JP6555391B2 - Prediction device, prediction system, prediction method, and program - Google Patents

Description

  The present invention relates to slope stability analysis.

  A technique for predicting the risk of slope failure based on slope stability analysis is known. For example, Patent Document 1 discloses a system that calculates a safety factor based on real-time measurement data and predicts a time when the safety factor reaches a predetermined value (1.0) and issues an alarm.

JP 2006-195650 A

  The technique described in Patent Document 1 calculates a safety factor based on real-time measurement data.

  One of the objects of the present invention is to make it possible to predict the safety of a slope by using a predicted value of rainfall.

  A prediction apparatus according to an aspect of the present invention includes a first calculation unit that calculates a relational expression between a moisture amount and a rainfall based on a measured moisture value of soil constituting a slope and a measured rainfall value on the slope, 2nd calculation means which calculates the predicted value of the parameter | index which shows the safety | security of the said slope based on the calculated said relational expression and the rainfall predicted value in the said slope.

  The prediction system which concerns on 1 aspect of this invention is provided with the said prediction apparatus and the output apparatus which alert | reports the predicted value of the said index | index to a user.

  The prediction method according to one aspect of the present invention calculates a relational expression between the amount of water and the amount of rainfall based on the actual measurement of the amount of water in the soil constituting the slope and the actual measurement of the amount of rainfall on the slope, and the calculated relational expression And a predicted value of an index indicating the safety of the slope is calculated on the basis of the predicted rainfall amount on the slope.

  The program according to an aspect of the present invention calculates, on a computer, a relational expression between the amount of water and the amount of rain based on the actual amount of water measured on the soil constituting the slope and the actual amount of rain on the slope. Based on the relational expression and the predicted rainfall amount on the slope, a process of calculating a predicted value of an index indicating the safety of the slope is executed.

  According to the present invention, it is possible to predict the safety of a slope using a predicted value of rainfall.

FIG. 1 is a block diagram illustrating an example of a configuration of a prediction device. FIG. 2 is a block diagram illustrating an example of the configuration of the prediction system. FIG. 3 is a flowchart illustrating an outline of processing executed by the prediction apparatus. FIG. 4 is a schematic view illustrating numerical values calculated by the prediction device. FIG. 5 is a diagram illustrating an example of information displayed by the output device. FIG. 6 is a diagram illustrating an example of information displayed by the output device. FIG. 7 is a block diagram illustrating an example of a hardware configuration of a computer that implements the prediction device.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a prediction device 10 according to an embodiment of the present invention. The prediction device 10 is an information processing device that enables an index indicating the safety of a slope to be monitored to be calculated based on a predicted value of rainfall. The prediction device 10 includes at least a first calculation unit 11 and a second calculation unit 12.

  The first calculator 11 calculates a relational expression between the moisture state of the slope to be monitored and the rainfall on the slope. The first calculation unit 11 calculates a relational expression using these measured values (actually measured values). In the present embodiment, the measured value representing the moisture state of the slope is a numerical value representing the moisture content of the soil that constitutes the slope. The water content may be either volumetric water content or weight water content. These measured values are all obtained at predetermined time intervals (for example, every hour).

Here, when the water content at a certain point in time t m _t, rainfall and p _t, m _t, for example based on the tank model can be calculated by the following equation (1). Here, c _i is a coefficient of 0 or more and less than 1, which varies depending on the soil type (soil type). _{Further, f (p t, p t} -1, p t-2, ..., p tk) _{is, p t, p t-1} , p t-2, ..., given multivariable function to the p _tk variable It is. Note that n and k are appropriately determined.

Here, if the influence of the water content may ignore the small historical data, m _t can be expressed by the following equation (2). Here, F corresponds to the hydraulic conductivity and varies depending on the soil type. C is a coefficient indicating the water retention capacity of the soil. F and c may be calculated | required by the test in soil, and may be calculated | required using a predetermined | prescribed database.

