A flash flood induced landslide disaster risk early warning method and device and a storage medium

Abstract

The application discloses a mountain torrent induced landslide disaster risk early warning method and device and a storage medium, and relates to the technical field of geological disaster meteorological risk early warning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological disaster meteorological risk early warning, and in particular to a mountain torrent induced landslide disaster risk early warning method and device and a storage medium. BACKGROUND

[0002] The geological and geomorphological types in mountainous areas are complex, the rainfall in the East Asian monsoon region varies greatly in time and space, droughts and heavy rains occur frequently, and there are various types of mountain torrent geological disasters. The topography of small watersheds in mountainous areas changes greatly, the river bed gradient is large, the confluence speed is fast, the flood storage capacity is weak, and the residents in mountainous areas have more artificial cutting slope activities. Under the combined action of cutting slope housing and heavy rain, mountain torrent-landslide disasters are prone to occur, and often form a series of compound disaster chains. However, the traditional disaster warning is mainly based on a single disaster, and a single mountain torrent or landslide warning cannot effectively warn the compound disaster chain, and the accuracy and applicability are low.

[0003] In summary, the technical problems in the related art need to be improved. SUMMARY

[0004] The present application provides a mountain torrent induced landslide disaster risk early warning method, device and storage medium, which effectively improves the accuracy and applicability.

[0005] In one aspect, the present application provides a mountain torrent induced landslide disaster risk early warning method, comprising the following steps:

[0006] Obtaining a target area digital elevation model;

[0007] According to the target area digital elevation model, extracting a catchment unit, an outlet and an outlet elevation;

[0008] According to the catchment unit, the outlet and the outlet elevation, calculating a mountain torrent influence range;

[0009] According to the area ratio of the mountain torrent influence range in the slope unit and the slope unit area, calculating a mountain torrent influence intensity;

[0010] According to the cutting slope area of the slope unit, the slope unit area and the slope gradient, calculating a cutting slope intensity;

[0011] According to the mountain torrent influence intensity and the cutting slope intensity, calculating a critical rainfall of mountain torrent induced landslide;

[0012] According to the critical rainfall of mountain torrent induced landslide and the meteorological forecast rainfall, performing disaster risk early warning.

[0013] In some embodiments, according to the target area digital elevation model, the catchment unit, the outlet and the outlet elevation are extracted, comprising:

[0014] extracting a river network from the target area digital elevation model according to the confluence accumulation and the river network level;

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

[0016] extracting an outlet position from the river network according to the catchment area;

[0017] carrying out river classification on the river network by using a hydrological analysis module to obtain a river level;

[0018] dividing a target river according to the river level and the outlet position to obtain the catchment unit;

[0019] extracting the outlet and the outlet elevation from the catchment unit.

[0020] In some embodiments, the calculating a mountain flood influence range according to the catchment unit, the outlet and the outlet elevation comprises:

[0021] calculating a maximum retention amount of a basin according to a rainfall-runoff relationship parameter;

[0022] calculating a runoff corresponding to each of the catchment units in different river levels according to rainfall and the maximum retention amount of the basin;

[0023] calculating a detention time according to a flow length, the maximum retention amount of the basin and an average slope of a hydrological response unit;

[0024] calculating a confluence time according to the detention time;

[0025] calculating a peak time according to the confluence time;

[0026] calculating a unit line flood peak flow according to the runoff, an area of the hydrological response unit and the peak time;

[0027] calculating an outlet water depth according to the unit line flood peak flow and a unit terrain slope;

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

[0029] carrying out water level interpolation processing by using a preset interpolation method according to a plurality of the outlet water levels to obtain a water level surface;

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

[0031] regarding a grid with the elevation difference greater than 0 in the target area digital elevation model as the mountain flood influence range.

[0032] In some embodiments, the calculating the critical rainfall of the flash flood induced landslide according to the mountain torrent influence intensity and the cutting slope intensity comprises:

[0033] calculating a slope stability coefficient according to the mountain torrent influence intensity and the cutting slope intensity;

[0034] calculating the critical rainfall of the flash flood induced landslide according to the slope stability coefficient, a slope rock-soil body water conductivity coefficient, a slope gradient, an internal friction angle, the mountain torrent influence intensity, the cutting slope intensity, a specific catchment area and a rock-soil body bulk density.

