New models for calculating the electrical resistivity of loess affected by moisture content and NaCl concentration.

Saline loess is an important cause of environmental geo-issues in northwest China. In this research, electrical resistivity of loess with different moisture contents and NaCl concentrations was measured at three test frequencies. Results indicates the plastic limit (16%) and around 2% NaCl concentration are the critical content affecting the variation of loess electrical resistivity. The variation and conductivity for conductive paths are affected by moisture content and NaCl concentration respectively. Combined with three-phase composition and diffuse double-layer structure, new models that consider the effect of moisture content and NaCl concentration indicate good applicability in the validation datasets from different types of soil. A new model was verified by comparison between previous studies and experimental results. This research provides (i) theoretical support for the calibration of large-scale electrical field surveys and the observation of saline loess and (ii) a valuable reference for the prevention of environmental geo-crisis and the utilization of soil resources in northwestern China.