  Equations (1) and (2) can be used as prediction formulas for moisture content. In other words, when the predetermined time point after the prediction execution time is t, the first calculation unit 11 determines the current time point based on the predicted rainfall amount at that time point and the measured water content value before that time point. It is possible to calculate (that is, predict) the amount of water.

As the water content m _t, it may be a model is used other than the tank model. For example, the water content m _t, in addition to the primary function, quadratic function and experimentally or empirically calculated assuming other functions models are also applicable.

  The second calculation unit 12 indicates the safety of the slope at the time point using the relational expression calculated by the first calculation unit 11 and the predicted value of the rainfall on the slope at a predetermined time point where the actual measurement value does not exist. Calculate the predicted value of the indicator. Here, the point in time when the actual measurement value does not exist specifically refers to a future after a specific point in time (for example, the timing for performing the prediction), that is, the future as viewed from the point in time.

  In addition, the predicted value of rainfall may be provided from an external organization or a business operator. For example, in Japan, the Japan Meteorological Agency has published a forecast value of precipitation in 1km square mesh units (short-term precipitation forecast).

  In the present embodiment, the safety index is a safety factor. There are a plurality of types of safety factor definition formulas (stability analysis formulas), and the formulas are not limited to specific types. In the following description, it is assumed that the second calculation unit 12 calculates a predicted value based on the Ferrenius method (also referred to as simple division method or Swedish method) or the modified Ferrenius method.

  The safety factor Fs by the Ferrenius method can be expressed by the following equation (3), for example. Here, c, W, u, and φ are variables representing the adhesive strength, weight, pore water pressure, and internal friction angle, respectively. Α represents the inclination angle of the slope. Moreover, l represents the length of the sliding surface of the divided piece (slice) obtained by dividing the slope in the vertical direction. For convenience of explanation, the inclination angle α and the slip surface length l are constants here.

  Moreover, the safety factor Fs by the modified Ferrenius method can be expressed by the following equation (4), for example. Here, b represents the width of the slice. Here, the slice width b is a constant.

  Here, the adhesive force c, the weight W, the pore water pressure u, and the internal friction angle φ all change according to the amount of moisture in the soil. Therefore, both of these variables can be expressed as a function of the amount of water. For example, the expression (3) indicates that the adhesive force c, weight W, pore water pressure u, and internal friction angle φ are functions c (m), W (m), u (m), and φ (m) of the water content m, respectively. Is replaced by the following formula (5). Such substitution is also possible in the formula (4).

  Note that the functions c (m), W (m), u (m), and φ (m) may be different for each soil. The functions c (m), W (m), u (m), and φ (m) may be obtained in advance based on these variables and the actual measured water content, or may be estimated by simulation or the like. .

Here, (5) of m (1) or (2) Substituting the equation of m _t, the equation (6) below is obtained. Then, it is theoretically possible to calculate the safety factor Fs based on the past measured amount of moisture and the predicted value of past rainfall. Further, water content m _t is predicted if the safety factor Fs is also said to be predictable as well.

  As described above, the moisture content in the soil at a certain time in the future can be predicted if the moisture content before that time and the predicted value of the rain at that time are obtained. Therefore, the value newly required by the second calculation unit 12 at this time is only the predicted value of the rainfall at the time when the safety factor is calculated (that is, the future).

  The second calculation unit 12 outputs the predicted value of the calculated safety factor. The output here may be to transmit a prediction value to the outside of the prediction device 10 or to supply the prediction value to another component inside the prediction device 10. The second calculation unit 12 may record the predicted value on the storage medium.

  As described above, according to the present embodiment, it is possible to predict the safety factor based on the predicted value of rainfall at a predetermined time point. Therefore, according to the present embodiment, for example, when it is predicted that heavy rain falls locally due to the development of cumulonimbus clouds, it is possible to evaluate the influence of the rain on the slope.

