KR102478816B1 - Stability evaluation and management method for a slope using unmanned aerial vehicle - Google Patents

Abstract

The present invention relates to a method for evaluating and managing the stability of a slope by using an unmanned aerial vehicle, which can divide danger areas by classifying the stability of a slope in an investigation area by grade together with evaluation of the stability of the slope, and can continuously manage some danger areas having a reference value or lower. The method comprises: an investigation area selection and planning step of selecting an investigation area in which a rockfall or collapse is suspected or expected, and establishing a stability evaluation and management plan for the investigation area; an aerial data securement step of obtaining aerial photographs or images of the investigation area by using an unmanned aerial vehicle; a 3D modeling step of producing a 3D photograph image after performing 3D modeling on the investigation area from the obtained aerial photographs or images; a point cloud generation step of generating a point cloud on the produced 3D photograph image; a stability evaluation and classification step of obtaining and analyzing slope information of the investigation area by using the point cloud, evaluating the stability, and classifying the stability by grade; and a slope management step of repeating the aerial data securement step or the stability evaluation and classification step at periods if the grade of the stability is below the reference value.

Description

Stability evaluation and management method of slope using unmanned aerial vehicle {STABILITY EVALUATION AND MANAGEMENT METHOD FOR A SLOPE USING UNMANNED AERIAL VEHICLE}

The present invention secures precise photogrammetry data using unmanned aerial vehicles in the investigation area where rockfalls or collapses are suspected or expected, conducts erosion monitoring and stability evaluation, and continuously manages dangerous sections such as collapses or rockfalls based on the stability evaluation results. It relates to a method for evaluating and managing the stability of a slope using an unmanned aerial vehicle that performs

Recently, according to the continuous development of technology using unmanned aerial vehicles such as unmanned aerial vehicles or drones, simple fire suppression, rescue and pesticide spraying, as well as surveying, disaster or disaster monitoring, reverse engineering of buildings, etc. Its use in various fields is increasing.

Accordingly, in the above technical fields and various industrial fields, there are technologies that use unmanned aerial vehicles to take aerial photos or videos, and to improve the accuracy of spatial information expressed in 3D images based on the aerial data captured in this way. It is widely studied.

When spatial information expressed in 3D images based on the above aerial data is applied to the civil engineering field, the topography of a specific area is photographed, 3D modeling is analyzed, and topographical changes are detected or soils are classified. It is also evaluated by analyzing the stability of slopes, etc.

For example, Patent Registration No. 10-1365090 'Terrain Change Detection System Using UAV', Patent Registration No. 10-1787542 'Slope Stability Evaluation System and Method Using 3D Terrain Model and Soil Classification' and Registered Patent Publication No. No. 10-2156832, 'Slope surveying system and method using drones', etc.

In addition, in the case of the 'Method for Evaluating the Stability of Rock Slope Using a Drone' in Patent Registration No. 10-1891087, in which the inventor participated, the captured photos are matched to compare with the reference point on the ground to correct the error, and then use this to correct the individual rock mass. It is characterized by acquiring and extracting rock slope information such as slope direction, slope angle, and surface curvature, evaluating the risk of rock slope through stability evaluation, and grouping discontinuous surfaces of the same aspect.

However, the stability evaluation method of the slope using an unmanned aerial vehicle according to the prior art as described above first only performs stability evaluation on the slope of the investigation area, and accordingly, after the stability evaluation, the criteria for the risk area or the risk area are determined. There is a problem that there is no post-processing for the case, and secondly, when 3D modeling is performed only with pictures or video data taken from an unmanned aerial vehicle, the accuracy of the 3D image is reduced, and the evaluation index is simply a point cloud generated on the 3D image. There is a problem that it is difficult to secure the reliability of the stability evaluation because the stability is evaluated only with the slope direction, slope angle, and surface curvature through the slope.

The object of the present invention, which was conceived to solve the above problems, is an unmanned aerial vehicle capable of classifying risk areas by grade along with stability evaluation on the slope of the irradiation area, and continuously managing the risk area below the standard value. To provide a method for evaluating and managing the stability of slopes using

In addition, more precise 3D images are produced by comparing and analyzing 3D shape images acquired by LIDAR along with photos or video data taken from unmanned aerial vehicles. It is to provide a stability evaluation and management method for slopes using unmanned aerial vehicles that can secure the reliability of stability evaluation by analyzing and classifying them by grade.

Other objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings.

