A method for identifying potential risks of landslide-dammed lake geological disaster chain

Abstract

The present invention provides a method for identifying the potential risks of a landslide-dammed lake geological disaster chain, and relates to the technical field of geological disaster identification. The present invention obtains basic data and river valley data of the study area, performs terrain digitization processing, establishes and discretizes river valley and mountain valley data sets, and finally determines the dangerous terrain coefficient through the relative relationship between the width of the river valley or mountain valley and the length of the slopes on both sides. The hazard of the landslide-dammed lake disaster chain is evaluated based on the basic data and terrain coefficients, and the hazard level is divided and updated. The method of the present invention combines multiple factors, which is helpful for evaluating the risk of geological disasters and providing a data and methodological basis for responding to regional geological disasters.

Description

Technical Field

[0001] The invention relates to the technical field of geological disaster identification, and in particular to a method for identifying potential risks of a landslide-dammed lake geological disaster chain. Background Art

[0002] Landslide-barrier lake chain geological disasters can easily cause the effect of disaster amplification, seriously threatening people's lives and property safety. The occurrence of disaster chains is sometimes hidden. Even small landslides may form landslide-barrier lake chain geological disasters, such as the landslide-barrier lake disaster in Shanzao Village, Zhejiang Province on August 10, 2019. The landslide was very small and did not belong to the danger zone beforehand. Therefore, clarifying the generation environment of the disaster chain has great guiding significance for disaster prevention and mitigation. In addition to the potential risks of the landslide itself, the formation of the landslide-barrier lake geological disaster chain is often related to the special terrain conditions of the place where it occurs, which is called dangerous terrain conditions.

[0003] Therefore, it is urgent to develop a method for identifying the potential risks of the landslide-dammed lake geological disaster chain by taking into account dangerous terrain conditions. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a method for identifying the potential risks of a landslide-dammed lake geological disaster chain.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A method for identifying potential risks of a landslide-dammed lake geological disaster chain, comprising:

[0007] Obtain basic information on the study area and river valley data within the study area;

[0008] Performing numerical terrain processing on the research area to obtain a three-dimensional grid coordinate matrix;

[0009] Based on the three-dimensional grid coordinate lattice, a river and valley data set is established according to the river and valley data, and the river and valley lines are discretized according to the river and valley data set to obtain a discretized data point set;

[0010] Establishing a dynamic point set according to the discretized data point set, and determining the width of the river valley and the mountain valley and the gradient and length of the slopes on both sides according to the dynamic point set;

[0011] Determine the dangerous terrain coefficient based on the basic data, the width of the river valley and the valley, and the gradient and length of the slopes on both sides;

[0012] Determine the danger of the landslide-dammed lake disaster chain and the conditions for the formation of a dammed lake after the landslide is formed according to the basic data and the dangerous terrain coefficient;

[0013] The hazard level of the landslide-dammed lake hazard chain is divided and updated according to the hazard level of the landslide-dammed lake hazard chain and the conditions for the formation of a dammed lake after the landslide.

[0014] Preferably, the river valley data includes river distribution and valley data.

[0015] Preferably, the basic data include geological structure, earthquake probability, rainfall probability and landslide hazard.

[0016] Preferably, the horizontal spacing between the terrain grid points of the three-dimensional grid coordinate lattice is no more than 50 m.

[0017] Preferably, based on the three-dimensional grid coordinate lattice, a river and valley data set is established according to the river and valley data, and the river and valley lines are discretized according to the river and valley data set to obtain a discretized data point set, including:

[0018] Based on the three-dimensional grid coordinate lattice, each river main channel, tributary and valley line in the study area are picked up based on the river distribution and valley data to obtain the river and valley data set;

[0019] Discretization is performed according to each river main channel, tributary and valley line to obtain the discretized data point set.

