Regional rainfall type landslide forecasting method, equipment, medium and product

Abstract

The invention discloses a regional rainfall type landslide forecasting method and device, a medium and a product, and relates to the field of regional landslide evaluation and early warning forecasting, and the method comprises the following steps: in each rainfall infiltration moment, according to a sequence from a slope unit at the highest elevation point to a slope unit at the lowest elevation point, determining the rainfall infiltration time; hydrological analysis is carried out on each slope unit in sequence, water content distribution data of each slope unit is updated, then stability analysis is carried out on each slope unit in sequence from the slope unit at the lowest elevation point to the slope unit at the highest elevation point according to the water content distribution data of each slope unit, and stability analysis is carried out on each slope unit; the stability of each slope unit is updated, and landslide forecasting is carried out according to the stability of each slope unit; hydrological analysis and stability analysis comprise hydrological association and mechanical association between adjacent upstream and downstream slope units according to the upstream and downstream flow direction relation of all slope units. The accuracy of landslide forecasting can be improved.

Description

Technical Field

[0001] The present application relates to the field of regional landslide assessment and early warning forecasting, and in particular to a regional rainfall-type landslide forecasting method, equipment, medium and product. Background Art

[0002] At present, there are many regional landslide prediction methods, and many regional landslide prediction models are involved, such as SINMAP model, Trigrs model, SLIP model, FSLAM model, HIRESSS model, H-slider model, SHIA_Landslide model, TRIBS-VEGGIE-landslide model, etc. The basic calculation unit (i.e., basic analysis unit, also called prediction unit) of this type of prediction model is mainly a grid unit with regular shape. Although the grid unit has a high advantage in computer processing, it cannot accurately characterize the micro-geomorphological characteristics of the landslide. An actual slope body may be divided into several grid units, or a grid unit may contain multiple slope bodies. The instability of a single grid unit does not mean that a landslide is about to occur. Therefore, the prediction results of the grid unit have a low directional clarity, which easily leads to the problem of excessive workload for defense. In addition, the current physical prediction model is established for a single grid unit, that is, the calculation is performed one grid unit at a time, each calculation unit is regarded as a single entity, and the corresponding stability analysis equation is established around a single prediction unit (such as an infinite slope model for a single grid unit). Since the model equation only considers a single grid unit, the prediction results of the grid unit are not clear in direction, which easily leads to the problem of excessive workload for defense. Therefore, the current regional landslide prediction methods all have the problem of low accuracy of landslide prediction. Summary of the invention

[0003] The purpose of this application is to provide a regional rainfall-type landslide prediction method, equipment, medium and product to improve the accuracy of landslide prediction.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a method for predicting regional rainfall-induced landslides, the method comprising:

[0006] Obtain digital elevation model data of the area to be forecasted;

[0007] Extracting slope units from the digital elevation model data to obtain all slope units;

[0008] Determine the flow direction of each slope unit;

[0009] Based on the flow direction of each slope unit, the upstream and downstream flow direction relationship of all slope units is obtained;

[0010] At each rainfall infiltration moment, a hydrological analysis is performed on each slope unit in sequence, starting from the slope unit at the highest elevation to the slope unit at the lowest elevation, and the moisture content distribution data of each slope unit is updated. Afterwards, a stability analysis is performed on each slope unit in sequence, starting from the slope unit at the lowest elevation to the slope unit at the highest elevation, based on the moisture content distribution data of each slope unit, and the stability of each slope unit is updated. A landslide is predicted based on the stability of each slope unit. The hydrological analysis includes performing a hydrological correlation between upstream and downstream adjacent slope units based on the upstream and downstream flow direction relationship of all slope units. The stability analysis includes performing a mechanical correlation between upstream and downstream adjacent slope units based on the upstream and downstream flow direction relationship of all slope units.

[0011] Optionally, determining the flow direction of each slope unit specifically includes:

[0012] Calculating the flow direction of each grid cell in the digital elevation model data using the D8 flow direction algorithm;

[0013] For each slope unit, the grid row and column information contained in the slope unit is counted, and according to the flow direction of each grid unit in the digital elevation model data, the average flow direction of the grids inside the slope unit is obtained, and the average flow direction of the grids inside the slope unit is used as the flow direction of the slope unit to obtain the flow direction of each slope unit.

[0014] Optionally, the upstream and downstream flow direction relationship of all the slope units is used to determine whether any slope unit has an upstream adjacent slope unit, whether any slope unit has a downstream adjacent slope unit, and is also used to determine the upstream adjacent slope unit that has a common boundary with the slope unit and the downstream adjacent slope unit that has a common boundary with the slope unit; the upstream adjacent slope unit is the upstream adjacent slope unit that has a common boundary with the slope unit; the downstream adjacent slope unit is the downstream adjacent slope unit that has a common boundary with the slope unit.

