Mountain torrent induced landslide disaster risk early warning method and device and storage medium

Abstract

The invention discloses a mountain torrent-induced landslide disaster risk early warning method and device and a storage medium. The method comprises the following steps: acquiring a digital elevation model of a target area; extracting a catchment unit, a water outlet and a water outlet elevation according to the digital elevation model of the target area; calculating a mountain torrent influence range according to the water catchment unit, the water outlet and the water outlet elevation; calculating the mountain torrent influence intensity according to the area proportion of the mountain torrent influence range in the slope unit and the area of the slope unit; calculating the slope cutting strength according to the slope cutting area of the slope unit, the slope unit area and the slope gradient; calculating the critical rainfall of the mountain torrent induced landslide according to the mountain torrent influence intensity and the slope cutting intensity; and performing disaster risk early warning according to the critical rainfall of the mountain torrent induced landslide and weather forecast rainfall. According to the invention, disaster risk early warning is realized, and accuracy and applicability are improved. The method can be widely applied to the technical field of geological disaster meteorological risk early warning.

Description

Technical Field

[0001] The present invention relates to the technical field of geological disaster meteorological risk early warning, and in particular to a method, device and storage medium for early warning of landslide disaster risk induced by mountain torrents. Background Art

[0002] The geological and geomorphological types in mountainous areas are complex, the precipitation in the East Asian monsoon region varies greatly in time and space, droughts and rainstorms occur frequently, the types of flash flood geological disasters are diverse, and the number of landslides induced by rainfall and flash floods is large. The terrain of small watersheds in mountainous areas varies greatly, the riverbed gradient is large, the convergence speed is fast, and the flood storage capacity is weak. Mountain residents often carry out artificial slope cutting activities. Due to the combined effects of slope cutting for building houses and rainstorms, flash floods and landslides are very likely to occur, often forming a series of complex disaster chains. However, traditional disaster warnings are mainly based on single disasters, and a single warning of flash floods or landslides is difficult to warn of complex disaster chains, with low accuracy and low applicability.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the invention

[0004] The embodiments of the present invention provide a method, device and storage medium for early warning of landslide disaster risk induced by mountain torrents, which effectively improves accuracy and applicability.

[0005] On the one hand, an embodiment of the present invention provides a method for early warning of landslide disaster risk induced by mountain torrents, comprising the following steps:

[0006] Obtaining a digital elevation model of the target area;

[0007] Extracting water catchment units, water outlets and water outlet elevations according to the target area digital elevation model;

[0008] Calculate the impact range of the mountain torrent according to the water catchment unit, the water outlet and the water outlet elevation;

[0009] Calculate the intensity of the flash flood impact according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit;

[0010] Calculating the slope cutting strength according to the slope cutting area of ​​the slope unit, the slope unit area and the slope gradient;

[0011] Calculating the critical rainfall for flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity;

[0012] Disaster risk warnings are issued based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall.

[0013] In some embodiments, extracting the water catchment unit, the water outlet and the water outlet elevation according to the target area digital elevation model includes:

[0014] Extracting a river network from a digital elevation model of the target area according to the runoff accumulation and the river network level;

[0015] extracting a catchment area from said river network;

[0016] Extracting the water outlet location from the river network according to the water collection range;

[0017] Using a hydrological analysis module to classify the river network to obtain a river grade;

[0018] Dividing the target river according to the river grade and the water outlet position to obtain the water catchment unit;

[0019] The water outlet and the water outlet elevation are extracted from the water collection unit.

[0020] In some embodiments, the calculating the impact range of the flash flood according to the water catchment unit, the water outlet and the water outlet elevation includes:

[0021] Based on the rainfall-runoff relationship parameters, the maximum retention volume of the basin is calculated;

[0022] Calculate the runoff corresponding to each of the watershed units in rivers of different river grades according to the rainfall and the maximum retention capacity of the watershed;

[0023] Calculating the delay time based on the flow length, the maximum detention volume of the watershed and the average slope of the hydrological response unit;

[0024] Calculate the confluence time based on the lag time;

[0025] Calculating the peak time according to the confluence time;

[0026] Calculate the unit line flood peak flow according to the runoff, the hydrological response unit area and the peak time;

[0027] Calculate the water depth of the outlet according to the unit line flood peak flow and unit terrain slope;

[0028] Calculating the water level of the water outlet according to the water depth of the water outlet and the original elevation of the water outlet;

[0029] According to the water levels of the plurality of water outlets, a water level interpolation process is performed using a preset interpolation method to obtain a water level surface;

[0030] Subtracting the water level surface from the elevation surface of the target area to obtain an elevation difference;

[0031] The grids in the target area digital elevation model where the elevation difference is greater than 0 are taken as the flash flood impact range.

