KR102017313B1 - Method of Ground Subsidence Risk Rating for Prediction of Collapse According to the Excavation Case - Google Patents

Abstract

The present invention relates to a method of classifying an excavation ground risk in accordance with a ground condition and a system thereof which can evaluate stability to reduce land subsidence and damage. The system for classifying an excavation ground risk in accordance with a ground condition comprises a GSR sheet display module, a categorized score calculation module, a GSR score calculation module, and a land subsidence risk evaluation module. The GSR sheet display module considers various ground conditions and geological properties of influence factors to display a GSR sheet including influence factors of land subsidence classified as categories of existence of cavities, soil, rock, soil rock boundary, hydrogeology, and other factors to be given weights. The categorized score calculation module applies the weights in the categories to influence factor scores to calculate categorized scores. The GSR score calculation module checks ground conditions applied in accordance with a ground environment to apply a weight for each excavation ground condition to calculate category scores and then calculates a GSR score by summing. The land subsidence risk evaluation module classifies land subsidence risks into five grades in accordance with the GSR score to perform land subsidence risk evaluation.

Description

Method of Ground Subsidence Risk Rating for Prediction of Collapse According to the Excavation Case}

The present invention relates to a method for classifying excavation ground risks according to ground conditions, and more particularly, to a method for classifying excavation ground risks according to ground conditions for evaluating ground stability for ground depression occurrence and damage reduction.

Excavation work on the foundation is underway in construction projects, including large-scale buildings. However, when the excavation work is carried out, the stress on the ground and soil or rock, and the groundwater changes, causing ground depression or ground subsidence. Ground fluctuations that occur during excavation may not only cause economic damage by disrupting the excavation work, but may also lead to social problems as it may occur due to human life.

In order to cope with the risk of ground depression that may occur between excavation work, the ground survey is conducted on the site site before construction. Based on the survey results, the designer selects the construction method and performs the design in preparation for the ground depression that may occur at the site site. However, ground surveys are often not performed properly, and there are difficulties in conducting soil surveys for proper design because of various aspects of ground depression according to geological characteristics. In addition, the application of design and construction methods based on the survey contents of the ground survey report depends on the designer's competency, and there is no guide or manual.

In this environment, if the proper ground investigation is not performed, unpredicted ground is encountered at the construction stage, and it is difficult to cope with it, causing ground depression.

Korean Registered Patent No. 10-1808127 (2017.12.06.) (How to evaluate the risk of ground subsidence) Korea Registered Patent No. 10-1236214 (2013. 02. 18.) (Ground Subsidence Risk Assessment System Using Mine Geographic Information System)

Therefore, the technical problem of the present invention has been made in view of this point, the object of the present invention is to grasp the geological characteristics of the various soils encountered in the field, and to evaluate the risk of ground depression in the ground investigation stage before excavation occurs in the construction stage It is to provide a method for classifying excavation ground risks according to the ground conditions in order to respond to possible ground depressions.

Another object of the present invention is to provide an excavation ground risk classification system according to the ground conditions for performing the excavation ground risk classification method according to the above ground conditions.

Excavation ground risk classification method according to the ground conditions according to an embodiment in order to realize the object of the present invention, the GSR sheet display module considering the various ground conditions and geological characteristics of each influence factor. Weights are categorized into categories of cavity, soil, rock mass, soil + lock mass, hydro geology, and external factors Displaying a Ground Subsidence Risk (GSR) sheet comprising the ground depression impact factors; A score calculation module for each category calculates a category score (S) by applying the intra-category weight Xi to each of the influence factor scores Si; Calculating a GSR score by applying the weights for each excavation ground condition (Yi) to the calculated category score by checking the ground conditions applied according to the ground environment by the GSR score calculation module; And a ground depression risk assessment module performing a ground depression risk assessment by classifying the ground depression risk into five grades according to the GSR score.

[Xi * Si] (여기서, Si는 각 영향인자 점수, Xi는 카테고리 내 가중치)에 의해 산정될 수 있다. In one embodiment of the present invention, the score for each category, F (Si) =

[Xi * Si], where Si is each influencer score, and Xi is a weight in category.