[0015] Optionally, when any slope unit has an upstream adjacent slope unit, the upstream and downstream adjacent slope units include the slope unit and the upstream adjacent slope units that have a common boundary with the slope unit; when any slope unit has a downstream adjacent slope unit, the upstream and downstream adjacent slope units include the slope unit and the downstream adjacent slope units that have a common boundary with the slope unit.

[0016] Optionally, at each rainfall infiltration moment, hydrological analysis is performed on each slope unit in sequence, starting from the slope unit at the highest elevation point to the slope unit at the lowest elevation point, and the moisture content distribution data of each slope unit is updated, specifically including:

[0017] At each rainfall infiltration moment, the current slope units are obtained in sequence from the slope unit with the highest elevation point to the slope unit with the lowest elevation point. Starting from the slope unit with the highest elevation point as the current slope unit, the moisture content distribution data of the current slope unit is updated. According to the upstream and downstream flow relationship of all slope units, the hydrological association is performed between the current slope unit and the adjacent slope units downstream that have a common boundary with the current slope unit, and the moisture content distribution data of the adjacent slope units downstream that have a common boundary with the current slope unit are updated until the moisture content distribution data of all slope units are updated. The hydrological association includes allocating the surface runoff generated by the current slope unit to the adjacent slope units downstream that have a common boundary with the current slope unit. The hydrological association is used to update the moisture content distribution data of the adjacent slope units downstream that have a common boundary with the current slope unit.

[0018] Optionally, at each rainfall infiltration moment, according to the moisture content distribution data of each slope unit, in the order from the slope unit at the lowest elevation point to the slope unit at the highest elevation point, stability analysis is performed on each slope unit in turn, and the stability of each slope unit is updated, specifically including:

[0019] At each rainfall infiltration moment, the current slope units are obtained in sequence from the slope unit at the lowest elevation to the slope unit at the highest elevation. Starting from the slope unit at the lowest elevation, the stability of the current slope unit is updated according to the moisture content distribution data of the current slope unit. According to the upstream and downstream flow relationship of all slope units, the mechanical association between the current slope unit and the adjacent slope units with a common boundary with the current slope unit is performed, and the stability of the adjacent slope units with a common boundary with the current slope unit is updated until the stability of all slope units is updated. The mechanical association includes applying the remaining anti-sliding force of the current slope unit to the adjacent slope units with a common boundary upstream and the current slope unit. The slope unit has adjacent slope units with common boundaries; the mechanical association is used to update the stability of the upstream adjacent slope units with common boundaries with the current slope unit; the stability of the slope unit is judged by the safety factor of the slope unit; the safety factor of the slope unit is obtained by the ratio of the anti-sliding force of the slope unit to the sliding force of the slope unit; the anti-sliding force of the slope unit and the sliding force of the slope unit are obtained by the water content distribution data of the slope unit; when the safety factor of the slope unit is greater than or equal to 1, the slope unit is judged to be stable, and there is residual anti-sliding force when the slope unit is stable, and the residual anti-sliding force is obtained by subtracting the sliding force of the slope unit from the anti-sliding force of the slope unit; when the safety factor of the slope unit is less than 1, the slope unit is judged to be unstable.

[0020] Optionally, at each rainfall infiltration moment, landslide prediction is performed based on the stability of each slope unit, specifically including:

[0021] At each rainfall infiltration moment, the areas corresponding to the unstable slope units among all slope units are predicted to have landslide risks, and the areas corresponding to the stable slope units among all slope units are predicted to have no landslide risks.

[0022] In a second aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described regional rainfall-type landslide prediction methods.

[0023] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described regional rainfall-induced landslide prediction methods.

[0024] In a fourth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned regional rainfall-induced landslide prediction methods.

[0025] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0026] The present application provides a regional rainfall-type landslide prediction method, equipment, medium and product. The method extracts slope units from the digital elevation model data of the area to be predicted to obtain all slope units. The upstream and downstream flow direction relationship of all slope units is obtained based on the flow direction of each slope unit. Thus, the hydrological and mechanical correlations between upstream and downstream adjacent slope units are performed according to the upstream and downstream flow direction relationship of all slope units. Since the influence of the hydrological and mechanical correlations between upstream and downstream adjacent slope units (i.e., adjacent calculation units) on the landslide prediction results is taken into account, the underreporting rate and false alarm rate of the prediction results can be further reduced, thereby improving the accuracy of landslide prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in 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 paying creative work.

