Method, program, and system for determining effect of ground stabilization work on sloping ground

Abstract

To quantitatively determine an effect of ground stabilization work.SOLUTION: In order to evaluate ground stability: a first step (S1) of acquiring vibration measurement information from a plurality of points on a slope; a second step (S2) of acquiring frequency characteristics of vibrations at the plurality of points by performing frequency analysis of each of the acquired vibration measurement information; and a third step (S3) of evaluating stability of the slope based on relevance of the frequency characteristics of the vibrations at the plurality of points are performed. In order to determine an effect of a slope ground stabilization work: a fourth step (S6) of acquiring stability evaluation result before work by performing the first to third steps before the stabilization work; a fifth step (S8) of acquiring stability evaluation result after work by performing the first to third steps after the stabilization work; and a sixth step (S9) of determining effect of work based on comparison of the stability evaluation result before work and the stability evaluation result after work are performed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for determining the effect of construction for stabilizing the ground of sloping land, such as slopes along roads or railways and steep slopes in residential areas, and further relates to a program and a system therefor.

Background Art

[0002] As a method for determining the ground structure based on measuring vibrations, there is one disclosed in Patent Document 1 below. The technique disclosed in Patent Document 1 extracts surface waves based on frequency analysis of vibration measurement information, and estimates the ground structure from the dispersion curve of the surface waves. However, there is no suggestion regarding evaluating the stability of the ground of sloping land. As techniques for evaluating the stability of the ground of sloping land, for example, there are those disclosed in Patent Documents 2 to 4 below. Patent Document 2 discloses determining the collapse risk of a slope based on a mechanical model of the slope and rainfall data. Patent Document 3 discloses evaluating the stability of a slope by installing vibration receivers at multiple locations on the slope and comparing the vibration characteristics at each location. Patent Document 4 discloses observing multiple observation points on a slope with a positioning satellite and evaluating the stability of the slope based on the displacement velocity of each observation point.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] On sloping ground, if the ground stability is poor, there are problems such as landslides. Therefore, as shown in the above Patent Documents 1 to 4, appropriate evaluation of the ground stability of sloping ground has been carried out. On the other hand, in order to prevent landslides and the like on sloping ground and achieve stabilization, construction of ground anchors and the like has been carried out. However, there is no method for quantitatively determining the effect of ground stabilization construction.

[0005] The present invention has been made in view of the above points, and an object thereof is to provide a method, a program, and a system for determining the effect of ground stabilization construction on sloping ground.

Means for Solving the Problems

[0006] The method for determining the effect of ground stabilization construction according to the present invention is as follows. To be the subject of ground stabilization work Sloping ground In the dispersed A first step of acquiring vibration measurement information from a plurality of points, a second step of acquiring the frequency characteristics of vibrations at the plurality of points by performing frequency analysis on each of the acquired vibration measurement information, a third step of evaluating the stability of the sloping ground based on the relevance of the frequency characteristics of vibrations at the plurality of points, a fourth step of obtaining a stability evaluation result before construction by performing the first to third steps before performing construction for stabilizing the ground of the sloping ground, a fifth step of obtaining a stability evaluation result after construction by performing the first to third steps after performing construction for stabilizing the ground of the sloping ground, and a sixth step of determining the construction effect based on a comparison between the stability evaluation result before construction and the stability evaluation result after construction. Therefore, based on the ratio or difference between the first numerical value indicating the pre-construction stability evaluation result and the second numerical value indicating the post-construction stability evaluation result, a numerical value indicating the construction effect is calculated It comprises a sixth step.

[0007] According to the present invention, Since it is configured to acquire vibration measurement information from a plurality of dispersed points in a sloping ground to be the subject of ground stabilization work, it is suitable for the stability evaluation before and after the ground stabilization work for a sloping ground with an area-wide spread. Also, since it is configured to calculate a numerical value indicating the construction effect based on the ratio or difference between the first numerical value indicating the pre-construction stability evaluation result and the second numerical value indicating the post-construction stability evaluation result The effect of ground stabilization construction can be By numerical value Grasped quantitatively.

[0008] The present invention can be configured and implemented not only as a method invention but also as an apparatus (system) invention. Further, the present invention can be implemented in the form of a program for a processor such as a computer or a DSP, or in the form of a storage medium storing such a program.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Best Mode for Carrying Out the Invention

[0010] [System Configuration] FIG. 1 is a block diagram showing a configuration example of an apparatus / system used for implementing the method according to the present invention. This system includes one or more vibration meters 1 and a mobile computer 2. One vibration meter 1 can measure three-dimensional components (X, Y, Z) of vibration, and for example, incorporates sensors that sense the velocity or acceleration in the three axial directions (X, Y, Z) of three dimensions. This vibration meter 1 is installed on the ground to be measured (a sloping ground in this embodiment) and is configured to output vibration measurement information for each of the three-dimensional components (X, Y, Z). The vibration measurement information measured by the vibration meter 1 is taken into the computer 2 as digital vibration measurement information via the data capture unit 20. The mobile computer 2 is a portable small computer and includes, as is well known, a CPU (Central Processing Unit) 21, a memory (including an electronic memory and a hard disk, etc.) 22, a display and a user interface (UI / F) unit 23, a communication interface 24, and the like.