[0032] In some embodiments, the calculating the critical rainfall for flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity includes:

[0033] Calculating the slope stability coefficient according to the flash flood impact intensity and the slope cutting intensity;

[0034] The critical rainfall for the landslide induced by the mountain torrent is calculated based on the slope stability coefficient, the water conductivity of the slope rock and soil, the slope gradient, the internal friction angle, the impact intensity of the mountain torrent, the slope cutting strength, the specific catchment area and the bulk density of the rock and soil.

[0035] In some embodiments, the calculating of the hysteresis time according to the water flow length, the maximum retention capacity of the watershed and the average slope of the hydrological response unit comprises:

[0036] The hysteresis is calculated according to the flow length, the maximum retention volume of the watershed and the average slope of the hydrological response unit by using the hysteresis calculation formula, which is:

[0037]

[0038] Wherein, L is the lag time, l is the flow length, S is the maximum retention capacity of the basin, and y is the average slope of the hydrological response unit.

[0039] In some embodiments, the calculating the water depth of the outlet according to the unit line flood peak flow and the unit terrain slope includes:

[0040] According to the unit line flood peak flow and unit terrain slope, the outlet water depth is calculated by the outlet water depth calculation formula, and the outlet water depth calculation formula is:

[0041]

[0042] Wherein, h is the water depth of the outlet, Q is the peak flow of the unit line, and θ is the unit terrain slope.

[0043] In some embodiments, the calculating of the critical rainfall for the flash flood-induced landslide according to the slope stability coefficient, the slope rock and soil water conductivity, the slope gradient, the internal friction angle, the flash flood impact intensity, the slope cutting intensity, the specific rainwater collection area and the rock and soil bulk density includes:

[0044] The critical rainfall for the flash flood-induced landslide is calculated by the critical rainfall calculation formula according to the slope stability coefficient, the slope rock and soil water conductivity, the slope gradient, the internal friction angle, the flash flood impact intensity, the slope cutting strength, the specific rainwater collection area and the rock and soil bulk density. The critical rainfall calculation formula is:

[0045]

[0046] Where q is the critical rainfall for flash flood-induced landslide, T is the hydraulic conductivity of the slope rock and soil, θ is the slope gradient, and C ′ is a constant, φ is the internal friction angle, g is the slope stability coefficient, H is the flash flood impact intensity, K is the slope cutting strength, a is the specific catchment area, and r is the rock and soil bulk density.

[0047] On the other hand, an embodiment of the present invention provides a flash flood-induced landslide disaster risk warning device, comprising:

[0048] The first module is used to obtain the digital elevation model of the target area;

[0049] The second module is used to extract the water catchment unit, the water outlet and the water outlet elevation according to the digital elevation model of the target area;

[0050] The third module is used to calculate the impact range of the mountain torrent according to the water catchment unit, the water outlet and the water outlet elevation;

[0051] The fourth module is used to calculate the impact intensity of the flash flood according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit;

[0052] A fifth module is used to calculate the slope cutting strength according to the slope cutting area of ​​the slope unit, the slope unit area and the slope gradient;

[0053] The sixth module is used to calculate the critical rainfall of landslide induced by mountain torrents according to the mountain torrent impact intensity and the slope cutting intensity;

[0054] The seventh module is used to issue disaster risk warnings based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall.

[0055] In another aspect, an embodiment of the present invention provides a computer device, comprising:

[0056] at least one processor;

[0057] at least one memory for storing at least one program;

[0058] When the at least one program is executed by the at least one processor, the at least one processor implements the described method.

