Evaluation of ground-penetrating radar (GPR) and geology survey for slope stability study in mantled karst region

Engineering geological problems such as slope failure may be a result of the karst process. Slope stability evaluation is an effective way to minimize the losses caused by slope failure. In this study, a methodology is developed to evaluate the slope stability. First, a ground-penetrating radar (GPR) survey is conducted along the survey lines, which have a mixed orthogonal distribution in the study area. Detailed information of the stratum structure and karst feature is presented through GPR profiles interpretation. Concurrently, punctual data are obtained through surface geology investigations, borehole surveying and laboratory tests. Subsequently, a series of two-dimensional geological cross sections (in the horizontal direction and along the topographic dip direction) are generated based on the spatial database in the coordinate system relative to the geological map. Finally, numerical simulation is performed utilizing the finite element method. The horizontal deformation and distribution of the plastic zone are used to evaluate the cross-sectional stability along the topographic dip direction, whereas the vertical deformation is chosen as the criterion to evaluate the same in the horizontal direction. Slope stability analysis is conducted in terms of the above comprehensive analysis. To verify the validity of the method, an application is performed in Nan’an district in Chongqing city. The results of the numerical simulation indicate that a sliding surface is not formed, and regional collapse does not occur. The results prove that the slope is stable in the study site, which is consistent with the actual conditions.