JP5636585B1 - Diagnosis method of dam body using seismometer - Google Patents

Abstract

An object of the present invention is to easily and reliably diagnose a structure of a dam body by using a vibration waveform measured by a seismometer installed on the surface of or inside a dam body such as a pond and a dam and a dam body. SOLUTION: Seismometers S1 and S2 are installed on at least two locations on or inside the dam body Db, and vibration waveforms are continuously recorded by each seismometer, and two locations selected from the installed seismometers. The two selected locations are calculated by calculating the function using the deconvolution of the vibration waveform measured by the seismometers S1 and S2 installed in as a variable, and reading the travel time and amplitude of the calculated series of waveforms. The seismic wave propagation path between the seismometers S1 and S2 and the seismic wave propagation phenomena such as direct wave propagation, scattering and reflection of the P wave or S wave of the seismic wave in the surrounding area are evaluated to evaluate the state of seismic wave propagation in the levee body Diagnose internal structures. [Selection] Figure 2

Description

  The present invention relates to a method for diagnosing dam bodies such as ponds and dams and levee bodies, and more particularly, to a diagnostic method using vibration waveforms measured by a seismometer installed on or inside the dam body.

  Conventionally, elastic waves generated from seismic source devices are propagated inward from the ground surface, underground well walls, artificial structures, etc., and waves that are reflected or refracted from underground layers or structures are measured, and underground waves are measured. And seismic exploration methods for exploring structures are known.

  By the way, the seismic exploration is often used because geological structure information up to the deep underground can be obtained with high accuracy. However, the seismic source as an energy source in seismic exploration is explosives, mechanical seismic sources, electric discharges. Control vibrations (artificial vibrations) such as dynamic seismic sources, thermodynamic seismic sources, air-emitting seismic sources, and micro explosive epicenters are necessary, and there is a problem that the cost for boring surveys, explosives, and shakers increases.

  In addition, the conventional seismic exploration method uses the time and amplitude until a vertically incident seismic wave is reflected at the stratum boundary to determine the state of the seismic velocity and density distribution. Can be applied easily and reliably, but there is also a problem that the dam body such as a pond, a dam, and a bank such as a levee have a mountain-shaped cross section, that is, a shape that spreads downward and is difficult to apply.

  Therefore, ground exploration methods for exploring the geological structure of the ground by observing microtremors or natural seismic waves are disclosed in, for example, Japanese Patent Laid-Open Nos. 11-94948, 2006-275914, 2011-242231, etc. Is presented.

  However, the ground exploration method for exploring the geological structure of the ground by observing microtremors, natural seismic waves, etc., as disclosed in Japanese Patent Application Laid-Open Nos. 11-94948, 2006-275914, etc. The velocity wave is observed by the received geophone, the horizontal main components such as microtremors and seismic waves are regarded as shear waves, and the effective value of shear strain from the velocity waves where the rising and falling waves of the shear waves overlap It is characterized by exploring the geological structure of the ground by measuring the depth distribution from the ground surface in an amount equivalent to or measured at the same time with geophones placed at two different points on the ground surface By performing cross-correlation processing on the waveforms of these measured data, a predetermined process is performed on a synthetic shot record of a pseudo-reflected wave created by synthesizing the waveform when one is the epicenter and the other is the receiving point. Additionally integrated relates evaluation method for predicting ground motion amplification characteristics of the surface layers by observing the surface of the fine movement to synthesize visual data of underground structure in the measurement area.

  Therefore, if the seismic wave reflection intensity does not correspond to the underground density structure, such as dams such as ponds and dams, and embankments such as embankments, it is difficult for the seismic wave to reach deeper underground due to the shallow strong reflection layer. Or, when the density change is slow, it cannot be applied or is difficult to apply.

