JP6882729B2 - Internal quality evaluation method and internal quality analysis system - Google Patents

Description

The present invention relates to, for example, an internal quality evaluation method for evaluating an evaluation target member constituting a structure composed of a concrete member or the like, and an internal quality analysis system.

With concrete bridge pedestals, beams, concrete members such as culverts, composite members of steel members and concrete members such as shield tunnels, and structural members such as steel members in steel bridges, the repetitive load of a traveling vehicle While fatigue damage due to such factors has been a problem in the past, there is an increasing demand for internal quality evaluation by non-destructive / micro-destructive tests as maintenance management of structural members. For example, tomography using transmitted elastic waves. A method for evaluating the quality of concrete members by analysis and a method for inspecting concrete structures as shown in Patent Document 1 have been proposed.

For example, in the quality evaluation method of concrete members by tomography analysis using transmitted elastic waves, it is necessary to install a sensor on one main surface of the concrete member to be evaluated and input elastic waves from the other main surface. ..

However, when the evaluation target member such as an underground structure can be accessed only from one main surface side, that is, one side, the quality evaluation method of the concrete member by tomography analysis using transmitted elastic waves can be applied. There wasn't.

On the other hand, in the method for inspecting a concrete structure proposed in Patent Document 1, a measured Fourier spectrum calculated from vibration data measured when a weight is dropped from a predetermined height on the upper surface of a concrete member and a sound measurement Fourier spectrum. Although it is said that the degree of deterioration of the concrete member can be determined by comparing it with the reference Fourier spectrum when the weight is dropped on the concrete member, the deterioration inside the concrete member is due to the input of elastic waves from the surface. And cracks could not be detected.

Japanese Unexamined Patent Publication No. 2008-275520

Therefore, an object of the present invention is to provide an internal quality evaluation method and an internal quality analysis system capable of evaluating the internal quality of an evaluation target member from one main surface side.

In the present invention, a striking rod is inserted into a small-diameter hole which is a bottomed small-diameter hole having a bottom so that the tip abuts on the bottom, while opening to one main surface of the member to be evaluated. A receiving side that hits the end of the striking rod exposed from, inputs an elastic wave from a predetermined elastic wave input portion on the bottom portion through the tip, and arranges the elastic wave at a predetermined elastic wave receiving portion on the main surface. The quality of the inside of the evaluation target member is evaluated based on the calculation result of receiving the elastic wave propagated by the sensor and calculating the received information received by the receiving side sensor for a predetermined element, and the upper end of the striking rod. The measurement arrival time is obtained by subtracting the propagation time of the elastic wave propagating through the striking rod from the arrival time of the elastic wave from the transmitting side sensor mounted nearby to the receiving side sensor, and the calculation result is sent to the receiving side sensor. Based on the measurement arrival time of the elastic wave and the relative positional relationship between the receiving side sensor and the elastic wave input location, the elastic wave velocity distribution inside the evaluation target member is analyzed, and the analyzed elastic wave velocity is analyzed. It is characterized by being an internal quality evaluation method that is a distribution.

Alternatively, the transmitting side attached to the vicinity of the upper end of the striking rod inserted into the small-diameter hole which is a bottomed small-diameter hole having a bottom while opening to one main surface of the member to be evaluated so that the tip abuts on the bottom. An elastic wave that strikes the sensor and the end of the striking rod exposed from the one main surface, is input from a predetermined elastic wave input location at the bottom via the tip, and propagates inside the evaluation target member. Is received, and the inside of the evaluation target member is based on a calculation result obtained by calculating the reception information received by the receiving side sensor for a predetermined element and the receiving side sensor arranged at a predetermined elastic wave receiving position on the main surface. An analysis unit is provided to evaluate the quality of the seismic wave, and the propagation time of the elastic wave propagating through the striking rod is calculated from the arrival time of the elastic wave from the transmitting side sensor attached near the upper end of the striking rod to the receiving side sensor. The measurement arrival time is subtracted, and the analysis unit determines the evaluation target based on the measurement arrival time of the elastic wave to the receiving side sensor and the relative positional relationship between the receiving side sensor and the elastic wave input location. It is a configuration for analyzing the elastic wave velocity distribution inside the member, and is characterized by being an internal quality analysis system further provided with a display unit for displaying the results of the analyzed elastic wave velocity distribution.