[0011] An application program for implementing the method according to the present invention is stored in the memory 22 of the computer 2. The computer 2 is configured to realize a function as a device for determining the effect of ground stabilization construction on a sloping ground by executing this application program based on the vibration measurement information measured by the vibration meter 1. In the block frame of the computer 2 in the figure, as representative program modules, a frequency analysis module M1, a ground stability evaluation module M2, and a construction effect determination module M3 are illustrated.

[0012] The frequency analysis module M1 performs a process of obtaining the frequency characteristics (frequency response function) of vibration at a point by performing frequency analysis on the vibration measurement information acquired from the vibration meter 1 installed at an arbitrary point on the sloping ground which is the ground to be measured. By installing the vibration meter 1 at a plurality of points on the sloping ground and performing the process by the frequency analysis module M1 on the vibration measurement information acquired from each point, the frequency characteristics of vibration at the plurality of points can be obtained. By executing this frequency analysis module M1, the computer 2 functions as a first means for obtaining the frequency characteristics of vibration at the plurality of points by performing frequency analysis on each vibration measurement information acquired from the plurality of points on the sloping ground via the vibration meter 1.

[0013] It is known that the ground is always shaking with vibrations that cannot be felt by humans even in the quietest places, and the vibration meter 1 is configured to detect even minute vibrations of the ground and output the vibration measurement signal. Thus, the vibration meter 1 measures the natural vibrations in the ground to be measured, and in the implementation of the present invention, it is not necessary to generate vibrations using a special vibration generating device. Also, the computer 2 is configured to be able to record the digital data of the vibration measurement signal acquired from the vibration meter 1 corresponding to each point in the memory 22.

[0014] The ground stability evaluation module M2 performs a process of evaluating the stability of the slope based on the relevance of the frequency characteristics of vibrations at the plurality of points. By executing this ground stability evaluation module M2, the computer 2 functions as a second means for evaluating the stability of the slope based on the relevance of the frequency characteristics of vibrations at the plurality of points. As an example, as an index indicating the relevance of the frequency characteristics, it may include obtaining the amplitude ratio (response magnification) for each frequency component at two measurement points, and / or obtaining the coherence for each frequency component at the two measurement points. For example, the closer this amplitude ratio (response magnification) is to 1, the more similar the shaking characteristics are at both measurement points, and the higher the stability of the ground can be evaluated. Also, the closer the strength of the coherence is to 1, the more similar the shaking characteristics are at both measurement points, and the higher the stability of the ground can be evaluated. Thus, the stability evaluation result by the process of the ground stability evaluation module M2 can be presented as a specific numerical value (evaluation value).

[0015] The construction effect determination module M3 compares the stability evaluation result obtained through the processes by the frequency analysis module M1 and the ground stability evaluation module M2 before performing construction to stabilize the ground of the slope, which is the ground to be measured, with the stability evaluation result obtained through the processes by the frequency analysis module M1 and the ground stability evaluation module M2 after performing construction to stabilize the ground of the slope, and performs a process of determining the construction effect based on this comparison. By executing this construction effect determination module M3, the computer 2 compares the stability evaluation result obtained through the first and second means (modules M1, M2) before performing construction to stabilize the ground of the slope with the stability evaluation result obtained through the first and second means (modules M1, M2) after performing construction to stabilize the ground of the slope, and functions as a third means for determining the construction effect based on this comparison.

[0016] As an example, the construction effect determination module M3 calculates a numerical value indicating the construction effect based on the ratio or difference between a first numerical value indicating the pre-construction stability evaluation result and a second numerical value indicating the post-construction stability evaluation result. For example, if the ratio of the pre- and post-construction stability evaluation results (evaluation values) is close to 1, or the difference is close to 0, it means that there is little change in the ground stability before and after construction, so it can be determined that the effect of the construction was not significant. On the other hand, if the ratio of the pre- and post-construction stability evaluation results (evaluation values) is not close to 1, or the difference is large, it can be determined that the effect of the construction was significant. In this way, the effect of the construction actually carried out for ground stabilization can be quantitatively determined.

