1.Institute of Exploration Technology, CAGS, Chengdu Sichuan 611734, China;2.Technology Innovation Center for Risk Prevention and Mitigation of Geohazard, MNR, Chengdu Sichuan 611734, China
Clc Number:
P642.23
Fund Project:
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Abstract:
The rainfall conditions in the shallow hilly red layer area of Gongjue County in eastern Tibet are limited, and the occurrence and development of debris flows are mainly controlled by material source conditions and channel conditions, belonging to the “material source control type” of debris flows. Through geological investigation and statistical analysis, the conditions, mechanisms, and activity characteristics of debris flow formation were analyzed in detail. The following conclusion has been drawn: Gullies with a drainage area less than 1.0km2 and a longitudinal gradient of 100‰ to 300‰ are prone to debris flows; Due to the influence of structure, freeze-thaw weathering, and gypsum containing rocks, the sources of debris flows are relatively abundant, with slope erosion as the main type of source and a distribution characteristic of “multiple points and wide areas”. The supply form is characterized by “zero storage and whole extraction”; Controlled by the form of material supply, the formation of debris flows mainly includes three stages: slope erosion initiation, gully bed accumulation, and bottom erosion; Due to the influence of material sources, the fluid properties of debris flows in the area are mainly viscous transitional, and debris flows have the characteristics of multiple periods, medium to high frequencies, and smaller scale of single debris flows.