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Abstract Compression tests were performed to study the AC electrical resistivity of unsaturated loess with different stresses，strains，porosities，degree of saturations and current frequencies. Considering the inhomogeneity of micro pore distribution，the tortuosity of current flow and current frequency，an electrical resistivity model of equivalent circuit for unsaturated loess was proposed. Under different current frequencies，with the increasing of the stress and strain，the electrical resistivity decreased rapidly at first，and then remained basically unchanged after the stress exceeded 200 kPa and the strain exceeded than 0.084. With the decreasing of porosity，the electrical resistivity decreased rapidly at first，and then approached a stable value when the porosity was below 0.41. With the increasing of the degree of saturation，the electrical resistivity decreased sharply at first，and then approached a stable value when the degree of saturation was above 52.7%. The electrical resistivity of unsaturated loess was found to be closely related to its micro structure and can be divided into four stages. Under different stresses，with the increasing of current frequency，the electrical resistivity decreased rapidly at first，and then approached a stable value. In order to reduce the influence of current frequency on electrical resistivity，the range of 50 kHz–1 MHz was recommended when using AC electrical resistivity method to measure and evaluate unsaturated loess.
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Received: 09 June 2014
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2015, Vol. 34 
