JP6476522B2 - Rock mass stability evaluation method and program used therefor - Google Patents

Description

  The present invention relates to a rock mass stability evaluation method and a program used therefor.

Conventionally, as a method for preventing rock fall damage such as along railway lines, for example, a technique for quantitatively and efficiently detecting unstable rock blocks as shown in Non-Patent Documents 1 and 2 is known.
In Non-Patent Documents 1 and 2, as a method of quantitatively evaluating the stability of a rock mass, a method of measuring the vibration of the rock mass with a sensor attached to the rock mass and evaluating the risk of falling rocks from its vibration characteristics Is described.

“Determination of rockfall risk using vibration characteristics” Kenji Ogata, Hiroyuki Matsuyama, Yasuyuki Amano, JSCE Proceedings, No. 749, pp. 123-135, 2003.12 "Rock slope vibration measurement manual for extracting unstable rock block (draft)" Kazunori Fujisawa, Kenichi Asai, Masakazu Nagata, Koji Ishida, Materials of Civil Engineering Research Institute, No. 4051, 2007

However, the conventional rock mass stability evaluation method has the following problems.
In other words, in the methods described in Non-Patent Documents 1 and 2 described above, it is necessary to perform vibration measurement by directly installing a sensor on a rock mass. There is a problem that the working efficiency is lowered due to the unsatisfactory posture, and there is room for improvement in that respect. In particular, there are problems at the risk of incompletion along the railroad because there are restrictions on the place and time that can be measured because it is close to the railroad, and the efficiency is lowered and necessary measurement information cannot be obtained.

  The present invention has been made in view of the above-described problems, a rock mass stability evaluation method capable of performing measurement work with a stable posture in real time and improving work efficiency, and a program used therefor The purpose is to provide.

In order to achieve the above object, the rock mass stability evaluation method according to the present invention is a rock mass stability evaluation method for evaluating the stability of a rock mass protruding from a rock slope, and the material and shape of the rock mass The step of taking in data, the step of calculating the dominant frequency of the rock mass from the material and shape of the rock mass, the dominant frequency, the estimated stress generated at the tip of the back crack of the rock mass and the rock mass Calculating a relationship with the fall safety factor indicating the relationship between the tensile strength of the rock, a step of measuring the dominant frequency of the rock mass, and a step of selecting a fall safety factor corresponding to the actually measured dominant frequency, , the selected fall safety factor, when falling compared with evaluation reference value in the safety factor have a, a step of evaluating the stability of the rock mass, calculating the dominant frequency, the shape of the subject rock-mass If measurement is possible, the measured vertical direction If the shape of the target rock mass cannot be measured by calculating the dominant frequency using the rock mass shape as a parameter, directly acquiring the rock mass shape by the length and the maximum diameter in the depth direction with a laser scanner. Obtaining the rock mass shape by calculating the aspect ratio or automatically selecting the value that is the most severe condition in the analysis software, and the rock mass shape with the maximum diameter estimated from the target rock mass, the rock mass shape The dominant frequency is calculated using as a parameter .

In the rock mass stability evaluation method according to the present invention, the dominant frequency of the rock mass is calculated from the material and shape of the rock mass, and after calculating the relationship between the dominant frequency and the fall safety factor, A fall safety factor corresponding to the dominant frequency can be selected, and the selected fall safety factor can be compared with an evaluation reference value to quantitatively evaluate the stability of the rock mass. Therefore, it can be used for maintenance management, such as determining the priority of countermeasures, investigating changes over time in the risk of collapse of the target rock mass, and predicting the future.
As described above, according to the present invention, it is possible to remotely evaluate the stability of the rock mass, so that the efficiency of the rock fall risk evaluation work can be improved, and the measurement work is performed in a stable posture. be able to. Furthermore, since the vibration of the target rock mass is measured remotely, this vibration measurement can be performed constantly, and the stability of the target rock mass can be evaluated in real time.
In addition, when the shape of the target rock mass can be measured, the prevailing frequency can be calculated using the measured shape of the target rock mass as a parameter, so the stability of the rock mass can be evaluated with high accuracy. Can do.
Furthermore, even if the shape of the target rock mass cannot be measured, the rock mass shape estimated from the target rock mass is obtained, and the predominance frequency is calculated using the rock mass shape as a parameter to evaluate the rock mass stability. can do.

  In addition, the rock mass stability evaluation method according to the present invention, when calculating the dominant frequency, if there is a sample of the rock mass, using the sample to perform a material test of the rock mass, The dominant frequency may be calculated by using the material properties as parameters.

