Based on the insufficient electrochemical impedance theory system in terms of soil,the method using the electrochemical impedance spectroscopy (EIS)with its equivalent circuit parameters by fitting to characterize the soil structure and characteristics was put forward.In this method,EIS of silty clay with different compactive effort,water quality content,NaCl quality content of pore water and clay quality content were tested.The equivalent circuit of silty clay was fitted by Z-View software and then analy-sis the physical significance between the equivalent circuit parameters and silty clay characteristics.It can be concluded that the EIS presents a quasi Randles model when the silty clay water quality content equal to 9%.However,the EIS presents a non-Ran-dles model,attributing to the diffusion impedance of silty clay disappeared with the increasing of water quality content and NaCl quality content of pore water and the clay quality content decreasing.Through fitting the equivalent circuit,the condition and characteristics of pore water can be characterized by the solution resistance of its parameters,and the connectivity features for silty clay pore can be characterized by charge transfer resistance.Moreover,the double layer capacitance represents the compre-hensive characteristics for inside pores ion concentration of silty clay,while the diffusion impedance can reflect the density of silty clay.The proposed methods can measure the silty clay physical properties,extend the electrochemical impedance in the research of soil.%基于电化学阻抗在土体方面理论体系的不足，提出了用电化学阻抗谱（EIS）所拟合等效电路参数来表征土体结构和特性的方法。该方法通过测试粉质黏土在不同击实功、含水质量比、孔隙水中 NaCl 质量比和黏粒质量比下的电化学阻抗谱图，并利用 Z-View 软件拟合粉质黏土的等效电路，分析其等效电路参数与土体特性之间的物理意义。在含水质量比为9％时，粉质黏土的电化学阻抗谱呈现准 Randles 模型，随着其含水质量分数的增加、孔隙水中 NaCl 质量比的增大和黏粒质量比的降低，粉质黏土扩散阻抗消散，呈现非 Randles 模型。经等效电路模拟后发现：可以用其参数溶液电阻表征孔隙水的状态及特性；电荷转移电阻表征粉质黏土孔隙的连通特性；双电层电容表示粉质黏土内部孔隙离子浓度和土体电荷带电的综合特性；扩散阻抗则反映粉质黏土的密实度。表明所提出的方法可以形象衡量粉质黏土的物理性质，扩展了电化学阻抗在土体方面的研究。
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