  The effect of rainfall varies depending on the condition of the slope (soil quality, moisture content in the soil, etc.). Therefore, even when a certain amount of rainfall is predicted, whether or not the safety factor falls below a predetermined standard due to the rain varies depending on the location and state of the slope. The prediction device 10 can predict the safety factor for each location by using the prediction formula of the safety factor corresponding to the slope of the specific point and the predicted value of the rainfall at the point.

  For example, when the above-mentioned meteorological agency's short-term precipitation forecast (nowcast) is used, it is possible to obtain a predicted value of rainfall 1 to 6 hours after the announcement. On the other hand, for evacuation against earth and sand disasters, it is generally necessary to secure one hour for healthy persons and about four hours at the longest for elderly persons and persons with physical disabilities (which require time for movement). According to the present embodiment, it is possible to predict a safety factor that secures sufficient time for evacuation using such a general predicted value.

  Note that the prediction device 10 not only has a timing at which the predicted safety factor falls below a predetermined threshold (eg, “1.0”), but also a timing at which the safety factor returns to a value equal to or higher than the threshold after the safety factor falls below the predetermined threshold. It is also possible to predict. Therefore, according to the present embodiment, it is possible to predict the timing at which a place can be considered to have returned to a safe state after raining at a place.

[Second Embodiment]
FIG. 2 is a block diagram showing the overall configuration of the prediction system 20 according to another embodiment of the present invention. The prediction system 20 is a computer system for predicting safety of a slope. The prediction system 20 includes a prediction device 100 and an output device 200. In addition, although these apparatuses which comprise the prediction system 20 are illustrated one by one in FIG. 2, the actual number is not limited.

  The prediction device 100 has a function common to the prediction device 10 of the first embodiment. However, the prediction device 100 also has a function different from that of the prediction device 10 as described later. The prediction device 100 is configured by, for example, a server device or a personal computer.

  The output device 200 is a device that outputs a prediction result from the prediction device 100. The output here is intended to notify the user of information, and for example, means to visualize (that is, display) information, but may include other forms of output such as audio output. As the output device 200, for example, a display device such as a liquid crystal display, a mobile communication terminal such as a smartphone, or a personal computer can be used. The output device 200 may be connected to the prediction device 100 via a network, but may be configured as a part of the prediction device 100.

  Specifically, the prediction device 100 includes an acquisition unit 110, a calculation unit 120, and an output processing unit 130. In more detail, the calculation unit 120 includes a first calculation unit 121, a second calculation unit 122, a third calculation unit 123, and a fourth calculation unit 124.

  The acquisition unit 110 acquires various data. In the present embodiment, the data acquired by the acquisition unit 110 includes at least an actual measurement value of the moisture amount measured at a predetermined point, and an actual measurement value and a predicted value of the rain amount at the point. These values are obtained at predetermined time intervals (for example, every 30 minutes or every hour).

  The first calculation unit 121 calculates a relational expression between moisture in the soil and rainfall. The 1st calculation part 121 performs the same process as the 1st calculation part 11 of a 1st embodiment. In addition, the second calculation unit 122 calculates a safety factor prediction formula using the relational expression calculated by the first calculation unit 121, and predicts the safety factor based on the predicted rainfall amount. The second calculation unit 122 performs the same processing as the second calculation unit 12 of the first embodiment.

  The 3rd calculation part 123 compares the predicted value of the moisture content calculated using the relational expression calculated by the 1st calculation part 121 with an actual measurement value, and calculates a difference. Hereinafter, the difference in the amount of water calculated by the third calculation unit 123 is expressed as “Δm”. The 3rd calculation part 123 can calculate the predicted value of the moisture content in a certain time (for example, the newest time when the measured value is obtained) based on (1) Formula or (2) Formula. Δm may represent a difference in water content at a specific time point, or may be an average value of differences in water content at a plurality of time points.