[Yi * F(si)] = GSR(S) (여기서, Yi는 굴착지반 조건별 가중치, F(si)는 카테고리 별 점수)에 의해 구할 수 있다. In one embodiment of the invention, the GSR score is, Cate (Sj) =

[Yi * F (si)] = GSR (S), where Yi is weighted by excavation ground condition and F (si) is scored by category.

[

{Yi *

(Xi * Si)}]에 의해 수행될 수 있다. In one embodiment of the present invention, the ground depression risk assessment, GSR (S) =

[

{Yi *

(Xi * Si)}].

Excavation ground risk classification system according to the ground conditions according to an embodiment to realize the other object of the present invention, in consideration of the various ground conditions and the geological characteristics of each influence factor. GSR sheet showing the Ground Subsidence Risk (GSR) sheet, which includes weighted ground influence factors, classified into the presence of cavity, soil, rock, soil rock boundary, water quality, and other factors. Display module; A score calculation module for each category for calculating a category score (Sate) by applying an intra-category weight Xi to each of the influence factor scores Si; A GSR score calculation module for calculating a GSR score by applying a weight (Yi) for each excavation ground condition to a category score calculated by checking the ground condition applied according to the ground environment; And a ground depression risk assessment module for classifying the ground depression risk into five grades according to the GSR score to perform the ground depression risk assessment.

According to this invention, it is possible to predict the risk of ground depression in the ground survey stage before construction through GSR. As a result, it can contribute to reducing the economic and human damage caused by the ground depression that can occur in large-scale excavation work. In addition, the GSRp sheet enables rapid site stability prediction and evaluation in the field, which can be used to select response methods for ground depression.

1 is a block diagram illustrating an excavation ground risk classification system according to the ground conditions according to an embodiment of the present invention.
Figure 2 is a table for explaining the quantification grade and score of the ground depression influence factor.
3 is a table for explaining influence factor weights and preferences for each category.
Figure 4 is a table for explaining the impact recognition category and the weight applied according to the ground conditions before excavation.
5 is a table for explaining the risk of ground depression according to the GSR score.
6 is a flowchart illustrating a method for classifying excavation ground risks according to ground conditions according to an embodiment of the present invention.
7A to 7G are user interface screens of a ground hazard classification program implemented according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing the drawings, similar reference numerals are used for similar elements. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof.

1 is a block diagram illustrating an excavation ground risk classification system according to the ground conditions according to an embodiment of the present invention.

1, the excavation ground risk classification system 100 according to the ground conditions according to an embodiment of the present invention is a GSR sheet display module 110, a category calculation module 120 for each category, GSR score calculation module 130 And ground depression risk assessment module 140. In this embodiment, the excavation ground risk classification system 100 according to the ground conditions is the GSR sheet display module 110, the category calculation module 120 for each category, the GSR score calculation module 130 and the ground depression risk evaluation module 140 For the sake of convenience, the logical divisions are not hardware divisions.

The GSR sheet display module 110 considers various ground conditions and geological characteristics of each influence factor. Weights are categorized into categories of cavity, soil, rock mass, soil + lock mass, hydro geology, and external factors Display the GSR sheet containing the ground depression impact factors. The GSR sheet includes a blank for recording the score of each soil depression effect factor for the presence or absence of a cavity classified into categories, a blank for recording a score for each soil depression influence factor for the soil, and a score for each soil depression influence factor for the rock. Blanks for entry, scores for each soil depression influence factor on soil rock boundary Blanks for entry, blanks for entry of soil depression influence factors for water quality, scores for soil depression influence factors for other factors The blank for writing can be displayed. Each blank may be scored by the ground depression factor in such a manner that the user writes the score.

2 is a table for explaining quantification grades and scores of the ground depression influence factors displayed on the GSR sheet.

