Abstract: To study the influence of the spatial distribution characteristics of material composition on the deformation and failure of gravel soil slope under rainfall, four types of material composition spatial distribution gravel soil slopes and homogeneous slope model tests were conducted according to the characteristics of gravel soil slopes of different geneses. Results show that the role of spatial distribution of material composition played in the deformation and failure of gravel soil slope under rainfall depends on the directions of rainfall infiltration and stress adjustment. When the change direction of soil material intersects the rainfall infiltration direction at a large angle and is the same as the stress adjustment direction, the permeability of slope is actually the permeability of the constituent materials themselves, and the mechanical properties of slope approach the maximum value of the mechanical properties of soil materials that form the slope. When the change direction of soil material is the same as the rainfall infiltration direction and intersects the stress adjustment direction at a large angle, the slope permeability approaches the minimum value of the permeability of the constituent soil material, and the slope deformation and failure are controlled by the weak soil material. The deformation occurs in all parts of the slope under rainfall, and it adjusts to surroundings and thus affecting the surroundings. The fractured surface is more likely to occur in weak soil. Research contributes to the development of the slope disaster investigation, prediction, evaluation and prevention towards refinement.

Key words: gravel soil slope, laboratory model test, spatial distribution of material composition, stress adjustment, rainfall infiltration, pattern of deformation and failure