Method for establishing debris flow data management system

Abstract

The invention discloses a method for establishing a debris flow data management system, and belongs to the field of debris flow prevention and control. The system comprises a channel basic parameter module, a channel satellite picture module, a debris flow motion feature module and a debris flow prevention and treatment suggestion module. According to the system, through combination of channel basic parameter text description and debris flow satellite pictures, the debris flow channel can be known more conveniently. And an empirical formula calculation result and a numerical simulation calculation result of debris flow motion characteristics in a research area are summarized, and suggested correction parameters and a calculation formula are given, so that a user can conveniently perform selection calculation according to the actual situation of the channel. Finally, corresponding disaster prevention and reduction suggestions are given according to different debris flow channels, the disaster prevention and reduction effect is evaluated through numerical simulation results before and after prevention and treatment, the low-cost and high-efficiency universality principle is achieved, and reliable reference can be provided for debris flow disaster prevention and reduction.

Description

Technical Field

[0001] The present invention relates to the field of debris flow disaster prevention and control, and more specifically, to a method for establishing a debris flow data management system. Background Art

[0002] Debris flow is a sudden geological disaster widely distributed globally, generally occurring in mountainous, mid-mountainous, and low mountain and hilly areas. Its main hazards are to wash away towns, enterprises, factories, mines, and villages, causing casualties to humans and livestock, damaging houses and other engineering facilities, and destroying crops, forests, and cultivated land. Preventing and mitigating debris flow disasters is an important part of the national disaster reduction strategy. Precise identification of high-risk areas, early disaster reduction planning and disaster warning, and the need for low-cost and high-efficiency universality. Therefore, establishing a debris flow data management system can provide a reliable reference for debris flow disaster prevention and mitigation, which is of great significance for ensuring regional people's livelihood and important projects.

[0003] Process analysis and hazard prediction are crucial for preventing and mitigating debris flow disasters. Currently, there are mainly three methods for debris flow disaster process analysis: empirical formula method, experimental analysis method, and numerical simulation method. The empirical formula method is difficult to obtain a large amount of on-site data; the experimental analysis method has inconsistent experimental results with the actual situation due to the restriction of size effects; while the numerical simulation method overcomes the limitations of both, reproduces the disaster process through control equations, and makes the results more convincing. Therefore, the present invention mainly uses Massflow numerical simulation calculation and supplemented by a standardized empirical formula to calculate the debris flow movement characteristics and establish a debris flow data management system based on this. Summary of the Invention

[0004] The present invention provides a method for establishing a debris flow data management system. By combining the written description of the basic parameters of the gully with debris flow satellite images, it is more convenient to understand the debris flow gully. Summarize the empirical formula calculation results and numerical simulation calculation results of the debris flow movement characteristics in the study area, and give recommended correction parameters and calculation formulas for users to select and calculate according to the actual situation of the gully. Finally, give corresponding disaster prevention and mitigation suggestions for different debris flow gullies, and evaluate the disaster prevention and mitigation effects through the numerical simulation results before and after prevention and control, realizing the principle of low-cost and high-efficiency universality, and providing a reliable reference for debris flow disaster prevention and mitigation in the region.

[0005] To achieve the above object, an embodiment of the present invention provides a method for establishing a debris flow data management system, including:

[0006] The object of the present invention can be achieved through the following technical solutions: field investigation of debris flow, calculation of debris flow characteristic values, and research on debris flow disaster prevention and control.

[0007] Field investigation research is utilized and combined with the DEM digital elevation model and Google satellite images to obtain the basic data of the target area; the basic data includes: debris flow distribution characteristics, disaster-causing characteristics, and development characteristics.

[0008] The Massflow numerical simulation calculation and the empirical formula in the latest debris flow exploration specification are used to calculate the movement characteristics of debris flow. According to the calculation results, further combined with the quantitative scoring table for the susceptibility degree of debris flow gullies and the calculation results of the single outburst volume of debris flow in the TCAGHP006-2018 Debris Flow Disaster Prevention and Control Engineering Exploration Specification (Trial), a comprehensive evaluation of the entire gully is carried out to conduct the risk zoning of debris flow.