Referring to FIG. 2, ground depression influencing factors corresponding to the cavities of category 1 include the depth of overburden and the thickness of overburden. Depth of boundary between soil and rock-mass, and Dip of boundary between soil and rock-mass). Soil impact corresponding to category 3 soil is determined by shear strength, relative density / degree of compaction, dry unit weight, water content ), The liquid limit (Liquid limit). Ground depression impact factors corresponding to category 4 rock mass include rock type, distance to main fracture, and rock quality designation (RQD). Here, the rock types are rock etc, shale or slab, coal shale, mud stone, dolomite, limestone, gypsum, rock salt ( Rock salt). Soil impact factors corresponding to category 5 hydro geology include rainfall intensity, distance / depth to main channel, coefficient of permeability, and groundwater level fluctuations. (Fluctuation of groundwater table). The ground depression influence factor corresponding to the external factor of category 6 includes pipe-lines. The ground depression effect factors for each category may be mapped to scores.

Referring back to FIG. 1, the score calculation module 120 for each category calculates the category score Cate (S) by applying the intra-category weight Xi to each of the influence factor scores Si. The category-specific score may be calculated by Equation 1 below.

[Equation 1]

[Xi * Si]F (Si) =

[Xi * Si]

3 is a table for explaining influence factor weights and preferences for each category.

Referring to FIG. 3, in relation to category 1, the soil skin, which is the soil impact factor, is assigned a weight of 50%, and the weight of the soil, which is the soil impact factor, is assigned a weight of 50%. In relation to category 2, a 33.4% weight was assigned to the soil depth and the rock depth, and 66.6% was applied to the slope angle between the soil and the rock. In relation to category 3, soil types were weighted 30%, shear strength was weighted 17%, relative density / compaction weighted 18%, dry unit weight was weighted 3%, moisture The water content was assigned a weight of 15% and the liquid index was assigned a weight of 17%. In relation to category 4, the rock type was assigned a weight of 42%, the distance from the main insulation was assigned a weight of 31%, and the rock quality index (RQD) was assigned a weight of 27%. In relation to category 5, rainfall intensity was weighted 6.8%, distance / depth to river was weighted 11.4%, investment coefficient was weighted 15.9%, and groundwater level variation was weighted 65.9%. . Regarding category 6, the pipeline was given a weight of 100%.

Referring back to FIG. 1, the GSR score calculation module 130 calculates the GSR score by checking the ground conditions applied according to the ground environment, applying the weights Yi for each excavation ground condition to the calculated category score, and adding the weights. The GSR score may be calculated by Equation 2 below.

[Formula 2]

[Yi * F(si)] = GSR(S)Cate (Sj) =

[Yi * F (si)] = GSR (S)

Figure 4 is a table for explaining the impact recognition category and the weight applied according to the ground conditions before excavation.

Referring to FIG. 4, in the case where there is no cavity as the most common site and the condition for measuring the boundary between soil and rock, the soil / rock boundary (SR) category is given a weight of 1.3%, and the soil (SL) category The weight was 34.6%, the rock category (RM) category was weighted 22.5%, the hydrogel (HG) category was weighted 38.1%, and the external impact (EF) category was weighted 3.55%.

In the case of common sites with no cavities and where the boundary between soil and rock cannot be measured, the soil (SL) category has a weight of 35.1%, and the rock (RM) category has a weight of 22.8%. HG) category was assigned a weight of 38.6%, and the External Impact (EF) category was assigned a weight of 3.5%.

In the absence of cavities and all soil conditions, which are common sites, the soil (SL) category has a weight of 45.5%, the hydrogel (HG) category has a weight of 50%, and the external impact (EF) category has a weight. 4.5% was given.

In conditions where there are no common cavities and all are rock masses, the Rock (RM) category has a weight of 35.1%, the Hydrogen (HG) category has a weight of 59.5%, and the External Impact (EF) category has a weight of 5.4. % Was given.

For occasional sites with cavities and conditions where soil and rock boundaries can be measured, the CV category has a weight of 6.5% and the soil / rock boundary (SR) category has a weight of 1.2%. , The soil (SL) category has a weight of 32.4%, the rock (RM) category has a weight of 21.1%, the hydrogel (HG) category has a weight of 35.6%, and the external impact (EF) category has a weight of 3.2. % Was given.