  The ground exploration method for exploring the geological structure of the ground by observing microtremors, natural seismic waves, and the like presented in Japanese Patent Application Laid-Open No. 2011-242231 is capable of exploring in the depth direction. First stage of seismic velocity structure model showing horizontal and depth distribution of seismic velocity in the ground from position information, topographic information, reflection cross section information, seismic refraction information, and integrated measurement data group information And using the optimal relationship between density and seismic velocity, compare the second stage of the initial density structure model with the calculated gravity vector value and the observed gravity vector value, and the third stage of the modified density structure model, Comparing the calculated gravity tensor value and the observed gravity tensor value obtained from the observation, converting the optimum density structure model into the seismic velocity structure model, and converting the optimum density structure model into the seismic velocity structure model. A fifth stage that repeatedly generates a theoretical seismic wave refracted wave, a theoretical seismic wave wide-angle reflected wave, a theoretical seismic wave reflection section, and outputs an optimum density structure that satisfies a predetermined convergence condition as an estimated density structure, and is complex. There is a problem that analysis is necessary and there are many estimation parts.

Japanese Patent Laid-Open No. 11-94948 JP 2006-275914 A JP 2011-242231 A

  An object of the present invention is to provide a method for easily and reliably diagnosing the structure of a dam body using a vibration waveform measured by a seismometer installed on the surface of or inside a dam body such as a dam or a dam and a levee such as a dyke. It is what.

The dam body diagnosis method using the seismometer according to the first invention of the present application, which has been made to solve the above-mentioned problems, is provided with seismometers installed at least at two locations on the surface or inside of the dam body. While continuously recording the vibration waveform due to vibration from the ground located below the dam body, reverse superposition on the vibration waveform measured by the seismometers installed at two locations selected among the installed seismometers calculating a function of a variable, the waveform by calculating the set of functions, was calculated taking into account the respective section distance for interval attenuation amount obtained by reading the leg propagation time and amplitude obtained by reading the time run its at least one section each propagation speed or interval each damping characteristics, seismic waves propagate current of the direct wave or reflected wave, the P wave or S wave is a seismic wave embankment Wherein the diagnosing structure of embankment from seismic propagation characteristics evaluated by reflecting.

In the present invention, as shown in FIG. 1, an existing borehole observation hole (or a newly installed survey borehole is formed in the dam body Db or in the ground Gd so that the state of seismic wave propagation in the dam body Db and the surrounding ground Gd can be understood. established the seismometers S etc.) H, or of the seismometer S that is installed, seismograph S _1, select the S ₂ each seismometer S ₁ in two places as shown in FIG. 2, S ₂ Thus, the vibration waveforms U ₁ and U ₂ are continuously recorded, and the deconvolution of the vibration waveforms U ₁ and U ₂ is calculated as in the following equation (1).

Here, U ₁ and U ₂ are vibration waveforms in the two selected seismometers S ₁ and S ₂ . * Means superposition integration, and when there is a relationship of C = A * B, it is expressed as A = C * B ⁻¹ . That is, A means the deconvolution integral of C and B, and D in the equation (1) means the deconvolution of the vibration waveforms U ₁ and U ₂ by the seismometers S ₁ and S ₂ .

As shown in FIG. 2, assuming that the source waveform of the source E on the ground Gd is U _S , the vibration waveforms U ₁ and U _{2 obtained} by the seismometers S ₁ and S ₂ are as shown in the following equation (2). Can be expressed.

Here, a Green's function to _{G 1, S, G 2,} S is the vibration waveform U ₁ by each seismometer S _1, S ₂ from the epicenter _E, U ₂ each observation point. Substituting this into the equation (1) yields the following equation (3).

The deconvolution D relating to the vibration waveforms U ₁ and U ₂ does not depend on the source waveform, but only on the mechanical characteristics of the path from the position of the source to the observation point.

  Next, as shown in FIG. 3, it is assumed that the incident of the seismic wave from the seismic source E into the dam body Db can be expressed as an incident wave of a plane wave. Actually, in the foundation ground where civil structures such as a dam body are located, the propagation speed of the seismic wave is generally slower than that of the deep seismic base and the seismic wave is often incident from the base in a substantially vertical direction. In fact, the same assumptions are often made in the seismic evaluation of levee bodies. Therefore, it is assumed that there is a situation that satisfies the assumption.

