,文章配制3种不同pH值的酸性溶液对老黏土进行持续浸泡试验,系统开展比重、自由膨胀率、直剪、液塑限、粒度分析等室内土工试验,并利用扫描电子显微镜(scanning electron microscope, SEM)、X射线衍射仪(X-ray diffractometer, XRD)对土体微观结构及物质组成进行分析,从微观角度研究酸污染下老黏土工程特性演变规律。试验结果表明:在酸溶液的浸泡下,老黏土内部矿物不断溶蚀,土颗粒粒径减小,比表面积增加,微观结构变得松散、破碎,土体的比重、黏聚力、压缩模量、液塑限等工程指标数值下降,内摩擦角基本不变,自由膨胀率及渗透系数得到提高。基于试验结果,探究了酸污染下老黏土工程特性的演变机理,建立了老黏土抗剪强度、压缩模量、渗透系数、自由膨胀率的工程特性指标变化率随浸泡溶液pH值变化的数理模型,指出用黏聚力、压缩模量、渗透系数对酸污染后老黏土的污染等级进行评价较为合理。

关键词: 老黏土；工程特性；酸污染；演变规律

Funding

国家自然科学基金资助项目（51979068）；安徽省住房城乡建设科学技术计划资助项目（2022-YF018）和绿色建筑与装配式建造安徽省重点实验室开放基金资助项目（2021-JKYL-003）

合肥工业大学学报(自然科学版)

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