In order to achieve the above object, the method for evaluating and managing the stability of a slope using an unmanned aerial vehicle according to the present invention selects an investigation area where rockfall or collapse is suspected or expected, and establishes a stability evaluation and management plan for the investigation area. After performing the survey area selection and planning step, the aerial data acquisition step of securing aerial photos or images of the survey area using unmanned aerial vehicles, and performing 3D modeling of the survey area from the obtained aerial photos or images A 3D modeling step of producing a 3D photo image, a point cloud generation step of generating a point cloud on the produced 3D photo image, obtaining and analyzing slope information of the survey area using the point cloud, and then determining stability It includes a stability evaluation and classification step of evaluating and classifying by grade, and a slope management step of repeating the aeronautical data securing step or stability evaluation and classification step at regular intervals when the stability grade is below the standard value.

In addition, the step of selecting a research area and establishing a plan is characterized by designing a flight path for securing aerial data of the unmanned aerial vehicle along with surface geological survey of the selected research area.

In addition, in the aerial data securing step, a lidar is mounted on the unmanned aerial vehicle along with an aerial photograph or video of the survey area to obtain a 3D shape image of the survey area in three dimensions, and the 3D modeling The step is characterized in that the 3D photographic image is produced by performing 3D modeling of the aerial photograph or video on the 3D shape image.

In addition, the stability evaluation and classification step divides the slope information of the investigation area into safety performance and durability performance according to the size and condition using the surface geology and the point cloud of the investigation area, and has five grades from a to e. It is characterized in that each is classified and evaluated as.

In addition, the safety performance includes state safety performance, which is an evaluation index according to catchment topography, unstable geology, discontinuous surface characteristics, ground deformation, groundwater, drainage conditions, collapse history, rockfall and tensile cracks, and projection analysis and limit equilibrium analysis. The durability performance is an evaluation index according to the ground condition, surface protection hole, slope reinforcement hole, joint state and weathering progress.

In addition, in the slope management step, if the evaluated stability grade of the investigation area is grade c or less, it is selected as a risk area, and the aerial data securing step or stability evaluation and classification step is repeatedly performed at regular intervals, and vegetation in the risk area is selected. However, if the stability grade re-evaluated through protection facilities, reinforcement facilities, or drainage treatment facilities is changed to grade a or b, it is characterized in that management is terminated.

In the slope stability evaluation and management method using an unmanned aerial vehicle according to the present invention, along with the stability evaluation of the slope of the investigation area, the risk area is classified by grade, and the risk area below the standard value is classified as vegetation or protection facility, reinforcement facility or There is an effect that continuous management can be performed until drainage treatment facilities are installed.

In addition, more precise 3D images are produced by comparing and analyzing 3D shape images acquired by LIDAR along with photos or video data taken from unmanned aerial vehicles. By analyzing and classifying by grade, there is an effect of securing the reliability of stability evaluation.

1 is a flowchart showing an embodiment of a method for evaluating and managing the stability of a slope using an unmanned aerial vehicle according to the present invention;
2 is a captured screen showing a work process through an embodiment of the air data acquisition step and 3D modeling step in the embodiment of FIG. 1;
3 is a captured screen showing a work process through another embodiment of the air data acquisition step and the 3D modeling step in the embodiment of FIG. 1;
Figure 4 is a captured screen showing the work process of the point cloud generation step in the embodiment of Figure 1,
Figure 5 is a flow chart explaining the specific work process of the stability evaluation and classification step and slope management step in the embodiment of Figure 1,
6 is a captured screen showing the work process of rockfall simulation analysis, projection analysis of structural safety performance, and limit equilibrium analysis in the case of rockfall of state safety performance among safety performance evaluation indicators in the embodiment of FIG. 5,
7 is a captured screen displaying slope information such as plane, wedge, overturning failure or movement direction of falling rock on a 3D photograph image through the embodiment of FIG. 6;
8 shows that the safety grade from the embodiment of FIG. 3 is evaluated as grade c or less and selected as a risk area, and then the re-evaluated stability grade through vegetation, protection, reinforcement, or drainage treatment facilities is changed to grade b or higher, and management is terminated. This is a screenshot showing the process.

Hereinafter, a preferred embodiment of a method for evaluating and managing the stability of a slope using an unmanned aerial vehicle according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the method for evaluating and managing the stability of a slope using an unmanned aerial vehicle according to the present invention includes a survey area selection and planning step (S100), aerial data securing step (S200), 3D modeling step (S300), It includes a point cloud generation step (S400), a stability evaluation and classification step (S500), and a slope management step (S600).

In the investigation area selection and plan establishment step (S100), an investigation area in which rockfall or collapse is suspected or expected is selected, and a stability evaluation and management plan are established for the investigation area. For example, a safety evaluation company receives a request from the Ministry of Land, Infrastructure, and Transport, a local government, or a civil engineering or construction company, selects an investigation area, and establishes a stability evaluation and management plan for the selected investigation area. At this time, the optimal flight path is designed to secure the 3D shape image through the aerial data of the unmanned aerial vehicle, that is, aerial photographs or images, or LIDAR to be described later, along with the surface geological survey of the selected investigation area.

