Dangerous rock mass caving ground disaster investigation and evaluation method and system

Abstract

The invention discloses a dangerous rock mass caving ground disaster investigation and evaluation method and system. The method comprises the following steps: extracting a parent pattern spot and a dangerous rock mass pattern spot in a remote sensing image of an investigation area; dividing a high danger area and a potential danger area; extracting a first buffer pattern spot of the potential danger area; a convex hull is created, and a rock mass caving danger area is generated; after earth surface deformation occurs, obtaining a new investigation area remote sensing image, and extracting earth surface deformation area pattern spots; obtaining a second buffer pattern spot; and creating a new convex hull, and generating a new rock mass caving danger area. According to the scheme, before ground disasters such as landslide and flood occur, the rock mass caving danger area is obtained and divided on the remote sensing image in a mode of combining indoor analysis, field surveying and mapping and survey; after landslide, flood and other ground disasters occur and the local surface changes, a new rock mass caving danger area can be rapidly obtained and divided based on a new remote sensing image in combination with the modes of superposition gland analysis and the like.

Description

Technical Field

[0001] This invention relates to the field of geological hazard investigation and assessment technology, and in particular to a method and system for investigating and assessing landslides caused by unstable rock masses. Background Technology

[0002] Rockfall disasters typically occur in areas with fractured terrain, such as steep slopes and cliffs. They manifest as rock masses breaking off from the parent rock under gravity and rolling along the surface after contacting the ground (the toe of the parent rock) until they encounter buffer zones such as rivers, gullies, gentle terrain, or rockfall barriers (like rockfall dams). The resulting rockfalls leave behind rolling boulders, which are typically heavy and easily moved, allowing them to travel relatively far from the parent rock and causing significant damage.

[0003] Currently, many rockfall hazards overlap with areas of human activity, necessitating appropriate prevention and control measures to avoid loss of life and property during disasters. Specifically, for the prevention and control of rockfall disasters, preliminary investigation and assessment determine the stability of the rock mass and its hazard level. Combined with on-site reconnaissance, and based on the rolling prediction of the area after a rockfall, hazardous and safe zones are delineated. For rock masses with poor stability and a high risk of collapse, advance cutting or construction of rockfall barriers (ditches) can control the threat. For areas with relatively stable rock masses and a low hazard level, monitoring is the primary method, minimizing the entry of personnel and materials into the hazardous area.

[0004] However, after localized geological disasters such as landslides caused by rainfall, the local topography changes, and areas identified as safe through preliminary surveys may partially transform into dangerous areas. If personnel and materials enter these transformed dangerous areas, they face a significant risk of loss. Re-identifying dangerous and safe areas through on-site reconnaissance is not only time-consuming but also poses certain safety risks to the survey personnel. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for the investigation and assessment of landslides caused by unstable rock masses, which can quickly delineate dangerous areas after changes in local surface topography, thereby reducing the risk of loss.

[0006] According to a first aspect of the present invention, a method for investigating and assessing landslide hazards caused by unstable rock masses is provided, comprising: S1. Obtain the spatial model of the unstable rock mass in the survey area, remote sensing images of the survey area, and topographic and elevation data of the survey area; S2. Extract parent body patches and unstable rock mass patches from remote sensing images of the survey area; S3. Set the maximum rolling diameter of the collapsed rock mass; S4. Delineate high-risk and potential-risk areas in the remote sensing images of the survey area; S5. Extract the first buffer patch of the potential hazard zone. With the center point of the dangerous rock mass patch as the center point, set multiple radial analysis lines at equal angles. Each radial analysis line located in the potential hazard zone passes through at least two first buffer patches. S6. Extract the first buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line located in the potential danger zone, create a convex hull containing the dangerous rock mass patch, and merge it with the high-risk zone based on the convex hull to generate the rock mass collapse danger zone; S7. After surface deformation occurs, acquire new remote sensing images of the survey area and extract the surface deformation area patches. S8. Overlay the surface deformation area patch with the first buffer patch, and obtain the second buffer patch from the first buffer patch based on the overlay result; S9. Extract the second buffer patch that is closest to the center point of the dangerous rock mass patch on each radial analysis line, create a new convex hull containing the dangerous rock mass patch, and merge the new convex hull with the high-risk area to generate a new rock mass collapse hazard zone.