[0017] Also, as an example, the first numerical value may be the average value of the pre-construction stability evaluation results for a predetermined frequency band, and the second numerical value may be the average value of the post-construction stability evaluation results for the predetermined frequency band. Alternatively, not limited to the average value, the first and second numerical values may be representative values (such as minimum or maximum values) according to other appropriate criteria. By calculating the numerical value indicating the construction effect based on the average value or representative value in this way, the construction effect can be presented by one or a limited number of representative numerical values, making it very easy to understand. The predetermined frequency band is, for example, a predetermined low-frequency band.

[0018] Furthermore, as an example, the construction effect determination module M3 determines the construction effect based on a comparison between the pre-construction stability evaluation result and the post-construction stability evaluation result for a predetermined low-frequency band. The predetermined low-frequency band is the frequency band to which the slow oscillation of the ground belongs, for example, in the range of about 3 to 15 Hz. In such a frequency band to which the slow oscillation belongs, the degree of the ground stabilization construction effect is likely to appear prominently. Therefore, it is only necessary to compare the pre- and post-construction stability evaluation results for the predetermined low-frequency band without comparing the pre- and post-construction stability evaluation results over all frequency bands.

[0019] [An Example of Method and Program] FIG. 2 is a flowchart showing an embodiment of the method according to the present invention that can be executed using the system shown in FIG. 1. (a) shows a ground stability evaluation routine, which is performed based on the computer 2 executing the frequency analysis module M1 and the ground stability evaluation module M2. (b) shows a construction effect determination routine, which is performed based on the computer 2 executing the construction effect determination module M3.

[0020] In FIG. 2(a), in step S1, vibration measurement information is acquired from the vibration meters 1 installed at a plurality of points on the slope, which is the ground to be measured, and stored in the memory 22 of the computer 2 (this is referred to as the first step for convenience). Next, in step S2, by frequency-analyzing each acquired vibration measurement information, the frequency characteristics of the vibrations at the plurality of points are acquired and stored in the memory 22 of the computer 2 (this is referred to as the second step for convenience). The process of step S2 is performed by the frequency analysis module M1. Next, in step S3, the stability of the slope is evaluated based on the relevance of the frequency characteristics of the vibrations at the plurality of points (this is referred to as the third step for convenience). The process of step S3 is performed by the ground stability evaluation module M2. The stability evaluation result obtained by the process of step S3 is stored in the memory 22 of the computer 2 in association with the plurality of points that are the measurement targets (step S4). Specifically, in the process of step S3, as an index indicating the relevance of the frequency characteristics of the vibrations at the plurality of points, the amplitude ratio (response magnification) for each frequency component at two points and the coherence for each frequency component at the two points are obtained. When setting three or more measurement points, for each pair consisting of any two points, the amplitude ratio (response magnification) and coherence for each frequency component at the two points of each pair may be obtained. In step S4, the amplitude ratio (response magnification) and coherence obtained in step S3 are stored in the memory 22 as the stability evaluation results at the two points of each pair.

[0021] When performing construction effect determination, first, before carrying out construction to stabilize the ground of the inclined ground which is the ground to be measured, the construction effect determination routine in Fig. 2(b) is activated. In Fig. 2(b), in step S5, it is judged whether it is before carrying out construction to stabilize the ground of the inclined ground which is the ground to be measured. If it is before construction, go from YES in S5 to step S6, and by performing the ground stability evaluation routine shown in Fig. 2(a), the stability evaluation result before construction is obtained. The obtained stability evaluation result before construction is stored in the memory 22 by the process of step S4 described above. That is, the processes performed by steps S5 and S6 are processes of obtaining the stability evaluation result before construction by performing the first to third steps (ground stability evaluation routine) before carrying out construction to stabilize the ground of the inclined ground, and this is referred to as the fourth step for convenience. After performing step S6, return and wait until construction for ground stabilization is carried out (until construction is completed).

[0022] Next, after finishing the construction to stabilize the ground of the inclined ground, the construction effect determination routine in Fig. 2(b) is restarted. Since it is after construction is completed, step S5 in Fig. 2(b) branches to NO and proceeds to step S7. In step S7, it is judged whether the construction to stabilize the ground of the inclined ground has been completed. If the construction has been completed, go from YES in S7 to step S8, and by performing the ground stability evaluation routine shown in Fig. 2(a), the stability evaluation result after construction is obtained. In this step S8, for each pair of the same two points as those obtained in step S6, the stability evaluation results after construction are respectively obtained. The obtained stability evaluation results after construction are stored in the memory 22 by the process of step S4 described above. That is, the processes performed by steps S7 and S8 are processes of obtaining the stability evaluation result after construction by performing the first to third steps (ground stability evaluation routine) after carrying out construction to stabilize the ground of the inclined ground, and this is referred to as the fifth step for convenience. After step S8, proceed to step S9.

