For the potential application of electrical resistivity measurements in hydrogeological investigations, the knowledge of soil electrical conductivity mechanism with moisture content variation is the key issue. The impact of interconnections between pores and weak connection to physical processes were the two limitations for unsaturated soil electrical conductivity research. In this work, we introduced the concept of equivalent conductive pathway to analyze tortuosity. Based on media series–parallel analysis, a unit series–parallel unsaturated soil electrical conductivity model considering interconnections between pores was established, in which parameters with its own physical meaning. To verify the accuracy of the proposed model, soil resistivity test with moisture content variation was conducted. Soil electrical conductivity was predicted, which was compared with results from test and previous models. The results indicate that our model is expected to produce better results than the previous models. Overcoming the limitations of weak connection to physical processes in the empirical model, the error of soil resistivity was significantly reduced when the impact of interconnections between pores was considered. The average error of the proposed model for clay and sand was 30.6% and 17.4%, respectively, compared to 72.6% and 48.2% for the model that ignored the interconnections between pores. The findings of this study could provide a reference for hydrogeological investigations, such as levee leakage detection.

中文翻译：

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考虑孔隙之间互连的单元串并联非饱和土电导率模型


对于电阻率测量在水文地质调查中的潜在应用，了解含水率变化的土壤电导机制是关键问题。孔隙之间的互连和与物理过程的弱连接的影响是非饱和土壤电导率研究的两个限制。在这项工作中，我们引入了等效导电通路的概念来分析迂曲度。基于介质串并联分析，建立了考虑孔隙间互连的单元串并联非饱和土电导率模型，其中参数具有自身的物理意义。为了验证所提模型的准确性，进行了含水率变化的土壤电阻率测试。预测土壤电导率，并将其与测试和先前模型的结果进行比较。结果表明，我们的模型有望产生比以前的模型更好的结果。克服了经验模型中与物理过程的弱连接限制，当考虑孔隙间互连的影响时，土壤电阻率的误差显著降低。所提出的粘土和沙子模型的平均误差分别为 30.6% 和 17.4%，而忽略孔隙之间互连的模型为 72.6% 和 48.2%。本研究结果可为堤坝渗漏检测等水文地质调查提供参考。