  In the present invention, since a material test can be performed using a sample of the same material as the target rock mass, a material property value substantially equivalent to that of the target rock mass can be obtained. Since the dominant frequency can be calculated using this material physical property as a parameter, it is possible to evaluate the stability of the rock mass with high accuracy.

  In addition, the rock mass stability evaluation method according to the present invention sets the estimated material physical properties estimated from the geological information around the target rock mass when there is no sample of the rock mass when calculating the dominant frequency. Alternatively, a material physical property close to the estimated material physical property may be acquired from a database in which a rock block and a material physical property are associated in advance, and the dominant frequency may be calculated using the material physical property as a parameter.

  In the present invention, even when there is no sample of the target rock mass, the estimated material physical property estimated from the geological information around the target rock mass is set, and the estimated material from the database in which the rock mass and the material physical property are associated in advance. The material physical properties close to the physical properties can be obtained, and the stability of the rock mass can be evaluated by calculating the dominant frequency using the material physical properties as parameters.

  The program used for the rock mass stability evaluation method according to the present invention is a program used for the above-described rock mass stability evaluation method for use in evaluating the stability of a rock mass protruding from a rock slope. A nomogram showing the relationship between the dominant frequency calculated from the shape and material of the rock mass, the fall safety factor indicating the relationship between the estimated stress generated at the tip of the back crack of the rock mass and the tensile strength of the rock mass Is displayed.

In the present invention, after calculating the dominant frequency of the rock mass from the material and shape of the rock mass, displaying the nomogram showing the relationship between the dominant frequency and the fall safety factor, the rock mass actually measured using this nomogram A fall safety factor corresponding to the dominant frequency of the rock is selected, and the stability of the rock mass can be quantitatively evaluated by comparing the selected fall safety factor with an evaluation reference value.
Thus, in the present invention, by preparing the nomogram described above in advance, it is possible to easily obtain the fall safety factor by matching the dominant frequency of the target rock mass with the curve of the nomogram. It is possible to evaluate the fall safety factor with high accuracy in a short time.

  According to the rock mass stability evaluation method and the program used therefor according to the present invention, measurement work can be performed in a stable posture, and work efficiency can be improved.

It is the figure which showed typically the state of the measurement of the target rock mass in embodiment of this invention. It is a figure for demonstrating the measuring method of the shape of a target rock mass. It is a flowchart which shows a measuring method among the rock mass stability evaluation methods of this Embodiment. It is a figure of an example of the nomograph which shows the relationship between a fall safety factor and the dominant frequency. It is a figure of another example of the nomograph which shows the relationship between a fall safety factor and the dominant frequency.

  Hereinafter, a rock mass stability evaluation method according to an embodiment of the present invention and a program used therefor will be described with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention.

  As shown in FIGS. 1 and 2, the rock mass stability evaluation method according to the present embodiment uses a non-contact sensor 2 and an analysis device 3 for a target rock mass 1 that is protruding in an unstable state with respect to the wall surface 1 </ b> A. The measurement for evaluating the stability of the target rock mass 1 is performed according to the flowchart shown in FIG. 3, and the stability of the target rock mass 1 is further evaluated.

As shown in FIG. 1, the rock mass stability evaluation method is based on the first process (steps S <b> 1 and S <b> 2) for capturing data on the material and shape of the rock mass 1, and the material and shape of the rock mass 1. The second step (step S3) for calculating the dominant frequency, the third step (step S3) for calculating the relationship between the dominant frequency and the fall safety factor, and the fourth step (step) for measuring the dominant frequency of the rock mass 1 S3), the fifth step (step S3) for selecting the fall safety factor corresponding to the actually measured frequency, and comparing the selected fall safety factor with the reference value to evaluate the stability of the rock mass 1 And a sixth step.
From the first step to the fifth step, the measurement method shown in FIG. 3 is used.

