Rain-induced landslide critical start-up rainfall and instability early-warning time determination method

Abstract

The invention relates to a rain-induced landslide critical start-up rainfall and instability early-warning time determination method, which comprises the following steps: Step 1, determination of physical and mechanical property parameters of a slope and slope angle and slope vertical depth; Step 2, monitoring of landslide slope rainfall and monitoring data processing; Step 3, determination of landslide start-up groundwater level critical depth value; Step 4, determination of landslide start-up effective rainfall threshold; Step 5, determination of real-time critical start-up rainfall of the slope; Step 6, slope stability analysis and evaluation; and Step 7, determination of slope instability early-warning time. The invention creatively puts forward a landslide stability real-time start-up rainfall determination and slope stability evaluation method based on a limit equilibrium method and with the combination of real-time rainfall monitoring. By real-time monitoring of rainfall, slope critical start-up rainfall can be detected and determined. The method has important application prospect and value in landslide hazard monitoring early-warning and stability evaluation.

Description

technical field [0001] The invention relates to the field of rainfall-induced landslide stability evaluation and monitoring and early warning, in particular to a method for measuring landslide critical start-up rainfall and a method for evaluating slope stability based on rainfall monitoring. Background technique [0002] Landslide is the second largest geological disaster next to earthquake disaster, and its monitoring, early warning and prevention methods are important research contents in the field of geological disasters. The breeding and development of landslides are closely related to terrain, landform, geological structure and stratum lithology, and are also closely related to inducing factors such as rainfall, earthquakes and human activities. A large number of facts and studies have shown that the climate with abundant rainfall and heavy rain is the main factor inducing landslide disasters, and the dynamic effect caused by it is the root cause of landslide disasters...

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Problems solved by technology

However, this type of method often needs to analyze the similarity between other similar rainfall-induced landslides and the slope to be evaluated. Only when the fitting degree is high can it be applied to the judgment of the critical rainfall value of instability of a similar landslide to be evaluated, and The critical rainfall value of instability is influenced and controlled by different geological conditions of landslides. Therefore, this type of method has great blindness, randomness and uncertainty; Based on the study of rainfall data, three models for determining the critical value of rainfall have been established—the daily rainfall model, the previous rainfall model and the previous soil water content model. The basic method is to use mathematical statistics to analyze historical landslides and rainfall data. , taking its statistical critical point as the critical value of rainfall-induced landslide

However, this method requires a large number of samples and does not distinguish between landslide types and scales. The results obtained can only judge whether landslides will occur in a certain area under a certain critical value at a certain level of statistical experience, which has certain limitations; (3) The model test measurement method is a method of artificially simulating the slope shape, rainfall process and slope seepage state through indoor tests or in-situ tests, and obtains relevant data from monitoring devices, calculates and analyzes them, and finally obtains the critical start-up rainfall.

The theory of test monitoring is based on the principle of similarity, that is, the model is required to be similar to the prototype, and the model can reflect the situation of the prototype. However, the model is complex and has a limited similarity with the engineering prototype, and the equipment is expensive and requires multiple tests to exclude the influence of accidental factors. Feasibility; (4) The numerical analysis method uses the finite element method to simulate and analyze the evolution law of landslide stability under different rainfall conditions, and establishes the quantitative relationship between landslide stability and rainfall according to the stability evolution law, and determines the corresponding critical rainfall

However, this type of method is easily restricted by the degree of fitting between the constitutive relationship of the rock and soil mass and the mechanical response characteristics of the actual rock and soil mass, the user's own mastery, the complexity of the calculation process and the uncertainty of the calculation results. precision

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