冻融循环下酸污染黄土电阻率特征及其与抗拉强度的关系研究

    RESISTIVITY CHARACTERISTICS OF ACID-CONTAMINATED LOESS AND ITS RELATIONSHIP WITH TENSILE STRENGTH UNDER FREEZE-THAW CYCLES

    • 摘要: 随着区域工业化进程加速,黄土地区经受着季节性冻融循环与工业污染的影响,黄土体特性产生显著变化,力学性能的持续衰减,对黄土坡体及场地的稳定性构成威胁,成为制约区域地质安全的重要致灾因子。基于此,本文以铜川地区原状黄土为研究对象,以蒸馏水为基液,分别配制了4种不同浓度盐酸、硝酸和硫酸的污染液,通过室内冻融循环下的酸污染黄土单轴拉伸及其电阻率同步测试试验,探究了冻融作用下酸污染黄土抗拉强度与电阻率特征演变规律。试验结果表明:酸污染黄土电阻率随着冻融循环次数的增加逐步增大,且10~15次冻融循环后电阻率趋于稳定,而在单次冻融循环过程中,电阻率随着温度变化逐渐降低并进入稳态平衡阶段;在不同次数冻融循环作用下,随着盐酸和硝酸污染液浓度的增加,污染土的电阻率呈降低趋势,硫酸污染则表现出相反趋势。此外,酸污染黄土的电阻率与抗拉强度呈正相关关系。基于电阻率的演变规律,并结合污染液浓度、冻融循环次数以及电阻率参数,建立了相应的电阻率模型并验证了其有效性。该研究结果为酸污染土边坡稳定性分析及工程质量评价提供一定参考。

       

      Abstract: With the acceleration of regional industrialization,loess-covered areas are increasingly exposed to seasonal freeze-thaw cycles and industrial acidification,resulting in significant alterations in soil structure and a continuous decline in mechanical performance. These processes threaten the stability of loess slopes and engineering sites,posing a critical risk to regional geological safety. In this study,intact loess specimens from the Tongchuan region were treated with distilled water and acidified solutions of HCl, HNO3,and H2SO4 at four concentration levels. Under controlled laboratory conditions,the specimens underwent repeated freeze-thaw cycles,during which uniaxial tensile strength and electrical resistivity were measured synchronously. The test results indicate that the electrical resistivity of acidified loess increases progressively with the number of freeze-thaw cycles,stabilizing after approximately 10-15 cycles. Within each individual cycle,resistivity decreases with rising temperature until reaching a steady equilibrium. Under multiple freeze-thaw treatments,increasing the concentration of HCl or HNO3 solutions leads to a noticeable decrease in soil resistivity,whereas H2SO4 exhibits the opposite effect,increasing resistivity with higher concentration. Furthermore,a positive correlation is observed between resistivity and tensile strength across all acid treatments. Based on the observed evolution of resistivity and its dependence on acid concentration and freeze-thaw history,we developed and validated a predictive model for electrical resistivity. This model incorporates acid concentration,number of freeze-thaw cycles,and measured resistivity parameters,providing a practical tool for assessing the stability of acid-polluted loess slopes and for quality evaluation in geotechnical engineering applications.

       

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