[0028] Figure 1 A schematic flow chart of a method for regional rainfall-induced landslide prediction provided in one embodiment of the present application;

[0029] Figure 2 The forecast model flow chart for this application;

[0030] Figure 3 This is the precipitation data processing diagram;

[0031] Figure 4 This is the forecast result diagram of different working conditions at 24h;

[0032] Figure 5 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] The purpose of this application is to provide a regional rainfall-type landslide prediction method, equipment, medium and product to improve the accuracy of landslide prediction.

[0035] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] like Figure 1 As shown, the present application provides a regional rainfall-type landslide prediction method, comprising:

[0037] Step 101: Obtain digital elevation model data of the area to be forecasted.

[0038] Step 102: extract slope units from the digital elevation model data to obtain all slope units.

[0039] Step 103: Determine the flow direction of each slope unit.

[0040] The step 103 specifically includes:

[0041] The D8 flow direction algorithm is used to calculate the flow direction of each grid cell in the digital elevation model data.

[0042] For each slope unit, the grid row and column information contained in the slope unit is counted, and the average flow direction of the grids inside the slope unit is obtained according to the flow direction of each grid unit in the digital elevation model data. The average flow direction of the grids inside the slope unit is used as the flow direction of the slope unit to obtain the flow direction of each slope unit.

[0043] Step 104: based on the flow direction of each slope unit, the upstream and downstream flow direction relationship of all slope units is obtained.

[0044] In step 104, the upstream and downstream flow direction relationship of all slope units is used to determine whether any slope unit has an upstream adjacent slope unit, whether any slope unit has a downstream adjacent slope unit, and is also used to determine the adjacent slope units that have a common boundary with the upstream slope unit and the adjacent slope units that have a common boundary with the downstream slope unit; the upstream adjacent slope unit is the adjacent slope unit that has a common boundary with the upstream slope unit; the downstream adjacent slope unit is the adjacent slope unit that has a common boundary with the downstream slope unit.

[0045] Step 105: At each rainfall infiltration moment, a hydrological analysis is performed on each slope unit in sequence, starting from the slope unit at the highest elevation to the slope unit at the lowest elevation, and the moisture content distribution data of each slope unit is updated. Afterwards, a stability analysis is performed on each slope unit in sequence, starting from the slope unit at the lowest elevation to the slope unit at the highest elevation, based on the moisture content distribution data of each slope unit, and the stability of each slope unit is updated. A landslide is predicted based on the stability of each slope unit. The hydrological analysis includes performing a hydrological correlation between upstream and downstream adjacent slope units based on the upstream and downstream flow direction relationship of all slope units. The stability analysis includes performing a mechanical correlation between upstream and downstream adjacent slope units based on the upstream and downstream flow direction relationship of all slope units.

[0046] In step 105, when any slope unit has an upstream adjacent slope unit, the upstream and downstream adjacent slope units include the slope unit and the upstream adjacent slope units that have a common boundary with the slope unit; when any slope unit has a downstream adjacent slope unit, the upstream and downstream adjacent slope units include the slope unit and the downstream adjacent slope units that have a common boundary with the slope unit.

[0047] At each rainfall infiltration moment, hydrological analysis is performed on each slope unit in order from the slope unit with the highest elevation to the slope unit with the lowest elevation, and the moisture content distribution data of each slope unit is updated, including:

[0048] At each rainfall infiltration moment, the current slope units are obtained in sequence from the slope unit with the highest elevation point to the slope unit with the lowest elevation point. Starting from the slope unit with the highest elevation point as the current slope unit, the moisture content distribution data of the current slope unit is updated. According to the upstream and downstream flow relationship of all slope units, the hydrological association is performed between the current slope unit and the adjacent slope units downstream that have a common boundary with the current slope unit, and the moisture content distribution data of the adjacent slope units downstream that have a common boundary with the current slope unit are updated until the moisture content distribution data of all slope units are updated. The hydrological association includes allocating the surface runoff generated by the current slope unit to the adjacent slope units downstream that have a common boundary with the current slope unit. The hydrological association is used to update the moisture content distribution data of the adjacent slope units downstream that have a common boundary with the current slope unit.