In the occasional site where there are cavities and conditions where the boundary between soil and rock cannot be measured, the CV category has a weight of 6.6%, the soil category has a weight of 32.8%, and the rock ( The RM) category has a weight of 21.3%, the HG category has a weight of 36.1%, and the external impact (EF) category has a weight of 3.2%.

In the rare case of cavities and all soils, the CV category is weighted 8.3%, the soil category SL 41.7%, and the HG category weighted. 45.8% were assigned, and the weighted 4.2% for the EF category.

In the rare case of cavities and all rock formations, the cv category has a weight of 9.8%, the rock category has a weight of 31.7%, and the hydrogel (HG) category has a weight. 53.7% was assigned, and the external impact (EF) category was assigned a weight of 4.8.

Referring back to FIG. 1, the ground depression risk evaluation module 140 classifies the ground depression risk into five grades according to the GSR score to perform the ground depression risk assessment.

5 is a table for explaining the risk of ground depression according to the GSR score.

Referring to FIG. 5, when the GSR score is 0 to 20, the ground depression risk is classified as very poor ground. When the GSR score is 20 to 40, the ground depression risk is classified as poor ground, and the GSR score is 40 to 60. In this case, the risk of ground depression is usually classified as ground, and if the GSR score is 60 to 80, the ground risk is classified as good ground. If the GSR score is 80 to 100, the ground risk is classified as very good ground.

Prediction of ground depression is necessary to reduce ground damage, but in practice it was difficult to understand various influence factors and to consider ground conditions. However, according to the present invention, a literature investigation on the factors causing ground depression and expert consultation were conducted to derive the soil impact factors, and to select and quantify the characteristics of the ground needed to investigate each factor in the field. Grade was given.

Also consider the various soil conditions and the geological characteristics of each influencer. Influence factors are categorized into cavities, soils, rock masses, soil + lock masses, hydro geology, and external factors. Weighted. Each category was given different weights according to the ground conditions, and the evaluation results were summed to evaluate the grade of the survey ground.

By simplifying the above process, which can be complex to be applied in the field, writing the ground characteristic value on the GSRp sheet allows for the rapid evaluation and evaluation of the ground.

6 is a flowchart illustrating a method for classifying excavation ground risks according to ground conditions according to an embodiment of the present invention.

Referring to FIG. 6, the ground depression risk (GSR) sheet is displayed (step S100). The display of the GSR sheet may be performed by the GSR sheet display module 110 (shown in FIG. 1).

Then, it is checked whether the score for each ground depression effect factor is input (step S102). The check operation of whether the score for each ground depression effect factor is input may be performed by the score calculation module 120 (refer to FIG. 1) for each category.

If it is checked in step S102 that the score for each ground depression effect factor is input, the input score for each ground depression influence factor is stored (step S104). The score storage for each of the ground depression influence factors may be performed by the category calculation module 120 (shown in FIG. 1) for each category.

Subsequently, the score for each category is calculated by summing the product of each influence factor score and the weight in the category (step S106). The above-described category score calculation may be performed by the category score calculation module 120 (shown in FIG. 1).

Subsequently, the GSR score is calculated by summing the product of the weight for each excavation ground condition and the score for each category (step S108). The GSR score calculation may be performed by the GSR score calculation module 130 (shown in FIG. 1).

Then, it is checked whether the SGR score falls within the range of 80 or more and 100 or less (step S110). Checking whether the SGR score is included in the range of 80 to 100 may be performed by the ground depression risk assessment module 140 (shown in FIG. 1).

If it is checked in step S110 that the GSR score falls within the range of 80 or more and 100 or less, the GSR grade is calculated as the first grade (step S112).

If it is checked in step S110 that the GSR score is not in the range of 80 or more and 100 or less, it is checked whether the SGR score is in the range of 60 or more and less than 80 (step S114). Checking whether the SGR score is included in the range of 60 or more and less than 80 may be performed by the ground depression risk assessment module 140 (shown in FIG. 1).

If it is checked in step S114 that the GSR score falls within the range of 60 or more and less than 80, the GSR grade is calculated as the second grade (step S116).

