Small watershed debris flow starting accumulated rainfall threshold calculation method
By calculating the slope, rainfall intensity and dry density of the debris flow source area, the limitations of the debris flow initiation monitoring and early warning model in small watersheds in the northern foothills of the Qinling Mountains were resolved, and a scientific calculation of the cumulative rainfall threshold was achieved, which is suitable for actual monitoring and disaster prevention and mitigation.
Patent Information
- Application Number
- CN202511093921.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-06
- Publication Date
- 2025-09-05
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing technologies have little research on debris flow initiation monitoring and early warning models in small watersheds in the northern foothills of the Qinling Mountains and have great limitations. They are difficult to adapt to expanded applications in different regions and lack scientific calculation methods that consider multiple factors.
Through on-site surveys and measurements, the slope of the debris flow source area, rainfall intensity and dry density of the source accumulation body are obtained. Based on their relationship, the cumulative rainfall threshold for the initiation of debris flow in the small watershed is calculated, and scientific calculations are carried out using formulas.
It achieves accurate monitoring of the initiation of debris flows in small watersheds, provides a scientific calculation method, and the parameters are easy to obtain, which is suitable for actual monitoring, early warning and disaster prevention and mitigation projects.
Smart Images
Figure CN120597095A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of debris flow monitoring and early warning, and in particular to a method for calculating a threshold value of accumulated rainfall for triggering debris flow in a small watershed. Background Art
[0002] The northern foothills of the Qinling Mountains are characterized by complex geological structures, rugged terrain, and concentrated and intense rainfall, making them a high-risk area for geological disasters such as debris flows. In recent years, with the intensification of extreme climate and human activities, debris flows have become increasingly frequent in small watersheds in this region, posing a serious threat to the safety of life and property of local residents and the ecological environment. While research has yielded considerable results in debris flow monitoring and early warning, relatively little research exists on debris flow initiation monitoring and early warning models specifically for this region. Existing studies often consider single factors, resulting in results that are often limited in their scalability and applicability to different regions. Against this backdrop, a multi-factor method for calculating the cumulative rainfall threshold for debris flow initiation in small watersheds is urgently needed to provide technical support for monitoring and early warning of debris flow initiation in small watersheds. Summary of the Invention
[0003] The purpose of the present invention is to provide a method for calculating the cumulative rainfall threshold for initiating debris flows in a small watershed, which has the advantages of scientific measurement and use principles, easy parameter acquisition and simple use method.
[0004] To achieve the above object, the present invention provides a method for calculating the cumulative rainfall threshold for triggering debris flow in a small watershed, comprising the following steps: Step 1: Obtain the slope of the debris flow source area through on-site survey and measurement , rainfall intensity I and the dry density of the source deposit ; Step 2: Combine the slope of the debris flow source area , rainfall intensity I and the dry density of the source deposit The cumulative rainfall threshold for debris flow initiation in small watersheds was calculated based on the relationship between them.
[0005] Preferably, in step 1, rainfall intensity is obtained by arranging a rainfall monitoring instrument in the debris flow channel. I .
[0006] Preferably, in step 1, the dry density of the source deposit is obtained through field investigation and indoor testing. , the calculation formula is: ; Where, is the natural density of soil, kg / m3 , is the moisture content of the soil, %.
[0007] Preferably, the soil moisture content in step 1 is determined by a drying method.
[0008] Preferably, the calculation formula for the cumulative rainfall threshold for initiating debris flow in small watersheds in step 2 is: ; Where, is the slope of the accumulation body in the debris flow source area, is the dry density of the source deposit, I The rainfall intensity.
[0009] Therefore, the present invention adopts the above-mentioned method for calculating the cumulative rainfall threshold for the initiation of debris flow in a small watershed. By accurately determining the functional relationship between the three key influencing factors, the joint influence of the three factors of slope accumulation angle, dry density of material source accumulation body and rainfall intensity on the cumulative rainfall threshold for the initiation of debris flow is comprehensively considered. It has a more scientific measurement principle, a simple calculation form, and easy-to-acquire parameters. It also provides a reference for monitoring, early warning and prevention and control work for the initiation of debris flow in small watersheds, and is suitable for the actual monitoring, early warning and disaster prevention and mitigation projects for debris flow in small watersheds.
[0010] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is a schematic diagram of the initiation of debris flow in a small watershed according to the present invention. DETAILED DESCRIPTION
[0012] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.
[0013] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.
[0014] Example
[0015] See also Figure 1 The present invention provides a method for calculating the cumulative rainfall threshold for triggering debris flow in a small watershed, comprising the following steps: Step 1: Obtain the slope of the debris flow source area through on-site survey and measurement , by placing rainfall monitoring instruments in the debris flow channel to obtain rainfall intensity I Through field investigation and indoor tests, the dry density of the source deposit is obtained. , , is the natural density of soil, kg / m 3 , determined through on-site investigation, is the moisture content of the soil, %, determined by the drying method.