[0049] At each rainfall infiltration moment, according to the moisture content distribution data of each slope unit, the stability analysis is carried out on each slope unit in order from the slope unit with the lowest elevation point to the slope unit with the highest elevation point, and the stability of each slope unit is updated, including:

[0050] At each rainfall infiltration moment, the current slope units are obtained in sequence from the slope unit at the lowest elevation to the slope unit at the highest elevation. Starting from the slope unit at the lowest elevation, the stability of the current slope unit is updated according to the moisture content distribution data of the current slope unit. According to the upstream and downstream flow relationship of all slope units, the mechanical association between the current slope unit and the adjacent slope units with a common boundary with the current slope unit is performed, and the stability of the adjacent slope units with a common boundary with the current slope unit is updated until the stability of all slope units is updated. The mechanical association includes applying the remaining anti-sliding force of the current slope unit to the adjacent slope units with a common boundary upstream and the current slope unit. The slope unit has adjacent slope units with common boundaries; the mechanical association is used to update the stability of the upstream adjacent slope units with common boundaries with the current slope unit; the stability of the slope unit is judged by the safety factor of the slope unit; the safety factor of the slope unit is obtained by the ratio of the anti-sliding force of the slope unit to the sliding force of the slope unit; the anti-sliding force of the slope unit and the sliding force of the slope unit are obtained by the moisture content distribution data of the slope unit; when the safety factor of the slope unit is greater than or equal to 1, the slope unit is judged to be stable, and there is residual anti-sliding force when the slope unit is stable, and the residual anti-sliding force is obtained by subtracting the sliding force of the slope unit from the anti-sliding force of the slope unit; when the safety factor of the slope unit is less than 1, the slope unit is judged to be unstable.

[0051] At each rainfall infiltration moment, landslide prediction is carried out according to the stability of each slope unit, including:

[0052] At each rainfall infiltration moment, the areas corresponding to the unstable slope units among all slope units are predicted to have landslide risks, and the areas corresponding to the stable slope units among all slope units are predicted to have no landslide risks.

[0053] The technical solution of the regional rainfall landslide prediction method of the present application is described below with a specific embodiment:

[0054] The present application is based on the fact that micro-topography morphological characteristics have an important influence on the stability of rainfall infiltration in landslides. In field surveys, it is often found that there are micro-topography of various shapes on the landslide body, such as steep slopes, gentle slopes, platforms, etc. Under the action of rainfall, there is an obvious hydrological correlation between the upstream and downstream micro-topography. For example, under the action of rainfall, the surface runoff generated by the upstream steep slope will flow to the downstream slope with lower terrain, changing the hydrological response process of the downstream slope. The downstream platform will receive the surface runoff generated by the upstream slope, forming surface pressure infiltration, thereby affecting the infiltration response of the downstream slope. At the same time, under the action of rainfall, there is an obvious mechanical correlation between the upstream and downstream micro-topography units (in this application, slope units are used to characterize micro-topography characteristics, and slope units are called micro-topography units). For each micro-topography unit, the sliding force thereof will continue to increase under the rainfall factor. When a certain micro-topography unit When its own anti-sliding force is not enough to resist the sliding force, it will generate thrust on the adjacent micro-geomorphological units downstream. According to Newton's second law, the adjacent units will also generate supporting force on the unit. Therefore, for the regional scale, the hydromechanical correlation of the upstream and downstream adjacent micro-geomorphological units will lead to changes in the stability of the soil there and in the surrounding areas, thereby affecting the regional landslide assessment or prediction results. However, the current regional landslide prediction methods cannot consider the impact of the hydromechanical correlation of the upstream and downstream adjacent micro-geomorphological units on the analysis results, and cannot accurately simulate the hydromechanical correlation phenomenon of the upstream and downstream adjacent micro-geomorphological units. The present application provides a rainfall-type landslide prediction method that considers the hydromechanical correlation of the upstream and downstream micro-geomorphological units, which can accurately simulate the hydromechanical correlation phenomenon of the upstream and downstream adjacent micro-geomorphological units, thereby improving the accuracy of landslide prediction results.

[0055] At present, the basic analysis unit (forecast unit) of the forecast model is a grid unit, and the shape of the grid unit is a regular grid, which cannot reflect the micro-geomorphological characteristics, so there is no way to reflect the correlation between the upstream and downstream micro-geomorphology. In addition, the current forecast model is established for a single grid unit, that is, the calculation is performed one grid at a time, and the model equation does not consider the hydrological and mechanical correlation between adjacent grids. Therefore, the current regional landslide forecasting method cannot consider the impact of the hydrological and mechanical correlation between the upstream and downstream adjacent calculation units on the landslide forecasting results. Based on this, the present application provides a regional landslide physical forecasting method that can consider the hydrological and mechanical correlation between the upstream and downstream adjacent micro-geomorphological units, and the method includes the following steps:

[0056] 1. Extraction of micro-geomorphological units.

