酸污染黄土强度指标及电阻率评价研究  

Evaluation of Strength Index and Resistivity of Acid-contaminated Loess

作　　者：刘华[1,2] 胡文乐 胡鹏飞 谷宏全 牛泽林 Liu Hua;Hu Wenle;Hu Pengfei;Gu Hongquan;Niu Zelin(School of Civil Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,P.R.China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi'an 710055,P.R.China)

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

出　　处：《地下空间与工程学报》2022年第2期662-672,共11页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51608436)。

摘　　要：为利用电阻率特征反演酸污染原状黄土的强度指标特性,以评价不同程度污染黄土场地的工程性能。以蒸馏水为基液制备了不同污染状态的黄土试样,通过二相电阻率法测试了盐酸、硝酸和硫酸污染黄土的电阻率特征,并采用直剪试验得到了污染黄土的抗剪强度变化规律,进一步联系了电阻率与抗剪强度指标间的定量关系。试验结果表明:酸污染原状黄土的剪应力-剪应变曲线总体呈现应变硬化型变化;随着盐酸和硝酸污染浓度的增加,污染土抗剪强度弱化,电阻率减小;随硫酸污染浓度的增加,污染土抗剪强度增加,电阻率增加。同时,以污染浓度为中间变量进行关联,发现抗剪强度与电阻率呈较好的正相关性。建立酸污染土电阻率及黏聚力和污染浓度的模型关系,可以较好地表征3个参数的正相关关系。最终在硬化型曲线讨论的基础上提出了考虑酸污染溶液浓度影响的剪应力-剪应变曲线预测公式,并通过对抗剪强度黏聚力指标及电阻率参数的分析,初步建议了利用电阻率特征评价原状黄土受酸污染程度的等级标准。In order to verify the evolution law of the strength characteristics of acid-contaminated loess by resistivity method, the engineering performance of contaminated loess sites in different degrees was retrieved. Distilled water was used as the base liquid to prepare loess samples with different pollution states. The resistivity characteristics of the loess contaminated with hydrochloric acid, nitric acid, and sulfuric acid were studied by the two-phase resistivity test method, and the pollution was tested by the indoor tests using a quadruple direct shear tester. The change law of the shear strength of loess has been obtained. And the quantitative relationship between resistivity and shear strength index has been further discussed. The test results show that the shear stress-shear strain curve of acid-contaminated loess generally shows a hardening type;as the concentration of hydrochloric acid and nitric acid increases, the shear strength of the contaminated soil weakens and the resistivity decreases;as the concentration of sulfuric acid increases, the shear strength of the soil increases, and the resistivity increases. Taking the pollution concentration as the intermediate variable, the shear strength and resistivity are positively correlated. The model relationship between the resistivity and cohesiveness parameters of the acid-contaminated soil and the pollution concentration is established. The results can better characterize the correlation of the three parameters. Based on the discussion of the hardening curve, a prediction model for the shear stress-shear strain curve considering the influence of the concentration of acid pollution is proposed, and through the anti-shear strength cohesion index and resistance. Based on the analysis of the parameters, combined with the change rules of shear strength and resistivity, a grade standard for evaluating the degree of acid contamination of the undisturbed loess by the resistivity method is initially proposed.

关 键 词：原状黄土 酸污染 电阻率特征 抗剪强度指标 评价指标 

分 类 号：TU411[建筑科学—岩土工程]