  The fourth calculation unit 124 is based on the predicted value of the safety factor calculated by the second calculation unit 122 and the difference Δm calculated by the third calculation unit 123, and an error assumed for the predicted value of the safety factor. Is calculated. Hereinafter, the error of the safety factor calculated by the fourth calculation unit 124 is expressed as “ΔFs”. ΔFs is calculated by the following equation (7), for example.

  Here, Fs (m) represents the value of the safety factor obtained by substituting the amount of moisture m at the latest time into the prediction formula for the safety factor. Fs (m + Δm) represents the value of the safety factor obtained by substituting the value obtained by adding the moisture amount m and the difference Δm at the latest time into the safety factor prediction formula. Further, ∂Fs / ∂m represents a change rate of the safety factor Fs (m) with respect to the water content m at the time.

  The output processing unit 130 performs predetermined processing based on the predicted value of the safety factor calculated by the second calculation unit 122 and the error of the safety factor calculated by the fourth calculation unit 124. The processing executed by the output processing unit 130 is hereinafter referred to as “output processing”.

  The output process is, for example, a process for transmitting the predicted value and error of the safety factor to the output device 200. The output process may be a process of generating data for displaying the predicted value and error of the safety factor in a predetermined display mode and transmitting the data to the output device 200. For example, the output processing unit 130 may generate image data in a predetermined format such as JPEG, or may generate an e-mail addressed to the output device 200.

  FIG. 3 is a flowchart illustrating an outline of processing executed by the prediction device 100. It is assumed that the prediction device 100 has already acquired all necessary data when executing this process.

  First, the 1st calculation part 121 calculates these relational expressions using the measured value of the moisture content m in the soil, and the rainfall p (step S1). Next, the third calculation unit 123 calculates a difference Δm between the predicted value of the moisture content m and the actual measurement value based on the relational expression calculated in Step S1 (Step S2).

  Further, the second calculation unit 122 calculates the predicted value Fs of the safety factor based on the relational expression calculated in step S1 and the predicted value of the rainfall p (step S3). Then, the fourth calculation unit 124 calculates a safety factor error ΔFs based on the predicted value Fs calculated in step S3 and the difference Δm calculated in step S2 (step S4). When the predicted value Fs and the error ΔFs of the safety factor are calculated, the output processing unit 130 executes output processing (Step S5).

  FIG. 4 is a schematic diagram illustrating numerical values calculated in the present embodiment. In the figure, the vertical axis indicates the safety factor Fs, and the horizontal axis indicates time t. Moreover, the prediction apparatus 100 shall perform prediction in the time t1. Therefore, in this example, the time before time t1 is the past, and the time after time t1 is the future.

  In FIG. 4, the solid line before time t1 indicates the actual value of the safety factor. On the other hand, the alternate long and short dash line before time t1 indicates the predicted value of the safety factor. As described above, the predicted value of the safety factor does not necessarily match the actually measured value because the predicted value of the rainfall may be different from the actual rainfall. The safety factor error ΔFs increases as the difference Δm increases. Therefore, the safety factor error ΔFs increases as the accuracy of the predicted value of the rainfall p decreases, and decreases as the accuracy of the predicted value of the rainfall p increases. The error ΔFs of the safety factor is calculated based on the difference Δm at a specific time point (time t1 in FIG. 4), and is constant from time t1 to time T here.

  FIG. 5 is a diagram illustrating an example of information displayed by the output device 200. For example, the output device 200 displays a list of rainfall, moisture content, safety factor, safety factor after 4 hours, and safety factor errors (all predicted values) at a plurality of times after time t1. In addition, the output device 200 may display numerical values such as a safety factor in a graph as shown in FIG. 4 or may be displayed on a map.

  As described above, according to the present embodiment, in addition to predicting the safety factor based on the predicted value of rainfall at a predetermined time point as in the first embodiment, the safety factor can be expressed by the predicted value and the error. is there. This error changes according to the accuracy of the predicted value of the safety factor. Therefore, the user can select a subsequent action in consideration of an error with respect to the possibility of a disaster due to slope failure.