[0023] In step S9, a construction effect is determined based on a comparison between the pre-construction stability evaluation result stored in the memory 22 and the post-construction stability evaluation result (this is referred to as the sixth step for convenience). The processing of this step S9 is performed by the construction effect determination module M3. As a specific example, in step S9, a numerical value indicating the construction effect is calculated based on the ratio (increase rate) between a first numerical value indicating the pre-construction stability evaluation result and a second numerical value indicating the post-construction stability evaluation result. More specifically, the first numerical value is the average value of the pre-construction stability evaluation result for a predetermined low-frequency band (for example, a frequency band of about 3 to 15 Hz), and the second numerical value is the average value of the post-construction stability evaluation result for the predetermined low-frequency band. The calculated numerical value indicating the construction effect may be stored in the memory 22 so that it can be read out at any time as needed later, or may be appropriately displayed via the display 23 or the like. In this way, the construction effect can be clearly presented by a numerical value.

[0024] [Example] Furthermore, with reference to the figures after FIG. 3 as well, an example of the method according to the present invention will be described. FIG. 3 is an external perspective view showing an example of a sloping ground in a state before construction for ground stabilization, and FIG. 4(a) is a schematic longitudinal sectional view thereof. FIG. 4(b) is a schematic longitudinal sectional view of the sloping ground showing the state after ground stabilization construction.

[0025] FIG. 3 shows, for example, a slope where landsliding is progressing on a highway under construction, and shows a state where ground stabilization work by embedding and installing a plurality of ground anchors 32 has already been completed in the upper region 30 of the slope. The lower region 31 of the slope remains as natural ground and ground stabilization work has not yet been performed. In this embodiment, an example of determining the construction effect of the ground stabilization construction performed on this lower region 31 will be described.

[0026] Pre-construction stability evaluation In order to measure the vibration characteristics before ground stabilization work in the area to be judged (lower area 31), a plurality of vibration meters 1 are distributed and arranged at appropriate points in the area to be judged (lower area 31). As an example, five vibration meters 1 are installed horizontally at approximately the same height and at appropriate intervals at the upper part 31a of the area to be judged (lower area 31). For convenience, the points where each vibration meter 1 is installed are distinguished by the symbols No.1, No.2, No.3, No.4, and No.5 (see FIGS. 1 and 3). For example, assuming that point No.5 is the reference, the distances from the reference point No.5 are in the order of points No.4, No.3, No.2, and No.1. As will be described later, each of the other points forms a pair with the reference point No.5, and the ground stability is evaluated by evaluating the relevance of the frequency characteristics of vibration for four pairs (the pair of No.5 and No.4, the pair of No.5 and No.3, the pair of No.5 and No.2, and the pair of No.5 and No.1).

[0027] When the vibration meters 1 are installed in this way and the construction effect determination routine (FIG. 2(b)) is started, the computer 2 (FIG. 1) inputs the vibration measurement information at each point No.1 to No.5 via the data acquisition unit 20. Since it is before construction, the computer 2 executes step S6 of the construction effect determination routine shown in FIG. 2(b). In step S6, based on the vibration measurement information at each point No.1 to No.5 input to the computer 2, the ground stability evaluation routine shown in FIG. 2(a) is executed. Specifically, the frequency characteristics (frequency response function) of vibration at each point No.1 to No.5 are obtained by performing frequency analysis on the acquired vibration measurement information (S2 in FIG. 2(a)), and the stability of the area to be judged (lower area 31) is evaluated based on the relevance of the frequency characteristics of vibration at each point No.1 to No.5 (S3 and S4 in FIG. 2(a)). Note that as the vibration meter 1, five physically separate vibration meters 1 may be prepared and installed at each point No.1 to No.5, or alternatively, only one physically vibration meter 1 may be prepared, and this may be sequentially replaced and installed at each point No.1 to No.5 so that the vibration measurement information at each point No.1 to No.5 is sequentially taken into and stored in the computer 2.

[0028] As an example, in step S3 of the ground stability evaluation routine performed in step S6 of the construction effect determination routine, as the correlation of the frequency characteristics of vibrations at each measurement point Nos. 1 to 5, for each pair, the amplitude ratio (response magnification) for each frequency component at two paired points is obtained, and for each pair, the coherence for each frequency component at the two paired points is obtained. As a result, data consisting of the amplitude ratio (response magnification) for each frequency component for each pair (the pair of point No. 5 and No. 4, the pair of No. 5 and No. 3, the pair of No. 5 and No. 2, the pair of No. 5 and No. 1) is calculated for each of the three-dimensional axis directions (X, Y, Z) as the stability evaluation result of the first type before construction and stored in the memory 22. Also, data consisting of the coherence for each frequency component for each pair (the pair of point No. 5 and No. 4, the pair of No. 5 and No. 3, the pair of No. 5 and No. 2, the pair of No. 5 and No. 1) is calculated for each of the three-dimensional axis directions (X, Y, Z) as the stability evaluation result of the second type before construction and stored in the memory 22. By performing the ground stability evaluation of two different types (response magnification and coherence) in this way, the stability evaluation accuracy can be improved. Note that it is not limited to two types (response magnification and coherence), and either one alone may be sufficient, or the identification may be evaluated based on the correlation of other types of frequency characteristics.