As shown in FIG. 3, if there is a plane B that can define a plane wave incident on the levee body Db, a traveling wave from the plane B toward the dam body Db is defined as U _B ⁺ and the following equation (4) Can be expressed.

  Then, when the formula (4) is substituted into the formula (1) to calculate the deconvolution, the following formula (5) is obtained.

Here, G _{1, B and} G _{2, B} are response functions of the vibration waveforms U ₁ and U ₂ by the seismometers S ₁ and S ₂ with respect to U _B ⁺ in the plane B. Here, U _B ⁺ can be expressed as the following equation (6).

The vibration waveform itself observed by the seismometer depends on the location of the epicenter, but the deconvolution of the oscillation waveforms U ₁ and U _{2 in the} equation (4) does not depend on the seismic source waveform and the location of the epicenter. Instead, it depends only on the propagation path of the seismic wave from the plane B to the observation point and the mechanical properties in the surrounding ground Gd and the dam body Db.

In addition, when the plane B can be set to the plane of the boundary Z ₀ between the dam body Db and the ground Gd, the reverse superposition D of the above equation (5) depends only on the structure and mechanical characteristics inside the dam body Db, and the epicenter It is unique to the dam body, independent of the waveform and position.

In actual observation, the assumed assumption regarding the incident wave U _B ⁺ may not be satisfied, and noise due to wind or artificial factors may be included. Therefore, in order to obtain a more stable and reproducible waveform for the calculated series of deconvolution D, waveform processing by averaging processing, smoothing processing, filter processing, normalization processing, or the like is required. It is also effective for stabilization to superimpose or desuperimpose autocorrelation of a reference waveform such as a measurement waveform on the base. D ^ obtained as a result of applying the waveform processing to the deconvolution D is regarded as a function related to the deconvolution D and expressed as the following equation (7).

Thus, D ^ is the result calculated by the function F with the deconvolution D as a variable, and the result does not depend on the epicenter E and is stable so as to be specific to the dam body Db and the ground Gd. D ^ also continuously records the micro-vibration waveform during non-earthquake between observation points, and the propagation status of the seismic wave, such as the propagation path and surrounding seismic wave propagation characteristics, etc. It represents. Therefore, based on a characteristic waveform shape such as a peak for the waveform of D ^, the state of seismic wave propagation in the levee body with respect to the seismic wave propagation path and the surrounding P wave or S wave of the seismic wave or the reflected wave is evaluated. Thus, the structure and mechanical properties can be evaluated and estimated.

  Further, in the first invention of the present application, when calculating a function using a deconvolution related to a vibration waveform continuously measured by the seismometer as a variable, a function using the deconvolution repeatedly as a variable every predetermined period. The structure of the levee body can be diagnosed by calculating the state of seismic wave propagation in the levee body and diagnosing the structure of the dam body as secular change by comparing the time series of them (second invention). .

  When the invention 1 is repeatedly applied, the results are compared, and when D ^ shows a time series change, D ^ represents the structure and mechanical characteristics of the dam body and the surrounding ground independent of the epicenter. This is considered to be a result of reflecting changes over time. Therefore, it is possible to monitor changes in the structure and mechanical properties of the bank body.

  Furthermore, in the first aspect of the invention, the waveform record when calculating the function having the reverse superposition as a variable from the waveform record continuously measured by the seismometer extracts only the time of the occurrence of the earthquake from the continuous vibration observation record. Can also be used (third invention).