[0057] Compared with grid units, slope units have the advantage of being able to accurately reflect the topographic characteristics of the actual slope body. Patent No. ZL201810027926.8 proposes a slope unit extraction method, namely, a slope unit extraction method in DEM (Digital Elevation Model). The extracted slope unit is called a slope unit (HSU) with homogeneous characteristics. Each HSU has uniform slope and aspect terrain characteristics, and the HSU boundary is where the actual terrain has undulating turning points. The slope unit is a polygon, and each HSU has a centroid point and several boundary points. HSU can reflect the terrain undulation characteristics, the slope of the landslide, the slope direction and other micro-geomorphological characteristics, and has a uniform slope and slope direction inside. It is currently the most accurate prediction unit for identifying the micro-geomorphological characteristics of the landslide. When used in landslide research, it can be defined as a micro-geomorphological unit. Therefore, this application defines HSU as a micro-geomorphological unit. In this application, HSU is called micro-geomorphic unit. The extraction of micro-geomorphic unit is realized by the slope unit extraction method in DEM. The slope unit extracted by the slope unit extraction method in DEM is a slope unit with uniform characteristics. Generally speaking, 10,000 to 20,000 HSUs can be extracted from a county-level area of ​​thousands of square kilometers, and an area of ​​10-100km 2 Hundreds or thousands of HSUs may be extracted from a small watershed.

[0058] 2. Identification of upstream and downstream flow relationships of HSU.

[0059] The identification of HSU upstream and downstream flow relationship specifically includes the following steps:

[0060] (1) First, the D8 flow direction algorithm (there is a corresponding tool in the ARCGIS commercial software) is used to calculate the flow direction of each grid cell in the DEM of the study area.

[0061] (2) Count the grid row and column information contained in each HSU, obtain the average flow direction of the internal grid, and use it as the flow direction of the HSU.

[0062] (3) According to the flow direction of each HSU, identify the ID number of the downstream adjacent HSU that shares a common boundary with it (HSU is surface vector data, and each HSU is geometrically a polygon. After extracting the HSU, the HSU attribute table contains the ID number of each HSU) and name it as the downstream adjacent unit.

[0063] (4) Starting from the micro-geomorphic unit with the highest elevation at the regional scale (or the unit on the ridge line), steps (1) to (3) are executed repeatedly until the micro-geomorphic unit with the lowest elevation is reached. The upstream and downstream flow relationship of all micro-geomorphic units can be identified.

[0064] 3. Analysis of upstream and downstream HSU hydrological correlation.

[0065] At each rainfall infiltration moment (i.e. every hour), the following hydrological analysis algorithm is executed:

[0066] (a) Perform unsaturated-saturated infiltration analysis on each HSU to obtain the moisture content distribution data and surface runoff data.

[0067] (b) Based on the infiltration analysis results, determine whether each HSU generates surface runoff:

[0068] If there is no surface runoff, the hydrological analysis process of the HSU unit (ie, HSU) ends.

[0069] If surface runoff is generated, it is determined whether there is a downstream adjacent unit based on the identified upstream and downstream flow direction relationship; if there is no downstream adjacent unit, the hydrological analysis process of the HSU unit ends; if there is a downstream adjacent unit, the surface runoff is allocated to the downstream adjacent HSU unit.

[0070] (c) Update downstream HSU hydrological analysis data:

[0071] Infiltration analysis is conducted again for the downstream adjacent HSU unit, and the moisture content and surface runoff data of the downstream adjacent HSU are updated.

[0072] (d) Starting from the micro-relief unit with the highest elevation (or the unit on the ridge line), steps (a) to (c) are repeated until the micro-relief unit with the lowest elevation is reached, ensuring that the hydrological data of each HSU is updated.

[0073] Based on the above, surface runoff (surface runoff reflects the process that when the rainfall intensity at a certain moment exceeds the infiltration rate of the soil surface, the excess rainwater at that moment cannot infiltrate, thus forming surface runoff) is used as a link to achieve the hydrological connection between the upstream and downstream HSUs.

[0074] 4. Analysis of the mechanical correlation between upstream and downstream HSUs.

[0075] At each infiltration moment, after executing the hydrological correlation algorithm, the following mechanical correlation analysis algorithm is executed:

[0076] (S1) For each HSU, firstly calculate its safety factor Fs using the limit equilibrium method as the initial state.