[0029] Figures 5 and 6 are diagrams showing an example of the stability evaluation results obtained in step S3 of the ground stability evaluation routine. Figure 5 shows an example of the stability evaluation results regarding the first type of index, that is, the amplitude ratio (response magnification factor) for each frequency component, and Figure 6 shows an example of the stability evaluation results regarding the second type of index, that is, the coherence for each frequency component. Both Figures 5 and 6 show the stability evaluation results for the pair of point No.5 and No.1. Also, in Figures 5 and 6, (a) shows the stability evaluation results for the vibration component in the X direction, (b) shows the stability evaluation results for the vibration component in the Y direction, and (c) shows the stability evaluation results for the vibration component in the Z direction. In both Figures 5 and 6, the horizontal axis represents the frequency (Hz), the vertical axis in Figure 5 represents the amplitude ratio (response magnification factor), and the vertical axis in Figure 6 represents the coherence. Although not particularly shown, similarly for other pairs (the pair of point No.5 and No.4, the pair of No.5 and No.3, the pair of No.5 and No.2), the stability evaluation results regarding the amplitude ratio (response magnification factor) and coherence for each frequency component can be obtained. In Figure 5, the characteristic indicated by the symbol Rp shows the pre-construction stability evaluation result (response magnification factor) obtained by the processing in step S6. Also, in Figure 6, the characteristic indicated by the symbol Cp shows the pre-construction stability evaluation result (coherence) obtained by the processing in step S6.

[0030] The amplitude ratio (response magnification factor) of a certain frequency component can serve as an indicator for evaluating that the higher the value is closer to 1, the higher the ground stability at the two points to be measured. That is, if the amplitudes of the said frequency component at the two points to be measured are equal, the amplitude ratio (response magnification factor) is 1; if the amplitudes of the two differ, the value will show a deviation from 1 according to the difference. Similarly, the coherence (correlation) of a certain frequency component can serve as an indicator for evaluating that the higher the value is closer to 1, the higher the ground stability at the two points to be measured. That is, if the correlation of the said frequency component at the two points to be measured is high, the coherence is 1; if the correlation of the two is low, the value will show a deviation from 1 accordingly. For example, in Fig. 5, the value Rp indicating the pre-construction stability evaluation result for the amplitude ratio (response magnification factor) shows a relatively high value in the band of approximately 3 to 15 Hz, but it is still around 0.1 and quite far from 1. This indicates low ground stability. Similarly, in Fig. 6, the value Cp indicating the pre-construction stability evaluation result for the coherence shows a relatively high value in the band of approximately 3 to 15 Hz, but it is still around 0.1 and quite far from 1. This also indicates low ground stability.

[0031] Post-construction stability evaluation Subsequently, ground stabilization construction is carried out on the lower region 31 of the slope shown in Fig. 3. Fig. 4(b) shows the state after the ground stabilization construction. After cutting the natural ground in the lower region 31, a plurality of ground anchors 33 are embedded deeper than the slip line in the slope, thereby stabilizing the ground. After the completion of this construction, in order to measure the vibration characteristics after the ground stabilization construction in the area to be judged (lower region 31), vibration meters 1 are respectively installed at the same points No. 1 to No. 5 where measurements were taken before the construction.

[0032] When the vibration meter 1 is installed in this way and the construction effect judgment routine (Fig. 2(b)) is restarted, the computer 2 (Fig. 1) inputs the vibration measurement information at each location No. 1 to No. 5 via the data acquisition unit 20. Since the construction has ended, the computer 2 executes step S8 of the construction effect judgment routine shown in Fig. 2(b). In step S8, based on the vibration measurement information at each location No. 1 to No. 5 input to the computer 2, the ground stability evaluation routine shown in Fig. 2(a) is executed. In step S3 of the ground stability evaluation routine performed in step S8 of the construction effect judgment routine, as described above, as the relevance of the frequency characteristics of the vibrations at each measurement location No. 1 to No. 5, for each pair of two locations forming a pair, the amplitude ratio (response magnification) for each frequency component is obtained for each pair, and the coherence for each frequency component at the two locations forming the pair is obtained for each pair. As a result, data consisting of the amplitude ratio (response magnification) for each frequency component for each pair (the pair of location No. 5 and No. 4, the pair of No. 5 and No. 3, the pair of No. 5 and No. 2, the pair of No. 5 and No. 1) is calculated for each of the three-dimensional axis directions (X, Y, Z) as the stability evaluation result regarding the first type of index after construction and stored in the memory 22. Also, data consisting of the coherence for each frequency component for each pair (the pair of location No. 5 and No. 4, the pair of No. 5 and No. 3, the pair of No. 5 and No. 2, the pair of No. 5 and No. 1) is calculated for each of the three-dimensional axis directions (X, Y, Z) as the stability evaluation result regarding the second type of index after construction and stored in the memory 22.