  From continuous vibration observation records, by setting a threshold value for the vibration intensity, or by extracting the reverse superposition of the waveform at the time of the earthquake based on information on earthquakes announced by public organizations such as Hi-net, The seismic wave propagation characteristics can be evaluated efficiently. In particular, when using records during strong earthquakes, it is possible to grasp the dependence of seismic wave propagation characteristics on the intensity of ground motion. In addition, it can be applied to the monitoring of changes in the levee body time by paying attention to minute vibrations such as coda waves that are similar in strength and vibration characteristics and applying them to the waveforms of earthquakes that occur repeatedly.

  Furthermore, in the first invention, the waveform record when calculating the function having the reverse superposition as a variable from the waveform record continuously measured by the seismometer is from the continuous vibration observation record when the earthquake occurs. It is also possible to remove the waveform and use the removed waveform (fourth invention).

  In the third aspect of the present invention, the waveform other than the waveform at the time of the occurrence of the earthquake is considered to be a minute vibration due to the constant tremor. Since such vibrations are minute, they are easily affected by noise, and because they are not stationary sources in a specific direction, the waveform calculated by deconvolution may be unstable. Reproducible results can be obtained by acquiring time data and averaging processing. The waveform obtained as a result can be interpreted as seismic wave propagation characteristics by comparing and comparing with the waveform obtained from the vibration at the time of the earthquake.

  INDUSTRIAL APPLICABILITY The present invention can easily and reliably diagnose the structure of a dam body using vibration waveforms measured by a seismometer installed on the surface of or inside a dam body such as a pond and a dam and a levee such as a dyke.

Schematic showing an example of seismometer arrangement in a dam body and ground for carrying out the present invention Shows seismic wave propagation path in the epicenter and ground / dam body Shows the process of seismic wave propagation to the embankment (A) is a seismometer layout diagram, (b) is a vibration measurement wave meter of seismometers A, B, and C shown in (a), and (c) is an enlarged view of the vibration waveform shown in (b). , (D) is the calculation result of the deconvolution waveform for the vibration waveform of (b). Shows the seismic wave propagation process in the embankment including multiple reflections Shows changes in seismic wave propagation extracted from coda waves before and after strong earthquakes Relationship diagram between seismic intensity and seismic wave velocity Relationship diagram showing secular wave propagation velocity evaluated from vibration waveform at the time of earthquake Relationship diagram showing secular wave propagation velocity change over time by evaluation from microtremor vibration records other than when an earthquake occurred

  Next, embodiments of the present invention will be described below with reference to the drawings.

  FIG. 4 (a) shows a seismometer arrangement showing a preferred embodiment of the present invention. In the cross section of the levee body Db, there are three seismometers vertically from the top surface to the bottom surface of the dam body Db. Is installed.

  4 (b) to 4 (d) show the vibration waveform actually observed in the case of the arrangement of the seismometer in FIG. 4 (a) and the waveform obtained as a result of calculating the deconvolution. . The drawings are conceptual diagrams created with reference to actual investigation experiment results.

In FIG. 4B, the vibration waveforms U _A ^S , U _B ^S , and U _C ^S at the time of the earthquake of the three seismometers are obtained by performing the reverse superposition integration with U _A ^S , and D _A ^{S in} FIG. ~ D _C ^S. Also, D _A ^N to D _C ^N in FIG. 4D are obtained by performing deconvolution integration on the micro-vibration waveforms U _A ^N to U _C ^N during non-earthquake in FIG. 4C with U _A ^N. An averaging process was applied to the minute vibration waveforms during non-earthquakes.

  As the shape of the waveform that is commonly seen in the desuperimposition from the vibration waveform during an earthquake and the desuperimposition from a micro-vibration waveform during a non-earthquake, it is possible to confirm a peak that changes in a direction that causes a time delay from below to above . In this patent, the characteristic waveform shape calculated as the deconvolution integral is regarded as a characteristic representing the state of seismic wave propagation in the levee, and the structure and mechanical characteristics in the dam are diagnosed.

  In order to interpret the characteristic waveform shape calculated by deconvolution, an assumption is made about the seismic wave propagation process in the levee body. As shown in FIG. 5, it is assumed that the seismic wave vertically enters the levee from the foundation ground, and that the seismic wave propagates in the vertical direction also in the dam.

