Debris flow rainfall I-D curve threshold construction method and drainage basin debris flow early warning method

Abstract

The invention discloses a debris flow rainfall I-D curve threshold construction method and a debris flow early warning method. The I-D curve threshold construction method comprises the following stepsof firstly, acquiring basin underlying surface data required for a Richard model and Van Genuchten equation numerical simulation; starting a hydrologic simulation process under a given rainfall intensity condition; determining the stability and the runoff generation state of each grid in a drainage basin along a time sequence, and calculating the bulk density of a water and soil mixture; and recording data according with a control point to fit an I-D curve, and finally acquiring a set of I-D thresholds under a previous rainfall amount condition. The invention simultaneously provides a corresponding drainage basin debris flow early warning method. By using the method of the invention, the idea of fitting the curve through historical data statistical analysis is abandoned, and the breakthrough of constructing a debris flow generation condition threshold from the aspect of the measurement of the dynamic index of a debris flow characteristic is realized. The method can effectively solve the problem of using the I-D curve threshold to implement debris flow early warning in the drainage basin without data.

Description

technical field [0001] The invention relates to an early warning method for rainfall-induced debris flow, in particular to an early warning method for debris flow implemented by means of a rainfall intensity-rainfall duration curve threshold (I-D curve threshold), and belongs to the technical field of debris flow disaster prevention and control. Background technique [0002] Rainfall is a key factor in triggering mudslides. Scholars use rainfall parameters (or a combination of parameters) corresponding to debris flow events to study the empirical threshold of rainfall conditions that trigger debris flows. With the help of the established threshold relationship and continuous rainfall monitoring data, the purpose of debris flow forecasting is realized. The most widely studied empirical relationship is the rainfall intensity-rainfall duration threshold (I-D curve threshold) first proposed by Cain (1980), and its general expression is I=δD β , where I represents the average r...

AI Technical Summary

Problems solved by technology

This type of method mainly has five defects: First, in order to use the statistical method to fit the I-D curve, the monitoring data of rainfall data in the watershed and the observation data of debris flow activities in the watershed are necessary. , there is no complete meteorological disaster observation point in the basin, and there is a lack of rainfall monitoring data and debris flow activity observation data in the basin, so it is impossible to construct the I-D curve threshold applicable to this basin, and it is impossible to use it to implement debris flow early warning

Such a debris flow early warning scheme ignores the constraints of the I-D curve threshold in principle, and ignores the early warning boundary of the I-D curve threshold in actual early warning.

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