[0033] As described above, FIGS. 5 and 6 illustrate the stability evaluation results for the pair of point No. 5 and No. 1. In FIG. 5, the characteristic indicated by the symbol Ra represents the post-construction stability evaluation result (response magnification factor) obtained by the process of step S8. Also, in FIG. 6, the characteristic indicated by the symbol Ca represents the post-construction stability evaluation result (coherence) obtained by the process of step S8. For example, in FIG. 5, the value Ra indicating the post-construction stability evaluation result for the amplitude ratio (response magnification factor) shows a relatively high value in a band of approximately 5 to 15 Hz and is quite close to 1. This indicates that the ground stability has become much higher than before construction. Similarly, in FIG. 6, the value Ca indicating the post-construction stability evaluation result for coherence shows a relatively high value in a band of approximately 5 to 15 Hz and is quite close to 1. This also indicates that the ground stability has been significantly improved compared to before construction.

[0034] Judgment of construction effect For example, as can be seen from looking at the relationship between Rp and Ra in FIG. 5 and the relationship between Cp and Ca in FIG. 6, both indicators of the amplitude ratio (response magnification factor) Rp, Ra and coherence Cp, Ca have post-construction values Rp, Cp that are closer to 1 than the pre-construction values Rp, Cp. By comparing the pre-construction stability evaluation results Rp, Cp with the post-construction stability evaluation results Ra, Ca in this way, it is possible to determine the presence or absence of the effect of construction and the degree of the effect. That is, if the ratio or difference between the first numerical values (Rp, Cp) indicating the pre-construction stability evaluation result and the second numerical values (Ra, Ca) indicating the post-construction stability evaluation result is large, it can be determined that there is an effect due to construction, and the degree of the construction effect can be numerically determined by that ratio or difference. Referring to FIGS. 5 and 6, the difference between the first numerical values (Rp, Cp) indicating the pre-construction stability evaluation result and the second numerical values (Ra, Ca) indicating the post-construction stability evaluation result can be significantly recognized in a specific low-frequency band (for example, a band of approximately 3 to 15 Hz). This is due to the characteristics of the general crust composed of soil and / or rock, etc., and there is universality in focusing on a specific low-frequency band.

[0035] Therefore, in order to efficiently determine the effect of ground stability construction, focusing on a predetermined frequency band (for example, a low-frequency band of approximately 3 to 15 Hz), in step S9 (the third step) of the construction effect determination routine of this embodiment, representative values of the pre-construction stability evaluation results (Rp, Cp) for the predetermined frequency band and representative values of the post-construction stability evaluation results (Ra, Ca) for the predetermined frequency band are calculated, and the values of both are compared (to obtain a ratio or difference). This representative value may be, for example, an average value, or a representative value determined by other criteria (such as a maximum value or a minimum value, etc.). In the following description, an average value will be used as the representative value.

[0036] Specifically, in step S9 of FIG. 2(b), for each pair of measurement points (the pair of point No. 5 and No. 4, the pair of point No. 5 and No. 3, the pair of point No. 5 and No. 2, the pair of point No. 5 and No. 1), the average value of the amplitude ratio (response magnification) Rp before construction, (2) the average value of the amplitude ratio (response magnification) Ra after construction, (3) the average value of the coherence Cp before construction, and (4) the average value of the coherence Ca after construction in a predetermined low-frequency band (for example, approximately 3 to 15 Hz) are calculated.

[0037] FIG. 7 shows an example in which the average values of (1) the amplitude ratio (response magnification) before construction for each pair of points and (2) the amplitude ratio (response magnification) after construction for each pair of points calculated in this way are plotted. FIG. 7(a) shows a calculation example based on the vibration measurement information in the X direction, (b) shows a calculation example based on the vibration measurement information in the Y direction, and (c) shows a calculation example based on the vibration measurement information in the Z direction. Also, the plots indicated by circular marks show the average values of the amplitude ratio (response magnification) before construction, and the plots indicated by triangular marks show the average values of the amplitude ratio (response magnification) after construction.