[0035] In some embodiments, the calculating the lag time according to the flow length, the maximum retention amount of the basin and the average slope of the hydrological response unit comprises:

[0036] calculating the lag time according to the flow length, the maximum retention amount of the basin and the average slope of the hydrological response unit by a lag time calculation formula, the lag time calculation formula being:

[0037]

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

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

[0040] calculating the outlet water depth according to the unit line flood peak flow and the unit terrain slope by an outlet water depth calculation formula, the outlet water depth calculation formula being:

[0041]

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

[0043] In some embodiments, the calculating the critical rainfall of the flash flood induced landslide according to the slope stability coefficient, a slope rock-soil body water conductivity coefficient, a slope gradient, an internal friction angle, the mountain torrent influence intensity, the cutting slope intensity, a specific catchment area and a rock-soil body bulk density comprises:

[0044] calculating the critical rainfall of the flash flood induced landslide according to the slope stability coefficient, a slope rock-soil body water conductivity coefficient, a slope gradient, an internal friction angle, the mountain torrent influence intensity, the cutting slope intensity, a specific catchment area and a rock-soil body bulk density by a critical rainfall calculation formula, the critical rainfall calculation formula being:

[0045]

[0046] In the formula, q is a critical rainfall of the torrent-induced landslide, T is a water conductivity coefficient of the slope rock-soil mass, θ is a slope gradient of the slope, C ′ is a constant, φ is an internal friction angle, g is a slope stability coefficient, H is a torrent influence intensity, K is a cutting slope intensity, a is a specific catchment area, and r is a rock-soil mass bulk density.

[0047] In another aspect, an embodiment of the present application provides a torrent-induced landslide disaster risk early warning device, comprising:

[0048] A first module is configured to acquire a target area digital elevation model;

[0049] A second module is configured to extract a catchment unit, a water outlet, and a water outlet elevation according to the target area digital elevation model;

[0050] A third module is configured to calculate a torrent influence range according to the catchment unit, the water outlet, and the water outlet elevation;

[0051] A fourth module is configured to calculate a torrent influence intensity according to an area proportion of the torrent influence range in a slope unit and a slope unit area;

[0052] A fifth module is configured to calculate a cutting slope intensity according to a cutting slope area of the slope unit, the slope unit area, and a slope gradient;

[0053] A sixth module is configured to calculate a critical rainfall of the torrent-induced landslide according to the torrent influence intensity and the cutting slope intensity;

[0054] A seventh module is configured to perform disaster risk early warning according to the critical rainfall of the torrent-induced landslide and meteorological forecast rainfall.

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

[0056] at least one processor;

[0057] at least one memory configured to store 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 method.

[0059] In another aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method.

[0060] The present application has the following beneficial effects:

[0061] The embodiment of the present application firstly acquires a target area digital elevation model, extracts a catchment unit, a water outlet and a water outlet elevation according to the target area digital elevation model, calculates a mountain flood influence range according to the catchment unit, the water outlet and the water outlet elevation, then calculates a mountain flood influence intensity according to an area proportion of the mountain flood influence range in a slope unit and a slope unit area, calculates a cutting slope intensity according to a cutting slope area of the slope unit, the slope unit area and a slope gradient, calculates a critical rainfall of a mountain flood induced landslide according to the mountain flood influence intensity and the cutting slope intensity, and finally performs disaster risk early warning according to the critical rainfall of the mountain flood induced landslide and meteorological forecast rainfall, so that disaster risk early warning can be realized by combining the intensities of the mountain flood and the cutting slope, and the accuracy and applicability are improved.