[0020] Preferably, a dynamic point set is established according to the discretized data point set, and the width of the river valley and the mountain valley and the slope and length of the slopes on both sides are determined according to the dynamic point set, including:

[0021] In the direction perpendicular to the tangent of the river and the valley, with the discrete points of the river and the valley line as the center, a dynamic point set perpendicular to the direction of the river and the valley in the small section is established; the dynamic point set is the points within a range of 5 or 10 km away from the discrete points; the spacing of the dynamic point set is not greater than the horizontal spacing of the terrain grid points; the plane coordinates of the dynamic point set are calculated by the distance relationship with the calculation point; the elevation of the dynamic point set is obtained by grid interpolation based on the three-dimensional grid coordinate lattice;

[0022] According to the distance and height difference from the center point of the river and valley width, calculate the slope Data_Group (x, y, z, slope) of each point on the dynamic point set, where x, y, z are the coordinates of any point on the dynamic point set, and slope is the slope of any point on the dynamic point set;

[0023] Determine the width W of the valley and the valley according to the slope change curve; the formula of W is: W = F (Data_Group (x, y, z, slope));

[0024] In the dynamic point set, search for the point with the largest slope change in the process of slope rising on both sides from the center point of the river valley or valley. The length between the points with the largest slope change on both sides is the width of the river valley or valley. At the same time, the slope and length of the slope on both sides of the river valley and valley are determined according to the slope change curve; the slope length is the length of the line segment from the point with the largest slope change in the process of slope rising to the inflection point where the slope changes from rising to falling, and the slope is the slope of the entire slope length of this section.

[0025] Preferably, the dangerous terrain coefficient is determined according to the basic data, the width of the river valley and the valley, and the slope and length of the slopes on both sides, including:

[0026] Determine whether there is a record of landslide hazard in the basic data. If so, use the formula A = (L 1 / W-1) or A=(L 2 / W-1) to calculate the dangerous terrain coefficient A; where L 1 and L 2 The length of the slope on one side and the other side respectively;

[0027] If not, the dangerous terrain coefficient A is calculated using the formula A=A(W,L,α)=(L / W-1)*F(α); wherein α is the slope gradient; and F(α) is the slope influence function, which is obtained by statistically analyzing the relationship between the historical landslide data and the slope in the area.

[0028] Preferably, determining the danger of the landslide-dammed lake disaster chain and the conditions for the formation of a dammed lake after the landslide is formed according to the basic data and the dangerous terrain coefficient includes:

[0029] The accumulated rainfall in the upstream area of ​​each calculation point in each river valley and valley line is calculated according to the historical rainfall extreme value in the study area, and combined with the landslide hazard, the landslide-barrier lake disaster chain hazard Risk of each calculation point that can form a barrier lake is obtained; the formula of the landslide-barrier lake disaster chain hazard Risk1 of the barrier lake is: Risk1=F(f slide ,A); where f slide The hazard of the landslide;

[0030] According to the actual rainfall situation R and the dynamically updated landslide hazard, combined with the correlation of dangerous terrain conditions, the condition Risk2 for the formation of a barrier lake after the landslide is formed is calculated; Risk2 = F (f slide ,A,R).

[0031] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0032] The invention provides a method for distinguishing potential risks of a landslide-barrier lake geological disaster chain, comprising: obtaining basic data of a study area and river valley data in the study area; performing numerical terrain processing on the study area to obtain a three-dimensional grid coordinate lattice; establishing a river and valley data set based on the river valley data based on the three-dimensional grid coordinate lattice, and discretizing river and valley lines based on the river and valley data set to obtain a discretized data point set; establishing a dynamic point set based on the discretized data point set, and judging the width of river valleys and valleys and the slope and length of slopes on both sides based on the dynamic point set; determining a dangerous terrain coefficient based on the basic data, the width of river valleys and valleys and the slope and length of slopes on both sides; determining the danger of a landslide-barrier lake disaster chain and the conditions for the formation of a barrier lake after a landslide is formed based on the basic data and the dangerous terrain coefficient; and dividing and updating the danger level of the landslide-barrier lake disaster chain based on the danger of the landslide-barrier lake disaster chain and the conditions for the formation of a barrier lake after a landslide is formed. The present invention focuses on the assessment of regional dangerous terrain conditions, combines geological structure, rainfall, landslide hazard and other factors, and makes a risk assessment on the possibility of the formation of a landslide-barrier lake disaster chain. It helps to provide data and methodological basis for the investigation and protection of regional geological disaster risks by identifying dangerous factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 A flow chart of a method provided by an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of a technical route provided for an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of determining the width of a river valley or mountain valley and the length and gradient of a slope provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 A flow chart of a method provided by an embodiment of the present invention, such as Figure 1 As shown, the present invention provides a method for identifying potential risks of a landslide-dammed lake geological disaster chain, comprising:

