Abstract: As for the limitation of instability criterion of displacement predictive parameter in the rainfall-induced landslide and also according to the basic principle of the holographic information theory, this paper proposes a new appraisal parameter of vertical displacement direction ratio for slope stability as an effective displacement dynamic parameter in the analysis and evaluation of slope stability. It systematically analyzes the variation and relationship of displacement and groundwater in rainfall-induced landslide, and also determines the formation mechanism and variation of the surface vertical displacement direction ratio at the different stages of stability. Meanwhile, the quantitative relation of the surface vertical displacement direction ratio with the stability of landslide in the compression stage and the plastic deformation stage is explored. Based on the analysis results above, it establishes the overall instability monitoring and early warning criteria of the vertical displacement direction ratio of the landslide by using the basic principles of mathematical statistics. Finally, the posterior analysis and evaluation of the stability evolution process of the vertical displacement directional ratio are carried out by using actual data of A3 and B3 monitoring points of the Xintan landslide. It is found that the results of the analysis and forecast are consistent with the actual deformation instability law of the slope. It reveals that it is effective and practical for the landslide forecast and early warning.

Key words: Landslide induced by rainfall, vertical displacement direction rate, stability early warning criterion, Xintan landslide