Multifactor Analysis of Landslide Mechanisms: A Case Study of Yongji Expressway, China

Based on deformation monitoring and stability results obtained from geological mapping, geological drilling, macrolaboratory, and microlaboratory tests, the sliding mechanism of landslide in Guzhang County of Yongji expressway was studied. The bedding slope landslide results from cutting slope along the central white mud clay slip, and by on-site investigation and deep displacement monitoring, the clay is determined as the landslide surface. Combining the experimental results and similar geotechnical engineering experience, by back-calculation, the parameters of the soft interlayer are calculated as C(5 kPa) and phi (8.5 degrees). Based on X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRF) test, the results are concluded that the chlorite in clay interlayer is easily water softened, excavation slope after long-term heavy rainfall chlorite clay interlayer softening. Sustained rainfall and underground water levels showed a positive correlation when the slope is sliding, and the heavy rainfall continued to accelerate slope sliding. Furthermore, the slope surface displacement and profound displacement increase quickly, and rainfall and slope displacement also showed a positive correlation.