[0040] Step 100: Obtain basic data of the study area and river valley data within the study area;

[0041] Step 200: performing numerical terrain processing on the research area to obtain a three-dimensional grid coordinate matrix;

[0042] Step 300: Based on the three-dimensional grid coordinate lattice, a river and valley data set is established according to the river and valley data, and the river and valley lines are discretized according to the river and valley data set to obtain a discretized data point set;

[0043] Step 400: establishing a dynamic point set according to the discretized data point set, and determining the width of the river valley and the mountain valley and the slope and length of the slopes on both sides according to the dynamic point set;

[0044] Step 500: Determine the dangerous terrain coefficient according to the basic data, the width of the river valley and the valley, and the slope and length of the slopes on both sides;

[0045] Step 600: Determine the danger of the landslide-dammed lake disaster chain and the conditions for the formation of a dammed lake after the landslide is formed according to the basic data and the dangerous terrain coefficient;

[0046] Step 700: Classify and update the hazard level of the landslide-dammed lake hazard chain according to the hazard level of the landslide-dammed lake hazard chain and the conditions for the formation of a dammed lake after the landslide.

[0047] like Figure 2 As shown, by analyzing the formation environment of the landslide-barrier lake geological disaster chain, this embodiment believes that dangerous terrain conditions are an indispensable factor in the formation of the disaster chain. Therefore, this embodiment is to assess the possibility and danger of the landslide-barrier lake geological disaster chain by judging the dangerous terrain conditions. The specific steps of this technical solution are as follows:

[0048] Step 1: Obtain basic information on the geological structure, earthquake probability, rainfall probability, landslide hazard, etc. of the study area.

[0049] Step 2: Obtain regional river distribution, valley data, etc.

[0050] Step 3: High-precision terrain digitization:

[0051] Digital modeling of the terrain in the area is carried out to establish a three-dimensional grid coordinate lattice. The horizontal spacing of the grid points can be set to 10m, 20m, etc. as needed, or it can be set according to the size of the study area and computing power. It is recommended that the horizontal spacing d of the terrain grid points should not be greater than 50m, and the terrain grid data point set is obtained: Data_Grid(x,y,z), where x, y, z are the coordinates of the center point of the data set.

[0052] Step 4: Calculation and identification of dangerous terrain conditions

[0053] (1) Establishing river and valley datasets

[0054] Pick up each river trunk and tributary in the region; you can also pick up each valley line in the region according to the regional terrain distribution characteristics; thus establishing the river and valley line dataset of the region. The river and valley line dataset can be expressed as: Data_line(num), where num is the number of datasets.

[0055] (2) Discretize each river line and valley line

[0056] Discretize the river and valley lines. The length between discrete points is no greater than the grid spacing. If the river is wider or the valley is wider, the center point is used as the standard. The discretized data point set of the river and valley line is Data_line(num,x,y,z).

[0057] (3) Establishment of dynamic point set;

[0058] In the direction perpendicular to the tangent of the river and valley, with the discrete points of the river and valley line as the center, a dynamic point set perpendicular to the direction (tangent direction) of the river and valley in the small section is established; the dynamic point set is a point within a range of 5 or 10 km away from the discrete point, and the dynamic point set spacing is not greater than the terrain grid spacing. The plane coordinates of the dynamic point set can be calculated from the distance relationship with the calculation point, and the elevation can be obtained by grid interpolation based on the terrain data point matrix. Therefore, the coordinates of the dynamic point set are functions of the river line and the terrain grid, that is,

[0059] Data_Group(x,y,z)=F(Data_line,Data_grid).

[0060] (4) Determine the width of river valleys and valleys

[0061] The width of the river and valley can be determined based on the distance and height difference from the center point of the river and valley width, by calculating the slope Data_Group (x, y, z, slope) of each point on the dynamic point set, and judging the width of the river and valley based on the slope change curve. Figure 3As shown, in the dynamic point set, the center point of the river valley or valley is searched to both sides for the point with the maximum slope change during the slope rising process. The length between the points with the maximum slope change on both sides is the width of the river valley or valley.