If it is checked in step S114 that the GSR score is not included in the range of 60 or more and less than 80, it is checked whether the SGR score is in the range of 40 or more and less than 60 (step S118). Checking whether the SGR score is included in the range of 40 or more and less than 60 may be performed by the ground depression risk assessment module 140 (shown in FIG. 1).

If it is checked in step S118 that the GSR score falls within the range of 40 or more and less than 60, the GSR grade is calculated to be grade 3 (step S120).

If it is checked in step S118 that the GSR score is not included in the range of 40 or more and less than 60, it is checked whether the SGR score is in the range of 20 or more and less than 40 (step S122). Checking whether the SGR score is included in the range of 20 or more and less than 40 may be performed by the ground depression risk assessment module 140 (shown in FIG. 1).

If it is checked in step S122 that the GSR score falls within the range of 20 or more and less than 40, the GSR grade is calculated as 4 grades (step S124).

If it is checked in step S122 that the GSR score is not included in the range of 20 or more and less than 40, that is, if the GSR score is checked to be less than 20, the GSR grade is calculated as 5 grade (step S126).

7A to 7G are user interface screens of a ground hazard classification program implemented according to an embodiment of the present invention. In this embodiment, the ground hazard classification program may be stored and driven in a user computer, or may be stored and driven in a user mobile phone.

Referring to FIG. 7A, a user interface screen for inputting common presence information in the ground risk classification program is displayed. On one side of the screen, blanks for inputting the thickness of the soil skin and the topsoil, respectively, are displayed as ground depression influence factors corresponding to the presence or absence of a cavity of category 1. When the user enters a specific number on the blank, the number range displayed on the right side of the screen is activated.

Referring to FIG. 7B, a user interface screen for inputting information of soil and rock in a ground hazard classification program is displayed. On one side of the screen, blanks for inputting the boundary depth between the soil and the rock and the inclination angle between the soil and the rock as the ground depression influence corresponding to the category 2 soil rock boundary are displayed. When the user enters a specific number on the blank, the number range displayed on the right side of the screen is activated.

Referring to FIG. 7C, a screen of a user interface for inputting soil information in a ground hazard classification program is displayed. On one side of the screen, blanks for inputting the type, shear strength, relative density / compaction, dry unit weight, water content, and liquid index are displayed as soil depression influence factors corresponding to category 3 soils. When the user enters a specific number on the blank, the number range displayed on the right side of the screen is activated.

Referring to FIG. 7D, a user interface screen for inputting rock information in a ground hazard classification program is displayed. On one side of the screen, blanks for inputting rock type, distance from the main insulation, and rock quality index (RQD) are displayed as ground depression influence factors corresponding to rock mass of category 4. When the user enters a specific number on the blank, the number range displayed on the right side of the screen is activated.

Referring to FIG. 7E, a user interface screen for inputting repair information in the ground hazard classification program is displayed. On one side of the screen, blanks for inputting rainfall intensity, distance / depth to river, investment coefficient, and groundwater level fluctuation are displayed as soil depression influence factors corresponding to category 5 water quality. When the user enters a specific number on the blank, the number range displayed on the right side of the screen is activated.

Blanks for inputting repair information are displayed in a left region of the screen, and repair information is displayed in a box form in a right region of the screen, and is changed from an inactive state to an active state according to a user's repair information input.

Rainfall intensity is classified as less than 5 mm / h, 5-10 mm / h, 10-15 mm / h, 15-20 mm / h, 20 mm / h or more. Rivers and distances / depths are displayed classified as less than 400m, 400-200m, 200-100m, and less than 100m. Permeability coefficient (flow rate) is 1e ^-5 to 1e ^-8 cm / sec, 5e ^-5 to 1e ^-4 cm / sec, 1e ^-4 to e ^-3 cm / sec, e ^-3 to 5e ^-8 cm / sec, e- ³ ~ 0.1 cm / sec, 0.1 ~ 0.2 cm / sec, 0.2 ~ 1 cm / sec, 1 cm / sec or more are displayed. Groundwater level fluctuations are expressed as classified below 1 m / d, 1 to 2 m / d, 2 to 4 m / d, and 4 m / d or more.