[0062] Additional features and advantages of the application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0064] Figure 1 A flow chart of a mountain flood induced landslide disaster risk early warning method according to an embodiment of the present application;

[0065] Figure 2 A schematic diagram of a whole process of calculating a mountain flood influence range according to an embodiment of the present application;

[0066] Figure 3 A schematic diagram of a whole process of calculating a critical rainfall of a mountain flood induced landslide according to an embodiment of the present application;

[0067] Figure 4 A structural schematic diagram of a mountain flood induced landslide disaster risk early warning device according to an embodiment of the present application;

[0068] Figure 5 A hardware structural schematic diagram of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

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

[0070] It can be understood that the terms "first", "second" and the like used in the present application can be used herein to describe various concepts, but unless specifically stated, 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 embodiments of the present application, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "when" or "in response to determining".

[0071] The terms "at least one", "multiple", "each", "any" and the like used in the present application include one, two or more than two, multiple includes two or more than two, 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 understood by those skilled in the art to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

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

[0074] Compound chain disaster: refers to the compound disaster 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 among them, which aggravates or even triggers other disasters, thus forming a compound disaster.

[0075] In the related art, about 70% of the areas in China are mountainous areas, and the geological and geomorphological types are complex. At the same time, most of the areas are located in the East Asian monsoon region, and the rainfall is highly variable in time and space, drought and heavy rain occur frequently, and the types of mountain flood geological disasters are diverse, and the number of landslides caused by rainfall and mountain floods is large. According to the results of the national geological disaster survey, landslides account for 51% of geological disasters, and landslides caused by rainfall and mountain floods account for 90% of the total number of landslides. In recent years, under the trend of global warming and frequent extreme weather, a new type of basin compound chain disaster characterized by mountain flood-landslide is easily formed in the South China mountainous area. A heavy rainstorm caused by a typhoon in a local river basin induces mountain flood and geological disaster, resulting in many deaths, many missing persons, many sick and injured persons, and many people being urgently relocated. The direct economic loss is large. The topography of the mountainous small watershed changes greatly, the river bed gradient is large, the confluence speed is fast, the flood storage capacity is weak, and the residents in the mountainous area often cut the slope. The combined action of slope cutting for housing construction and heavy rain easily causes mountain flood-landslide disaster, which often forms a series of "disaster chain". The compound chain geological disaster formed by mountain flood and landslide disaster seriously threatens the social and economic safety of the mountainous area, and the disaster warning task is urgent. However, the current disaster warning is mainly single disaster, and the single mountain flood or landslide is warned. There is still no effective method for the warning of the rainfall-triggered mountain flood-landslide compound disaster chain, and the current rainfall threshold does not consider the influence of slope cutting for housing construction, which underestimates the influence of mountain flood and human activity on disaster. The main difference between the compound chain disaster and the single disaster is that the cumulative amplification effect occurs in the disaster starting and moving process after the superposition of mountain flood and disaster, which makes the influence range and duration of the disaster chain extended. Mountain flood can induce landslide, and after induction, the two types of disasters, mountain flood and landslide, still exist in a time and space scale, have superposition and amplification, and have progressive relationship.

[0076] Therefore, the embodiment of the present application analyzes the role of human slope cutting activity and the process of landslide disaster induced by mountain flood disaster, first simulates the influence range of mountain flood under a certain rainfall condition based on the runoff and confluence process in the small watershed unit, and calculates the influence intensity of mountain flood. Then, the degree of slope cutting in the target area is calculated, the slope cutting intensity is calculated, then the mountain flood influence factor and the slope cutting intensity are introduced into the landslide disaster critical rainfall model, the landslide critical rainfall threshold considering the influence of mountain flood and human activity is calculated, and finally the disaster warning is carried out.

