基于电阻率法的非饱和路基水汽迁移试验研究

Experimental Study of Water Vapor Migration in Unsaturated Roadbed Based on Resistivity Method

非饱和土路基中水分的迁移不仅以液态形式发生,同时也会以气态形式发生,水汽的耦合迁移作用会在路基长期运营过程中对路基的长期稳定性及服役性能造成严重影响。因此,开展了针对典型非饱和土路基的电阻率测试及水汽迁移试验,研究了初始含水率和初始压实度对电阻率的影响,揭示了水汽迁移过程中非饱和土路基的电阻率变化规律,建立了电阻率-含水率模型。研究结果表明:随着含水率、压实度的增加,黏性土的电阻率均减小,呈指数特征,且电阻率对含水率这一影响因素更为敏感。随着迁移时间增加,土体顶部电阻率越来越小,土体底部电阻率越来越大。不同初始含水率试验,初始含水率增大,顶部土壤电阻率衰减率先增大后减小。不同压实度试验,压实度越大,土体顶部电阻率降低程度越小。电阻率-含水率模型计算结果与试验数据较吻合,模型拟合程度良好。

In unsaturated soil roadbeds,water migration occurs not only in liquid form but also in gas form.The coupled migration of water vapor can severely impact the long-term stability and service performance of the roadbed throughout its service life.We conducted resistivity tests and water vapor migration tests on representative unsaturated soil roadbeds to investigate the effects of initial water content and initial degree of compaction on resistivity.The aim was to uncover the resistivity variation pattern of unsaturated soil roadbeds during water vapor migration and establish a water content-resistivity model.The results indicate that the resistivity of clayey soil decreases exponentially with an increase in water content and compaction degree.Resistivity is more sensitive to changes in water content.Furthermore,as migration time increases,the resistivity decreases at the top of the soil while increasing at the bottom.Higher initial water content initially intensifies resistivity attenuation at the top of the soil,followed by a subsequent decrease.As for different compaction tests,greater compaction results in a smaller decrease in resistivity at the top of the soil.The calculated results from the resistivity-water content model align well with the experimental data,exhibiting a good model fit.