When the user enters the rainfall intensity as 7 mm / h as repair information and clicks the checkbox, the classification box in the range of 5 to 10 is activated. If the user enters the river and distance / depth as 300m as repair information and clicks the checkbox, the classification box in the 400-200 range is activated. When the user enters a permeability coefficient of 0.11 cm / sec as repair information and clicks the check box, the classification box in the range of 0.1-0.2 is activated. If the user inputs groundwater level change of 1.5m / d as repair information and clicks the checkbox, the classification box in the range 1-2 is activated.

Referring to FIG. 7F, a user interface screen for inputting external outward information is displayed in the ground hazard classification program.

Referring to FIG. 7G, a user interface screen displaying a calculation result in the ground risk classification program is displayed. In the left area of the screen, the GSR score and the GSR grade are displayed as the calculation result, and in the right area of the screen, the GSR score is corresponding to each of the very good ground, the good ground, the normal but the poor ground, and the very poor ground. Ratings and scores are displayed.

As described above, according to the present invention, it is possible to predict the risk of ground depression in the ground survey step before construction through the GSR. As a result, it can contribute to reducing the economic and human damage caused by the ground depression that can occur in large-scale excavation work. In addition, the GSRp sheet enables rapid site stability prediction and evaluation in the field, which can be used to select response methods for ground depression.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

100: ground grading system 110: GSR sheet display module
120: score calculation module for each category 130: GSR score calculation module
140: Ground depression risk assessment module

Claims (8)

The GSR sheet display module takes into account the various soil conditions and the geological characteristics of each influencer. Weights are categorized into categories of cavity, soil, rock mass, soil + lock mass, hydro geology, and external factors Displaying a Ground Subsidence Risk (GSR) sheet comprising the ground depression impact factors;
A score calculation module for each category calculates a category score (S) by applying the intra-category weight Xi to each of the influence factor scores Si;
Calculating a GSR score by applying the weights for each excavation ground condition (Yi) to the calculated category score by checking the ground conditions applied according to the ground environment by the GSR score calculation module; And
Digging ground risk classification method according to the ground conditions, characterized in that the ground sediment risk assessment module comprises the step of classifying the ground sediment risk according to the GSR score to the ground sediment risk assessment. The method of claim 1, wherein the score for each category is F (Si) =

Digging ground risk classification method according to the ground conditions, characterized in that it is calculated by [Xi * Si] (where Si is each influence factor score, Xi is the weight in the category). The method according to claim 2, wherein the GSR score is, Cate (Sj) =

[Yi * F (si)] = GSR (S), where Yi is weighted by excavation ground condition and F (si) is classified by category. 4. The risk of ground depression according to claim 3, wherein GSR (S) =

[

{Yi *

(Xi * Si)}] method according to the ground conditions characterized in that carried out by the ground conditions. Taking into account the various soil conditions and the geological characteristics of each influencer. Weights are categorized into categories of cavity, soil, rock mass, soil + lock mass, hydro geology, and external factors A GSR sheet display module for displaying a GSR sheet including a ground depression effect factor;
A score calculation module for each category for calculating a category score (Sate) by applying an intra-category weight Xi to each of the influence factor scores Si;
A GSR score calculation module for calculating a GSR score by applying a weight (Yi) for each excavation ground condition to a category score calculated by checking the ground condition applied according to the ground environment; And
Digging ground risk classification system according to the ground conditions, characterized in that it comprises a ground sinking risk assessment module for performing the ground sinking risk assessment by classifying the ground sinking risk into five grades according to the GSR score. The score according to claim 5, wherein the score for each category is F (Si) =

Digging ground risk classification system according to the ground conditions, characterized in that it is calculated by [Xi * Si] (where Si is each influence factor score, Xi is the weight in the category). The method according to claim 6, wherein the GSR score is, Cate (Sj) =

[Yi * F (si)] = GSR (S), where Yi is weighted by excavation ground condition and F (si) is scored by category. The method of claim 7, wherein the ground depression risk assessment, GSR (S) =

[

{Yi *

(Xi * Si)}] according to the ground conditions, characterized in that the ground hazard classification system.

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