[0077] The embodiment of the present application provides a mountain torrent induced landslide disaster risk early warning method, and relates to the technical field of geological disaster meteorological risk early warning. The mountain torrent induced landslide disaster risk early warning method provided by the embodiment of the present application can be applied to a terminal, can be applied to a server, and can also be software running in the terminal or the server. In some embodiments, the terminal can be a smart phone, a tablet computer, a notebook computer, a desktop computer, a smart speaker, a smart watch, a vehicle-mounted terminal and the like, but is not limited thereto; the server end can be configured as an independent physical server, can be configured as a server cluster or a distributed system formed by multiple physical servers, can be configured as a cloud server providing basic cloud computing services such as cloud service, cloud database, cloud computing, cloud function, cloud storage, network service, cloud communication, middleware service, domain name service, security service, CDN and big data and artificial intelligence platform, and the server can also be a node server in a blockchain network; and the software can be an application for implementing the mountain torrent induced landslide disaster risk early warning method, 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 devices or portable devices, tablet devices, multi-processor 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, and the like. 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, and the like that perform specific tasks or implement specific abstract data types. The present application can also be practiced in a distributed computing environment, in which tasks are performed by remote processing devices connected by 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 embodiments of the present application will be specifically explained below in combination with the drawings:

[0080] Figure 1 is an optional flowchart of the mountain torrent induced landslide disaster risk early warning method provided by the embodiment of the present application, Figure 1 The method in can include but is not limited to steps S101 to S107.

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

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

[0083] Step S103, calculating the mountain flood influence range according to the catchment unit, the water outlet and the water outlet elevation;

[0084] Step S104, calculating the mountain flood influence intensity according to the area proportion of the mountain flood influence range in the slope unit and the slope unit area;

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

[0086] Step S106, calculating the critical rainfall of the mountain flood induced landslide according to the mountain flood influence intensity and the cutting slope intensity;

[0087] Step S107, conducting the disaster risk early warning according to the critical rainfall of the mountain flood induced landslide and the meteorological forecast rainfall.

[0088] The steps S101 to S107 shown in the embodiments of the present application realize the disaster risk early warning, and improve the accuracy and applicability.

[0089] In step S101 of some embodiments, the target area digital elevation model can be obtained through a geological information library. The target area digital elevation model can also be obtained through other ways, which are not limited thereto.

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

[0091] The river network is extracted from the target area digital elevation model according to the flow accumulation and the river network level;

[0092] The catchment range is extracted from the river network;

[0093] The water outlet position is extracted from the river network according to the catchment range;

[0094] The river classification is obtained by using the hydrological analysis module to classify the river network;

[0095] The target river is divided according to the river classification and the water outlet position, and the catchment unit is obtained;

[0096] The water outlet and the water outlet elevation are extracted from the catchment unit.

[0097] In some embodiments, the river network of different river network levels can be extracted from the target area digital elevation model according to the confluence accumulation and the river network level. It can be understood that the river network and its branches extracted based on the digital elevation model DEM have a certain hydrological significance. Based on the idea of surface runoff simulation, the confluence accumulation of different river network levels is different, and the higher the level of the river network, the greater the confluence accumulation. Then the catchment area is extracted from the river network, and the water outlet position is extracted from the river network according to the catchment area. It can be understood that the snap pour point tool in the hydrology tool set in the ARCGIS spatial analysis tools tool box can be used to find the point with the highest confluence accumulation within a specified distance as the water outlet position of the hydrological response unit. Then the river network is classified by using the hydrological analysis module to obtain the river level, and the target river is divided according to the river level and the water outlet position to obtain the catchment unit. In ArcGIS, the calculation of the catchment unit is performed by using the basin tool in the hydrology tool set. Finally, the discrete water outlets and water outlet elevations of the rivers of different levels are extracted from the catchment unit. The water outlet is the lowest point of the hydrological response unit.

[0098] In some embodiments, in step S103, calculating the mountain flood influence range according to the catchment unit, the water outlet and the water outlet elevation can include but is not limited to the following steps:

[0099] According to the rainfall runoff relationship parameters, the maximum retention capacity of the basin is calculated;

[0100] According to the rainfall and the maximum retention capacity of the basin, the runoff corresponding to each catchment unit in the river of different river levels is calculated;

[0101] According to the flow length, the maximum retention capacity of the basin and the average slope of the hydrological response unit, the detention time is calculated;

[0102] According to the detention time, the confluence time is calculated;

[0103] According to the confluence time, the peak time is calculated;

[0104] According to the runoff, the area of the hydrological response unit and the peak time, the unit line flood peak flow is calculated;

[0105] According to the unit line flood peak flow and the unit terrain slope, the water depth of the water outlet is calculated;

[0106] According to the water depth of the water outlet and the original elevation of the water outlet, the water level of the water outlet is calculated;

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

[0108] Subtracting the water level surface from the target area elevation surface, an elevation difference is obtained;

[0109] The grid with an elevation difference greater than 0 in the target area digital elevation model is taken as the mountain torrent influence range.