In the aerial data securing step (S200), as shown in FIGS. 1 and 2, aerial photos or images of the survey area are secured using an unmanned aerial vehicle. That is, multiple photos or videos may be taken using an unmanned aerial vehicle, but may be taken along multiple flight routes with one unmanned aerial vehicle or along different flight routes with multiple unmanned aerial vehicles. Images may be taken simultaneously using the above cameras, that is, stereo cameras. Any method of shooting is sufficient as long as it is possible to increase the degree of matching so that 3D modeling described later can be easily performed by taking an aerial photograph or video of the survey area.

In the 3D modeling step (S300), a 3D photo image is produced after performing 3D modeling of the survey area from the aerial photograph or image obtained as shown in FIGS. 1 and 2 . Combine multiple aerial photos taken of the survey area to remove overlapping parts, connect and match the remaining images, and prepare 3D photo images by correcting errors in comparison with GCP (Ground Control Point) during the matching process do.

In the case of the aerial data acquisition step (S200) and the 3D modeling step (S300), when a 3D photo image is produced by performing 3D modeling with only aerial photographs or images as shown in FIG. 2, the left and right deviation is not large, but the altitude difference A lot of correction is required, especially the 3D modeling process can be complicated.

Therefore, as shown in FIG. 3, in the aerial data acquisition step (S200), a lidar is mounted on the unmanned aerial vehicle along with an aerial photograph or video of the survey area to obtain a 3D image of the survey area in three dimensions. Acquire a shape image. Lidar can accurately draw the surroundings by emitting laser pulses, receiving the light reflected from nearby objects and measuring the distance to the object.

At this time, in the 3D modeling step (S300), the 3D photographic image is produced by performing 3D modeling of the aerial photograph or image on the 3D shape image. That is, there is an advantage in that the correction process for the altitude difference generated when performing the 3D modeling using only the aerial photograph can be minimized by comparing with the 3D shape image through the LIDAR.

In the point cloud generating step (S400), a point cloud is created on the 3D photo image produced as shown in FIGS. 1 and 4 . A point cloud is a set of points spread over a three-dimensional space (x, y, z coordinates), and a point cloud is created on a 3D photo image produced through 3D modeling. Through this point cloud, it is possible to precisely analyze the slope of the survey area, and through this, various information on the slope including the slope direction, slope angle, and surface curvature of the slope can be obtained.

In the stability evaluation and classification step (S500), as shown in FIGS. 1 and 5, slope information of the survey area is obtained using the point cloud, analyzed, and then stability is evaluated and classified into grades. More specifically, the stability evaluation and classification step (S500) divides the slope information of the investigation area into safety performance and durability performance according to the scale and condition using the surface geology and the point cloud of the investigation area, and ranges from a to e. It can be evaluated by classifying each into five grades of

For example, depending on scale and condition, a for no labile lipids, b for partial distribution (robust), c for locally distributed (fracture), d for generally distributed (fracture), and generally distributed. (crushing, leaking, etc.) can be evaluated as e.

In addition, safety performance is evaluated through state safety performance, which is an evaluation index according to catchment topography, unstable geology, discontinuous surface characteristics, ground deformation, groundwater, drainage conditions, collapse history, rockfall and tensile cracks, and evaluation through projection analysis and limit equilibrium analysis. It may include structural safety performance, which is an index, and the durability performance may include evaluation indicators according to ground conditions, surface protection holes, slope reinforcement holes, joint conditions, and weathering progress.

In the state safety performance of the above safety performance, catchment topography is the number of inside and outside catchment topography, unstable geology is the distribution scale and state of faults and shear zones, folds, dikes, etc., and discontinuous surface characteristics are extensibility, crevices, roughness, filling, The degree of weathering and interval are referred to as the ground deformation. Surface cracks, surface cracks, deep cracks, etc., rockfalls are the scale of occurrence and expected rockfall energy, and tensile cracks are progress or not. Each evaluation index of state safety performance as described above can be achieved through the surface geological survey of the investigation area, but in the case of falling rocks, as shown in the rockfall simulation analysis of FIG. 6, it can be obtained as slope information.

In addition, among the safety performance, the structural safety performance can analyze the presence and degree of wedge failure, plane failure, and overturning failure through planar projection analysis as shown in FIG. 6 from the slope information, and through limit equilibrium analysis, Safety factor can be analyzed during rainy season and earthquake.

In addition, in the evaluation index of the durability performance, the ground condition is the ratio of the estimated value of the Schmidt hammer strength to the initial value and the soil hardness, the surface protection ball is the vegetation coverage rate and the damaged area ratio, and the slope reinforcing ball is the close contact between the head of the reinforcing ball and the ground It is the degree of uniformity and damage of the head of the road and reinforcing hole, and the joint state and weathering progress are as they are named.