[0007] According to the aforementioned method for investigating and assessing landslide disasters involving unstable rock masses, in S2, the maximum rolling diameter of the collapsed rock mass includes: The spatial model of the unstable rock mass is vertically projected onto the horizontal plane to form a projection pattern. The length L of the diagonal of the minimum circumscribed rectangle of the projection pattern is measured, and the maximum rolling diameter W1 of the collapsed rock mass is set as αL; 1≤α≤2.

[0008] According to the aforementioned method for investigating and assessing landslide hazards caused by unstable rock masses, in S4, the high-risk areas and potential hazard areas in the remote sensing images of the survey area are delineated as follows: Determine whether the outline of the parent image extends to both sides of the remote sensing image of the survey area. If so, divide the remote sensing image of the survey area by the outline of the parent image, and retain the image portion containing the dangerous rock mass patch as the analysis area. If not, draw a line connecting the center points of the dangerous rock mass patch and the parent image patch, draw a perpendicular line to the line, divide the remote sensing image of the survey area by the perpendicular line, retain the image portion containing the dangerous rock mass patch and delete the parent image patch as the analysis area. Measure the height of the spatial model, draw a circle with the center point of the dangerous rock mass patch as the center and the height of the spatial model as the radius, and the area covered by the circle in the analysis area is recorded as the high-risk area; The area within the analysis zone after removing high-risk areas is designated as the potential hazard zone.

[0009] According to the aforementioned method for investigating and assessing rock mass collapse hazards, in step S6, the first buffer patch closest to the center point of the rock mass patch on each radial analysis line located in the potential hazard zone is extracted. A convex hull containing the rock mass patch is created. Based on the convex hull and the high-risk area, the rock mass collapse hazard zone is generated, including: Extract radial analytical lines located in potentially hazardous areas; Select the first radial analysis line on the outermost side, and find the first buffer patch that is closest to the center point of the dangerous rock mass patch along the radial analysis line; Select an adjacent radial analysis line and check if it passes through the identified first buffer patch. If yes, select the next adjacent radial analysis line and check. If no, find the first buffer patch closest to the center point of the dangerous rock mass patch along the radial analysis line. Repeat this step to traverse all radial analysis lines located in the potential hazard zone to extract the first buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line. Create a convex hull; all the extracted first buffer patches and dangerous rock mass patches are located within the convex hull. Extract the region in the convex hull that overlaps with the analysis area, and merge this region with the high-risk area to generate the rock mass collapse hazard zone.

[0010] According to the aforementioned method for investigating and assessing landslides caused by unstable rock masses, in step S8, the surface deformation area patch is overlaid with the first buffer patch, and the second buffer patch is obtained from the first buffer patch based on the overlay result, including: Overlay and cover the surface deformation area patch and the first buffer patch; Traverse each first buffer patch and extract the first buffer patches that overlap with the surface deformation area patches; Analyze the percentage of the area covered by each first buffer patch; if the percentage exceeds a first threshold, delete the first buffer patch; if the percentage does not exceed the first threshold, retain the uncovered portion of the first buffer patch as an intermediate patch. The intermediate patch and the first buffer patch, which is not covered by the surface deformation area patch, constitute the second buffer patch.

[0011] According to the aforementioned method for assessing and investigating landslides caused by unstable rock masses, 70% ≤ first threshold ≤ 80%.

[0012] According to the aforementioned method for investigating and assessing landslides caused by unstable rock masses, in S7, the surface deformation area patches include landslide area patches and / or flood-damaged area patches.

[0013] According to a second aspect of the present invention, a method and system for investigating and assessing landslides caused by rockfalls is provided, comprising a processor and a memory, wherein the memory stores a plurality of instructions; the processor loads instructions from the memory to execute the method for investigating and assessing landslides caused by rockfalls.