In the measurement method, as shown in FIG. 3, first, in steps S <b> 1 to S <b> 3, the relationship between the dominant frequency of the rock mass and the fall safety factor is estimated from the material property information and shape information of the target rock mass 1.
Here, the fall safety factor (n in equation (1) described later) is a parameter indicating the relationship between the estimated stress generated at the tip of the back crack of the rock mass 1 and the tensile strength of the rock mass 1. The rock mass 1 is more stable as the fall safety factor is larger, and the rock mass 1 is expected to fall below 1 or less. The relationship between the fall safety factor and the dominant frequency is estimated from the maximum diameter and aspect ratio of the rock mass 1 (ratio of the vertical length (vertical dimension) and depth length (horizontal dimension) of the rock mass 1). The

  First, in step S1, material data for analysis (material properties of rock mass) is input. Specifically, in step S10, it is selected whether or not a sample of the target rock 1 or a nearby rock is available. When a sample of the target rock mass 1 is available for the rock mass 1 to be evaluated for stability (step S10: YES), the material physical properties (tensile strength, Young) of the target rock mass 1 obtained in steps S11 and S12. Rate, density, etc.). In other words, in step S11, each sample material test is performed using a sample collected from the target rock mass 1 (or a rock mass in the vicinity thereof), and material properties (tensile strength, Young's modulus, density, etc.) are confirmed. In step S12, the material property parameters of the rock mass 1 obtained in step S11 are input to the analysis apparatus 3 shown in FIG.

  On the other hand, when it is difficult to obtain a sample of the target rock mass 1 (step S10: NO), in step S13, the material physical properties (tensile strength) of the target rock mass 1 are obtained from the surrounding geological information (such as rock mass information). , Young's modulus, density, etc.). And the material physical property of the nearest target rock mass is selected based on the database prepared beforehand, and the material physical property value of the rock mass 1 is input into an analyzer (step S14).

  Next, in step S2 following step S1 (step S12 or step S14), the shape of the target rock mass 1 is investigated. First, in step S10, it is selected whether or not the shape of the target rock mass can be measured. If the shape of the target rock mass can be directly measured or measured with a laser scanner or the like (step S20: YES), in step S21 the rock mass shape such as the measured vertical length, depth length, and maximum diameter is measured. Is obtained, and the shape parameter is input to the analysis device 3 shown in FIG.

On the other hand, when it is impossible to measure the shape of the target rock mass (step S20: NO), in step S22, the rock mass estimated from the target rock mass, such as the value of the rough maximum diameter of the rock mass, for example. The shape is acquired, and the shape parameter is input to the analysis device 3.
In addition, when measurement is impossible and the length in the vertical direction and the length in the depth direction cannot be obtained, calculation for multiple aspect ratios or the value that will be the most severe condition on the analysis software side is automatically selected. To do.

Next, in step S3, the relationship between the prevailing frequency and the fall safety factor is calculated from the material physical property and rock mass shape information of the target rock mass input to the analysis device 3, and the vibration measuring device is used locally. The dominant frequency of the rock mass is measured, and the fall safety factor corresponding to the actually measured dominant frequency is selected. That is, the fall safety factor is estimated from the calculated relationship between the dominant frequency and the fall safety factor and the vibration measurement result.
As a vibration measuring apparatus, a non-contact sensor 2 such as a laser Doppler velocimeter that can be measured remotely from a non-contact basis is basically used.

Here, step S3 will be specifically described. First, in step S30, it is selected whether or not it is possible to bring an analysis tool to the site.
In step S30, when the analysis device 3 can be brought into the measurement site, or when data is taken back and evaluated after measurement (step S30: YES), the vibration frequency measurement device is used to measure the dominant frequency of the rock mass, The dominant frequency is acquired by reading the vibration measurement result of the rock mass measured at this site into the analysis device (step S31). Subsequently, in step S32, the fall safety factor is calculated from the relationship between the fall safety factor and the prevailing frequency calculated in advance. This ends the measurement.

  On the other hand, if the analysis device cannot be brought to the site and a simple evaluation is desired at the site (step S30: NO), the relationship between the fall safety factor and the dominant frequency obtained in advance by the analysis device 3 is printed as a nomogram. Then, bring it to the site (step S33). In step S34, vibration measurement of the rock mass is performed at the site, and the dominant frequency is extracted from the obtained vibration measurement result (vibration waveform). Thereafter, in step S35, the fall safety factor is estimated from the extracted dominant frequency value and the nomogram. This ends the measurement.

  Next, the stability of the rock mass is evaluated from the magnitude of the value of the fall safety factor obtained by the measurement method described above. Specifically, the stability of the rock mass is evaluated by comparing the selected fall safety factor with the evaluation reference value in the fall safety factor. Alternatively, periodic measurements may be performed on the same rock mass, and the future risk of collapse may be predicted from the state of the fall safety factor change, and used for maintenance management.

As shown in FIGS. 3 and 4, a nomogram representing the relationship between the fall safety factor and the dominant frequency will be described.
The program used in the rock mass stability evaluation method of the present embodiment is a program used for evaluating the stability of a rock mass protruding from a rock slope, and is calculated from the shape and material of the rock mass. A nomogram showing the relationship between the dominant frequency and the fall safety factor indicating the relationship between the estimated stress generated at the tip of the back crack of the rock and the tensile strength of the rock is displayed.