[Modification]
The present invention is not limited to the embodiment described above. The present invention can apply various modifications that can be understood by those skilled in the art to the above-described embodiments. For example, the present invention can be carried out in the forms shown in the following modified examples. Further, the present invention may be implemented by combining a plurality of modified examples, or by replacing a part of the configuration of the embodiment with the configuration of the other embodiment.

(1) Modification 1
The prediction device 100 may predict the safety factor for a plurality of points. In this case, the prediction device 100 calculates the relational expression between the moisture amount and the rainfall for each of a plurality of points, and calculates the predicted value of the safety factor at these points. In addition, the predicted value of rainfall may also differ for each of a plurality of points. Similarly, the prediction device 100 may calculate a difference in moisture amount and an error in safety factor at a plurality of points.

  FIG. 6 is a diagram illustrating a display example of information by the output device 200. In this example, the output device 200 expresses each point on the map with a grid (mesh) of a predetermined size, and visualizes the safety factor by the color of each mesh. For each mesh, the output device 200 is, for example, “dangerous” if the predicted value of the safety factor (or the sum of the predicted value and the error) is in the range of 1.0 to 1.2. If it is “very dangerous”, the user is notified.

  The output device 200 may display information other than the predicted value of the safety factor (rainfall predicted value, safety factor error, etc.) numerically in the mesh, or separately display a plurality of information on a plurality of maps. It may be displayed.

(2) Modification 2
The stability analysis formula in the embodiment of the present invention is not limited to a formula of a specific method. As the stability analysis formula, in addition to the Ferrenius method and the modified Ferrenius method, the Bishop method, Yanbu method, etc. can be applied. These stability analysis formulas can also describe necessary variables as a function of moisture content.

(3) Modification 3
In the embodiment of the present invention, the index indicating the safety of the slope is not limited to the safety factor. Further, the numerical value indicating the moisture state of the slope is not limited to the moisture amount. For example, the amount of water has a correlation with the attenuation rate of the vibration waveform in the soil. Therefore, if the correlation between the moisture content and the attenuation rate can be obtained, the stability analysis formula can be described as a function of the attenuation rate.

(4) Modification 4
In the embodiment of the present invention, the constituent elements of the slope are not limited to soil. For example, the slope may include concrete, mortar, tree root systems, and the like.

(5) Modification 5
Part or all of the prediction devices 10 and 100 may be realized by a computer executing a predetermined program.

  FIG. 7 is a block diagram illustrating an example of a hardware configuration of a computer 300 that implements the prediction apparatuses 10 and 100. The computer 300 includes a processor 310, a memory 320, a storage 330, and an interface 340.

  The processor 310 is, for example, a CPU (Central Processing Unit). The memory 320 corresponds to a main storage device. The storage 330 corresponds to an auxiliary storage device. The storage 330 is configured by, for example, a hard disk or a flash memory. The storage 330 may include a reader / writer for a removable recording medium such as an optical disk or a flexible disk. The interface 340 transmits / receives data to / from an external device (such as the output device 200).

  The processor 310 can function as the first calculation unit 11 and the second calculation unit 12 of the prediction device 10 by executing a program stored in the storage 330. Alternatively, the processor 310 can function as the acquisition unit 110, the calculation unit 120, and the output processing unit 130 of the prediction device 100 by executing a program stored in the storage 330.

(7) Modification 7
In the embodiment of the present invention, in addition to a prediction device and a prediction system, a prediction method for predicting an index indicating the safety of a slope can be considered. Further, the embodiment of the present invention may be in the form of a program for causing a computer to function as a prediction device, or a computer-readable recording medium (such as an optical disk, a magnetic disk, or a semiconductor memory) that records the program. Such a program may be downloaded to a certain apparatus via a network and function the apparatus as a slope evaluation apparatus.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2015-145424 for which it applied on July 23, 2015, and takes in those the indications of all here.

