Numerical value measuring and calculating method for dam body collapse space-time evolution of barrier dam

Abstract

The invention provides a numerical value measuring and calculating method for dam body collapse space-time evolution of a barrier dam. The method comprises the following steps that a barrier dam model is established by using physical parameters and geometric dimension parameters; an overflow model is established based on the characteristics that barrier dam collapse overflow is a simplified, one-dimensional, multi-phase and isothermal laminar flow water-soil mixture; the overflow model is simplified through depth integral hypothesis to obtain a multi-phase overflow model; dam body shearing force provided by overflow and the shear strength of a dam body are obtained, and whether erosion occurs or not is judged; and natural slope toes of all positions of the dam body and the internal friction angle of a critical soil body are measured and calculated based on time, and if the natural slope toe of the current position is larger than the internal friction angle of the critical soil body, the soil body of the current position enters the overflow. According to the method, measurement and calculation are carried out through the numerical value of the barrier dam model, the erosion surface change and the collapse opening space-time evolution caused by barrier dam collapse can be scientifically and accurately obtained, and the scientific level of debris flow and secondary disaster prevention and control of the debris flow and environmental protection is improved.

Description

technical field [0001] The invention belongs to the technical field of mountain disaster prevention and environmental management, and in particular relates to a numerical calculation method for the temporal and spatial evolution of a dam body failure. Background technique [0002] Large-scale geological disasters such as rock avalanches, landslides and mudslides can lead to partial blockage of river channels and the formation of barrier dams. The formation and destruction of barrier dams are common geophysical geomorphological processes in mountainous areas around the world. Barrier dams typically consist of loose, poorly sorted soils that are highly prone to failure. Flash flooding from dam failures poses a continuing threat to residents, livelihoods and downstream local infrastructure. These megafloods are short-lived and typically orders of magnitude greater than the flow of steady rivers. Floods and can greatly change the topography along river courses, and are the ma...

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Problems solved by technology

[0005] In the prior art, the calculation of key parameters of barrier dam failure (overflow volume, breach evolution) mostly relies on traditional experience or semi-empirical formulas. The erodibility of the dam body, and then calculate the evolution of the breach with a fixed shape and the peak discharge of the downstream flood c through empirical formulas. Although this method is based on a certain physical meaning, it cannot reflect the respective and mutual interactions between the dam breach flood and the soil mass. Mechanical changes, dynamic evolution, and the shape of the dam breach should be determined by the surface overflow and the properties of the dam body. There is no physical basis for using a fixed shape breach in this literature

[0006] In another document with the patent application number 201910803602.3, it is disclosed that the empirical relationship between the water storage capacity of the dam, the amplification factor, and the outflow is established to predict the amount of debris flow after the dam breaks, but this method has strong empirical Lacking physical meaning, this method cannot reflect the particularity brought by different shapes and properties of the dam body. At the same time, the shape of the breach also adopts a fixed geometric shape, which cannot reflect the mechanical action and the relationship between the solid and liquid phases when the dam breaks. Dynamic evolution, and the inability to consider that the overflow flood has always maintained the characteristics of pure water, that is, the property change caused by the intermixing of overflow and solid phase substances during the erosion process

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