Centrifugal model tests on large-scale landslide with broken-line slip surface under rainfall

Based on the technical support of the large geotechnical centrifuge, centrifugal model tests are performed to study the effects of rainfall and excavation on the deformation and stability of large-scale landslide with broken-line slip surface. The marking points, the particle image velocimetry technology and the sensors which can withstand high centrifugal force are applied during the tests. The earth pressure, pore water pressure and displacement vector field are obtained to make a comprehensive analysis on the characteristics of deformation and failure and the instability modes of large-scale landslide induced by rainfall. The test results show: (1) The unloading by excavation in the slope with large change of slip shape is easy to cause the local landslide in large-scale landslide with broken-line slip; (2) Under the rainfall and excavation, failure in the excavation slope is the earliest, and it has the maximum displacement; (3) Affected by the rainfall, large displacement occurs at the toe of slope and serious failure occurs on surface. A secondary slip surface occurs under the excavation slope, and two main slip surfaces located on the head of the slope and the down edge of the excavation area with change of the angle of the slip surface. The centrifugal mode tests indicate that the characteristics of deformation and failures of large-scale landslide with broken-line slip surface exhibit slide in different grades and blocks under the influence of excavation and rainfall. The stability analysis shows that the rainfall reduces the factor of safety of large-scale landslide, and the head of slope, excavation slope and slope toe are instable.