[0110] In some embodiments, the maximum retention capacity of the basin can be calculated according to the rainfall-runoff relationship parameter by using the SCS model (runoff curve method) first, wherein the calculation formula of the maximum retention capacity of the basin is: In the formula, S is the maximum retention capacity of the basin, CN is the rainfall-runoff relationship parameter, which is an important dimensionless parameter in the SCS model for describing the rainfall-runoff relationship, and reflects the comprehensive characteristics of the antecedent moisture condition (AMC), slope, soil type and land use status, and can better reflect the influence of underlying surface conditions on the runoff process. The CN value can be set by empirical value or experimental observation, and the CN value of the basin can be determined and adjusted according to the land use mode, treatment condition, hydrological condition and soil type of the basin. Then, according to the rainfall and the maximum retention capacity of the basin, the runoff corresponding to each hydrological response unit in different river levels is calculated, wherein the calculation formula of the runoff is: In the formula, R is the runoff, P is the rainfall, and S is the maximum retention capacity of the basin. Then, according to the flow length, the maximum retention capacity of the basin and the average slope of the hydrological response unit, the lag time is calculated by the lag time calculation formula, wherein the lag time calculation formula is: In the formula, 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. Then, according to the lag time, the runoff concentration time is calculated, wherein the calculation formula of the runoff concentration time is: In the formula, t c is the runoff concentration time, and L is the lag time. According to the runoff concentration time, the peak time is calculated, wherein the calculation formula of the peak time is: In the formula, t p is the peak time, and t c is the runoff concentration time. According to the runoff, the area of the hydrological response unit and the peak time, the unit line flood peak flow of each hydrological response unit is calculated by using the map algebra function of arcgis, wherein the calculation formula of the unit line flood peak flow is: In the formula, Q is the unit line flood peak flow, A is the area of the hydrological response unit, R is the runoff, and t p is the peak time. Then, according to the unit line flood peak flow and the unit terrain slope, the outlet water depth is calculated by the outlet water depth calculation formula, wherein the outlet water depth calculation formula is: In the formula, h is the water depth of the outlet, 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, wherein the calculation formula of the outlet water level is: W = G + h, wherein 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 plurality of outlet water levels, the water level is interpolated by using a preset interpolation method to obtain a water level surface. For example, 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 target area elevation surface to obtain an elevation difference, and the grid with an elevation difference greater than 0 in the target area digital elevation model is taken as the mountain flood affected range, and the grid with an elevation difference less than 0 is not affected by the mountain flood. It can be understood that due to the limitation of the number of discrete points and the order of magnitude of the water level, the water level difference is much larger than the reality, so error checking is needed, that is, the calculation result is further reclassified to extract the actual range.

[0111] In some embodiments, in step S104, the mountain flood impact intensity can be calculated according to the area proportion of the mountain flood affected range in the slope unit and the area of the slope unit, wherein the calculation formula of the mountain flood impact intensity is: In the formula, H is the mountain flood impact intensity, A F is the area proportion of the mountain flood affected range in the slope unit, and A is the area of the slope unit.

[0112] In some embodiments, in step S105, the influence of human activities in a small watershed dominated by agriculture on geological disasters in a mountainous area is mainly through two aspects of changing the terrain and changing the groundwater circulation. Human activities can include reclamation, house building and road construction, so the cutting slope intensity index is selected to express. The form of cutting slope can include types such as road construction, house building or planting. The cutting slope intensity can be calculated according to the cutting slope area of the slope unit, the area of the slope unit and the slope gradient, wherein the calculation formula of the cutting slope intensity is: In the formula, K is the cutting slope intensity, A K is the cutting slope area of the slope unit, A is the area of the slope unit, and θ is the slope gradient.

