Characteristics of Movement, Erosion and Deposition of Debris Flows in Jiamaqimei Gully, Bomi, Xizang
英文摘要
The Jiamaqimei Gully is Known as disastrous bebris gully across the Sichuan-Xizang Highway. In the gully there are two types of debris flows, e. g. the viscng to their flow regimes, the viscous debris flows may be subdivided into three groups, i.e. the continuous, the intermittent and creeping. The intermittent debris flow contains a lot of stones and its density in above 2.2t/m3. In the moving process, it appears as a series of pulses and interruptions. Since this types of debris flow has the greatest energy, it is the major bed-forming flow in the gully. At the lower reaches of gully, erosion and deposition of debris flows appear chiefly as the changes of the deposited bar, which is dependent on the changes of the energy of intermittent debris flows. When they suddenly decrease in energy, the intermittent debris flows will stop as whole and form a deposited bar. The height of the bar rises alongside the increase of discharge of the debris flow. The higher the bar is, the greater energy the debris flow behind the bar accumulates. At this time, a debris flow with high energy occurs, the bar will be lowered down or be swept away. At the same time the bed of the gully will be deepened and widened on the right side. For the last 30 years, sometimes a bar is produced and the bed becomes higher; sometimes the bar is cleared away and the bed is deepended and widened on the rhght. In general, the vertical erosion ispredominant.
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