IDENTIFICATION AND MAIN CONTROLLING FACTOR ANALYSIS OF COLLAPSE AND LANDSLIDE BASED ON FINE DEM——TAKING JIACHA-LANGXIAN SECTION OF YARLUNG ZANGBO SUTURE ZONE AS AN EXAMPLE

Jiacha-Langxian section of the Yarlung Zangbo suture zone is located in the southeastern part of the Qinghai-Tibet Plateau. The terrain is highly undulated and the geological disasters are densely distributed. This paper is mainly based on 10 m precision image data acquired by airborne radar, satellite remote sensing data, and high precision drone aerial data to identify the geological hazards of collapse and landslide, and to study its main control factors. We identified 41 collapses and 92 landslides, and used statistical methods to analyze the correlation between main controlling factors and hazards. The thickness identification of the identified collapse and landslides establishes a functional relationship between the area and the volume of the hazards. The estimation of the scale of the collapse and landslide on the base of known area is realized. This paper clarifies the spatial distribution of geological hazards in the area, and studies the main controlling factors of geological hazards of collapse and landslides in the area. The results show that the landslide is mainly developed on the south bank of the Yarlung Zangbo River and the middle and lower part of the slope of the north bank, while the collapse mainly occurs in the middle and upper part of the slope of the north bank. From the analysis of stratum lithology, geological structure, rock mass structure, climatic conditions and human engineering, the collapse is mainly concentrated in conglomerate and granite areas, while landslides are often developed in phyllite. The collapse in the study area is controlled by the slope, the slope direction and the elevation. The slope is the main controlling factor. Landslides are mainly controlled by faults. Slopes have a certain influence on the development of landslides. Elevation and slope direction have little effect on landslides. The landslide is mainly traction type, and the directions of most landslides are generally perpendicular to the direction of the fracture. The collapse is mainly based on the slip type. By analyzing the structural plane of the rock mass, the development of the structural plane can be analyzed, and the genetic mechanism is analyzed.