[0059] On the other hand, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0060] The beneficial effects of the present invention are as follows:

[0061] The embodiment of the present invention first obtains a digital elevation model of the target area, extracts the watershed unit, the water outlet and the water outlet elevation according to the digital elevation model of the target area, and calculates the impact range of the flash flood according to the watershed unit, the water outlet and the water outlet elevation, and then calculates the impact intensity of the flash flood according to the area ratio of the flash flood impact range in the slope unit and the slope unit area, and calculates the slope cutting strength according to the slope unit cutting area, the slope unit area and the slope gradient, and then calculates the critical rainfall of the flash flood-induced landslide according to the flash flood impact intensity and the slope cutting strength, and finally performs a disaster risk warning according to the critical rainfall of the flash flood-induced landslide and the meteorological forecast rainfall, so that the disaster risk warning can be achieved by combining the intensity of the flash flood and the slope cutting strength, thereby improving the accuracy and applicability.

[0062] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0064] Figure 1 This is a flow chart of a method for early warning of landslide disaster risk induced by flash floods according to an embodiment of the present invention;

[0065] Figure 2 A schematic diagram of an overall process of calculating a flash flood impact range according to an embodiment of the present invention;

[0066] Figure 3 A schematic diagram of an overall process for calculating critical rainfall for landslides induced by rainfall and flash floods according to an embodiment of the present invention;

[0067] Figure 4 This is a schematic structural diagram of a flash flood-induced landslide disaster risk warning device according to an embodiment of the present invention;

[0068] Figure 5 The figure is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the attached claims.

[0070] It is understood that the terms "first", "second", etc. used in this application can be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another concept. For example, without departing from the scope of the embodiment of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination".

[0071] The terms "at least one", "multiple", "each", "any", etc. used in this application, at least one includes one, two or more, multiple includes two or more, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0072] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0073] Before describing the embodiments of the present application in detail, some nouns and terms involved in the embodiments of the present application are first described. The nouns and terms involved in the embodiments of the present application are subject to the following explanations.

[0074] Compound chain disasters: refers to compound disasters caused by the interaction and mutual influence of different types of natural disasters. These natural disasters can be meteorological disasters, geological disasters, biological disasters, etc. There is interaction and mutual influence between them, exacerbating or even triggering other disasters, thus forming compound disasters.

[0075] In the relevant technology, about 70% of my country's area is mountainous, with complex geological and geomorphological types. At the same time, most areas are located in the East Asian monsoon region, with large temporal and spatial variations in precipitation, frequent droughts and rainstorms, and various types of flash floods and geological disasters. There are many landslides caused by rainfall and flash floods. According to the results of the national geological disaster survey, landslides account for as much as 51% of geological disasters, and landslides caused by rainfall and flash floods account for 90% of the total landslides. In recent years, under the general trend of global warming and frequent extreme weather, it is easy to form a new type of basin-wide composite chain disaster characteristics of flash floods and landslides in the mountainous areas of South China. The typhoon caused heavy rains in a small river basin in a certain place, inducing flash floods and geological disasters, resulting in many deaths, missing persons, injuries and illnesses due to the disaster, and emergency relocation and resettlement of many people, with many direct economic losses. The terrain of small watersheds in mountainous areas varies greatly, the riverbed gradient is large, the confluence speed is fast, the flood storage capacity is weak, and the residents in mountainous areas often cut slopes artificially. Due to the combined effects of slope cutting and house building and heavy rain, flash floods and landslides are very likely to occur, often forming a series of "disaster chains". The compound chain geological disasters formed by flash floods and induced landslides seriously threaten the social and economic security of mountainous areas, and the disaster early warning task is urgent. However, the current disaster early warning is still mainly for single disasters, and only early warnings are given for flash floods or landslides. There is still a lack of effective methods for early warning of the flash flood-landslide compound disaster chain triggered by rainfall, and the current rainfall critical value has not yet considered the impact of slope cutting and house building, and underestimated the impact of flash floods and human activities on disasters. The main difference between compound chain disasters and single disasters is that after the superposition of flash floods and disasters, a cumulative amplification effect is produced in the process of disaster initiation and transmission, which extends the scope and duration of the disaster chain. Mountain torrents can induce landslides. After induction, the two types of disasters, mountain torrents and landslides, still exist in the same time and space scale, resulting in superposition and amplification. There is a progressive relationship, as well as a superposition and amplification relationship.

