STUDY ON THE MOVEMENT CHARACTERISTICS OF THE ROCKFALL EVENT AT THE BACK EDGE OF LAOSHUCUO REGION IN WU GORGE

In this study, a detailed geological investigation was carried out on the rockfall event at the back edge of Laoshucuo region in Wu Gorge, and the numerical back analysis calculation and parameter susceptivity analysis were carried out on movement characteristics of the rockfall event. Based on the back analysis and field investigation of the rockfall event, it could be seen that the process of rockfall movement involved a free fall-impact slope(about 550 m altitude),rolling along the slope, Secondary impact slope(about 400 m altitude) and rolling along the slope. The energy reduction of the rockfall was mainly affected by the normal velocity loss of it when impacting on the slope. Considering that the state of slope cover being affected by various factors in nature, a susceptivity analysis of the normal recovery coefficient R_n,which represents the normal velocity loss of rockfall, was carried out in this study. It could be seen that the movement mode of the rockfall event in the final stage would be changed from rolling motion along the slope to bouncing motion on the slope with the increase of the normal recovery coefficient R_n. The speed of the rockfall entering the water of Changjiang River would increase significantly, which would cause a great impact on the water near entry point and affected the safe navigation of nearby vessels. Therefore, the actual and extreme conditions of the slope cover should be taken into account when preventing and evaluating the rockfall disaster at the back edge of the high steep slope in the study area in the future.