[0009] According to the buildings at the gully mouth, retaining projects are selected, and the numerical simulation is carried out on the debris flow after adding the retaining project to calculate its movement characteristics; by comparing the debris flow characteristic values before and after prevention and control, the prevention and control effect of the retaining measures is evaluated.

[0010] By sorting out the above-mentioned investigation data and calculation data, a debris flow data management system is compiled; the debris flow data management system includes the basic parameters of the gully, satellite pictures of the gully, debris flow movement characteristics, and debris flow prevention and control suggestions.

[0011] According to the improvement of the above-mentioned plan, the field investigation of debris flow includes on-site investigation and data collection. Among them, the on-site investigation is implemented through satellite images and remote sensing interpretation; the data collection is implemented through literature query and gully historical data.

[0012] According to the improvement of the above-mentioned plan, the specific on-site investigation includes:

[0013] According to the Chinese specification TCAGHP006-2018 Debris Flow Disaster Prevention and Control Engineering Exploration Specification (Trial), the gully type is determined, and the InSAR technology is used to study the surface deformation amplitude in the study area in the past 5 years to assist in discriminating the debris flow gully type.

[0014] Based on the existing data and high-precision DEM data, the gully geomorphic conditions, geological background, meteorological and hydrological conditions, vegetation coverage rate, and human activities are investigated. Among them, the investigation of gully geomorphic conditions includes the determination of the gully location, the measurement of the areas of the formation area, flow area, accumulation area or solid material supply area, elevation, calculation of the average longitudinal slope of the gully, the slope of landslides and collapses in the gully, and the determination of the gully shape coefficient, and the calculation of the loose material source volume. The investigation of the geological background includes aspects such as the tectonic position, the exposed strata and lithology in the gully, the degree of fault development, and neotectonic movement. The investigation of meteorological and hydrological conditions includes temperature and precipitation. The investigation of the vegetation coverage rate includes the vegetation coverage rate along the debris flow gully. The investigation of human activities includes the statistics of the degree of damage to forest vegetation in the gully, steep slope cultivation, etc., and the buildings and populations threatened when debris flow occurs.

[0015] Analyze the channel parameters obtained from the above steps. The analysis includes: analysis of the distribution characteristics of debris flow channels, analysis of the basin area, analysis of the channel length, channel longitudinal slope drop, analysis of the potential source volume, and analysis of the valley morphology and development trend.

[0016] According to the improvement of the above scheme, the data collection specifically includes: natural environment, disaster history, geological environment, geological structure, and research status.

[0017] Through on-site investigation and data collection, the distribution characteristics, disaster-causing characteristics, development characteristics, etc. of debris flows can be specifically obtained.

[0018] According to the improvement of the above scheme, the calculation of debris flow characteristic values includes numerical simulation calculation and empirical formula calculation, and by comparing the differences in the results of the two calculation methods, the traditional empirical formula is corrected. Among them, the numerical simulation calculation is implemented by performing numerical simulation through Massflow software; the empirical formula is implemented by calculating according to the latest debris flow exploration specification and the recommended formula for the research area.

[0019] According to the improvement of the above scheme, the numerical simulation calculation specifically includes:

[0020] The Massflow numerical simulation software predicts and simulates the possible debris flows in the debris flow channels of the research area. Massflow starts from the Navier-Stokes equation of fluid mechanics and derives the mass and momentum control equations based on the depth-integrated continuum mechanics equation. Massflow can consider characteristics such as complex terrain and gully bed erosion, and has second-order accuracy and adaptive solution function. Its control equations are as follows:

[0021] Mass conservation equation:

[0022] Momentum conservation equation:

[0023]

[0024]

[0025] In the formula: ρ is the fluid density / (kg·m 3 ); t is the time; u, v are the fluid velocities in the x and y directions (m / s); g x , g y , g z are the gravity components on each coordinate axis; Z b is the riverbed elevation (m); h is the mud depth of the debris flow fluid (m); τ b is the shear stress at the bottom (Pa); kap is the earth pressure coefficient.