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

[0114] According to the mountain flood impact intensity and the cutting slope intensity, the slope stability coefficient is calculated;

[0115] According to the slope stability coefficient, the slope rock-soil body water conductivity coefficient, the slope gradient, the internal friction angle, the mountain flood impact intensity, the cutting slope intensity, the specific rainfall area and the rock-soil body bulk density, the critical rainfall of mountain flood induced landslide is calculated.

[0116] In some embodiments, the slope stability coefficient can be calculated according to the flood impact intensity and the cutting slope intensity. It can be understood that the influence of flood and human activities on geological disasters is fundamentally to change the landform and the groundwater circulation, thereby affecting the slope stability. Assuming that when K = 1 and H = 1, i.e., the human activities and the flood effect are the strongest, the slope stability coefficient is reduced by 50%. That is, in the natural state, the slope stability coefficient is 0.5, and under the strong influence of human activities and flood, the slope is in a critical state. Exemplarily, the slope stability coefficient g can be set to 0.5. Then, according to the slope stability coefficient, the slope rock-soil water conductivity coefficient, the slope gradient, the internal friction angle, the flood impact intensity, the cutting slope intensity, the specific catchment area and the rock-soil bulk density, the critical rainfall of the landslide induced by the flood is calculated by the critical rainfall calculation formula, which is: wherein q is the critical rainfall of the landslide induced by the flood, T is the slope rock-soil water conductivity coefficient, θ is the slope gradient, C ′ is a constant, φ is the internal friction angle, g is the slope stability coefficient, H is the flood impact intensity, K is the cutting slope intensity, a is the specific catchment area, and r is the rock-soil bulk density. Exemplarily, when the slope stability coefficient g is 0.5, the critical rainfall calculation formula is:

[0117] In some embodiments, in step S107, the disaster risk warning can be performed according to the critical rainfall of the landslide induced by the flood and the meteorological forecast rainfall. Exemplarily, the meteorological forecast rainfall can be compared with the critical rainfall, and if the meteorological forecast rainfall is greater than the critical rainfall, the disaster risk warning is issued. 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 thus the disaster risk warning is issued.

[0118] In some embodiments, the overall process of calculating the flood impact range is as shown in Figure 2 The river network can be extracted by the digital elevation model (DEM), and the confluence unit is divided according to the river level to obtain discrete outlets. Then, the runoff R and the confluence flow Q (i.e., the unit line flood peak flow) are calculated by using the SCS model according to the rainfall P, the outlet water depth h is calculated by the Manning formula, the outlet water level W is obtained by superimposing the terrain height, the water level surface is obtained by Krging interpolation, and finally the water level surface and the digital elevation surface are error checked and tangent to obtain the flood impact range.

[0119] In some embodiments, the overall process of calculating the critical rainfall of the landslide induced by the rainfall flood is as shown in Figure 3As shown, first, a digital elevation model of a research area is acquired, and a river structure and a unit are divided, then in a slope unit, an index of human engineering activities (i.e. cutting slope strength) is calculated, in a hydrological unit, a mountain torrent influence range based on the hydrological unit is calculated, and finally, in combination with the cutting slope strength, the mountain torrent influence range and a landslide model based on the slope unit, a rainfall critical threshold of a mountain torrent-landslide compound chain disaster, i.e. a critical rainfall of a mountain torrent induced landslide, is calculated.

[0120] The beneficial effects of implementing the embodiments of the present application include that the embodiments of the present application first acquire a digital elevation model of a target area, extract a catchment unit, a water outlet and a water outlet elevation according to the digital elevation model of the target area, calculate a mountain torrent influence range according to the catchment unit, the water outlet and the water outlet elevation, then calculate a mountain torrent influence strength according to an area proportion of the mountain torrent influence range in a slope unit and a slope unit area, calculate a cutting slope strength according to a cutting slope area of the slope unit, the slope unit area and a slope gradient, calculate a critical rainfall of a mountain torrent induced landslide according to the mountain torrent influence strength and the cutting slope strength, and finally, perform disaster risk early warning according to the critical rainfall of the mountain torrent induced landslide and meteorological forecast rainfall, so that disaster risk early warning can be realized by combining the strengths of the mountain torrent and the cutting slope, the accuracy and applicability are improved. Meanwhile, the embodiments overcome the limitations of traditional single disaster early warning, and improve the accuracy and effectiveness of critical rainfall calculation.

