FORMATION MECHANISM AND ENGINEERING GEOLOGICAL PROPERTIES OF MIDDLE-LOWER DIP ANGLE DISCONTINUITIES OF AN AREA IN SOUTHWEST, CHINA

Middle-lower angle structural plane is one of important geological flaws,analysis on the formation mechanism and physical and mechanical characteristics of middle-lower angle structural plane,which can offer reliable evidence to constructions of projects.Taking a hydropower station for example,engineering geological properties of middle-lower angle structural plane are analyzed in detail.Combing with geological phenomena,geological history and earth stress distribution of dam areas are analyzed to obtain the formation mechanism of middle-lower angle structural plane.The probable failure patterns of dam foundation are proposed,and the limit equilibrium method is applied to analyze its stability.The result indicates that the dam is stable.