The evaluation target member may be a concrete member, a steel member, or a synthetic member combining these.
Further, the predetermined elastic wave receiving points on the main surface may be arranged at predetermined intervals or randomly arranged as long as they are located on the main surface at appropriate intervals from the small diameter hole. You may. Further, the number may be appropriately determined.

Further, the reception information received by the receiving side sensor may be an appropriate element such as a speed, an amplitude, an attenuation factor thereof, or a Q value in the received information.
Evaluating the quality inside the evaluation target member described above means, for example, a high quality in which the quality is deteriorated due to deterioration or cracks inside the evaluation target member due to fatigue, aging deterioration, or the like, or the state is in a precise state. It means to evaluate things.

According to the present invention, the internal quality of the member to be evaluated can be evaluated from one main surface side.
More specifically, since elastic waves are input from a predetermined elastic wave input location inside a small-diameter hole that opens in one main surface of the evaluation target member, for example, a portion where the quality is deteriorated such as deterioration or cracks inside the evaluation target member. If there is, the elastic wave that propagates inside the evaluation target member and is affected by the portion of the evaluation target member whose quality has deteriorated is received by the receiving side sensor arranged at a predetermined elastic wave receiving location on the main surface. can do.

Further, since the quality inside the evaluation target member is evaluated based on the calculation result obtained by calculating the reception information received by the receiving side sensor for a predetermined element, the internal quality of the evaluation target member can be evaluated accurately. ..

Further, the small-diameter hole is a bottomed small-diameter hole having a bottom, and a striking rod is inserted into the bottom small-diameter hole so that the tip abuts on the bottom, and the end of the striking rod exposed from the one main surface. The elastic wave is input from the bottom portion through the tip of the striking rod, and the elastic wave is generated from the arrival time of the elastic wave from the transmitting side sensor attached near the upper end portion of the striking rod to the receiving side sensor. Since the measurement arrival time is obtained by subtracting the propagation time propagating through the striking rod, elastic waves can be easily input from the bottom of the small-diameter hole and the accurate arrival time can be grasped. More specifically, since the end exposed from the main surface of the striking rod inserted into the small-diameter hole so that the tip abuts on the bottom is impacted, the elastic wave propagating through the striking rod passes through the tip. Although it can be input to the inside of the evaluation target member from the bottom, the arrival time of the elastic wave to the receiving side sensor, which is a parameter for calculating the elastic wave velocity distribution inside the evaluation target member, that is, the elastic wave input time. When is set to the impact time, the propagation time of the elastic wave propagating in the impact rod becomes longer, and the elastic wave velocity distribution inside the evaluation target member cannot be calculated accurately.

Therefore, the measurement arrival time is obtained by subtracting the propagation time of the elastic wave propagating from the striking rod from the arrival time of the elastic wave from the transmitting side sensor attached near the upper end of the striking rod to the receiving side sensor. The accurate arrival time can be grasped, and the elastic wave velocity distribution inside the evaluation target member can be accurately calculated.

Further, based on the measurement arrival time of the elastic wave to the receiving side sensor and the relative positional relationship between the receiving side sensor and the elastic wave input location, the elastic wave velocity distribution inside the evaluation target member is analyzed. By evaluating the quality inside the member to be evaluated based on the analyzed elastic wave velocity distribution, the measurement arrival time of the elastic wave to the receiving side sensor, and the receiving side sensor and the elastic wave input location Based on the relative positional relationship, it is possible to analyze the elastic wave velocity distribution inside the evaluation target member with respect to the elastic wave received by the receiving side sensor. Therefore, since the quality inside the evaluation target member is evaluated based on the analyzed elastic wave velocity distribution, the internal quality of the evaluation target member can be evaluated more accurately.

