饱和砂土不同孔隙率的电阻率特性研究

为研究砂土物理性质随时间变化特性,开展了饱和砂土孔隙率变化的电阻率特性研究。研制了二电极交流电法电阻率测试设备,分析通电时间、接触电阻等影响因素验证设备的可靠性;开展孔隙水不同电阻率、砂土不同饱和度和孔隙率情况下砂土的电阻率特性研究,着重探讨了饱和砂土不同孔隙率的电阻率特性。结果表明:采用该设备测试土体电阻率时,通电历史的影响可以忽略,电极与土体间的接触电阻与土体的饱和度有关;饱和砂土电阻率与其孔隙率具有十分明显的幂函数关系;并通过极差和信噪比参数分析了砂土中孔隙水的电阻率、饱和度和孔隙率对砂土电阻率的影响程度。

Electrical resistivity characteristics of saturated sand with varied porosities

In order to investigate the temporal and spatial characteristics of physical properties of sand, the studies on electrical resistivity properties of saturated sand with varied porosities should be carried out primarily. Firstly, the resistivity measurement devices are developed by using the two-electrode AC electrical method, and the reliability of the devices is verified by considering the effects of electrifying time and contact resistance. Using the devices, the electrical resistivities of sand under varied effects of resistivity of pore water, saturation and porosity of sand are studied. And the resistivity of saturated sand varing with the porosity is highlighted. The results show that the effect of conduction history can be ignored using the devices, and that the contact resistance between electrode and soil is remarkably related to the saturation of sand. The influences of the resistivity of water, saturation and porosity of sand on the resistivity of sand have a decreasing order. There is a remarkable power function between the resistivity of saturated sand and its porosity. Their influence sequences on the resistance of sand are sorted by the noise-signal ratio and range analysis.