[0014] Beneficial effects: The above scheme allows for the identification and delineation of rockfall hazard zones on remote sensing images before geological disasters such as landslides and floods occur, through a combination of indoor analysis and field surveying and reconnaissance. After landslides, floods, and other geological disasters occur, resulting in local changes to the ground surface, new rockfall hazard zones can be quickly identified and delineated based on new remote sensing images, combined with overlay analysis and other methods. This enables timely monitoring and warning systems to be set up, preventing personnel and materials from entering new rockfall hazard zones and causing losses.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 This is a flowchart of the method of the present invention; Figure 2 A schematic diagram of extracting parent body patches and unstable rock mass patches from remote sensing images of the survey area; Figure 3 A schematic diagram illustrating the division of high-risk and potentially hazardous areas in remote sensing images of the survey area; Figure 4 A schematic diagram showing the setup of radial analysis lines and the extraction of the first buffer patch. Figure 5 A schematic diagram for generating a rock collapse hazard zone. Detailed Implementation

[0017] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0019] In the description of this invention, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] Reference Figure 1-5 The present invention provides a method for investigating and assessing landslide disasters caused by rockfalls, comprising: S1. Obtain the spatial model of the unstable rock mass in the survey area, remote sensing images of the survey area, and topographic and elevation data of the survey area; S2. Extract parent body patches and unstable rock mass patches from remote sensing images of the survey area; S3. Set the maximum rolling diameter of the collapsed rock mass; S4. Delineate high-risk and potential-risk areas in the remote sensing images of the survey area; S5. Extract the first buffer patch of the potential hazard zone. With the center point of the dangerous rock mass patch as the center point, set multiple radial analysis lines at equal angles. Each radial analysis line located in the potential hazard zone passes through at least two first buffer patches. S6. Extract the first buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line located in the potential danger zone, create a convex hull containing the dangerous rock mass patch, and merge it with the high-risk zone based on the convex hull to generate the rock mass collapse danger zone; S7. After surface deformation occurs, acquire new remote sensing images of the survey area and extract the surface deformation area patches. S8. Overlay the surface deformation area patch with the first buffer patch, and obtain the second buffer patch from the first buffer patch based on the overlay result; S9. Extract the second buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line, create a new convex hull containing the dangerous rock mass patch, and merge the new convex hull with the high-risk area to generate a new rock mass collapse hazard zone.

[0022] Specifically, in step S1, a drone carrying surveying equipment (such as photography equipment, laser scanning equipment, etc.) flies over the survey area to acquire spatial data and image data of the parent rock mass (a stable mountain or steep slope with virtually no risk of collapse) and the unstable rock mass (rock masses outside the parent rock mass that have a risk of collapse). Based on this data, models are created for the parent rock mass and the unstable rock mass, thereby extracting the spatial model of the unstable rock mass. Remote sensing images and topographic elevation data of the survey area can be obtained directly from relevant units to reduce the workload.

[0023] In step S2, the parent body patch and the unstable rock mass patch are first extracted directly from the remote sensing image. Then, the boundary of the patch is corrected by combining the data from the on-site reconnaissance and measurement, so as to accurately obtain the dividing line and outer contour line of the parent body patch and the unstable rock mass patch.

[0024] In step S3, the maximum rolling diameter of the collapsed rock mass is set. This specifically includes: vertically projecting the spatial model of the unstable rock mass onto a horizontal plane to form a projection pattern; measuring the length L of the diagonal of the minimum bounding rectangle of the projection pattern; and setting the maximum rolling diameter of the collapsed rock mass W1 = α × L; 1 ≤ α ≤ 2. α is a coefficient; in actual operation, α takes a fixed value within this range, and then analysis is performed.

[0025] Furthermore, in some embodiments, step S3 may be specifically performed as follows: The spatial model of the unstable rock mass is vertically projected onto a horizontal plane to form a projection pattern; the minimum circumscribed circle diameter D of the projection pattern is measured; and the maximum rolling diameter W1 of the collapsed rock is set to β × D; 1.5 ≤ β ≤ 2. β is a coefficient; in actual operation, β takes a fixed value within this range, and then analysis is performed.

[0026] Some unstable rock masses appear narrow on remote sensing image patches, but in reality, their bases bulge towards the parent rock mass. In such cases, the size of the rocks produced after a collapse may far exceed the diagonal length of the minimum bounding rectangle of the unstable rock mass patch. To address this, a spatial model of the unstable rock mass is vertically projected onto a horizontal plane to form a projected patch. The maximum rolling diameter of the collapsed rock mass rocks is then determined by measuring the projected patch, which offers greater reliability.

[0027] After a rock mass collapses, it breaks into multiple stones that roll along the ground. The maximum height and maximum rolling diameter of these stones relative to the ground surface are considered during this process. The topographic features corresponding to the first buffer zone can obstruct the movement of these stones, and the maximum rolling diameter can serve as a size reference for the first buffer zone.

