Landslide Investigations in the Northwest Section of the Lesser Khingan Range in China Using Combined HDR and GPR Methods

In the northwest section of the Lesser Khingan Range located in the high-latitude permafrost region of northeast China, landslides occur frequently due to permafrost melting and atmospheric precipitation. High-density resistivity (HDR) and ground penetrating radar (GPR) methods are based on soil resistivity values and characteristics of radar-wave reflection, respectively. The combination of these methods together with geological drilling can be used to determine the stratigraphic distribution in this region, which will allow precise determination of the exact location of the sliding surface of the landslide. Field measurements show that the resistivity values and radar reflectivity characteristics of the soil in the landslide mass are largely different from the soil outside the landslide mass. The apparent resistivity values exhibit abrupt change at the position of the sliding surface in the landslide mass, and the apparent resistivity value decreased suddenly. In addition, the radar wave shows strong reflection at the position of the sliding surface where the amplitude of the radar wave exhibits a sudden increase. Drilling results indicate that at the location of the sliding surface of the landslide mass in the study area, the soil has high water content, which is entirely consistent with the GPR and HDR results. Thus, in practice, sudden changes in the apparent resistivity values and abnormal radar-wave reflection can be used as a basis for determining the locations of sliding surfaces of landslide masses in this region.