[0076] In view of this, the embodiment of the present invention analyzes the role of human slope cutting activities and mountain torrents in the process of inducing landslide disasters. First, based on the runoff and confluence process in the small watershed unit, the impact range of mountain torrents under certain rainfall conditions is simulated, and the impact intensity of mountain torrents is calculated. Then the slope cutting degree and slope cutting intensity of the target area are calculated, and then the mountain torrent impact factor and slope cutting intensity are incorporated into the critical rainfall model of landslide disasters, and the critical rainfall threshold of landslides considering the impact of mountain torrents and human activities is calculated, and finally disaster warning is carried out.

[0077] A flash flood-induced landslide disaster risk warning method provided in an embodiment of the present application relates to the field of geological disaster meteorological risk warning technology. A flash flood-induced landslide disaster risk warning method provided in an embodiment of the present application can be applied to a terminal, can also be applied to a server, and can also be software running in a terminal or a server. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, and a car terminal, etc., but is not limited to this; the server side can be configured as an independent physical server, or it can be configured as a server cluster or distributed system composed of multiple physical servers, and can also be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network; the software can be an application that implements a flash flood-induced landslide disaster risk warning method, etc., but is not limited to the above forms.

[0078] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0079] The following is a detailed explanation of the embodiments of the present application in conjunction with the accompanying drawings:

[0080] Figure 1 is an optional flow chart of a flash flood-induced landslide disaster risk warning method provided in an embodiment of the present application. Figure 1 The method may include but is not limited to steps S101 to S107.

[0081] Step S101, obtaining a digital elevation model of a target area;

[0082] Step S102, extracting the water catchment unit, the water outlet and the water outlet elevation according to the digital elevation model of the target area;

[0083] Step S103, calculating the impact range of the flash flood according to the water catchment unit, the water outlet and the water outlet elevation;

[0084] Step S104, calculating the intensity of the flash flood impact according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit;

[0085] Step S105, calculating the slope cutting strength according to the slope unit cutting area, the slope unit area and the slope gradient;

[0086] Step S106, calculating the critical rainfall for flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity;

[0087] Step S107: issuing a disaster risk warning based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall.

[0088] Steps S101 to S107 shown in the embodiment of the present application implement disaster risk warning and improve accuracy and applicability.

[0089] In step S101 of some embodiments, the digital elevation model of the target area may be obtained through a geological information database or other methods, without limitation.

[0090] In some embodiments, in step S102, extracting the water catchment unit, the water outlet and the water outlet elevation according to the target area digital elevation model may include but is not limited to the following steps:

[0091] Extract the river network from the digital elevation model of the target area according to the runoff accumulation and river network level;

[0092] Extracting catchment areas from river networks;

[0093] Extract the outlet location from the river network according to the catchment area;

[0094] Use the hydrological analysis module to classify the river network and obtain the river level;

[0095] According to the river level and outlet location, the target river is divided into water catchment units;

[0096] Extract the outlet and outlet elevation from the catchment cell.

[0097] In some embodiments, river networks of different river network levels can be first extracted from the digital elevation model of the target area according to the cumulative runoff and the river network level. It is understandable that the river network and its branches extracted based on the digital elevation model DEM have certain hydrological significance. Using the idea of ​​surface runoff simulation, the river networks of different river network levels represent different cumulative runoff. The higher the level of the river network, the greater the cumulative runoff. Then the catchment range is extracted from the river network, and the outlet position is extracted from the river network according to the catchment range. It is understandable that the snap pour point tool in the hydraulic toolset under the ARCGIS spatial analysis tools toolbox can be used to find the point with the highest cumulative runoff within a specified distance as the outlet position of the hydrological response unit. Then, the hydrological analysis module is used to classify the river network to obtain the river level, and the target river is divided according to the river level and the outlet position to obtain the catchment unit. Among them, in ArcGIS, the calculation of the catchment unit is calculated using the basin tool in the hydraulic toolset. Finally, the outlets and outlet elevations of discrete rivers at all levels are extracted from the catchment unit. The outlet is the lowest point of the hydrological response unit.