[0062] W=F(Data_Group(x,y,z,slope))

[0063] (5) Determine the slope and length of the slopes on both sides

[0064] By calculating the slope of each point on the dynamic point set, the slope of the river valley and the slopes on both sides of the valley (α 1 and α 2 ) and length (L 1 and L 2 ). Therefore, the slope α on each side is a function of the dynamic point set, which is the average value of each point from the bottom of the valley to the highest point of the slope (the nth point). The slope length L can be calculated based on the distance and slope. Figure 3 As shown, the slope length is the length of the line segment from the point of maximum slope change during the slope rising process to the inflection point where the slope changes from rising to falling, and the slope is the slope of the entire slope length of this segment.

[0065]

[0066] L j =n j d / cosα j , (j=1,2)

[0067] Of course, in some places where the terrain is more complex and the slope changes greatly, it is also possible to analyze the complexity of the slope change at each point and calculate the slope and slope length in sections.

[0068] (6) Setting and judging dangerous terrain coefficient

[0069] i) If there are landslide hazard records or relevant data in the area, the slope drop on both sides can be calculated. If the length of the slope on both sides of the river is more than twice the width of the valley, the basic conditions of dangerous terrain are met. The higher the multiple, the greater the risk factor. Therefore, the expression of the risk factor (A) is:

[0070] A=(L 1 / W-1)

[0071] or

[0072] A=(L 2 / W-1)

[0073] ii) If there is no landslide hazard record or relevant data in the area, it is necessary to consider the slope data, refer to the relationship between landslide and slope, and add the slope influence function: F(α). In this way, the terrain hazard coefficient can be a function of the valley width (W), slope length (L) and slope (α).

[0074] A=A(W,L,α)=(L / W-1)*F(α)

[0075] Step 5: Danger of landslide-dammed lake disaster chain

[0076] (1) Based on the historical rainfall extremes in the region (year, month, day, hour), the cumulative rainfall in the upstream area of ​​each calculation point in each river valley and valley line can be calculated, and then combined with the landslide hazard (f slide ), and the conditions and danger of forming a barrier lake at each calculation point are obtained. The danger of the landslide-barrier lake disaster chain is a function of the landslide danger and dangerous terrain conditions:

[0077] Disaster chain risk: Risk1 = F(f slide ,A)

[0078] (2) Based on the actual rainfall conditions (R) and the dynamically updated landslide hazard, combined with the correlation of dangerous terrain conditions, the conditions for the formation of a barrier lake after the landslide is formed are calculated.

[0079] Disaster chain risk: Risk2 = F(f slide ,A,R)

[0080] (3) In summary, the hazard level of the landslide-dammed lake disaster chain can be divided and updated based on the calculation results.

[0081] The beneficial effects of the present invention are as follows:

[0082] The present invention can classify the danger level of the landslide-dammed lake geological disaster chain in advance by judging the dangerous conditions of the terrain. It can also dynamically adjust and judge the possibility of the formation of the landslide-dammed lake geological disaster chain based on the real-time rainfall and landslide danger conditions, providing a reference for comprehensive assessment of the danger of geological disasters, hidden danger investigation, and early prevention.

[0083] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0084] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, 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 the present invention.