[0028] In step S4, high-risk areas and potential-risk areas are delineated in the remote sensing image of the survey area, specifically including: First, determine whether the outline of the parent image patch extends to both sides of the remote sensing image of the survey area. If so, the remote sensing image of the survey area is divided by the outline of the parent image patch. In this case, the remote sensing image of the survey area can be divided into three parts by the outline of the parent image patch (the parent image patch itself, the image containing the dangerous rock mass patch, and the image without the parent image patch and the dangerous rock mass patch). The image part containing the dangerous rock mass patch is retained as the analysis area. If not, first draw the line connecting the center point of the dangerous rock mass patch and the center point of the parent image patch, and then draw the perpendicular line of this line (the perpendicular line passes through the center point of the parent image patch). The perpendicular line extends to the boundary of the remote sensing image of the survey area. The remote sensing image of the survey area is divided by this perpendicular line (the remote sensing image of the survey area is divided into two parts: the image containing the dangerous rock mass patch and the image without the dangerous rock mass patch). The image part containing the dangerous rock mass patch is retained. This part of the image contains some parent images. After deleting the parent images, this part of the image is used as the analysis area. The height of the spatial model is measured, and a circle is drawn with the center point of the dangerous rock mass patch as the center and the height of the spatial model as the radius. The area within the analysis area that overlaps with the circle (i.e. the part where the analysis area overlaps with the circle) is recorded as the high-risk area. The area within the analysis zone after removing high-risk areas is designated as the potential hazard zone.

[0029] In some embodiments, step S4 specifically includes: First, determine whether the outline of the parent image extends to the boundaries of both sides of the remote sensing image of the survey area. If so, the remote sensing image of the survey area is divided by the outline of the parent image. In this case, the remote sensing image of the survey area can be divided into three parts by the outline of the parent image (the parent image itself, the image containing the dangerous rock mass image, and the image without the parent image and the dangerous rock mass image). The part containing the dangerous rock mass image is retained as the analysis area. If not, first draw the line connecting the center point of the dangerous rock mass image and the center point of the parent image, and then draw a dividing line perpendicular to the line. The dividing line passes through the parent image and extends to the boundary of the remote sensing image of the survey area. The remote sensing image of the survey area is divided by this perpendicular line (the remote sensing image of the survey area is divided into two parts: the image containing the dangerous rock mass image and the image without the dangerous rock mass image). The part containing the dangerous rock mass image is retained. This part of the image contains some parent images. After deleting the parent images, this part of the image is used as the analysis area. The height of the spatial model is measured, and a circle is drawn with the center point of the dangerous rock mass patch as the center and the height of the spatial model as the radius. The area within the analysis area that overlaps with the circle (i.e. the part where the analysis area overlaps with the circle) is recorded as the high-risk area. The area within the analysis zone after removing high-risk areas is designated as a potential hazard zone. The distance between the boundary line and the center point of the unstable rock mass patch is 2 to 3 times the height of the spatial model.

[0030] In step S5, the extraction of the first buffer patch is achieved through a combination of office and field work. Office work, combined with topographic elevation data, directly extracts patches of terrain features that can impede rock rolling, such as roads, rivers, ditches, and protrusions (like hills and ridges), as the first buffer patch. The width of roads is typically not less than W1, the width of rivers and ditches is typically not less than 0.5 × W1, and the height of protrusions is typically not less than 0.75 × W1. Other terrain features that can impede rock rolling (such as paddy fields, ponds, flat land, woodland, and gently sloping dry land) can be accurately obtained through on-site reconnaissance.

[0031] The topographic features corresponding to the first buffer zone effectively hinder the rolling rocks formed after the collapse of the unstable rock mass, preventing the rocks from rolling further downhill. Based on this principle, the first buffer zone is extracted within the potential danger zone.

[0032] After extracting the first buffer zone of the potential hazard area, multiple radial analysis lines are set at equal angles, with the center point of the unstable rock mass patch as the center point. Each radial analysis line located in the potential hazard area must pass through at least two first buffer zones. If it is found that a radial analysis line only passes through one first buffer zone, the first buffer zone can be extracted from the remote sensing image (or obtained through supplementary on-site reconnaissance).