Further, as an aspect of the present invention, the analysis is performed so that the difference between the measurement arrival time of the elastic wave received by the receiving side sensor and the analysis arrival time by analysis considering the detour in which the elastic wave propagates is reduced. The elastic wave velocity distribution may be calculated by adjusting the reciprocal of the velocity in.
According to the present invention, an accurate analysis result can be calculated.

Further, as an aspect of the present invention, the AE sensor is used as the receiving side sensor, and the analysis is a three-dimensional elastic wave tomography analysis using the elastic wave received by the AE sensor, and the elastic wave velocity distribution is measured. , Elastic wave three-dimensional velocity distribution may be used.
According to the present invention, the quality inside the evaluation target member can be evaluated three-dimensionally.

Further, as an aspect of the present invention, a plurality of the receiving side sensors are provided, analysis elements based on the arrangement of the receiving side sensors and the small diameter holes are set, and the elastic wave velocity distribution calculated for each analysis element is statistically obtained. May be interpolated.
According to the present invention, the quality inside the evaluation target member can be evaluated in detail over a wide range in the evaluation target member.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an internal quality evaluation method and an internal quality analysis system capable of evaluating the internal quality of an evaluation target member from one main surface side.

Schematic diagram of elastic wave velocity distribution analysis system. Block diagram of the elastic wave velocity distribution analysis system. The schematic diagram of the propagation time measurement method of a striking rod. Explanatory drawing of the propagation time measurement result of a striking rod. Flow diagram of elastic wave tomography analysis. Explanatory drawing of the specimen. Velocity distribution graph by three-dimensional elastic wave tomography. Distribution graph of in-plane average value of elastic wave velocity in the height direction. Explanatory drawing about repair and evaluation of crack. Explanatory drawing of analysis result of V-shaped repaired specimen.

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 shows a schematic diagram of the elastic wave velocity distribution analysis system 1, and FIG. 2 shows a block diagram of the elastic wave velocity distribution analysis system 1.

As shown in FIGS. 1 and 2, the elastic wave velocity distribution analysis system 1 used in the quality evaluation method for evaluating the internal quality of the concrete member 100 receives the measurement / analysis device 10 and the elastic wave as received information. It is composed of a sensor 20 and a sensor 20.

The measurement / analysis device 10 is arranged in a control / analysis device 11 composed of a CPU, a storage unit 12 composed of a ROM or RAM, an operation unit 13 composed of an operation switch provided in the housing, and the housing. It is composed of a display unit 14 such as a liquid crystal. The storage unit 12, the operation unit 13, and the display unit 14 are connected to the control / analysis device 11 and are controlled by the control / analysis device 11.

The control / analysis device 11 cooperates with various control programs and analysis programs stored in the storage unit 12 to control each device connected to the control / analysis device 11, or as an elastic wave vibration by a sensor 20 described later. An analysis result display graph (see FIG. 7) capable of analyzing the received received information and evaluating the analysis result can be displayed.

The storage unit 12 stores the above-mentioned various programs, measured measurement data, analysis results analyzed based on the measurement data, and the like.
The display unit 14 is a liquid crystal monitor that displays an analysis result display graph or the like analyzed by the control / analysis device 11.

The sensor 20 is composed of an AE sensor that is connected to the measurement / analysis device 10 and can receive elastic wave vibration as reception information under the control of the control / analysis device 11 and transmit it to the control / analysis device 11. , An appropriate number can be provided on the surface 100a of the concrete member 100. In this embodiment, a 60 kHz resonance type sensor is used as the sensor 20.

In the evaluation method of the concrete member 100 using the elastic wave velocity distribution analysis system 1 configured in this way, a striking rod that is inserted into a small-diameter hole 101 described later and functions as a wave guide for inputting elastic waves inside the concrete member 100. 30 is further used.