Claims

1. A method for identifying potential risks of landslide-dammed lake geological disaster chain, characterized in that: include: Obtain basic information on the study area and river valley information within the study area; Performing numerical terrain processing on the research area to obtain a three-dimensional grid coordinate matrix; Based on the three-dimensional grid coordinate lattice, a river and valley data set is established according to the river and valley data, and the river and valley lines are discretized according to the river and valley data set to obtain a discretized data point set; Establishing a dynamic point set according to the discretized data point set, and determining the width of the river valley and the mountain valley and the gradient and length of the slopes on both sides according to the dynamic point set; Determine the dangerous terrain coefficient based on the basic data, the width of the river valley and the valley, and the gradient and length of the slopes on both sides; Determine the danger of the landslide-dammed lake disaster chain and the conditions for the formation of a dammed lake after the landslide is formed according to the basic data and the dangerous terrain coefficient; Divide and update the hazard level of the landslide-barrier lake hazard chain according to the hazard level of the landslide-barrier lake hazard chain and the conditions for the formation of the barrier lake after the landslide; The river valley data include river distribution and valley data; the basic data include geological structure, earthquake probability, rainfall probability and landslide hazard; A dynamic point set is established according to the discretized data point set, and the width of the river valley and the mountain valley and the slope and length of the slopes on both sides are determined according to the dynamic point set, including: In the direction perpendicular to the tangent of the river and the valley, with the discrete points of the river and the valley line as the center, a dynamic point set perpendicular to the direction of the river and the valley in the small section is established; the dynamic point set is the points within a range of 5 or 10 km away from the discrete points; the spacing of the dynamic point set is not greater than the horizontal spacing of the terrain grid points; the plane coordinates of the dynamic point set are calculated by the distance relationship with the calculation point; the elevation of the dynamic point set is obtained by grid interpolation based on the three-dimensional grid coordinate lattice; According to the distance and height difference from the center point of the river and valley width, calculate the slope Data_Group (x, y, z, slope) of each point on the dynamic point set, where x, y, z are the coordinates of any point on the dynamic point set, and slope is the slope of any point on the dynamic point set; Determine the width W of the valley and the valley according to the slope change curve; the formula of W is: W = F (Data_Group (x, y, z, slope)); In the dynamic point set, the point with the maximum slope change during the slope rising process is searched from the center point of the river valley or valley to both sides. The length between the points with the maximum slope change on both sides is the width of the river valley or valley. At the same time, the slope and length of the slope on both sides of the river valley and valley are determined according to the slope change curve. The slope length is the length of the line segment from the point with the maximum slope change during the slope rising process to the inflection point where the slope changes from rising to falling. The slope is the slope of the entire slope length of this section. Determine the dangerous terrain coefficient based on the basic data, the width of the river valley and the valley, and the slope and length of the slopes on both sides, including: Determine whether there is a record of landslide hazard in the basic data. If so, calculate the dangerous terrain coefficient A using the formula A=(L1 / W-1) or A=(L2 / W-1); where L1 and L2 are the slope lengths on one side and the other side respectively; If not, the dangerous terrain coefficient A is calculated using the formula A=A(W,L,α)=(L / W-1)*F(α); where α is the slope gradient; F(α) is the slope gradient influence function, which is obtained by statistically analyzing the relationship between the historical landslide data and the slope gradient in the area; Determine the hazards of the landslide-dammed lake disaster chain and the conditions for the formation of a dammed lake after the landslide is formed based on the basic data and the dangerous terrain coefficient, including: The accumulated rainfall in the upstream area of ​​each calculation point in each river valley and valley line is calculated according to the historical rainfall extreme value in the study area, and combined with the landslide hazard, the landslide-barrier lake disaster chain hazard Risk of each calculation point that can form a barrier lake is obtained; the formula of the landslide-barrier lake disaster chain hazard Risk1 of the barrier lake is: Risk1=F(f slide ,A); where f slide The hazard of the landslide; According to the actual rainfall situation R and the dynamically updated landslide hazard, combined with the correlation of dangerous terrain conditions, the condition Risk2 for the formation of a barrier lake after the landslide is formed is calculated; Risk2 = F (f slide ,A,R).

2. The method for identifying potential risks of landslide-dammed lake geological disaster chain according to claim 1 is characterized in that: The horizontal spacing between the terrain grid points of the three-dimensional grid coordinate lattice is no more than 50m.

3. The method for identifying potential risks of landslide-dammed lake geological disaster chain according to claim 1 is characterized in that: Based on the three-dimensional grid coordinate lattice, a river and valley data set is established according to the river and valley data, and the river and valley lines are discretized according to the river and valley data set to obtain a discretized data point set, including: Based on the three-dimensional grid coordinate lattice, each river main channel, tributary and valley line in the study area are picked up based on the river distribution and valley data to obtain the river and valley data set; Discretization is performed according to each river main channel, tributary and valley line to obtain the discretized data point set.

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