[0121] As shown in Figure 4 The embodiments of the present application also provide a mountain torrent induced landslide disaster risk early warning device, which comprises:

[0122] A first module 801 is configured to acquire a digital elevation model of a target area;

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

[0124] A third module 803 is configured to calculate a mountain torrent influence range according to the catchment unit, the water outlet and the water outlet elevation;

[0125] A fourth module 804 is configured to calculate a mountain torrent influence strength according to an area proportion of the mountain torrent influence range in a slope unit and a slope unit area;

[0126] A fifth module 805 is configured to calculate a cutting slope strength according to a cutting slope area of the slope unit, the slope unit area and a slope gradient;

[0127] A sixth module 806 is configured to calculate a critical rainfall of a mountain torrent induced landslide according to the mountain torrent influence strength and the cutting slope strength;

[0128] A seventh module 807 is configured to perform disaster risk early warning according to the critical rainfall of the mountain torrent induced landslide and meteorological forecast rainfall.

[0129] The contents in the method embodiments are applicable to the device embodiments, the device embodiments specifically implement the functions same as the method embodiments, and achieve the same beneficial effects as the method embodiments.

[0130] As shown in Figure 5 The embodiment of the application further provides a computer device, which comprises:

[0131] at least one processor 901;

[0132] at least one memory 902, used for storing at least one program;

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

[0134] The contents in the method embodiments are applicable to the device embodiments, the device embodiments specifically implement the functions same as the method embodiments, and achieve the same beneficial effects as the method embodiments.

[0135] The embodiment of the application further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method shown in Figure 1 .

[0136] The contents in the method embodiments are applicable to the storage medium embodiments, the storage medium embodiments specifically implement the functions same as the method embodiments, and achieve the same beneficial effects as the method embodiments.

[0137] The preferred embodiments of the application are described above with reference to the drawings, and the scope of the application is not limited by the above. Any modification, equivalent replacement and improvement made by those skilled in the art without departing from the scope and essence of the application should be within the scope of the application.

Claims

1. A flash flood induced landslide disaster risk early warning method, characterized in that, The method comprises the following steps: obtaining a target area digital elevation model; extracting a catchment unit, an outlet and an outlet elevation according to the target area digital elevation model; calculating a mountain flood influence range according to the catchment unit, the outlet and the outlet elevation; calculating a mountain flood influence intensity according to an area proportion of the mountain flood influence range in a slope unit and a slope unit area; calculating a cutting slope intensity according to a cutting slope area of a slope unit, the slope unit area and a slope gradient; calculating a critical rainfall of a mountain flood induced landslide according to the mountain flood influence intensity and the cutting slope intensity; carrying out a disaster risk early warning according to the critical rainfall of the mountain flood induced landslide and a meteorological forecast rainfall.

2. The method of claim 1, wherein, The extracting a catchment unit, an outlet and an outlet elevation according to the target area digital elevation model comprises: extracting a river network from the target area digital elevation model according to a flow accumulation and a river network level; extracting a catchment range from the river network; extracting an outlet position from the river network according to the catchment range; carrying out river classification on the river network by using a hydrological analysis module to obtain a river level; dividing a target river according to the river level and the outlet position to obtain the catchment unit; extracting the outlet and the outlet elevation from the catchment unit.