The striking rod 30 is a steel rod longer than the depth of the small diameter hole 101, and the upper end portion 30b is the surface of the concrete member 100 in a state where the lower end portion 30a of the striking rod 30 is abutted against the bottom portion 101a of the small diameter hole 101 and inserted. It will protrude above 100a.

As described above, in the evaluation method of the concrete member 100 using the elastic wave velocity distribution analysis system 1 and the striking rod 30, first, a small diameter hole 101 is formed at an appropriate position of the concrete member 100.
Then, the lower end portion 30a abuts on the bottom portion 101a inside the small diameter hole 101, and the striking rod 30 strikes inside the small diameter hole 101 so that the other portion does not come into contact with other portions such as the inner surface of the small diameter hole 101. Insert the rod 30.

In this state, an elastic wave is input by striking the upper end portion 30b of the striking rod 30 which is inserted into the small diameter hole 101 and projects upward from the surface 100a with the iron ball H.
In the present embodiment, a hole having a depth of 200 mm and a diameter of 12 mm is drilled from the surface 100a of the concrete member 100 using an electric drill (not shown), and the small diameter hole 101 has a length of 300 mm and a diameter of 6 mm. A striking rod 30 which is an iron rod-shaped body was inserted, and the tip of the striking rod 30 was impacted with an iron ball H having a diameter of 15 mm.

In this way, the striking rod 30 is arranged so as not to come into contact with the inner surface of the small diameter hole 101, and the elastic wave generated at the upper end portion 30b of the striking rod 30 propagates through the striking rod 30 and reaches the deepest portion of the small diameter hole 101. An elastic wave can be propagated from a certain bottom 101a to the inside of the concrete member 100.

Regarding the input of elastic waves due to the impact of the iron ball H, as shown in FIG. 3, a sensor 20 is installed near the upper end portion 30b of the impact rod 30, and the sensor position of the impact rod 30 is transferred to the tip of the impact rod 30. By subtracting the propagation time, the input time of the elastic wave at the bottom 101a of the small diameter hole 101, that is, the elastic wave input time is obtained.

Specifically, when calculating the propagation time in the striking rod 30, as shown in FIG. 3, the striking rod 30 is installed in the vicinity of the sensor 20 installed on the surface 100a of the concrete member 100, and the striking rod 30 is provided with the striking rod 30. The time from the installed sensor 20 to the sensor 20 installed on the surface 100a was set. Then, the maximum frequency 19 of the elastic wave when hit with a steel ball of φ15 mm due to the relationship between the frequency obtained from the waveform obtained by each sensor 20 (see FIG. 4) and the frequency of the existing hit ball diameter and the excitation elastic wave. It was almost the same as 0.4 kHz.
The sensor 20 attached near the upper end portion 30b of the striking rod 30 is referred to as the transmitting side sensor 21, and the sensor 20 attached to the surface 100a of the concrete member 100 is referred to as the receiving side sensor 22.

Three-dimensional elastic wave tomography analysis is performed using the elastic waves obtained by each sensor 20 in the above manner, the elastic wave velocity distribution inside the concrete member 100 is calculated, and based on the calculated elastic wave velocity distribution. The quality of the inside of the concrete member 100 is evaluated, and the elastic wave tomography analysis thereof will be described together with FIG.

Elastic wave tomography analysis is broadly divided into "creation of input data (step s1)", "calculation of arrival time by wavy line tracking method (data input: step s2)", and "interpolation of velocity distribution by local regression smoothing (step)". s4) ”is executed.
Each step will be described in detail below.

In step s1, input data for performing elastic wave tomography analysis is created.
Specifically, elastic wave tomography shows the arrival time of elastic waves from the transmitting side sensor 21 to the receiving side sensor 22, the positions of the hitting point (bottom 101a of the small diameter hole 101) and the receiving side sensor 22, and the velocity for each analysis element. It is the input data for executing the analysis.