[0033] In step S6, the first buffer patch closest to the center point of the dangerous rock mass patch is extracted from each radial analysis line located in the potential hazard zone. A convex hull containing the dangerous rock mass patch is created. Based on the convex hull and the high-hazard zone, a rock mass collapse hazard zone is generated, which specifically includes: Extract radial analytical lines located in potentially hazardous areas; Select the first radial analysis line on the outermost side, and find the first buffer patch that is closest to the center point of the dangerous rock mass patch along the radial analysis line; Select the second radial analysis line adjacent to the first radial analysis line, and check whether the radial analysis line passes through the first buffer patch that has been found; if so, select the next adjacent radial analysis line to check; if not, find the first buffer patch closest to the center point of the dangerous rock mass patch along the radial analysis line; repeat this step to traverse all radial analysis lines located in the potential hazard zone, and extract the first buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line located in the potential hazard zone; A convex hull (i.e., the minimum convex polygon envelope) is created based on the dangerous rock mass patch and the selected first buffer patch. All extracted first buffer patches and dangerous rock mass patches are included in this convex hull.

[0034] Extract the area overlapping the analysis area within the convex hull region and merge this area with the high-risk area to generate a rockfall hazard zone. Appropriate monitoring should be implemented in this area, and personnel and materials should be prevented from entering as much as possible.

[0035] Step S7 mainly refers to surface changes caused by landslides and floods. These surface changes have relatively clear boundaries, and the surface changes in other areas are not significant, making them easier to analyze. After surface deformation occurs, new remote sensing images of the survey area are acquired, and surface deformation area patches (i.e., landslide patches and flood-damaged area patches) are extracted.

[0036] In step S8, the surface deformation area patch is overlaid with the first buffer patch, and the second buffer patch is obtained from the first buffer patch based on the overlay result. This specifically includes: The surface deformation area patch is superimposed and covered with the first buffer patch below; Traverse each first buffer patch and extract the first buffer patches that overlap with the surface deformation area patches; Analyze the percentage of the area covered by each extracted first buffer patch; if the percentage exceeds a first threshold, delete the first buffer patch; if the percentage does not exceed the first threshold, retain the uncovered portion of the first buffer patch as an intermediate patch. The intermediate patch and the first buffer patch, which is not covered by the surface deformation area patch, constitute the second buffer patch.

[0037] The range of the first threshold is 70% ≤ first threshold ≤ 80%. In actual operation, the first threshold is set to a fixed value within this range for analysis.

[0038] In step S9, the specific operation is the same as in step S6, and will not be described again.

[0039] It should be noted that the present invention is well applicable to localized surface changes caused by landslides and floods, and can quickly and accurately delineate new danger zones based on these changes. However, its applicability is lower for large-scale surface changes caused by earthquakes, as the analysis involves numerous surface deformation zones and significant changes in geological conditions.

[0040] The present invention also provides a method and system for investigating and assessing landslides caused by unstable rock masses, which includes a processor and a memory, wherein the memory stores multiple instructions; the processor loads instructions from the memory to execute the method for investigating and assessing landslides caused by unstable rock masses.

[0041] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for investigating and assessing landslide hazards caused by unstable rock masses, characterized in that, include: S1. Obtain the spatial model of the unstable rock mass in the survey area, remote sensing images of the survey area, and topographic and elevation data of the survey area; S2. Extract parent body patches and unstable rock mass patches from remote sensing images of the survey area; S3. Set the maximum rolling diameter of the collapsed rock mass; S4. Delineate high-risk and potential-risk areas in the remote sensing images of the survey area; S5. Extract the first buffer patch of the potential hazard zone. With the center point of the dangerous rock mass patch as the center point, set multiple radial analysis lines at equal angles. Each radial analysis line located in the potential hazard zone passes through at least two first buffer patches. S6. Extract the first buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line located in the potential danger zone, create a convex hull containing the dangerous rock mass patch, and merge it with the high-risk zone based on the convex hull to generate the rock mass collapse danger zone; S7. After surface deformation occurs, acquire new remote sensing images of the survey area and extract the surface deformation area patches. S8. Overlay the surface deformation area patch with the first buffer patch, and obtain the second buffer patch from the first buffer patch based on the overlay result; S9. Extract the second buffer patch that is closest to the center point of the dangerous rock mass patch on each radial analysis line, create a new convex hull containing the dangerous rock mass patch, and merge the new convex hull with the high-risk area to generate a new rock mass collapse hazard zone. In S2, setting the maximum rolling diameter of the collapsed rock mass includes: vertically projecting the spatial model of the unstable rock mass onto a horizontal plane to form a projection patch, measuring the length L of the diagonal of the minimum circumscribed rectangle of the projection patch, and setting the maximum rolling diameter W1=αL of the collapsed rock mass; α is a coefficient with a value range of 1≤α≤2.