[0098] In some embodiments, in step S103, the flood impact range is calculated according to the water catchment unit, the water outlet and the water outlet elevation, which may include but is not limited to the following steps:

[0099] Based on the rainfall-runoff relationship parameters, the maximum retention volume of the basin is calculated;

[0100] According to the rainfall and the maximum retention volume of the watershed, the runoff corresponding to each watershed unit in rivers of different river levels is calculated;

[0101] The lag time is calculated based on the flow length, the maximum retention volume of the watershed, and the average slope of the hydrological response unit;

[0102] Based on the lag time, calculate the confluence time;

[0103] Calculate the peak time based on the confluence time;

[0104] Calculate the peak flow of unit line according to runoff, hydrological response unit area and peak time;

[0105] Calculate the water depth of the outlet according to the unit line flood peak flow and unit terrain slope;

[0106] Calculate the water level at the outlet according to the water depth and original elevation of the outlet;

[0107] According to the water levels of multiple water outlets, a preset interpolation method is used to perform water level interpolation processing to obtain a water level surface;

[0108] Subtract the water level surface from the target area elevation surface to obtain the elevation difference;

[0109] The grids with elevation difference greater than 0 in the digital elevation model of the target area are regarded as the impact range of the flash flood.

[0110] In some embodiments, the maximum retention capacity of the watershed can be calculated using the SCS model (runoff curve method) based on the rainfall-runoff relationship parameters, wherein the calculation formula for the maximum retention capacity of the watershed is: In the formula, S is the maximum retention capacity of the basin, and CN is the rainfall-runoff relationship parameter, which is an important dimensionless parameter used in the SCS model to describe the rainfall-runoff relationship. It reflects the comprehensive characteristics of the basin's antecedent moisture condition (AMC), slope, soil type and land use status, and can better reflect the impact of underlying surface conditions on the runoff process. The CN value can be set by empirical values ​​or experimental observations, and the CN value of the basin can be determined and adjusted according to the land use mode, treatment conditions, hydrological conditions and soil type of the basin. Then, according to the rainfall and the maximum retention capacity of the basin, the runoff corresponding to each watershed unit in the rivers of different river levels is calculated, where the runoff calculation formula is: In the formula, R is the runoff, P is the rainfall, and S is the maximum retention of the basin. The hysteresis is calculated according to the flow length, the maximum retention of the basin, and the average slope of the hydrological response unit using the hysteresis calculation formula, where the hysteresis calculation formula is: In the formula, L is the lag time, l is the flow length, S is the maximum retention of the basin, and y is the average slope of the hydrological response unit. Then, the confluence time is calculated based on the lag time, where the calculation formula for the confluence time is: Where, t c is the confluence time, and L is the lag time. According to the confluence time, the peak time is calculated, where the calculation formula of the peak time is: Where, t p is the peak time, t c is the confluence time. According to the runoff, hydrological response unit area and peak time, the map algebra function of ArcGIS is used to calculate the unit line flood peak flow of each water confluence unit. The calculation formula of the unit line flood peak flow is: Where Q is the peak flow rate of the unit line, A is the hydrological response unit area, R is the runoff, t p is the peak time. Then, according to the unit line flood peak flow and unit terrain slope, the outlet water depth is calculated by the outlet water depth calculation formula, where the outlet water depth calculation formula is: Wherein, h is the outlet water depth, Q is the unit line flood peak flow, and θ is the unit terrain slope. According to the outlet water depth and the original elevation of the outlet, the outlet water level is calculated, where the calculation formula of the outlet water level is: W=G+h, where W is the outlet water level, G is the original elevation of the outlet, and h is the outlet water depth. Then, according to the multiple outlet water levels, the water level interpolation processing is performed using the preset interpolation method to obtain the water level surface. Exemplarily, the value of each outlet water level can be interpolated into a water level surface by kriging. Finally, the water level surface is subtracted from the elevation surface of the target area to obtain the elevation difference, and the grid with an elevation difference greater than 0 in the digital elevation model of the target area is used as the range affected by the flash flood, while the grid with an elevation difference less than 0 is not affected by the flash flood. It is understandable that due to the limitation of the number of discrete points and the order of magnitude of the water level in the interpolated water level surface, the water level difference is much larger than the actual one. Therefore, error checking is required, that is, further reclassifying the calculation results to extract the range that conforms to the actual situation.