Specifically, the arrival time of the elastic wave from the transmitting side sensor 21 to the receiving side sensor 22 is measured, and the AIC (Akaike's Information Criterion) method is used and the propagation time of the striking rod 30 is subtracted to obtain the arrival time of the elastic wave. , Input data. The arrival time at this time is defined as the measurement arrival time.

Further, the hitting point, that is, the coordinate value of the bottom portion 101a of the small-diameter hole 101 and the coordinate of the position where the receiving side sensor 22 is attached are used as input data, and the evaluation target range R (see FIG. 6) of the concrete member 100 is set to the small-diameter hole. It is divided based on the positions of 101 and the receiving sensor 22, and a plurality of analysis elements K (see FIG. 6) are set and used as input data.

Subsequently, the input data created in step s1 is input to the elastic wave velocity distribution analysis system 1 using the operation unit 13 (step s2).
First, the reciprocal of the speed (hereinafter referred to as slowness) is set and input as the speed parameter for each analysis element K set in step s1 (step s21). In this embodiment, the speed in the initial analysis element was set to 4000 m / sec.

Next, the analysis arrival time is calculated by the wavy line tracking method (step s22).
In the concrete member 100, the impedance (density) is between the transmitting point where the elastic wave is transmitted (bottom 101a in the present embodiment) and the receiving point where the propagated elastic wave is received (transmitting side sensor 21 in the present embodiment). Since there are cement pastes, aggregates, boundary phases, cracks, vacant spaces, etc. with different propagation velocities, it is difficult for elastic waves that pass through the inside of the concrete member 100 to take a linear path and detour. Propagate.

Therefore, in order to obtain this wavy line path more accurately, the analysis arrival time is calculated using a wavy line tracking method that can consider the detour of elastic waves due to reflection or diffraction. In particular, in the present embodiment, in order to obtain more accurately, the analysis arrival time was calculated using a wavy line tracking algorithm that is a three-dimensional extension of the two-dimensional wavy line tracking method of the elastic wave propagation path proposed by Sassa et al.

Then, the time error between the analysis arrival time calculated in step s22 and the actually measured arrival time (measured arrival time) used as the input data in step s1 is calculated (step s23), and the calculated time error is evaluated. (Step s24).

Specifically, when the time error is larger than the predetermined value (step s24: No), the process returns to step s21 to change the slowness in the analysis element, steps s22 and s23 are executed, and the time error is smaller than the predetermined value. Repeat these until.

When the time error calculated in step s23 becomes smaller than a predetermined value (step s24: Yes), the velocity distribution of each analysis element inside the concrete member 100 is calculated based on these input data and the like (step s3).

Here, in elastic wave tomography analysis, it is possible to acquire more detailed information by finely dividing the analysis element, but for that purpose, a large number of dots (small diameter) are made so that the wavy line passes through each analysis element without fail. It is necessary to attach the bottom 101a) of the hole 101 and a large number of receiving side sensors 22, and if each analysis element is improperly divided too finely, the wavy lines in the analysis element are reduced and an appropriate velocity distribution cannot be evaluated.

Therefore, in order to obtain more detailed information with appropriate analysis element dimensions, the velocity distribution of each analysis element obtained as a result of the above wavy line tracking is statistically interpolated using local quadratic regression smoothing (step). s4). Then, the interpolated velocity distribution is visualized (step s5), displayed on the display unit 14, and the present analysis is completed.

Further, the user evaluates the internal quality of the concrete member 100, that is, the damaged state, based on the analysis result displayed on the display unit 14.
Although the details of the method for evaluating the quality inside the concrete member 100 based on the analysis result are omitted, the evaluation may be performed in comparison with a preset threshold value.

Specifically, the threshold value for evaluating the quality of the member to be evaluated by comparing the analysis result with the threshold value can be set by a value, a mathematical formula, or an area when the analysis result is displayed as a graph. .. The threshold value itself is set by an appropriate threshold value such as a threshold value set based on the result of the demonstration experiment, a threshold value based on the simulation result, or a value based on the actual value, and for example, accumulation of the actual value, use, and use. It may be a threshold value that changes appropriately depending on the above.

