Stability analysis of a slope under impact of a rock block using the generalized interpolation material point method (GIMP)

The present paper presents a study of a particular instability mechanism observed in coastal ranges of southeastern Brazil. It consists of the failure of a saturated soil slope hit by a rock block detached from higher ground. In the rainy season lasting from November to March, slopes are near or at complete saturation. It is also common under these conditions, that blocks of rock masses of gneissic origins, mainly detaching from the rock mass and sliding along relief joints in higher elevations, acquire momentum to impact lower ground slopes consisting mainly by soil masses eventually saturated. The impact generates pore pressures, which can lead to failure of the slope. The present paper proposes to analyze this condition by using the generalized interpolation material point method (GIMP), a method suitable for analyzing the dynamic character of the problem as well as the generated failure mechanism and ensuing run-out of the failed mass. The paper presents details of the problem and of the coupled fluid-mechanical formulation of GIMP used in analysis. It also presents and discusses the obtained results of the analysis carried out. The paper also comments on the suitability of GIMP for analysis of this type of complex slope stability condition.