[0026] In this invention, the Voellmy model is selected as the flow model. The Voellmy model is an improvement of the Coulomb model and is applicable to mudflows and debris flow disasters. It takes into account the turbulence coefficient, which can limit the higher movement speed of the fluid. The expression of its turbulence coefficient is as follows:

[0027]

[0028] In the formula: τ b is the shear stress at the bottom (Pa); σ is the normal stress (Pa); μ is the friction coefficient; ρ is the density of the debris flow (kg·m -3 ); ξ is the turbulence coefficient / (m·s -2 ).

[0029] Substitute the debris flow channel parameters collected from the above field investigation into the Massflow numerical simulation software to obtain the movement characteristics of the debris flow, such as the depth of the debris flow, flow velocity, flow intensity, flow rate, area of the deposition fan, and the total amount of flow passing through at one time.

[0030] According to the improvement of the above scheme, the specific calculation of the empirical formula includes:

[0031] Query the latest debris flow exploration specifications and recommended formulas for the study area for calculation to obtain the characteristic values of the debris flow velocity in the study area; obtain the characteristic values of the debris flow discharge and the total amount of flow passing through at one time in the study area through the rainstorm flood method.

[0032] Since the existing classification of debris flow intensity is mainly based on the size of the mud depth or the product of the mud depth and the flow velocity, the relevant characteristic values obtained by the above method are used in arcgis to multiply the mud depth and flow velocity of the debris flow using a raster calculator to obtain the debris flow intensity map, and based on this intensity map, the debris flow risk area is divided according to the latest TCAGHP006 - 2018 Specification for Exploration of Debris Flow Disaster Prevention and Control Projects (Trial).

[0033] Table 1 shows the classification basis for the debris flow hazard in the study area

[0034]

[0035] Analyze the important characteristic values such as the mud depth, flow velocity, and flow intensity of the debris flow in the study area, explore the differences between the numerical simulation calculation and the results of the empirical formula calculation, and correct the empirical formula based on the numerical simulation results. Among them, the flow velocity calculation is corrected by dividing according to the longitudinal slope drop of the channel, and the total amount of flow passing through the debris flow at one time is corrected by dividing according to the basin area.

[0036] The movement characteristics and hazard zoning of the debris flow can be specifically obtained through numerical simulation calculation and empirical formula calculation.

[0037] Improved according to the above solution, the debris flow disaster prevention and control research includes disaster prevention and mitigation suggestions, numerical simulation by adding retaining projects, and comparison of debris flow characteristic values before and after prevention and control.

[0038] Disaster prevention and mitigation suggestions select corresponding basic prevention and control systems and prevention and control engineering measures based on the debris flow gully type and the construction of the gully mouth group.

[0039] The basic prevention and control system includes: a system for controlling the movement of debris flow, using retaining, conditioning, and drainage projects to enable the debris flow to pass or accumulate smoothly in a safe area, thereby reducing or avoiding harm to the protected object; a system for preventing the occurrence of debris flow, using comprehensive management means such as slope protection, gully cleaning, beach treatment projects, and administrative management decrees to improve the basin environment, promote soil and water conservation, and thus reduce the occurrence of debris flow; a system for preventing the harm of debris flow, taking preventive measures, warning measures, and project protection measures to reduce or avoid the harm caused by debris flow to relevant projects and personnel during the activity process.

[0040] The prevention and control engineering measures include: drainage projects, retaining projects, solid source and slope treatment projects, and the solid source and slope treatment projects include: slope cutting projects, drainage projects, and ecological protection projects.

[0041] After selecting the basic prevention and control system and prevention and control engineering measures, conduct Massflow numerical simulation on the debris flow gully to obtain the movement characteristic values after adding the retaining project.