At this time, the upper traveling wave of the seismic wave passing through the horizontal plane Z ₁ of the seismometer 1 is U ₁ ⁺ , the lower traveling wave is U ₁ ^−, and similarly U ₂ ⁺ and U ₂ ⁻ for the seismometer 2. At this time, each relationship can be expressed by the following equation (8).

Here, G _1,1 ^{− +} and G _2,2 ^{− +} are response functions indicating the corresponding relationship between U ₁ ⁺ and U ₁ ⁻ , and U ₂ ⁺ and U ₂ ⁻ . The ^{_{G 2,1 +, G C, 2}} + from each plane Z ₁ of the upper traveling wave to the plane Z _2, the response function from the plane Z ₂ to the plane Z _C comprising crest and G _{2, C} ⁻ , G _1,2 ⁻ are response functions of the downward traveling wave from the plane Z _C to the plane Z _{2 and} from the plane Z ₂ to the plane Z ₁ , respectively, and r represents a reflection coefficient on the plane Z _C. Further, when expressed as the following equation (9), the vibration waveform at each observation point is the sum of the upward traveling wave and the downward traveling wave, so that the following equations (10) and (11) are obtained. The vibration waveform at the observation point is the sum of the upward traveling wave and the downward traveling wave.

  Here, the above equation (11) becomes the following equation (12) from the definition of deconvolution, and can be expressed as equation (13). Become.

In addition, the reverse superposition U ₂ * U ₁ ⁻¹ of the equation (14) is composed of a function that does not depend on the incident wave and depends only on the structure and mechanical properties of the levee as shown in the following equation (15). Will be.

Here, rG ₁₁ is a response function until the upward traveling wave in the plane Z ₁ is reflected by the bank crest and becomes a downward traveling wave and passes through the plane Z ₁ again. It will be smaller than the traveling wave. Therefore, if this influence is small, that is, 1 + rG ₁₁ ≈1, the following equation (16) is obtained.

The first term of the equation (16) represents the response function of the upward traveling wave from the plane Z ₁ to the plane Z ₂ , and the second term is the one in which the upward traveling wave that has passed through the Z ₂ is reflected by the bank C. back and forth again a lower traveling wave is representative of the response as it passes through the Z _2. From this, the second term clearly appears at a later time than the first term, and the waveform appearing at the earliest time of the deconvolution U ₂ * U ₁ ^-1 is the response of the upward traveling wave from the plane Z ₁ to the plane Z _2. You can see that it represents a function.

On the other hand, if the Taylor expansion can be performed for the 1 + rG ₁₁ in the equation (15) as in the following equation (17), the following equation (18) is obtained.

In the formula (18), the first term and the second term are the same as before, and the third term is that the upward traveling wave from the plane Z ₁ is reflected by the ridge top C and the wave after one round trip is the plane Z _1. It can be regarded as a response when the light is reflected and further incident on the plane Z ₂ , and it is considered that the wave after further reciprocating is also incident after the fourth term. Therefore, the reverse superimposition U ₂ * U ₁ ⁻¹ depends only on the structure and mechanical properties inside the bank body above the plane Z ₁ , and it is the upward traveling wave from the plane Z ₁ to the plane Z ₂ and the bank It represents the response due to multiple reflection formed between the top C and the plane Z ₁ .

From the above, for the result calculated by deconvolution, it is considered that there is a response when the impulse input is virtually oscillated on the plane Z ₁ , and the waveform is affected by the upward traveling wave first. Next, the influence of the reflected wave near the ridge top C appears, and then the influence of total reflection again on the plane Z ₁ appears. After that, the influence of the wave corresponding to the overlapping reflection on the bank top C and the plane Z ₁ appears.