[0016] Step 2: Combine the slope of the debris flow source area , rainfall intensity I and the dry density of the source deposit The cumulative rainfall threshold for debris flow initiation in a small watershed is calculated based on the relationship between the two. The calculation formula is: ; Where, is the slope of the accumulation body in the debris flow source area, is the dry density of the source deposit, I is the rainfall intensity, mm / h.
[0017] Implementation Case 1: In recent years, debris flow activity has been frequent in a gully at the northern foot of the Qinling Mountains, often causing severe damage to infrastructure such as roads and houses at the gully entrance. To effectively identify critical indicators for debris flow initiation in a small watershed, a targeted monitoring and early warning model was proposed. This method calculates the cumulative rainfall threshold based on the cumulative rainfall parameter used in debris flow monitoring and early warning. The specific steps are as follows: Step 1: Through field investigation and data measurement, the slope of the debris flow source area was determined to be 42°. Rainfall monitoring instruments were placed in the debris flow channel to obtain a real-time rainfall intensity of 43 mm / h. Through field investigation and indoor experiments, the natural density of the source deposit was determined to be 1350 kg / m 3 The moisture content was determined to be 12% by the drying method, and the dry density of the source accumulation was determined by the formula kg / m 3 .
[0018] Step 2: Substitute the relevant parameters determined in step 1 into the following formula to determine the cumulative rainfall threshold for debris flow in the small watershed: ; When monitoring and warning the initiation of debris flows in small watersheds, the cumulative rainfall threshold obtained using this method accurately matches the actual critical threshold for the initiation of debris flows in small watersheds, achieving the expected monitoring and early warning effect.
[0019] Implementation Case 2
[0020] In recent years, debris flows have frequently occurred in a small watershed in Sichuan, causing severe damage to infrastructure and resulting in casualties. To effectively identify critical indicators for debris flow initiation, a targeted monitoring and early warning model is proposed. This paper calculates the cumulative rainfall threshold for small watershed debris flow monitoring and early warning, based on the cumulative rainfall threshold parameter used in small watershed debris flow monitoring and early warning. The specific steps are as follows: Step 1: Through field investigation and data measurement, the slope of the debris flow source area was obtained to be 51°; by placing rainfall monitoring instruments in the debris flow channel, the real-time rainfall intensity was obtained to be 61mm / h; through field investigation and indoor experiments, the natural density of the source deposit was obtained to be 1420kg / m 3 The moisture content was determined to be 13% by the drying method, and the dry density of the source accumulation was determined by the formula kg / m 3 .
[0021] Step 2: Substitute the relevant parameters determined in the first step into the following formula to determine the cumulative rainfall threshold for debris flow in the small watershed: ; When monitoring and warning the initiation of debris flows in small watersheds, the cumulative rainfall threshold obtained using this method accurately matches the actual critical threshold for the initiation of debris flows in small watersheds, achieving the expected monitoring and early warning effect.
[0022] Therefore, the present invention adopts the above-mentioned method for calculating the cumulative rainfall threshold for the initiation of debris flow in a small watershed. By accurately determining the functional relationship between the three key influencing factors, the joint influence of the three factors of slope accumulation angle, dry density of material source accumulation body and rainfall intensity on the cumulative rainfall threshold for the initiation of debris flow is comprehensively considered. It has a more scientific measurement principle, a simple calculation form, and easy-to-acquire parameters. It also provides a reference for monitoring, early warning and prevention and control work for the initiation of debris flow in small watersheds, and is suitable for the actual monitoring, early warning and disaster prevention and mitigation projects for debris flow in small watersheds.
[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for calculating the cumulative rainfall threshold for debris flow initiation in a small watershed, characterized by: The following steps are involved: Step 1: Obtain the slope of the debris flow source area through on-site survey and measurement , rainfall intensity I and the dry density of the source deposit ; Step 2: Combine the slope of the debris flow source area , rainfall intensity I and the dry density of the source deposit The cumulative rainfall threshold for debris flow initiation in small watersheds was calculated based on the relationship between them.
2. The method for calculating the cumulative rainfall threshold for triggering debris flows in a small watershed according to claim 1, characterized in that: In step 1, rainfall intensity is obtained by placing rainfall monitoring instruments in the debris flow channel. I .
3. The method for calculating the cumulative rainfall threshold for triggering debris flows in a small watershed according to claim 2, characterized in that: In step 1, the dry density of the source deposit is obtained through field investigation and indoor experiments. , the calculation formula is: ； Where, is the natural density of soil, kg / m 3 , is the moisture content of the soil, %.
4. The method for calculating the cumulative rainfall threshold for triggering debris flows in a small watershed according to claim 3, characterized in that: The soil moisture content in step 1 is determined by the drying method.
5. The method for calculating the cumulative rainfall threshold for triggering debris flows in a small watershed according to claim 4, characterized in that: The calculation formula for the cumulative rainfall threshold for debris flow initiation in small and medium-sized watersheds in step 2 is: ； Where, is the slope of the accumulation body in the debris flow source area, is the dry density of the source deposit, I The rainfall intensity.