[0077] This step S1 calculates the initial safety factor as the initial state, and updates the moisture distribution data based on the hydrological association (updating the surface flow data and the surface runoff data is ultimately for updating the moisture distribution data). The moisture distribution data is used for calculating the safety factor. Since the safety factor calculation formula includes matrix suction (pore water pressure), the matrix suction is very important and needs to be calculated through the moisture distribution data. The moisture content at different points in the soil (i.e., the moisture distribution data) is different, and its matrix suction is different, and the safety factor is also different. The purpose of updating the moisture content by hydrological association is to solve the change of matrix suction, and then calculate the safety factor according to the change of matrix suction.

[0078] (S2) Determine the stability of the HSU unit at the foot of the slope or at the lowest point in elevation. If the safety factor Fs of the HSU at the foot of the slope is less than 1, it means that the HSU cannot remain stable by its own anti-sliding force at the current infiltration moment, and the stability analysis process of the unit at the foot of the slope is terminated. According to the upstream and downstream flow direction relationship, continue to identify the stability of the HSU unit upstream of the foot of the slope.

[0079] (S3) In this process, if the safety factor Fs of a certain HSU unit is greater than or equal to 1, it means that the HSU unit can maintain stability by relying on its own anti-slip force. According to the flow direction relationship, it is determined whether the HSU unit has an upstream adjacent HSU unit:

[0080] If there is no upstream neighboring unit, the stability analysis process for that HSU unit is terminated.

[0081] If there is an upstream adjacent unit, the residual anti-slip force N of the HSU unit is solved according to the following formula, and the residual anti-slip force N is applied to the upstream adjacent HSU as a supporting force:

[0082] N = anti-slip force T-slip force S

[0083] Among them, the anti-slip force T and the sliding force S are obtained through the safety factor of HSU. The anti-slip force T is the numerator of the safety factor, and the sliding force S is the denominator of the safety factor. The safety factor of HSU is calculated using the limit equilibrium method.

[0084] (S4) Update the stability of the upstream adjacent HSU: re-conduct stability analysis for the upstream adjacent HSU unit and update its safety factor. Execute steps (S3)-(S4) repeatedly to update the stability of all upstream HSU units.

[0085] The mechanical correlation calculation method of this application is from bottom to top, starting from the foot of the slope and continuously solving the residual anti-slip force. This application combines the actual findings to find that the foot of the slope is the most likely location for landslides to start. Therefore, this application starts the stability analysis from the HSU at the lowest elevation point at the foot of the slope, and uses the residual anti-slip force as the mechanical correlation link between the upstream and downstream HSUs until the HSU at the highest elevation point ends, which can achieve the mechanical correlation of the upstream and downstream HSUs at the regional scale.

[0086] The flow chart of the technical solution of this application is as follows Figure 2 As shown, compared with the prior art, the present application establishes a rainfall-type landslide prediction method that can take into account the hydromechanical correlation of upstream and downstream micro-geomorphological units at a regional scale. Based on this, the spatial position, quantity and real-time stability of potential sliding micro-geomorphological units are dynamically updated, which can not only publish the forecast information of each micro-geomorphological unit, but also help to identify the scope of potential landslides. Among them, the dynamic update of the spatial position, quantity and real-time stability of potential sliding micro-geomorphological units is achieved by dividing a day into 24 forecast moments, and running a hydromechanical correlation analysis process at each forecast moment, so as to achieve dynamic updates, that is, to achieve dynamic results at different forecast moments. Compared with the current forecast model, which publishes forecast results for grid units, the directionality is not clear, and the correlation between grids is not considered, the present application publishes forecast results for micro-geomorphological units, which is more clear than grid units, and takes into account the correlation between micro-geomorphological units. The flow chart of the forecast model of the present application is shown as follows Figure 2 As shown. The forecast information of each micro-geomorphic unit is released according to different forecast times. Theoretically, under the premise of satisfying the calculation time, any time interval can be set as the forecast time, such as 10 minutes, 30 minutes or 60 minutes. The identification of the potential landslide range is based on the mechanical association. At each forecast time, by updating the stability of each HSU from the foot of the slope upward, it is possible to identify which HSUs are unstable and which HSUs are supported downstream and will not become unstable, thus delineating the potential sliding area.