[0042] Compare the debris flow movement characteristic values before and after adding the retaining project to verify the prevention and control effect of the retaining measure and evaluate the prevention and control effect.

[0043] Through the survey data and calculation data in the above steps, compile a debris flow database system for the research area. By establishing a convenient query debris flow data management system, organize the research results of the above steps. By combining the text description of the basic gully parameters with the debris flow satellite images, it is more convenient to understand the debris flow gully. Summarize the empirical formula calculation results and numerical simulation calculation results of the debris flow movement characteristics in the research area, and give recommended correction parameters and calculation formulas for users to select and calculate according to the actual situation of the gully. Finally, give corresponding disaster prevention and mitigation suggestions for different debris flow gullies, and evaluate the disaster prevention and mitigation effect through the numerical simulation results before and after prevention and control, realizing the principle of universality with low cost and high efficiency, and providing a reliable reference for debris flow disaster prevention and mitigation. Through the database system, organize the debris flow data in the research area, which has the characteristics of convenient use, low cost, and strong professionalism, and is of great significance for local government disaster prevention and mitigation. Description of the Drawings

[0044] Figure 1 It is the flow chart of the present invention

[0045] Figure 2 Schematic diagram of the debris flow data management system of the present invention Specific embodiments

[0046] The implementation of the present invention will be described in detail below in conjunction with the accompanying drawings. However, they do not constitute a limitation to the present invention and are only for illustration purposes. At the same time, the advantages of the present invention will be made clearer and easier to understand through the description.

[0047] The debris flow database system of the Emei-Mianning section of the Chengdu-Kunming Railway is taken as an example to describe the present invention in detail, which is also instructive for the establishment of debris flow disaster database systems in other regions.

[0048] The Emei-Mianning section of the Chengdu-Kunming Railway mainly passes through 7 counties and districts, with a length of about 330 km. The topography and landforms in the study area are extremely complex and diverse. There are criss-cross mountains in the region, which belong to the Daliangshan Mountains and the Daxueshan Mountains. The Chengdu-Kunming Railway winds through the mountains and is located on the eastern edge of the Hengduan Mountains in southwestern Sichuan. Most of this area is in the mountainous area with intense geological structure denudation, the terrain is very complex, and it is also an area of intense seismic activity. The Emei-Mianning section of the Chengdu-Kunming Railway belongs to the debris flow-prone area, and there are mainly 116 debris flow channels such as Zilegou.

[0049] Through on-site investigations, the discrimination of debris flow channels in the Emei-Mianning section of the Chengdu-Kunming Railway, the surface changes in the past five years in the Emei-Mianning section of the Chengdu-Kunming Railway, the distribution characteristics of the channels, and the parameter analysis of the channels were collected. At the same time, through methods such as data collection, the natural environment, disaster history, geological environment, geological structure, and research status of Zilegou were obtained.

[0050] According to the above-collected data, the debris flow movement characteristic values in the Emei-Mianning section of the Chengdu-Kunming Railway were calculated by two methods: Massflow numerical simulation and empirical formula. Among them, the local recommended formula was selected for the empirical formula in the Emei-Mianning section of the Chengdu-Kunming Railway.

[0051] Dilute debris flow:

[0052] In the formula, Vc is the average cross-sectional velocity of the debris flow, with the unit of (m / s); n is the roughness coefficient of the clear-water riverbed, which is obtained by referring to the hydrological handbook; R is the hydraulic radius, with the unit of (m / s), and generally the average mud depth can be used instead; I is the hydraulic gradient of the debris flow (expressed as a decimal), and generally the longitudinal slope of the gully bed can be used instead; is the sediment correction coefficient; γH is the unit weight of the solid matter in the debris flow, with the unit of (t / m 3 )

[0053] Viscous debris flow:

[0054] In the formula, V c —Average cross-sectional velocity of the debris flow (m / s); H c —Average mud depth (m); I c—Hydraulic gradient, replaced by the longitudinal slope rate of the gully bed; n c —Roughness coefficient of viscous debris flow.