In addition, when the plane Z ₂ coincides with the plane Z _C including the bank top C, 1 + rG ₂₂ = 1, G _2,1 ⁺ = G _{C, 1} ⁺ , so the reverse superposition U ₂ * U ₁ ⁻¹ is (19), and shows the response of the upward traveling wave between the plane Z ₁ and the embankment C and the subsequent overlap reflection.

By interpreting as described above, the transition of the peak in Fig. 4 (d) is considered to represent the transition of seismic wave propagation. The section propagation speed can be calculated by considering the propagation distance. In addition, the section attenuation can be obtained from the peak height difference, and the attenuation characteristics for each section can be evaluated by considering the propagation distance.

Here, the waveform including the overlapping reflection portion of the reverse superimposition U ₂ * U ₁ ^-1 between the base and the bank top is shown in FIG. As for FIG. 6, the waveform after receiving strong vibration due to a strong earthquake of about 400 Gal or more is also indicated by a broken line. If the propagation time of the first peak corresponding to the upward traveling wave before receiving strong vibration is T _0, and the peak changes to propagation time T ₀ ′ after receiving strong ground motion, T ₀ ′ is It can be seen that it is delayed from T ₀ . This is due to the fact that the seismic wave propagation speed decreased because the rigidity decreased due to repeated loading due to strong vibration. Subsequent T ₁ in order for the peak _', T _2' when _... to, it is understood that they are also delayed similarly. This means that they correspond to double reflection.

Therefore, if we consider that the amount of peak height reduction between the peaks represents the attenuation of the seismic wave propagation intensity during one round trip, the horizontal axis of the waveform before and after the earthquake is normalized with the respective initial peaks T ₀ and T ₀ ′. When comparing the attenuation characteristics of the two, it can be seen that the wave height is lower after the earthquake and the attenuation is increasing.

  As described above, it is possible to obtain information on the propagation speed and attenuation of the seismic wave by adding a physical interpretation of the seismic wave propagation state with respect to the characteristic waveform shape such as a peak from the result extracted by deconvolution. it can. The actual levee body structure may have a complicated structure, but by applying numerical analysis techniques such as the finite element method, the interpretation of the dam body structure and the consistency of the results of both are achieved. It is possible to predict the structure and physical properties.

  Therefore, by applying the above method to seismic waveforms including large-scale earthquakes, changes in seismic wave propagation characteristics due to the strength of the earthquake can be evaluated.

FIG. 7 shows how the seismic wave propagation velocity changes with respect to various maximum acceleration seismic waveforms. The seismic wave propagation velocity is obtained by regarding the time T ₀ of the initial motion peak described above as the seismic wave propagation time between seismometers and dividing the distance between seismometers by that, and in FIG. And the normalized value by dividing by the square value of the propagation velocity at the time of minute vibration, that is, the apparent rigidity ratio. From this figure, it can be seen that as the acceleration increases, the apparent rigidity ratio, that is, the seismic wave propagation velocity, decreases. This reflects the nonlinearity of the levee body stiffness. Such characteristics and quantitative parameters can be evaluated by comparing such characteristics with a conventionally proposed approximate expression.

  By applying it repeatedly to normal earthquakes that occur repeatedly, large-scale earthquakes, and aftershocks that occur frequently thereafter, time-series changes in seismic wave propagation characteristics can be tracked. As shown in FIG. 7, the seismic wave propagation characteristics also depend on the intensity of the seismic wave. In order to remove this effect, attention is paid to the coda wave of the earthquake. It is known that the attenuation of the envelope of the S coder wave does not depend on the epicenter distance or the intensity of the epicenter, and therefore the seismic wave propagation characteristic at a certain intensity can be evaluated by paying attention to the coder wave. .

  Coda waves are not a group of waves coming from the epicenter, but the direction of arrival is from a fairly wide angle. Therefore, the influence of the uncertainty of the epicenter is considered to be canceled by the averaging process. Therefore, by obtaining the deconvolution of the coder wave and obtaining the average value, it is possible to evaluate the stable seismic wave propagation characteristics that do not depend on the epicenter or the earthquake intensity. Moreover, by applying to repeated earthquakes, it is possible to evaluate how the seismic wave propagation characteristics change before and after strong ground motion as shown in FIG.