By analyzing each evaluation index described above, as shown in FIG. 7, information on the slope is displayed on the 3D photo image for each color corresponding to each evaluation index to check the entire or partial irradiation area, and also when evaluating stability. It can also be displayed by class.

As shown in FIGS. 1, 5 and 8, in the slope management step (S600), the aerial data acquisition step (S200) to the stability evaluation and classification step (S500) are repeatedly performed at regular intervals when the stability grade is below the standard value. . In other words, after performing the stability evaluation work on the first investigation area and classifying it by grade, if the stability grade exceeds the standard value, no further management is required. It is to repeat the stability evaluation work by setting a period.

At this time, in the case of risk areas below the standard during the initial stability evaluation, the risk of the slope must be eliminated through vegetation, protection facilities, reinforcement facilities, or drainage treatment facilities. cannot be performed, so continuous management is required for dangerous areas.

Therefore, in the slope management step (S600), as shown in FIGS. 5 and 8, if the evaluated stability grade of the survey area is lower than grade c, it is selected as a risk area, and the aerial data securing step (S200) to stability are selected for a certain period. The evaluation and classification step (S600) is repeatedly performed. However, if the stability level re-evaluated through vegetation, protection facilities, reinforcement facilities, or drainage treatment facilities in the above risk area is changed to grade a or b, management is terminated.

As described above, the stability evaluation and management method of the slope using an unmanned aerial vehicle according to the present invention classifies the risk area by grade along with the stability evaluation of the slope of the investigation area, and the risk area below the standard value is divided into vegetation or protection facilities. However, there is an effect that continuous management can be performed until reinforcement facilities or drainage treatment facilities are installed.

In addition, more precise 3D images are produced by comparing and analyzing 3D shape images acquired by LIDAR along with photos or video data taken from unmanned aerial vehicles. It is effective to secure the reliability of stability evaluation by analyzing and classifying by grade.

The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical spirit of the present invention in various forms. Therefore, such improvements and changes will fall within the protection scope of the present invention as long as they are obvious to those skilled in the art.

S100: Survey area selection and plan establishment stage
S200: Aviation data acquisition step
S300: 3D modeling step
S400: point cloud generation step
S500: Stability evaluation and classification step
S600: Slope management step

Claims (6)

A survey area selection and plan establishment step of selecting a survey area where rockfalls or collapses are suspected or expected, and establishing a stability evaluation and management plan for the survey area, and securing aerial photos or images of the survey area using unmanned aerial vehicles. A 3D modeling step of producing a 3D photo image after performing 3D modeling of the survey area from the obtained aerial photograph or image, and a point of generating a point cloud on the produced 3D photo image A cloud generation step, a stability evaluation and classification step of obtaining and analyzing slope information of the survey area using the point cloud, evaluating stability and classifying it into grades, and if the stability grade is below a reference value, the stability evaluation and classification step Including the slope management step of repeatedly performing the aerial data acquisition step or the stability evaluation and classification step,
In the step of selecting the research area and establishing a plan,
Design a flight path to secure aerial data of the unmanned aerial vehicle along with surface geological survey of the selected survey area,
In the step of securing aviation data,
Obtaining a 3D shape image obtained by imaging the irradiation area in three dimensions by mounting a lidar on the unmanned aerial vehicle along with an aerial photograph or video of the irradiation area,
The 3D modeling step,
Performing 3D modeling of the aerial photograph or video on the 3D shape image to produce the 3D photographic image,
The stability evaluation and classification step,
Using the surface geology and the point cloud of the investigation area, the slope information of the investigation area is divided into safety performance and durability performance according to scale and condition, classified into five grades from a to e, respectively, and evaluated,
The safety performance is
State safety performance, which is an evaluation index according to catchment topography, unstable geology, discontinuous surface characteristics, ground deformation, groundwater, drainage conditions, collapse history, rockfall and tensile cracks,
Including structural safety performance, which is an evaluation index through projection projection analysis and limit equilibrium analysis,
The durability performance is
It is an evaluation index according to the ground condition, surface protection work, slope reinforcement work, joint state and weathering progress,
In the slope management step,
If the evaluated stability grade of the investigation area is grade c or less, select it as a risk area and repeat the above-mentioned air data acquisition step or stability evaluation and classification step at regular intervals,
Stability evaluation and management method of a slope using an unmanned aerial vehicle, characterized in that the management is terminated when the stability grade re-evaluated through vegetation or protection facilities, reinforcement facilities or drainage treatment facilities in the dangerous area is changed to grade a or b. delete delete delete delete delete

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