STUDY ON THE EVOLUTION MODEL OF NEOGENIC LANDSLIDE (COLLAPSE) HAZARDS IN ROCK MASS OF HYDRO-FLUCTUATION BELT

The Hydro-Fluctuation Belt of the Three Gorges Reservoir is a sensitive area for the stability of the reservoir bank slope. The geological disasters occurred many times in the reservoir area were related to the deterioration of the rock mass. With the passage of time,the deterioration of the rock mass in the Hydro-Fluctuation Belt is increasing,and new landslides continue to emerge. Based on field investigation and office analysis,We have summarized the types of rock mass deterioration and the evolution mode of new landslide hazards in the Hydro-Fluctuation Belt from Zigui to Badong in the Three Gorges Reservoir Area. The results have shown that the lithology of the study area is mainly carbonate rock and clastic rock. The degradation types of carbonate rocks mainly include dissolution(subsurface erosion),fracture manifestation,expansion and mechanical erosion. The degradation types of clastic rocks mainly include loosening(spalling),erosion(abrasion),structural plane disintegration and block fracture,and soft-hard interphase erosion,Among them,the loose/flaking type is the most developed. Based on this binding surface development characteristics,slope structure,lithology and structural characteristics and the boundary,obtained the model of new landslide hazard point formed by rock mass degradation and evolution in different Hydro-Fluctuation Belt. Carbonate bank slopes are mainly characterized by base crushing,base hollowing and dumping,and forward slip. The clastic rock bank slopes are mainly dominated by soft-hard interphase collapse(collapse),apparent dip wedge sliding,forward sliding and reverse dumping. The research results can provide technical support for geological disasters monitoring in the Three Gorges Reservoir area.