[0038] Also, FIG. 8 shows an example in which the average value of the coherence before construction for each pair of points calculated in this way and the average value of the coherence after construction for each pair of points are plotted. FIG. 8(a) shows an example of calculation based on vibration measurement information in the X direction, (b) shows an example of calculation based on vibration measurement information in the Y direction, and (c) shows an example of calculation based on vibration measurement information in the Z direction. Also, the plots indicated by circular marks show the average value of the coherence before construction, and the plots indicated by triangular marks show the average value of the coherence after construction.

[0039] In both FIGS. 7 and 8, No. 1 to No. 4 on the horizontal axis are abbreviations indicating each pair of points. No. 1 indicates the pair of point No. 5 and No. 1, No. 2 indicates the pair of point No. 5 and No. 2, No. 3 indicates the pair of point No. 5 and No. 3, and No. 4 indicates the pair of point No. 5 and No. 4. In both FIGS. 7 and 8, it can be seen that in all measurement point pairs and directions, the calculated values are closer to 1 after construction than before construction. This indicates that the ground has been integrated and stabilized by the ground stabilization construction (construction of the ground anchor 33) in the construction target area 31, and it can be understood that the construction effect can be verified. When looking at FIGS. 7 and 8, it can be seen that both the amplitude ratio (response magnification factor) and the coherence tend to increase in value from No. 1 to No. 4 on the horizontal axis. This means that the closer the distance between each of points No. 1 to No. 4 paired with the reference point No. 5 and the reference point No. 5, the higher the correlation of the vibration characteristics.

[0040] Furthermore, in step S9 of FIG. 2(b), for each pair of points (each pair indicated by abbreviations No. 1 to No. 4, that is, the pair of point No. 5 and No. 1, the pair of point No. 5 and No. 2, the pair of point No. 5 and No. 3, the pair of point No. 5 and No. 4), the ratio (increase rate) of the calculated value of the stability evaluation result before construction (that is, the average value of the first numerical value (response magnification Rp or coherence Cp)) shown in FIGS. 7 and 8 to the calculated value of the stability evaluation result after construction (that is, the average value of the second numerical value (response magnification Ra or coherence Ca)) shown in FIGS. 7 and 8 is calculated for each of the vibration direction components X, Y, Z, and a numerical value indicating the construction effect for each of the vibration direction components X, Y, Z is calculated. As another example, instead of calculating the ratio (increase rate), a difference may be calculated.

[0041] FIG. 9 shows an example in which the ratios (increase rate = after construction ÷ before construction) of the response magnifications Rp and Ra for each pair of points (each pair indicated by abbreviations No. 1 to No. 4) for each of the vibration direction components X, Y, Z calculated in this way are plotted. FIG. 10 shows an example in which the ratios (increase rate = after construction ÷ before construction) of the coherences Cp and Ca for each pair of points (each pair indicated by abbreviations No. 1 to No. 4) for each of the vibration direction components X, Y, Z calculated in this way are plotted. From FIGS. 9 and 10, it can be seen that both the amplitude ratio (response magnification) and the coherence tend to decrease in value from No. 1 to No. 4 on the horizontal axis. This means that the farther the distance between each of the points No. 1 to No. 4 paired with the reference point No. 5 and the reference point No. 5, the lower the pre-construction correlation between the two points, and the numerical value of the construction effect quantitatively expressed by the ratio of the stability evaluation results before and after construction (increase rate = after construction ÷ before construction) becomes a relatively large value. That is, it is possible to obtain a construction effect determination value with a larger dynamic range by determining the construction effect using the stability evaluation result based on the measurement at point No. 1 farther from the reference point No. 5 than the stability evaluation result based on the measurement at point No. 4 closer to the reference point No. 5.

[0042] In step S9 of Fig. 2(b), the ratios (increase rates) of the response magnification factors before and after construction and the ratios (increase rates) of coherence as shown in Figs. 9 and 10 are stored in the memory 22 as final determination result data, visually displayed on the display 23, and can also be printed out on paper by a printer or the like. Thus, it is possible to determine / confirm the effect of the construction for ground stabilization performed on the ground to be constructed (area 31). For example, referring to Fig. 9, the ratio (increase rate) of the response magnification factors before and after construction at point No. 1 is about 2.2 for the X-direction component, about 4.2 for the Y-direction component, and about 3.2 for the Z-direction component, and it can be specifically understood numerically that ground stabilization of about 2 to 4 times has been achieved. Similarly, referring to Fig. 10, the ratio (increase rate) of coherence before and after construction at point No. 1 is about 3.5 for the X-direction component, about 4.4 for the Y-direction component, and about 4.4 for the Z-direction component, and it can be specifically understood numerically that ground stabilization of about 3 to 4 times has been achieved. On the other hand, if the construction effect for ground stabilization is low, unlike the illustrated example, the ratio (increase rate) of the response magnification factors before and after construction and / or the ratio (increase rate) of coherence will show a low value of around 1 time, so it can be specifically understood numerically that the construction effect was small.