A demonstration experiment using the specimen 110, which was carried out for the analysis performed in this way, will be described.
In the demonstration experiment, as shown in FIG. 6, a rectangular parallelepiped specimen 110 having a size of 600 × 400 × 250 mm was used.

The specimen 110 has an ordinary concrete portion 111 (W / C: 55%, compression strength: 24 N / m ² ) and a low-strength mortar portion 112 (W / C: 60, compression strength: 15 N / m ² ) on the upper surface side. A plurality of receiving side sensors 22 were installed on a 600 × 400 mm surface of the low-strength mortar portion 112, that is, on the surface 110a of the specimen 110.

As shown in FIG. 6A, which is a plan view of the specimen 110, the receiving side sensor 22 and the small diameter hole 101 are arranged with respect to the specimen 110, and the receiving side sensor 22 and the small diameter hole 101 are arranged. Based on the above, the evaluation target range R was set to a range of 300 × 300 mm × 250 mm in depth at the central portion.

Further, as shown by a grid-like thin broken line in FIG. 6A and FIG. 6B which is a front view, 9 × 10 is taken into consideration in consideration of the positions of the receiving side sensor 22 and the small diameter hole 101 with respect to the evaluation target range R. X7 analysis elements, that is, a total of 630 analysis elements K were set.

The velocity distribution at each height from the bottom, which was obtained in the demonstration experiment using the specimen 110 as described above and analyzed by three-dimensional elastic wave tomography, is shown in FIG. The distribution of the internal average values is shown in FIG. The elastic wave velocity indicates the data after interpolation by the above-mentioned local regression smoothing, and the velocity in the depth direction indicates the average value of the analysis elements having a thickness of 5 mm.

From this, it was confirmed that the elastic wave velocity in the low-strength mortar portion 112 (200 mm or more) was approximately 2500 m / sec or less, and there was almost no change in the elastic wave velocity.
On the other hand, in the ordinary concrete portion 111, it was confirmed that the elastic wave velocity tends to increase as the depth increases.

Further, in the specimen 110, it is considered that the low-strength mortar portion 112 and the ordinary concrete portion 111 have discontinuous surfaces of elastic wave velocities at a height of 200 mm. No sudden changes were confirmed.

However, the elastic wave velocity in the low-strength mortar portion 112 is lower than that in the ordinary concrete portion 111, and the layer is obtained three-dimensionally. Therefore, the elastic wave velocity inside the concrete member 100 is obtained by the above analysis. It was confirmed that the structure can be grasped and the quality evaluation based on it is possible.

Next, the results of a demonstration experiment in which a small-diameter hole 101 is provided around the crack 121 of the specimen 120 repaired by the filling method and three-dimensional elastic wave tomography is applied by the same method as described above will be described.

The specimen 120 shown in FIG. 9A is created by cutting out a wall surface less than 50 years after construction, and cracks 121 penetrating in the thickness direction are formed (see FIG. 9A-1). The water-cement ratio of the base concrete constituting the specimen 120 is about 53%, and the maximum crack width of the crack 121 is about 1.0 mm. Therefore, it is possible to confirm water leakage to the extent of constant exudation from the crack 121.

Regarding the filling of the crack 121, the crack 121 and its periphery are excavated in a V shape of about 120 mm in the surface direction and about 80 mm in the deep direction (see FIG. 9 (a-2)), and a repair material (water-cement ratio: 25) is excavated inside the crack 121. %) To form a V-shaped filling portion 122 (see FIG. 9 (a-3)).

Then, a small-diameter hole 101 having a diameter of 120 mm and a depth of 200 mm is provided on the outside of the filling portion 122 (see FIG. 9A-4), and a plurality of receiving side sensors 22 are mounted on the surface 120a of the specimen 120 (see FIG. 9A-4). 9 (a-5)), the striking rod 30 is inserted into the small diameter hole 101 (see FIG. 9 (a-6)), and the upper end portion 30b of the striking rod 30 is impacted with the iron ball H by the above method. Then, the elastic wave was input, and the elastic wave propagated by the receiving side sensor 22 installed on the surface 120a was received.

