Calculating method for maximal lifting height of viscous debris flow and application of calculating method

Abstract

The invention discloses a calculating method for maximal lifting height of viscous debris flow and an application of the calculating method. The method comprises the following steps: taking a mud level line, in a natural channel, of the viscous debris flow as a datum line, and taking a maximal distance, lifted by the debris flow, of the perpendicular datum line on the mud level line in the process that the viscous debris flow encounters an obstacle as a maximal value of lifting height of the viscous debris flow; and determining volume-weight gamma c of the viscous debris flow, an included angle theta between a debris flow motion direction and a channel obstacle, average longitudinal shrinking slope J of the debris flow channel, a viscosity coefficient eta, yielding stress tau b and depth H of debris flow above an original channel surface, thereby determining the maximal lifting height value of the debris flow which encounters the obstacle in a motion process. The method is high in calculated result, simple and convenient in calculating, used for designing safety height of debris flow blocking engineering and adaptive to engineering needs.

Description

technical field [0001] The invention relates to a method for measuring and calculating the maximum rush-up height of a viscous mud-rock flow when encountering an obstacle, and its application in determining the design height of a prevention and control project, belonging to the field of mud-rock flow prevention and control. Background technique [0002] Debris flow disaster is one of the main types of mountain disasters, causing hundreds of millions of dollars in economic losses every year. At present, engineering prevention and control is the most effective measure to prevent and control debris flow disasters. However, during the long-term use of prevention and control projects, the damage caused by debris flows to the prevention and control projects cannot be ignored. Even if these projects are damaged, the scale of debris flows will increase on the original basis, greatly increasing the damage caused by debris flows. For example, in 2010, the large mudslide disaster in Z...

AI Technical Summary

Problems solved by technology

For example, if a sand dam is built in a debris flow channel, the debris flow will encounter the sand dam during its progress and cause the debris flow to turn over the non-overflow section of the sand dam and scour the dam abutment and the slope behind the dam, which will easily cause the sand dam unstable

According to the "Code for Design of Debris Flow Prevention and Control Engineering" (DZ / T0239-2004), the non-overflow section of the sand check dam is 0.5-1.0m higher than the overflow section. In this case, only the overflow when the dam body is silted to full storage capacity The dam height design of the dam part ignores the scour generated by the impact of debris flow on the sand check dam, which will easily cause the debris flow to overturn the non-overflow section of the sand check dam, scour the abutment and the slope behind the dam, and cause damage

Existing debris flow calculations mainly use the energy method to analyze the debris flow as a whole. The resulting height is the height of the overall center of gravity of the debris flow. Obviously, the height of the center of gravity is lower than the actual height of the debris flow. It reflects the difference in flow velocity distribution of debris flow within the flow depth range; and the formula is simple, without considering the characteristics of the debris flow itself and the nature of the channel, the accuracy of the calculated value is not high, and it is easy to cause hidden dangers to the protection engineering design

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