[0055] Compare the differences between the numerical simulation results and the calculation results of the empirical formula, and modify the empirical formula.

[0056] Table 2 shows the improved reference table for the calculation formula of debris flow velocity in the E'mian section of the Chengdu-Kunming Railway

[0057]

[0058] Table 3 shows the improved reference table for the calculation formula of the total flow volume in one pass in the E'mian section of the Chengdu-Kunming Railway

[0059]

[0060] Analyze the above-mentioned characteristic values of debris flow movement, obtain the debris flow intensity map, and divide the debris flow risk area according to the intensity map in the latest TCAGHP006-2018 Code for Investigation of Debris Flow Disaster Prevention and Control Engineering (Trial).

[0061] Analyze the prevention and control systems and measures for 116 debris flow gullies in the E'mian section of the Chengdu-Kunming Railway. After selecting relevant prevention and control systems and measures, use numerical simulation to calculate the debris flow gullies after prevention and control again, and compare and analyze the characteristic values of debris flow movement before and after prevention and control, so as to verify the prevention and control effect of the retaining measures for debris flow gullies in the E'mian section of the Chengdu-Kunming Railway and evaluate the prevention and control effect.

[0062] Compile the debris flow database system for the E'mian section of the Chengdu-Kunming Railway through the investigation data and calculation data in the above steps.

[0063] The above has introduced the technical solution provided by this application in detail. Specific examples are used in this article to elaborate on the principle and implementation method of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application. For those of ordinary skill in the art in this technical field, this application can be modified and improved, and these modifications and improvements are also included in the protection scope of the claims of this application.

Claims

1. The present invention provides a method for establishing a debris flow data management system, which includes a basic channel parameter module, a channel satellite image module, a debris flow movement characteristic module, and a debris flow prevention and control suggestion module. A debris flow data management system composed of these four modules can be used for debris flow disaster prevention and reduction.

2. The method for establishing a debris flow data management system according to claim 1, wherein: The channel basic parameter module and the channel satellite image module constitute the channel parameter page of the data management system. This parameter page includes the channel name, the affiliated district or county, the longitude and latitude position of the channel, the debris flow type, the basin area, the channel length, the longitudinal slope drop of the channel, the total reserve of loose material sources, the dynamic reserve of loose material sources, the relative elevation difference of the basin, the debris flow density, the susceptibility score of the debris flow channel, the channel bed bending coefficient, and the degree of blockage in the channel. At the same time, the channel satellite image is attached to the page.

3. The method for establishing a debris flow data management system according to claim 1, wherein: The debris flow movement characteristic module constitutes the debris flow characteristic value page of the data management system. This characteristic value page includes the alluvial fan area, the interaction between the flushed material and the buildings at the gully mouth, the hazard assessment, and the debris flow mud depth, flow velocity, discharge, and total one-time flow volume obtained from numerical simulation calculations; The flow velocity, discharge, and total one-time flow volume calculated by the empirical formula; And the flow velocity correction coefficient and the total one-time flow volume correction coefficient obtained by comparing the two methods, and based on this, the recommended flow velocity formula and the recommended total one-time flow volume formula for this channel are given.

4. The method for establishing a debris flow data management system according to claim 1, wherein: The debris flow prevention and control suggestion module constitutes the debris flow prevention and control measure page of the data management system. This prevention and control measure page includes the protection system and protection engineering measures and the protection location of the queried debris flow gully, and gives the comparison of the movement characteristic value results before and after prevention and control. The movement characteristic values include the maximum mud depth, the alluvial fan mud depth, the maximum flow velocity, the alluvial fan flow velocity, the flow intensity, the alluvial fan flow intensity, the gully mouth discharge, the total one-time flow volume, the alluvial fan area. At the same time, the protection effect is evaluated for the user's reference.

Images