The arrangement of the receiving side sensor 22 and the position of the small diameter hole 101 in the specimen 120 are as shown in FIGS. 9 (b) and 9 (c), and the evaluation target range R is 600 mm × in the center of the plan view of the specimen 120. The depth was 600 mm and the depth was 250 mm. In this embodiment, five 60 kHz resonance type sensors are installed on the surface as the receiving side sensor 22.

As a result of the three-dimensional elastic wave tomography obtained by the demonstration experiment using the specimen 120, the three-dimensional velocity distribution by the elastic wave tomography is shown in FIG. 10 (a), and FIG. 10 (b) shows FIG. The velocity distribution in the cross section A shown in (a) is shown.

From FIG. 10 (a), a warm-colored low-velocity region along the Y-axis direction was confirmed, and on the lower surface side, an oblique warm-colored low-velocity region was formed along a V-shaped excavated cross section. You can check. On the other hand, on the left side surface of the specimen 120 (a portion of the specimen 120 away from the filling portion 122), the low speed region cannot be confirmed, and it can be confirmed that the overall speed is high. It was.

Further, paying attention to the velocity distribution of the cross section A which is the central portion of the evaluation target range R shown in FIG. 10B, the elastic wave velocity is relatively high around the filling portion 122, whereas the elastic wave velocity is relatively high around the filling portion 122. In particular, a region with a slow speed was confirmed, and it was confirmed that the shape was similar to the excavated V-shape.

As described above, in order to apply the elastic wave tomography method to a structure that can be accessed only from one side such as an underground structure, the present invention utilizes a small-diameter small-diameter hole 101 to form a concrete member. A method of obtaining an internal velocity structure of a concrete member 100 by generating an elastic wave inside the 100 and performing a tomographic analysis, and based on this, performing a quality evaluation of the inside of the concrete member 100, and an elastic wave velocity distribution analysis for that purpose. System 1.

More specifically, an elastic wave is input from the bottom 101a of the bottomed small-diameter hole 101 drilled from the surface 100a on one side of the concrete member 100, and the receiving side is arranged on the surface 100a on one side of the concrete member 100. The inside of the concrete member 100 receives the elastic wave propagated by the sensor 22, based on the arrival time of the elastic wave to the receiving side sensor 22 and the relative positional relationship between the receiving side sensor 22 and the bottom 101a by inputting coordinates. This is an internal quality evaluation method for a concrete member 100 that analyzes an elastic wave velocity distribution and evaluates the internal quality of the concrete member 100 based on the analyzed elastic wave velocity distribution. The receiving side sensor 22 arranged on the surface 100a on one side of the concrete member 100, the control / analysis device 11 for analyzing the elastic wave velocity distribution inside the concrete member 100, and the elastic wave velocity of the analyzed elastic wave velocity distribution. It is provided with a display unit 14 for displaying the distribution result, and the internal quality can be evaluated from the side of the surface 100a on one side of the concrete member 100.

More specifically, since elastic waves are input from the bottom 101a of the bottomed small-diameter hole 101 drilled from the surface 100a on one side of the concrete member 100, for example, the quality such as deterioration and cracks inside the concrete member 100 is deteriorated. If there is a part, the elastic wave that propagates inside the concrete member 100 and is affected by the part where the quality of the inside of the concrete member 100 has deteriorated is received by the receiving side sensor 22 arranged on the surface 100a on one side. Can be done.

Further, based on the arrival time of the elastic wave to the receiving side sensor 22 and the relative positional relationship between the receiving side sensor 22 and the bottom 101a of the small diameter hole 101 by the coordinate input, the elastic wave received by the receiving side sensor 22 is made of concrete. Since the elastic wave velocity distribution inside the member 100 is analyzed and the quality inside the concrete member 100 is evaluated by the analyzed elastic wave velocity distribution, the quality inside the concrete member 100 can be evaluated accurately. ..