In preparing the nomogram, the evaluation index _xn shown in the equation (1) is defined considering that the fall safety factor and the dominant frequency are affected by the elastic modulus, density, and tensile strength of the rock mass.
Here, in the formula (1), n is a fall safety factor, E is a rock mass elastic modulus (MPa), ρ is a rock mass density (t / m ³ ), str is a rock mass tensile strength (MPa), b is a constant (b = 0.56) estimated from the analysis result.

The relationship between the evaluation index _xn and the dominant frequency is approximated by a quadratic function shown in equation (2).
Here, f _n is the dominant frequency (Hz) when the fall safety factor is n, and α and β are constants for each aspect ratio. α and β are estimated by the least square method for each aspect ratio. Table 1 shows α and β for each aspect ratio.

These (1), by using the equation (2), knowing the material properties of the rocks, it is possible to obtain a relationship between the fall safety factor n dominant frequency f _n.
In addition, when the aspect ratio of the target rock mass is not in Table 1, it is estimated by linearly complementing the values in Table 1. Here, the relationship between the estimated fall safety factor and the dominant frequency is that when the diameter of the rock mass is about 1 m. In order to reflect the size of the rock mass, γ shown in Equation (3) is multiplied by the obtained dominant frequency. Here, in Equation (3), L is the diameter of the target rock mass.

3 and 4 show an example of a nomograph created using the above equations (1) and (2).
FIG. 3 is a nomograph showing only a rock block made of granite and having an aspect ratio (height / depth) of 1.
The nomograph in FIG. 4 is a block of granite and represents a plurality of aspect ratios. By preparing such a nomogram in advance, it is possible to easily determine the fall safety factor by comparing the dominant frequency of the target rock mass with a curve having a similar aspect ratio. In addition, when the aspect ratio of the target rock mass cannot be estimated, the safety side evaluation can be performed by using a nomograph having an aspect ratio of 0.6 to 0.7.

  The above calculation is performed in the measurement system, and the relationship between the fall safety factor corresponding to the material properties and size of the rock mass and the dominant frequency is obtained. The fall safety factor is obtained from this relationship and the rock vibration measurement result using the remote non-contact vibration measuring device, and the stability is evaluated.

Next, the rock mass stability evaluation method configured as described above and the operation of the program used therefor will be specifically described.
In the rock mass stability evaluation method according to the present embodiment, as shown in FIG. 3, the dominant frequency of the rock mass 1 is calculated from the material and shape of the rock mass 1, and the relationship between the dominant frequency and the fall safety factor is calculated. After that, select the fall safety factor corresponding to the prevailing frequency of the actually measured rock mass, and compare the selected fall safety factor with the evaluation reference value to quantitatively evaluate the stability of the target rock mass 1 can do. Therefore, it can be used for maintenance management such as determination of the priority order of countermeasures, investigation of changes over time in the risk of collapse of the target rock mass 1 and prediction of the future.
Thus, in this Embodiment, since it becomes possible to evaluate the stability of the target rock mass 1 remotely, it is possible to improve the efficiency of the rock fall risk evaluation work and to stabilize the measurement work. It can be done with the posture. Further, since the vibration of the target rock mass 1 is remotely measured, this vibration measurement can be performed at all times, and the stability of the target rock mass can be evaluated in real time.

  Moreover, in this Embodiment, since a material test can be performed using the sample of the same material as the target rock mass 1 in steps S11 and S12, a material property value substantially equivalent to the target rock mass 1 is obtained. Can do. Since the dominant frequency can be calculated using this material physical property as a parameter, it is possible to evaluate the stability of the rock mass with high accuracy.

  In this embodiment, even if there is no sample of the target rock mass 1 in steps S13 and S14, the estimated material physical properties estimated from the geological information around the target rock mass 1 are set in advance. A material physical property close to the estimated material physical property can be acquired from a database in which the mass and the material physical property are associated with each other, and the dominant frequency can be calculated using the material physical property as a parameter to evaluate the stability of the rock mass.

  Furthermore, in this embodiment, since the dominant frequency can be calculated using the actually measured shape of the target rock mass 1 as a parameter in step S21, the stability of the rock mass can be evaluated with high accuracy. it can.

