中文摘要：

通过压缩试验,对不同应力、应变、孔隙率、饱和度、电流频率等条件下的黄土电阻率特性进行研究。基于非饱和黄土的等效电路,综合考虑饱和度附加的孔隙微观分布的不均匀性、电流在土中流通的曲折性、电流频率等影响因素,推导其电阻率模型。结果表明:不同电流频率下,电阻率均随应力和应变的增加先急速减小,当应力增大到200 k Pa,同时应变增加到0.084后,电阻率逐渐稳定;电阻率均随着孔隙率的减小先急速降低,当孔隙率减小到0.41后,电阻率逐渐趋于稳定;电阻率均随着饱和度的增加先急速降低,当饱和度增加到52.7%时,电阻率逐渐趋于稳定;电阻率的变化规律与土体结构的变化密切相关,可以分为4个阶段;不同应力条件下,电阻率均随着电流频率的增加先快速降低,当电流频率增加到50 k Hz时,电阻率逐渐趋于平稳;在采用交流电阻率法对非饱和黄土进行测试和评价时,为了降低电流频率对电阻率值影响而导致的误差,建议将电流频率控制在50k Hz~1 MHz范围内。

英文摘要：

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.