ROCK FALL STUDY IN DIFFERENT AREAS OF SOUTHWEST ANGOLA

In this work, a rock fall assessment was carried out in two distinct areas in southwest Angola. One is located next to Chapel of Nossa Senhora do Monte in the urban area of Lubango. The other area is located on the road between the city of Lubango and the tourist area of Tundavala. The rock mass of the first area belongs to the Tundavala Formation of the Chela Group and consists of quartzitic-sandstone with a sub-horizontal bedding attitude. The rock mass in the second area is composed of quartzitic-sandstone and red siliceous volcaniclastic rocks belonging to the Chela Group. Precipitation and anthropogenic action were defined as important causes for the occurrence of rock falls. Several slope sections were used to run rock fall analysis. The slope profiles and the origin, dimension and paths of the falling rocks were defined and studied using the Rocfall software of Rocscience packages. For each slope section different simulations were performed, assuming two different mass values for each seeder positions. It was observed that the characteristics associated with the coefficients of restitution and the friction angle of the materials that make up the slopes correspond to determining factors for the trajectory, speed, and bounces of the falling rock blocks. The existing rock fall can cause vehicular damage and cause human injury. Slope stabilization procedures are proposed based on the results of the rock fall assessment.