[0111] In some embodiments, in step S104, the intensity of the impact of the flash flood may be calculated according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit, wherein the calculation formula for the intensity of the flash flood impact is: Where H is the intensity of mountain torrent impact, A F is the area ratio of the flash flood affected area in the slope unit, and A is the slope unit area.

[0112] In some embodiments, in step S105, in a small watershed in a mountainous area where agriculture is the main economy, the impact of human activities on geological disasters in a small watershed where agricultural activities are the main economy is mainly through two aspects: changing the topography and changing the groundwater cycle. Human activities may include reclamation and planting, building houses and roads, so the selection index may be expressed by considering the slope cutting intensity index. The form of slope cutting may include building roads, cutting slopes to build houses or planting. The slope cutting intensity may be calculated based on the slope cutting area of ​​the slope unit, the slope unit area and the slope gradient, wherein the calculation formula for the slope cutting intensity is: Where K is the slope strength, A K is the slope unit cutting area, A is the slope unit area, and θ is the slope gradient.

[0113] In some embodiments, in step S106, the critical rainfall for flash flood-induced landslide is calculated according to the flash flood impact intensity and the slope cutting intensity, which may include but is not limited to the following steps:

[0114] Calculate the slope stability coefficient based on the intensity of mountain torrent impact and the intensity of slope cutting;

[0115] The critical rainfall for flash flood-induced landslide is calculated based on the slope stability coefficient, slope rock and soil water conductivity, slope gradient, internal friction angle, flash flood impact intensity, slope cutting strength, specific catchment area and rock and soil bulk density.

[0116] In some embodiments, the slope stability coefficient can be calculated first according to the intensity of the impact of mountain torrents and the intensity of the slope cutting. It can be understood that the fundamental impact of mountain torrents and human activities on geological disasters is to change the landform and groundwater circulation, thereby affecting the stability of the slope. Assuming that K=1, H=1, that is, when human activities and mountain torrents are the strongest, the stability coefficient of the slope is reduced by 50%. That is to say, under the natural state, the slope stability coefficient is 0.5, and the slope is in a critical state due to the strong influence of human activities and mountain torrents. Exemplarily, the slope stability coefficient g can be set to 0.5. Then, according to the slope stability coefficient, the water conductivity of the slope rock and soil body, the slope gradient, the internal friction angle, the intensity of the impact of mountain torrents, the slope cutting strength, the specific catchment area and the bulk density of the rock and soil body, the critical rainfall calculation formula is used to calculate the critical rainfall of the mountain torrent-induced landslide. The critical rainfall calculation formula is: Where q is the critical rainfall for flash floods to induce landslides, T is the hydraulic conductivity of the slope rock and soil, θ is the slope gradient, and C is ′ is a constant, φ is the internal friction angle, g is the slope stability coefficient, H is the intensity of mountain torrents, K is the slope cutting strength, a is the specific catchment area, and r is the bulk density of the rock and soil. For example, when the slope stability coefficient g is 0.5, the critical rainfall calculation formula is:

[0117] In some embodiments, in step S107, a disaster risk warning may be issued based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall. For example, the meteorological forecast rainfall may be compared with the critical rainfall, and a disaster risk warning may be issued if the critical rainfall is exceeded. When the meteorological forecast rainfall is 10 mm and the critical rainfall is 9 mm, the meteorological forecast rainfall is greater than the critical rainfall, and a disaster risk warning may be issued.

[0118] In some embodiments, the overall process of calculating the impact range of flash floods is as follows: Figure 2 As shown in the figure, we can first extract the river network through the digital elevation model DEM, and divide the confluence units according to the river level to obtain discrete outlets. Then, according to the rainfall P, the SCS model is used to calculate the runoff R and confluence Q (i.e., the unit line flood peak flow). The water depth h of the outlet is calculated by the Manning formula, and then the outlet water level W is obtained by superimposing the terrain height. Then, through Krging interpolation, the water level surface is obtained. Finally, the water level surface and the digital elevation surface are error-checked and tangent to obtain the impact range of the flash flood.