2. The method for investigating and assessing landslide hazards caused by unstable rock masses according to claim 1, characterized in that, In S4, the high-risk and potentially hazardous areas in the remote sensing image of the survey area are delineated as follows: Determine whether the outline of the parent image extends to both sides of the remote sensing image of the survey area. If so, divide the remote sensing image of the survey area by the outline of the parent image, and retain the image portion containing the dangerous rock mass patch as the analysis area. If not, draw a line connecting the center points of the dangerous rock mass patch and the parent image patch, draw a perpendicular line to the line, divide the remote sensing image of the survey area by the perpendicular line, retain the image portion containing the dangerous rock mass patch and delete the parent image patch as the analysis area. Measure the height of the spatial model, draw a circle with the center point of the dangerous rock mass patch as the center and the height of the spatial model as the radius, and the area covered by the circle in the analysis area is recorded as the high-risk area; The area within the analysis zone after removing high-risk areas is designated as the potential hazard zone.

3. The method for investigating and assessing landslide hazards caused by unstable rock masses according to claim 2, characterized in that, In S6, the first buffer patch closest to the center point of the unstable rock mass patch is extracted from each radial analysis line located in the potential hazard zone. A convex hull containing the unstable rock mass patch is created. Based on the convex hull and the high-risk zone, the rock mass collapse hazard zone is generated, including: Extract radial analytical lines located in potentially hazardous areas; Select the first radial analysis line on the outermost side, and find the first buffer patch that is closest to the center point of the dangerous rock mass patch along the radial analysis line; Select an adjacent radial analysis line and check if it passes through the identified first buffer patch. If yes, select the next adjacent radial analysis line and check. If no, find the first buffer patch closest to the center point of the dangerous rock mass patch along the radial analysis line. Repeat this step to traverse all radial analysis lines located in the potential hazard zone to extract the first buffer patch closest to the center point of the dangerous rock mass patch on each radial analysis line. Create a convex hull; all the extracted first buffer patches and dangerous rock mass patches are located within the convex hull. Extract the region in the convex hull that overlaps with the analysis area, and merge this region with the high-risk area to generate the rock mass collapse hazard zone.

4. The method for investigating and assessing landslide hazards caused by unstable rock masses according to claim 1, characterized in that, In S8, the surface deformation area patch is overlaid with the first buffer patch, and the second buffer patch is obtained from the first buffer patch based on the overlay result, including: Overlay and cover the surface deformation area patch and the first buffer patch; Traverse each first buffer patch and extract the first buffer patches that overlap with the surface deformation area patches; Analyze the percentage of the area covered by each first buffer patch; if the percentage exceeds a first threshold, delete the first buffer patch; if the percentage does not exceed the first threshold, retain the uncovered portion of the first buffer patch as an intermediate patch. The intermediate patch and the first buffer patch, which is not covered by the surface deformation area patch, constitute the second buffer patch.

5. The method for investigating and assessing landslide hazards caused by unstable rock masses according to claim 1, characterized in that, The range of the first threshold is: 70% ≤ first threshold ≤ 80%.

6. The method for investigating and assessing landslide hazards caused by unstable rock masses according to claim 1, characterized in that, In S7, the surface deformation area patches include landslide area patches and / or flood-damaged area patches.

7. The method for investigating and assessing landslide hazards caused by unstable rock masses according to claim 1, characterized in that, In S5, the extraction of the first buffer patch includes an office processing method, in which the office processing combines topographic elevation data to extract topographic features that can hinder rock rolling as the first buffer patch.

8. A system for investigating and assessing landslides caused by unstable rock masses, characterized in that: It includes a processor and a memory, the memory storing multiple instructions; the processor loads instructions from the memory to execute the rockfall landslide disaster investigation and assessment method as described in any one of claims 1-7.

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