[0087] The following example shows that from August 15 to 31, 2014, Fengjie experienced continuous heavy rains, and regional landslides occurred in the territory on August 31. The heavy rainfall eventually induced 583 actual landslide points. The effect of using the forecasting method provided by this application to forecast regional rainfall-type landslides is described. According to the quantitative precipitation estimation (Quantative Precipitation Estimation, QPE) and quantitative precipitation forecast (Quantative Precipitation Prediction, QPF) data provided by the Chongqing Meteorological Bureau, as shown in the figure below: Figure 3 As shown, Figure 3 Part (a) shows the previous precipitation QPE data. Figure 3Part (b) shows the QPF data of precipitation on that day, which is Figure 3 It can be seen that the maximum cumulative precipitation in some areas of Jiangbei on August 31 was 92.40 mm. The previous precipitation in Jiangbei was significantly greater than that in Jiangnan, with a maximum value of 179.10 mm, which occurred in the northwest region of the territory. The present invention uses the previous precipitation data and the hourly QPF data on August 31 as input to predict the landslide in the study area on August 31. In order to facilitate the comparison of the forecast effect, two working conditions are set:

[0088] Case 1: The upstream and downstream HSU hydromechanical correlation is not considered.

[0089] Case 2: Considering the upstream and downstream HSU hydromechanical correlation.

[0090] According to the above description of this application, working condition 1 is actually the initial state of working condition 2. The forecast results of working condition 1 and working condition 2 at 24h are as follows: Figure 4 As shown, Figure 4 Part (a) shows the forecast result of condition 1 at 24h. Figure 4 Part (b) shows the forecast result of condition 2 at 24h. Figure 4 It can be seen that cluster landslides occurred in the northwest region of the country where the previous precipitation and the precipitation on the day were large, which shows that the spatial distribution of landslides is well correlated with the spatial distribution of precipitation data. Figure 4 It can be seen from parts (a) and (b) that the number of unstable HSUs in condition 2 is higher than that in condition 1, indicating that more HSUs are unstable after considering the hydro-mechanical correlation of upstream and downstream HSUs. To further compare the forecasting effect, Table 1 gives the underreporting rate results of the two conditions at 20h, 22h, and 24h. As shown in Table 1, at different forecasting times, the underreporting rate of condition 1 is 8.4-9.0%, and the underreporting rate of condition 2 is 3.7-5.5%. Taking the 24th hour as an example, among 583 landslide points, condition 1 successfully predicted 534 landslide points with an underreporting rate of 8.4%; condition 2 successfully predicted 561 landslide points with an underreporting rate of 3.7%. Based on the above results analysis, the forecasting method after considering the hydro-mechanical correlation can further reduce the underreporting rate of the forecast results, meet the requirements of business forecasting, and is suitable for regional rainfall-type landslide forecasting.

[0091] Table 1 Forecast effect comparison statistics

[0092]

[0093] From the above, it can be seen that compared with the current regional landslide prediction method, which does not take into account the impact of the hydrological and mechanical correlation between the upstream and downstream adjacent calculation units on the landslide prediction results, the underreporting rate and false alarm rate of the prediction results are high, and the accuracy of the landslide prediction is low. The rainfall-type landslide prediction method established in this application, which can consider the hydrological and mechanical correlation of the upstream and downstream micro-geomorphological units, further reduces the underreporting rate and false alarm rate of the prediction results, improves the accuracy of the landslide prediction, and achieves better results.

[0094] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 5 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store regional rainfall-type landslide forecast data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a regional rainfall-type landslide forecast method is implemented.

[0095] Those skilled in the art will understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components. In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0096] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0097] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0098] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0099] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0100] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0101] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A regional rainfall-type landslide prediction method, characterized in that: The regional rainfall-type landslide prediction method comprises: Obtain digital elevation model data of the area to be forecasted; Extracting slope units from the digital elevation model data to obtain all slope units; Determine the flow direction of each slope unit; Based on the flow direction of each slope unit, the upstream and downstream flow direction relationship of all slope units is obtained; At each rainfall infiltration moment, a hydrological analysis is performed on each slope unit in sequence, starting from the slope unit at the highest elevation to the slope unit at the lowest elevation, and the moisture content distribution data of each slope unit is updated. Afterwards, a stability analysis is performed on each slope unit in sequence, starting from the slope unit at the lowest elevation to the slope unit at the highest elevation, based on the moisture content distribution data of each slope unit, and the stability of each slope unit is updated. A landslide is predicted based on the stability of each slope unit. The hydrological analysis includes performing a hydrological correlation between upstream and downstream adjacent slope units based on the upstream and downstream flow direction relationship of all slope units. The stability analysis includes performing a mechanical correlation between upstream and downstream adjacent slope units based on the upstream and downstream flow direction relationship of all slope units.

2. The regional rainfall-type landslide prediction method according to claim 1, characterized in that: Determining the flow direction of each slope unit specifically includes: Calculating the flow direction of each grid cell in the digital elevation model data using the D8 flow direction algorithm; For each slope unit, the grid row and column information contained in the slope unit is counted, and according to the flow direction of each grid unit in the digital elevation model data, the average flow direction of the grids inside the slope unit is obtained, and the average flow direction of the grids inside the slope unit is used as the flow direction of the slope unit to obtain the flow direction of each slope unit.

