Experimental Study On Soil Resistivity Of Reservoir Landslide Based On Electrical Resistivity Imaging

Landslide is a serious threat to human production and life of multiple geological disasters.Groundwater is one of the main factors that induce landslide deformation and failure.Rapid and accurate measurement of the internal moisture distribution and migration characteristics of the slope is of great significance to the monitoring,early warning and prevention of the slope.Electrical resistivity imaging is a comprehensive,non-destructive and rapid detection method based on the electrical difference of rock and soil media,which is widely used in the detection of hidden dangers of embankments and groundwater detection of landslide bodies.Because the resistivity of rock and soil is affected by many factors such as mineral type,pore structure,pore liquid composition,measurement temperature and measurement technology,its resistivity characteristics are complex.In this paper,the multi-factor experimental study of landslide soil resistivity is carried out systematically,and the resistivity model is established to provide reference for electrical resistivity imaging in the inversion analysis of landslide water content.The main research results are as follows :(1)The influence of temperature,porosity and saturation on the resistivity of landslide soil is studied through laboratory tests.The results show that the resistivity of landslide soil decreases with the increase of temperature,moisture content and saturation,and increases with the increase of porosity.There is a significant negative correlation between resistivity and saturation,moisture content and temperature.Based on the test results,the resistivity model considering saturation,porosity and temperature is established.(2)In order to study the effect of pore fluid composition on the resistivity of landslide soil,the ion type and concentration of the leaching solution of Baijiabao landslide soil and the nearby river water in the Three Gorges Reservoir area were detected.On this basis,the experimental scheme was designed to study the conductive characteristics of the pore fluid as six salt solutions and its influence on the resistivity of landslide soil.The results show that the resistivity of salt solution is greatly affected by temperature and concentration,and is less affected by the type of salt solution.The resistivity of landslide soil is greatly affected by salt solution concentration and temperature,and the type of salt solution is small.In order to consider the influence of salt solution on the resistivity of soil,the correction coefficient K is introduced to correct the resistivity model established above,which provides reference for further accurate resistivity model of landslide soil.(3)In the process of field application of electrical resistivity imaging,the measurement method and parameters will affect the inversion resolution of resistivity.Through the field test of Baijiabao landslide,the influence of electrode running mode,electrode spacing and power supply voltage on the resistivity imaging resolution is systematically studied.The results show that the vertical resolution of Wenna α device is better than that of Wenna β device.The horizontal resolution of Wenna β device is higher than that of Wenna α device.In the Wenna αpole device,the increase of power supply voltage can enhance the anti-interference ability of geoelectric information and make the inversion results more credible.The increase of electrode distance can significantly enhance the effective detection depth,which makes the geoelectric information in the target detection range more abundant and improves the reliability of inversion.The resistivity model is verified based on the inversion results of electrical resistivity imaging and field drilling information.The verification results show that the overall error between the calculated resistivity value and the measured value is small.The water content distribution of four electrical measuring lines of Baijiabao landslide was obtained by using the verified resistivity model analysis.The results show that the optimized electrical resistivity imaging pole-running device,measurement parameters and the established resistivity model can be well used for the resistivity measurement and water content inversion analysis of landslide,which can provide reference for the popularization and application of electrical resistivity imaging in the measurement and monitoring of water content of landslide.