[0119] In some embodiments, the overall process of calculating the critical rainfall for landslide induced by rainfall flash flood is as follows: Figure 3As shown in the figure, we can first obtain the digital elevation model of the study area, divide the river structure and units, then calculate the human engineering activity index (i.e., slope cutting intensity) in the slope unit, and calculate the flash flood influence range based on the hydrological unit in the hydrological unit. Finally, we can combine the slope cutting intensity, flash flood influence range and the landslide model based on the slope unit to calculate the critical rainfall threshold of the flash flood-landslide complex chain disaster, i.e., the critical rainfall for flash flood-induced landslides.

[0120] The beneficial effects of implementing the embodiments of the present invention include: the embodiments of the present invention first obtain the digital elevation model of the target area, extract the water catchment unit, the water outlet and the water outlet elevation according to the digital elevation model of the target area, and calculate the flash flood impact range according to the water catchment unit, the water outlet and the water outlet elevation, and then calculate the flash flood impact intensity according to the area proportion of the flash flood impact range in the slope unit and the slope unit area, and calculate the slope cutting intensity according to the slope unit cut slope area, the slope unit area and the slope gradient, and then calculate the critical rainfall of the flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity, and finally carry out disaster risk warning according to the critical rainfall of the flash flood-induced landslide and the meteorological forecast rainfall, so that the disaster risk warning can be realized by combining the intensity of the flash flood and the slope cutting intensity, thereby improving the accuracy and applicability. At the same time, this embodiment overcomes the limitations of the traditional single disaster warning and improves the accuracy and effectiveness of the critical rainfall calculation.

[0121] like Figure 4 As shown, the embodiment of the present invention also provides a flash flood-induced landslide disaster risk warning device, comprising:

[0122] The first module 801 is used to obtain a digital elevation model of a target area;

[0123] The second module 802 is used to extract the water catchment unit, the water outlet and the water outlet elevation according to the digital elevation model of the target area;

[0124] The third module 803 is used to calculate the impact range of the mountain torrent according to the water catchment unit, the water outlet and the water outlet elevation;

[0125] The fourth module 804 is used to calculate the impact intensity of the flash flood according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit;

[0126] The fifth module 805 is used to calculate the slope cutting strength according to the slope cutting area of ​​the slope unit, the slope unit area and the slope gradient;

[0127] The sixth module 806 is used to calculate the critical rainfall for flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity;

[0128] The seventh module 807 is used to issue disaster risk warnings based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall.

[0129] The contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0130] like Figure 5 As shown, an embodiment of the present invention further provides a computer device, including:

[0131] at least one processor 901;

[0132] At least one memory 902, used to store at least one program;

[0133] When at least one program is executed by at least one processor, the at least one processor implements Figure 1 The method shown.

[0134] The contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0135] The embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, Figure 1 The method shown.

[0136] The contents of the above method embodiments are all applicable to the present storage medium embodiments. The functions specifically implemented by the present storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0137] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A flash flood-induced landslide disaster risk early warning method, characterized in that: The following steps are involved: Obtaining a digital elevation model of the target area; Extracting water catchment units, water outlets and water outlet elevations according to the target area digital elevation model; Calculate the impact range of the mountain torrent according to the water catchment unit, the water outlet and the water outlet elevation; Calculate the intensity of the flash flood impact according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit; Calculating the slope cutting strength according to the slope cutting area of ​​the slope unit, the slope unit area and the slope gradient; Calculating the critical rainfall for flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity; Disaster risk warnings are issued based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall.

2. The method according to claim 1, characterized in that: The step of extracting the water catchment unit, the water outlet and the water outlet elevation according to the target area digital elevation model comprises: Extracting a river network from a digital elevation model of the target area according to the runoff accumulation and the river network level; extracting a catchment area from said river network; Extracting the water outlet location from the river network according to the water collection range; Using a hydrological analysis module to classify the river network to obtain a river grade; Dividing the target river according to the river grade and the water outlet position to obtain the water catchment unit; The water outlet and the water outlet elevation are extracted from the water collection unit.

