STUDY ON THE DEVELOPMENT CHARACTERISTICS AND GENETIC PATTERNS OF COLLAPSES IN THE TAIHANG MOUNTAIN GRAND CANYON, CHINA

Taihang Mountain Grand Canyon is located in Huguan County,Shanxi Province,which is a part of the South Taihang Mountain in China. After hundreds of millions of years,it has formed a large alpine canyon landscape system represented by canyon groups,peak forest stone pillars,river waterfalls,caves and so on,which has now been built into a "5A" Scenic spot and has the title of "National Geopark" in China. Meantime,the Taihang Mountain Grand Canyon is situated at the surface transition zone between the second and third topography ladders in China. Due to strong tectonic activities and serious surface erosion,as well as unique climate changes in this area,a series of collapse disasters occur frequently,damaging roads and facilities,which often endanger the safety of residents and tourists. Through geological disaster investigation,318 collapse disasters have been identified in the grand canyon area,which are dominated by high-level small-scale rock collapses. They are mainly distributed between 700 and 1100 meters above sea level,with an average drop of about 120 meters and a maximum of more than 300 meters. These collapses are mostly developed in areas where faults and weak rock strata are dense,and are distributed in bands along both sides of the canyon,showing the characteristics of cluster,multiple occurrence and recurrence when rainfall is concentrated in this canyon. Based on the analysis of the disaster-pregnant environment for the collapse of the scenic spot,it is found that under the action of the major disaster factors such as topographic landform,stratigraphic lithology,rock mass structure,surface agency and human activities,the collapse disaster-forming patterns consist of steep collapse zone,ladder-shaped collapsed rock chain,catastrophic collapse and sliding zone,and waterfront collapse zone. Finally,this paper summarizes four collapse types including collapse rolling stone type,collapse chain type,fragmentation type and falling rock surge type,and then puts on the related prevention and control suggestions for these disaster types. This study can provide reference and support for geological disaster prevention and mitigation in canyon areas,development and construction of scenic spots in Taihang Mountain,geological environmental protection and community safety.