DESCRIPTION OF SYMBOLS 10, 100 Prediction apparatus 11 1st calculation part 12 2nd calculation part 20 Prediction system 110 Acquisition part 120 Calculation part 121 1st calculation part 122 2nd calculation part 123 3rd calculation part 124 4th calculation part 130 Output processing part 200 Output apparatus

Claims (12)

A first calculating means for calculating a relational expression between the moisture content and the rainfall based on the measured moisture value of the soil constituting the slope and the measured rainfall value on the slope;
Second calculation means for calculating a predicted value of an index indicating safety of the slope, based on the calculated relational expression and a predicted rainfall amount on the slope;
A prediction device comprising: The m _t, the water at time t weight, a _{p t,} rainfall at time _{t, f (p t, p} t-1, p t-2, ..., p t-k) _a, p _{t, p t-1} , P _t−2 ,..., P _t−k as variables, a predetermined multivariable function, c _i , a coefficient different from 0 to less than 1 depending on the type of soil, and n and k as predetermined values The relational expression is represented by the following formula:

The prediction device according to claim 1. The second calculating means calculates a predicted water amount of the slope based on the calculated relational expression and a predicted rainfall amount on the slope, and calculates a predicted value of the index based on the predicted water amount. calculate,
The prediction device according to claim 2. c (m), W (m), u (m), and φ (m) are the cohesive strength, weight, pore water pressure, internal friction angle, α, and the slope angle of the slope, respectively. If the l, and the length of the sliding surface of the split pieces obtained by dividing the slope in the vertical direction, the second calculating means, by substituting the water content predicted value at time t by the following equation of m _t, the Calculate the expected value of the indicator,

The prediction device according to claim 3. Furthermore,
Third calculating means for calculating a difference between a predicted amount of water calculated using the relational expression calculated by the first calculating means and a measured amount of water;
Fourth calculation means for calculating an error of the predicted value of the index based on the predicted value of the index and the difference;
The prediction device according to claim 1, comprising: The prediction apparatus according to claim 5, further comprising: an output processing unit that performs an output process on the predicted value of the index calculated by the second calculation unit. The first calculation means calculates the relational expression for each of a plurality of points,
The second calculation means calculates a predicted value of the index for each of the plurality of points,
The output processing means outputs information corresponding to the calculated predicted value of the index to the output means;
The prediction device according to claim 6. The third calculation means calculates the difference for each of the plurality of points,
The fourth calculation means calculates an error in the predicted value of the indicator for each of the plurality of points,
The output processing means outputs information corresponding to the predicted value of the index and the error of the predicted value of the index to the output means.
The prediction device according to claim 7. The prediction device according to any one of claims 1 to 8,
An output device for notifying the user of the predicted value of the index;
A prediction system comprising: Based on the measured moisture content of the soil that constitutes the slope and the measured rainfall value on the slope, a relational expression between the moisture content and the rainfall is calculated,
Based on the calculated relational expression and the predicted rainfall amount on the slope, a predicted value of an index indicating the safety of the slope is calculated.
Prediction method. On the computer,
A step of calculating a relational expression between the amount of moisture and the amount of rainfall based on the actually measured amount of water of the soil constituting the slope and the measured amount of rainfall on the slope;
Calculating a predicted value of an index indicating safety of the slope based on the calculated relational expression and a predicted rainfall amount on the slope;
The computer-readable program recording medium which recorded the program for performing this. On the computer,
Based on the measured moisture content of the soil that constitutes the slope and the measured rainfall value on the slope, a relational expression between the moisture content and the rainfall is calculated,
Based on the calculated relational expression and the predicted rainfall amount on the slope, a predicted value of an index indicating the safety of the slope is calculated.
A program that executes processing.

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