Ddeformation history analysis and movement process simulation debris flow in Sanggu Valley Glacier debris flow in southern Tibet

Abstract:The glacial debris flow in the Yarlung Zangbo River basin in southeastern Tibet is large in scale, long in duration and strong in impact. This study on the deformation characteristics and influencing factors of the Sanggugou debris flow will provide a scientific reference for the prediction, early warning and prevention of glacial debris flow disasters in southeastern Tibet. As it is difficult to quantitatively describe the formation mechanism of large-scale debris flows using traditional methods, this paper reveals the relationship between the outbreak of Sanggugou debris flows and factors such as material sources and rainfall based on on-site surveys of debris flows in the Sanggugou Basin, drone aerial photography, satellite image information, and geological and meteorological data. A method combining InSAR and RAMMS technology to comprehensively analyze the material source deformation analysis before the debris flow outbreak and the movement characteristics of the debris flow during the outbreak is proposed. First, based on the SBAS-InSAR technology, the deformation of the Sanggugou debris flow during the two outbreaks was analyzed. Combined with satellite images, drone images, and on-site surveys, the deformation process inversion and disaster trend prediction before the outbreak of historical geological disasters in Sanggugou were achieved. Through deformation monitoring and analysis, it was found that the material sources at the rear edge of the debris flow formation area gradually moved to the front edge due to the infiltration of rainfall, revealing its development process under the action of hydrodynamics. The RAMMS debris flow numerical simulation software was used to simulate the movement process of the Sanggugou debris flow during the outbreak. According to the accumulation depth and flow velocity of the debris flow under asynchronous time conditions, the evolution process of the study area was divided into three stages: initial movement, acceleration movement, and deceleration-final. This method combines the deformation history analysis of glacial debris flow with the simulation of the movement process to provide a scientific basis for the development trend and prediction of debris flow, and provide a reference for engineering prevention and control design.