3. The method of claim 1, wherein, The calculating a mountain flood influence range according to the catchment unit, the outlet and the outlet elevation comprises: calculating a maximum retention of a basin according to a rainfall runoff relationship parameter; calculating a runoff of each catchment unit corresponding to different river levels in a river according to a rainfall and the maximum retention of the basin; calculating a lag time according to a flow length, the maximum retention of the basin and an average slope of a hydrological response unit; calculating a confluence time according to the lag time; calculating a peak time according to the confluence time; calculating a unit line flood peak flow according to the runoff, an area of the hydrological response unit and the peak time; calculating an outlet water depth according to the unit line flood peak flow and a unit terrain slope; calculating an outlet water level according to the outlet water depth and an original elevation of the outlet; carrying out water level interpolation processing by using a preset interpolation method according to a plurality of outlet water levels to obtain a water level surface; subtracting the water level surface from a target area elevation surface to obtain an elevation difference; regarding a grid with the elevation difference greater than 0 in the target area digital elevation model as the mountain flood influence range.

4. The method of claim 1, wherein, The calculating a critical rainfall of a mountain flood induced landslide according to the mountain flood influence intensity and the cutting slope intensity comprises: calculating a slope stability coefficient according to the mountain flood influence intensity and the cutting slope intensity; calculating the critical rainfall of the mountain flood induced landslide according to the slope stability coefficient, a slope rock-soil body water conductivity coefficient, a slope gradient, an internal friction angle, the mountain flood influence intensity, the cutting slope intensity, a specific catchment area and a rock-soil body bulk density.

5. The method of claim 3, wherein, The calculating a lag time according to a flow length, the maximum retention of the basin and an average slope of a hydrological response unit comprises: calculating a lag time according to a flow length, the maximum retention of the basin and an average slope of a hydrological response unit by using a lag time calculation formula, the lag time calculation formula being: In the formula, L is the lag time, l is the length of the water flow, S is the maximum retention of the flow area, and y is the average slope of the hydrological response unit.

6. The method of claim 3, wherein, The water outlet water depth is calculated according to the unit line flood peak flow and the unit terrain slope, and the water outlet water depth calculation formula is: The water outlet water depth is calculated according to the unit line flood peak flow and the unit terrain slope, and the water outlet water depth calculation formula is: In the formula, h is the water outlet water depth, Q is the unit line flood peak flow, and θ is the unit terrain slope.

7. The method of claim 4, wherein, The critical rainfall of the mountain torrent induced landslide is calculated according to the slope stability coefficient, the slope rock-soil body water conductivity coefficient, the slope gradient, the internal friction angle, the mountain torrent influence intensity, the cutting slope intensity, the specific catchment area, and the rock-soil body bulk density, and the critical rainfall calculation formula is: The critical rainfall of the mountain torrent induced landslide is calculated according to the slope stability coefficient, the slope rock-soil body water conductivity coefficient, the slope gradient, the internal friction angle, the mountain torrent influence intensity, the cutting slope intensity, the specific catchment area, and the rock-soil body bulk density, and the critical rainfall calculation formula is: wherein q is a critical rainfall of the torrent-induced landslide, T is a water conductivity coefficient of the slope rock-soil mass, θ is a slope gradient, C ′ is a constant, φ is the internal friction angle, g is a slope stability coefficient, H is a torrent influence intensity, K is a cutting slope intensity, a is a specific catchment area, and r is a rock-soil mass bulk density.

8. A flash flood induced landslide disaster risk early warning device, characterized in that, It comprises: The first module is configured to acquire a digital elevation model of a target area. The second module is configured to extract a catchment unit, a water outlet, and a water outlet elevation according to the digital elevation model of the target area. The third module is configured to calculate a mountain torrent influence range according to the catchment unit, the water outlet, and the water outlet elevation. The fourth module is configured to calculate a mountain torrent influence intensity according to an area ratio of the mountain torrent influence range in a slope unit and a slope unit area. The fifth module is configured to calculate a cutting slope intensity according to a cutting slope area of a slope unit, the slope unit area, and a slope gradient. The sixth module is configured to calculate a critical rainfall of a mountain torrent induced landslide according to the mountain torrent influence intensity and the cutting slope intensity. The seventh module is configured to perform a disaster risk early warning according to the critical rainfall of the mountain torrent induced landslide and a meteorological forecast rainfall.

9. A computer apparatus, comprising: It comprises: 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 of any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1-9. The computer program is executed by the processor to implement the method of any one of claims 1-7.

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