[0043] In the above embodiment, the relevance of the frequency characteristics of vibration is evaluated for four pairs of measurement points (the pair of No. 5 and No. 4, the pair of No. 5 and No. 3, the pair of No. 5 and No. 2, and the pair of No. 5 and No. 1). However, it is not limited to this. The relevance of the frequency characteristics of vibration may be evaluated for at least one pair of measurement points (for example, the pair of No. 5 and No. 1), and based on this, the construction effect may be determined as described above.

[0044] In addition, if it is found as a result of implementing the determination method according to the present invention that the construction effect is small, if necessary, it may be designated as a dangerous location, and necessary measures such as further performing additional stabilization work may be taken.

[0045] The index related to the relevance of the frequency characteristics of the vibration obtained in step S3 (the third step) of FIG. 2(a) is not limited to both the amplitude ratio (response magnification factor) and coherence for each frequency component described above, and may be either one of them, or not limited thereto, and may be other types of indices.

Explanation of Signs

[0046] 1 Vibration meter 2 Mobile computer 20 Data acquisition unit 21 CPU (Central Processing Unit) 22 Memory 23 Display and User Interface (UI / F) unit 24 Communication interface 32, 33 Ground anchor M1 Frequency analysis module M2 Ground stability evaluation module M3 Construction effect determination module

Claims

Step 1 of obtaining vibration measurement information from a plurality of dispersed points on a slope to be subjected to ground stabilization construction; Step 2 of obtaining the frequency characteristics of vibrations at the plurality of points by performing frequency analysis on each of the obtained vibration measurement information; Step 3 of evaluating the stability of the slope based on the correlation of the frequency characteristics of vibrations at the plurality of points; Step 4 of obtaining a pre-construction stability evaluation result by performing the first to third steps before performing construction for stabilizing the ground of the slope; Step 5 of obtaining a post-construction stability evaluation result by performing the first to third steps after performing construction for stabilizing the ground of the slope; Step 6 of calculating a numerical value indicating the construction effect based on the ratio or difference between a first numerical value indicating the pre-construction stability evaluation result and a second numerical value indicating the post-construction stability evaluation result in order to determine the construction effect based on the comparison between the pre-construction stability evaluation result and the post-construction stability evaluation result; A method for determining the effect of ground stabilization construction, comprising the steps described above. Claim 2 The method according to claim 1, wherein Step 3 includes obtaining an amplitude ratio for each frequency component of vibrations at the plurality of points as an index indicating the correlation of the frequency characteristics of vibrations at the plurality of points. Claim 3 The method according to claim 1 or 2, wherein Step 3 includes obtaining a coherence for each frequency component of vibrations at the plurality of points as an index indicating the correlation of the frequency characteristics of vibrations at the plurality of points. Claim 4 The method according to claim 2 or 3, wherein in Step 3, it is evaluated that the higher the amplitude ratio or the coherence is closer to 1, the higher the stability of the slope. Claim 5 The method according to any one of claims 1 to 4, wherein Step 3 includes obtaining an index indicating the correlation of the frequency characteristics of vibrations at two paired points for each of a plurality of pairs, and obtaining a stability evaluation result at a plurality of dispersed points on the slope based on the index obtained for each pair. Claim 6 The method according to any one of claims 1 to 5, wherein the first numerical value is an average value or a representative value of the pre-construction stability evaluation result for a predetermined frequency band, and the second numerical value is an average value or a representative value of the post-construction stability evaluation result for a predetermined low-frequency band. Claim 7 A program for causing a computer to execute each of the steps in the method according to any one of claims 1 to 6. **Claim 8** A vibration meter, a first means for obtaining frequency characteristics of vibrations at a plurality of dispersed points in a sloping ground to be subjected to ground stabilization work by frequency-analyzing each vibration measurement information obtained via the vibration meter from the plurality of dispersed points in the sloping ground; a second means for evaluating the stability of the sloping ground based on the relevance of the frequency characteristics of the vibrations at the plurality of points; a third means for comparing the stability evaluation result obtained via the first and second means before performing construction for stabilizing the ground of the sloping ground with the stability evaluation result obtained via the first and second means after performing construction for stabilizing the ground of the sloping ground, and determining a construction effect based on this comparison, the third means calculating a numerical value indicating the construction effect based on a ratio or difference between a first numerical value indicating the stability evaluation result before construction and a second numerical value indicating the stability evaluation result after construction; A system for determining the effect of ground stabilization work, comprising the above. **Claim 9** The system according to claim 8, wherein the second means includes obtaining, for each of a plurality of pairs, an index indicating the relevance of the frequency characteristics of the vibrations at two paired points, and obtaining a stability evaluation result at a plurality of dispersed points in the sloping ground based on the index obtained for each pair.

Images