3. The method according to claim 1, characterized in that The calculating the impact range of the mountain torrent according to the water catchment unit, the water outlet and the water outlet elevation includes: Based on the rainfall-runoff relationship parameters, the maximum retention volume of the basin is calculated; Calculate the runoff corresponding to each of the watershed units in rivers of different river grades according to the rainfall and the maximum retention capacity of the watershed; Calculating the delay time based on the flow length, the maximum detention volume of the watershed and the average slope of the hydrological response unit; Calculate the confluence time based on the lag time; Calculating the peak time according to the confluence time; Calculate the unit line flood peak flow according to the runoff, the hydrological response unit area and the peak time; Calculate the water depth of the outlet according to the unit line flood peak flow and unit terrain slope; Calculating the water level of the water outlet according to the water depth of the water outlet and the original elevation of the water outlet; According to the water levels of the plurality of water outlets, a water level interpolation process is performed using a preset interpolation method to obtain a water level surface; Subtracting the water level surface from the elevation surface of the target area to obtain an elevation difference; The grids in the target area digital elevation model where the elevation difference is greater than 0 are taken as the flash flood impact range.

4. The method according to claim 1, characterized in that: The method of calculating the critical rainfall for flash flood-induced landslide according to the flash flood impact intensity and the slope cutting intensity includes: Calculating the slope stability coefficient according to the flash flood impact intensity and the slope cutting intensity; The critical rainfall for the landslide induced by the mountain torrent is calculated according to the slope stability coefficient, the water conductivity of the slope rock and soil, the slope gradient, the internal friction angle, the impact intensity of the mountain torrent, the slope cutting strength, the specific catchment area and the bulk density of the rock and soil.

5. The method according to claim 3, characterized in that: The calculating of the time delay according to the water flow length, the maximum retention capacity of the watershed and the average slope of the hydrological response unit includes: The hysteresis is calculated according to the flow length, the maximum retention volume of the watershed and the average slope of the hydrological response unit by using the hysteresis calculation formula, which is: Wherein, L is the lag time, l is the flow length, S is the maximum retention capacity of the basin, and y is the average slope of the hydrological response unit.

6. The method according to claim 3, characterized in that The calculating of the water depth of the water outlet according to the unit line flood peak flow and the unit terrain slope includes: According to the unit line flood peak flow and unit terrain slope, the outlet water depth is calculated by the outlet water depth calculation formula, and the outlet water depth calculation formula is: Wherein, h is the water depth of the outlet, Q is the peak flow of the unit line, and θ is the unit terrain slope.

7. The method according to claim 4, characterized in that The critical rainfall for the landslide induced by the mountain torrent is calculated according to the slope stability coefficient, the water conductivity of the slope rock and soil, the slope gradient, the internal friction angle, the intensity of the mountain torrent impact, the slope cutting strength, the specific rainfall collection area and the rock and soil bulk density, including: The critical rainfall for the flash flood-induced landslide is calculated by the critical rainfall calculation formula according to the slope stability coefficient, the slope rock and soil water conductivity, the slope gradient, the internal friction angle, the flash flood impact intensity, the slope cutting strength, the specific rainwater collection area and the rock and soil bulk density. The critical rainfall calculation formula is: Where q is the critical rainfall for flash flood-induced landslide, T is the hydraulic conductivity of the slope rock and soil, θ is the slope gradient, and C ′ is a constant, φ is the internal friction angle, g is the slope stability coefficient, H is the flash flood impact intensity, K is the slope cutting strength, a is the specific catchment area, and r is the rock and soil bulk density.

8. A flash flood-induced landslide disaster risk warning device, characterized in that: include: The first module is used to obtain the digital elevation model of the target area; The second module is used to extract the water catchment unit, the water outlet and the water outlet elevation according to the digital elevation model of the target area; The third module is used to calculate the impact range of the mountain torrent according to the water catchment unit, the water outlet and the water outlet elevation; The fourth module is used to calculate the impact intensity of the flash flood according to the area ratio of the flash flood impact range in the slope unit and the area of ​​the slope unit; A fifth module is used to calculate the slope cutting strength according to the slope cutting area of ​​the slope unit, the slope unit area and the slope gradient; The sixth module is used to calculate the critical rainfall of landslide induced by mountain torrents according to the mountain torrent impact intensity and the slope cutting intensity; The seventh module is used to issue disaster risk warnings based on the critical rainfall for flash floods to induce landslides and the meteorological forecast rainfall.

9. A computer device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images