  Furthermore, in the present embodiment, even if the shape of the target rock mass cannot be measured in step S22, the rock mass shape estimated from the target rock mass 1 is acquired, and the dominant frequency is obtained using the rock mass shape as a parameter. Can be calculated to evaluate the stability of the rock mass.

Also, in this embodiment, the dominant frequency of the rock mass is calculated from the material and shape of the rock mass, and after displaying the nomogram showing the relationship between the dominant frequency and the fall safety factor, actual measurement is performed using this nomogram. The fall safety factor corresponding to the dominant frequency of the selected rock mass is selected, and the stability of the rock mass can be quantitatively evaluated by comparing the selected fall safety factor with the evaluation reference value.
Thus, in the present invention, by preparing the nomogram described above in advance, it is possible to easily obtain the fall safety factor by matching the dominant frequency of the target rock mass with the curve of the nomogram. It is possible to evaluate the fall safety factor with high accuracy in a short time.

  In the rock mass stability evaluation method and the program used therefor according to the present embodiment described above, measurement work can be performed in a stable posture in real time, and work efficiency can be improved.

As described above, the rock mass stability evaluation method according to the present invention and the embodiment of the program used therefor have been described. However, the present invention is not limited to the above-described embodiment, and is appropriately changed without departing from the scope of the present invention. Is possible.
For example, in the above-described embodiment, the procedure based on the presence or absence of the sample of the target rock block (steps S11 to S14) in step S10 and the procedure based on whether the shape of the target rock block can be measured in step S20 (steps S21 and S22). However, the present invention is not limited to the provision of the above-described procedures (steps S11 to S14, S21, and S22). In short, it is only necessary to be able to calculate the dominant frequency of the rock mass from the material and shape of the rock mass, and instead of the procedure of this embodiment (steps S11 to S14, S21, S22), It is also possible to calculate the dominant frequency of the rock mass by other methods based on the material and shape of the rock mass.

    Further, in the present embodiment, in the step of calculating the relationship between the dominant frequency and the fall safety factor, a method of creating a nomogram showing this relationship is adopted, but the present invention is not limited to this, and a method that does not use a nomogram It doesn't matter.

  In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with well-known constituent elements without departing from the spirit of the present invention, and the above-described embodiments may be appropriately combined.

1 rock mass 2 non-contact sensor 3 analyzer

Claims (4)

A rock mass stability evaluation method for evaluating the stability of a rock mass protruding from a rock slope,
Importing data on rock mass material and shape;
From the material and shape of the rock mass, calculating the dominant frequency of the rock mass;
Calculating the relationship between the prevailing frequency and the fall safety factor indicating the relationship between the estimated stress generated at the tip of the back crack of the rock mass and the tensile strength of the rock mass;
Measuring the dominant frequency of the rock mass;
A process of selecting a fall safety factor corresponding to the actual measured dominant frequency,
Comparing the selected fall safety factor with an evaluation reference value in the fall safety factor and evaluating the stability of the rock mass;
I have a,
When calculating the dominant frequency,
If the shape of the target rock mass can be measured, the rock mass shape with the measured vertical length, depth length, and maximum diameter is directly measured or obtained with a laser scanner, and the dominant frequency is used as a parameter. To calculate
If the shape of the target rock mass cannot be measured, calculate the shape of the rock mass by calculating multiple aspect ratios or automatically selecting the values that will be the most severe conditions in the analysis software, and the maximum estimated from the target rock mass A rock mass stability evaluation method , comprising: obtaining a rock mass shape by diameter and calculating the dominant frequency using the rock mass shape as a parameter . When calculating the dominant frequency, if there is a sample of the rock mass,
2. The rock mass stability evaluation method according to claim 1, wherein a material property of the rock mass is obtained by performing a material test using the sample, and the dominant frequency is calculated using the material physical property as a parameter. . When calculating the dominant frequency, if there is no sample of the rock mass,
Set the estimated material properties estimated from the geological information around the target rock mass, obtain the material physical properties close to the estimated material physical properties from a database in which the rock mass and the material physical properties are associated in advance, and use the material physical properties as parameters The rock mass stability evaluation method according to claim 1, wherein a dominant frequency is calculated. A program used for the rock mass stability evaluation method according to any one of claims 1 to 3 , for use in evaluating the stability of a rock mass protruding from a rock slope,
A nomogram showing the relationship between the dominant frequency calculated from the shape and material of the rock mass, and the fall safety factor indicating the relationship between the estimated stress generated at the tip of the back crack of the rock mass and the tensile strength of the rock mass The program used for the rock mass stability evaluation method characterized by displaying.

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