Further, as shown by the wavy line in FIG. 4 (d) , reverse superposition can be calculated in the same way for minute vibrations during non-earthquakes such as microtremors. Microvibration and vibration during an earthquake can be distinguished by setting a threshold value or by comparing with information from a highly sensitive seismic network such as Hi-net. Compared with the one calculated from the waveform at the time of the earthquake, the minute vibration has a large influence of noise and may be difficult to interpret as the seismic wave propagation characteristics, but by referring to the interpretation about the thing at the time of the earthquake, Physical interpretation is also possible.

  Furthermore, with regard to continuous vibration, it is a feature that seismic wave propagation characteristics can be evaluated at any time without waiting for the occurrence of an earthquake. Therefore, by tracking this change over time, it is possible to monitor changes in seismic wave propagation characteristics due to changes in water conditions due to rainfall and water storage in the dam body and changes in stiffness due to consolidation subsidence ( (See FIG. 9).

  The above method can be used not only for monitoring a dam body but also for detecting defects in seismometers and observation systems. For example, regarding the reversal of the polarity of the seismometer due to a human error in the seismometer, the sign of the function of the propagation characteristic is reversed, which is unreasonable, and can be detected. Moreover, when trouble occurs due to sudden influence such as a power failure or deterioration during long-term operation, the function shape of the unreasonable propagation characteristic can be detected. Therefore, this method is also effective for monitoring and management of seismic observation systems.

  This method is effective not only for actual structures such as actual dams and dikes, but also for model experiments using a shaking table and reduced model experiments using a centrifugal loading device.

B plane, C dike top, Db embankment, E epicenter, Gd ground, G _{1, S} green function, G _{2, S} green function, H observation hole, S seismometer, S ₁ seismometer 1, S ₂ seismometer 2 , T propagation time, T ₀ propagation time, T ₀ 'propagation time, T ₁ propagation time, T ₁ ' propagation time, T ₂ propagation time, T ₂ 'propagation time, T ₃ propagation time, U vibration waveform, U ₁ vibration waveform, U ₂ vibration waveform, U _S vibration waveform, Z ₀ boundary, Z ₁ plane, Z ₂ plane, Z _C plane

Claims (4)

Seismometers are installed on at least two locations on the surface or inside the dam body, and each seismometer continuously records the vibration waveform due to vibration from the ground located below the dam body . deconvolution about inner vibration waveform measured by the installed seismometer in two places selected in calculating a function of a variable, the waveform by calculating the set of functions, leg propagation time obtained by reading the time run its In addition, at least one of the section propagation velocity or the section attenuation characteristic calculated by considering the section distance for the section attenuation obtained by reading the amplitude and the direct wave of the P wave or S wave that is the seismic wave in the levee body or seismometer for seismic wave propagation characteristics evaluated by reflecting seismic waves propagation phenomenon of the reflected wave, wherein the diagnosing structure of embankment Method of diagnosing stomach Tsutsumi body.   When calculating a function using the deconvolution as a variable for the vibration waveform continuously measured by the seismometer, a function using the deconvolution as a variable is calculated repeatedly every fixed period, and The dam body diagnosis method using a seismometer according to claim 1, wherein the state of seismic wave propagation in the body is evaluated to diagnose the structure in the dam body as secular change.   Waveform recording when calculating a function having a deconvolution as a variable from the waveform recording continuously measured by the seismometer is extracted from the continuous vibration observation record and used only when an earthquake occurs. A method for diagnosing a bank body using the seismometer according to claim 1.   The waveform record when calculating the function with the reverse superposition as a variable from the waveform record continuously measured by the seismometer is removed from the continuous vibration observation record when the earthquake occurs, and the removed waveform is A method for diagnosing a dam body using the seismometer according to claim 1, wherein the seismometer is used.