3. The regional rainfall-type landslide prediction method according to claim 1, characterized in that: The upstream and downstream flow direction relationship of all slope units is used to determine whether any slope unit has an upstream adjacent slope unit and a downstream adjacent slope unit, and is also used to determine the upstream adjacent slope unit that has a common boundary with the slope unit and the downstream adjacent slope unit that has a common boundary with the slope unit; the upstream adjacent slope unit is the upstream adjacent slope unit that has a common boundary with the slope unit; the downstream adjacent slope unit is the downstream adjacent slope unit that has a common boundary with the slope unit.

4. The regional rainfall-type landslide prediction method according to claim 3 is characterized in that: When any slope unit has an upstream adjacent slope unit, the upstream and downstream adjacent slope units include the slope unit and the upstream adjacent slope units that have a common boundary with the slope unit; when any slope unit has a downstream adjacent slope unit, the upstream and downstream adjacent slope units include the slope unit and the downstream adjacent slope units that have a common boundary with the slope unit.

5. The regional rainfall-type landslide prediction method according to claim 4 is characterized in that: At each rainfall infiltration moment, hydrological analysis is performed on each slope unit in order from the slope unit with the highest elevation to the slope unit with the lowest elevation, and the moisture content distribution data of each slope unit is updated, including: At each rainfall infiltration moment, the current slope units are obtained in sequence from the slope unit with the highest elevation point to the slope unit with the lowest elevation point. Starting from the slope unit with the highest elevation point as the current slope unit, the moisture content distribution data of the current slope unit is updated. According to the upstream and downstream flow relationship of all slope units, the hydrological association is performed between the current slope unit and the adjacent slope units downstream that have a common boundary with the current slope unit, and the moisture content distribution data of the adjacent slope units downstream that have a common boundary with the current slope unit are updated until the moisture content distribution data of all slope units are updated. The hydrological association includes allocating the surface runoff generated by the current slope unit to the adjacent slope units downstream that have a common boundary with the current slope unit. The hydrological association is used to update the moisture content distribution data of the adjacent slope units downstream that have a common boundary with the current slope unit.

6. The regional rainfall-type landslide prediction method according to claim 5, characterized in that: At each rainfall infiltration moment, according to the moisture content distribution data of each slope unit, the stability analysis is carried out on each slope unit in order from the slope unit with the lowest elevation point to the slope unit with the highest elevation point, and the stability of each slope unit is updated, including: At each rainfall infiltration moment, the current slope units are obtained in sequence from the slope unit at the lowest elevation to the slope unit at the highest elevation. Starting from the slope unit at the lowest elevation, the stability of the current slope unit is updated according to the moisture content distribution data of the current slope unit. According to the upstream and downstream flow relationship of all slope units, the mechanical association between the current slope unit and the adjacent slope units with a common boundary with the current slope unit is performed, and the stability of the adjacent slope units with a common boundary with the current slope unit is updated until the stability of all slope units is updated. The mechanical association includes applying the remaining anti-sliding force of the current slope unit to the adjacent slope units with a common boundary upstream and the current slope unit. The slope unit has adjacent slope units with common boundaries; the mechanical association is used to update the stability of the upstream adjacent slope units with common boundaries with the current slope unit; the stability of the slope unit is judged by the safety factor of the slope unit; the safety factor of the slope unit is obtained by the ratio of the anti-sliding force of the slope unit to the sliding force of the slope unit; the anti-sliding force of the slope unit and the sliding force of the slope unit are obtained by the water content distribution data of the slope unit; when the safety factor of the slope unit is greater than or equal to 1, the slope unit is judged to be stable, and there is residual anti-sliding force when the slope unit is stable, and the residual anti-sliding force is obtained by subtracting the sliding force of the slope unit from the anti-sliding force of the slope unit; when the safety factor of the slope unit is less than 1, the slope unit is judged to be unstable.

7. The regional rainfall-type landslide prediction method according to claim 6 is characterized in that: At each rainfall infiltration moment, landslide prediction is carried out according to the stability of each slope unit, including: At each rainfall infiltration moment, the areas corresponding to the unstable slope units among all slope units are predicted to have landslide risks, and the areas corresponding to the stable slope units among all slope units are predicted to have no landslide risks.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the regional rainfall-type landslide prediction method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the regional rainfall-type landslide prediction method described in any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the regional rainfall-type landslide prediction method described in any one of claims 1 to 7 is implemented.

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