A Debris Flow Forecasting Method Based on Watershed Coupling with Soil and Water

Abstract

The invention discloses a debris flow forecasting method based on soil and water coupling in a drainage basin, and aims to overcome the technical defect of insufficient consideration of soil and water conditions triggering a debris flow due to the fact that in the existing debris flow forecasting method, whether a debris flow happens or not is judged only by a rainfall threshold value acquired by a statistical forecast method. According to the characteristic that the debris flow is a mixture of water and soil, the debris flow forecasting method based on the coupling of unstable soil slope and surface runoff in a small drainage basin under the condition of rainfall is provided. According to a volume weight p-value of the mixture of the water and soil coupling in the drainage basin of a forecasting area, probability interval of occurrence of the debris flow under the condition of the rainfall is determined to be forecasted, and corresponding warning level of the debris flow is released as needed. The debris flow forecasting method is reliable in principle, scientific and simple in calculation. Since a distributed hydrologic model and a mechanics judging formula are introduced to expand soil stability and runoff of a point scale to a drainage basin scale, the technical problem that the existing forming mechanism of debris flow only focuses on the point scale and cannot be applied to debris flow forecasting is solved, and forecasting precision is improved.

Description

technical field [0001] The invention relates to a mud-rock flow forecasting method, in particular to a mud-rock flow forecasting method based on the water-soil coupling mechanism of a river basin. Background technique [0002] The formation of channel debris flow must meet three basic conditions: suitable terrain and landform conditions, rich source of loose soil and rock debris solid matter, and appropriate rainfall and water source excitation. These three are also the main criteria for judging whether a debris flow occurs in the study of debris flow forecasting. In the study of debris flow forecasting, researchers pay more attention to the use of rainfall as an external excitation condition, and regard rainfall conditions as the basis for judging the formation of debris flow in the basin. At present, most of the forecasting methods put into practical application are of this kind. The specific technical idea of ​​this type of forecasting technology is to determine the cri...

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Problems solved by technology

This forecasting technique has three shortcomings: 1. There is often a lack of long series of debris flow event data for certain debris flow valleys, and the lack of sufficient samples for statistical analysis; The determined critical rainfall conditions are used as the watershed forecast threshold with different underlying surface conditions; 3. The basis of the forecast is based on the fact that the topography and loose solid matter conditions in the forecast area remain unchanged, but in fact the loose solid matter changes greatly, and The amount of loose solid matter has a great influence on the critical rainfall for triggering debris flow

For a long time, many researchers have carried out analysis and research on slope soil stability under the conditions of slope soil water content and pore water pressure changes, and established debris flow initiation models, but this type of initiation model can only evaluate a point or a slope. Whether the soil on the surface is stable cannot judge whether large-scale debris flow can be formed in a watershed, and it cannot be directly used for debris flow forecasting

In recent years, some scholars have also proposed the research direction of establishing a hydraulic-like debris flow start-up forecasting model based on the hydrological model of the basin and taking the hydrological characteristics of the basin as the main line, but no specific ideas or methods have been proposed, and it cannot be used for debris flow forecasting

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