Anaysis on Genetic Model of Wenjiagou Debris Flows in Wenchuan Earthquake Area, Sichuan

详细信息   

• 责任者：Liu Chuanzheng (Steering Centre for Geo-Hazard Emergency ; Ministry of Land and Resources ; Belting 100081 ; China)
• 刊名：Geological Review
• 出版年：2012
• 卷期：58(4)
• 关键词：泥石流 ; debris flows ; 汶川地震2008 ; Wenchuan earthquake 2008 ; 四川 ; Sichuan Province
• 页码：p.709-716
• 图表：illus., 2 tables, 8 refs.
• 分类号：1702
• issnNo：ISSN0371-5736
• isbnNo：CN11-1952/P

摘要

The eight events of debris flow happened in Wenjiagou catchment in the Wenchuan earthquake area, Sichuan, are different from either the general ravine type or the slope slipping type of debris flow, they are resulted from rainfall-induced infiltrating deformation-failure and erosion of the earthquake--landslide mass. The total volume of the eight events of debris flow from the Wenjiagou earthquake--landslide mass is about 180 ×10⁴m³, in which, the maximum one with the volume of 115 ×10⁴m³ happened in Aug. 13, 2010. The mechanism of the Wenjiagou debris flows is that of rainfall-induced seepage and piping, temporary dam water, bursting mass sliding of landslide mass in the early valley-forming stage, and headward erosion, washing and digging away, sideerosion and collapse, mixing flow （similarly to the stirring machine action） in the late valley-enlarging stage. The two events of debris flow happened in June 21,2008, and July 31,2010, are resulted from the mechanism of the early valley-forming stage, and the others are resulted from the mechanism of the late valley-enlarging stage. The inherent mechanism of the slope failure and induced debris flow is that the capacity of rainfall infiltration is not enough to cause groundwater stagnant and water-level increasing in losing landslide mass. When temporary dam water is increasing up to the horizontal level, the hydrodynamic pressure is up to the maximum value, then the slope stability decreases to the lowest, and finally, the critical condition of failure slide will be appeared in the surface of landslide mass.