Further, the striking rod 30 is inserted into the small diameter hole 101 so that the lower end portion 30a abuts on the bottom portion 101a, and the upper end portion 30b of the striking rod 30 exposed from the surface 100a on one side is impacted to pass through the lower end portion 30a. Since the elastic wave is input from the bottom 101a and the propagation time of the elastic wave propagating through the striking rod 30 is subtracted from the impact time to obtain the elastic wave input time, the elastic wave can be easily input from the bottom 101a of the small diameter hole 101. , It is possible to accurately grasp the elastic wave input time which is the starting point of the arrival time of the elastic wave to the receiving side sensor 22.

More specifically, the lower end portion 30a of the striking rod 30 strikes the upper end portion 30b exposed from the surface 100a on one side of the striking rod 30 inserted into the small diameter hole 101 so as to abut the bottom portion 101a of the small diameter hole 101. Although the elastic wave propagating in the rod 30 can be input into the concrete member 100 from the bottom portion 101a of the small diameter hole 101 via the lower end portion 30a of the striking rod 30, the elastic wave velocity distribution inside the concrete member 100 can be obtained. The arrival time of the elastic wave to the receiving side sensor 22, which is a parameter to be calculated, becomes long.
That is, if the elastic wave input time is set as the impact time, the propagation time of the elastic wave propagating through the impact rod 30 becomes longer, and the elastic wave velocity distribution inside the concrete member 100 cannot be calculated accurately.

Therefore, by subtracting the propagation time of the elastic wave propagating through the striking rod 30 from the striking time to obtain the elastic wave input time, the accurate arrival time can be grasped and the elastic wave velocity distribution inside the concrete member 100 is accurately calculated. can do.

In addition, the reciprocal of the velocity (slowness) in the analysis is adjusted so that the difference between the arrival time of the elastic wave received by the receiving sensor 22 and the arrival time of the analysis by the analysis considering the detour in which the elastic wave propagates is reduced. Since the elastic wave velocity distribution is calculated, accurate analysis results can be calculated.

Further, since the AE sensor was used as the receiving side sensor 22 and the three-dimensional elastic wave tomography analysis using the elastic wave received by the AE sensor was performed and the elastic wave three-dimensional velocity distribution was used as the elastic wave velocity distribution, the concrete member. The internal quality of 100 can be evaluated in three dimensions.

Further, a plurality of receiving side sensors 22 are provided, an analysis element K is set based on the arrangement of the receiving side sensor 22 and the small diameter hole 101, and the elastic wave velocity distribution calculated for each analysis element K is statistically interpolated. Therefore, the quality inside the concrete member 100 can be evaluated in detail over a wide range.

In correspondence between the configuration of the present invention and the embodiment, the member to be evaluated of the present invention corresponds to the concrete member 100.
Similarly below
One main surface corresponds to the surface 100a and
The predetermined elastic wave input location corresponds to the bottom 101a and corresponds to the bottom 101a.
The predetermined elastic wave receiving location corresponds to the predetermined location on the surface 100a, and corresponds to the predetermined elastic wave receiving location.
The small diameter hole corresponds to the small diameter hole 101,
The bottom corresponds to the bottom 101a
The receiving side sensor corresponds to the receiving side sensor 22.
The relative positional relationship corresponds to the relative positional relationship by inputting coordinates.
The striking rod corresponds to the striking rod 30 and
The end of the striking rod corresponds to the upper end 30b and
The tip of the striking rod corresponds to the lower end 30a,
The analysis element corresponds to the analysis element K,
The analysis unit corresponds to the control / analysis device 11.
The display unit corresponds to the display unit 14 and
The internal quality analysis system corresponds to the elastic wave velocity distribution analysis system 1.
The reciprocal of speed corresponds to slowness,
The present invention is not limited to the configuration of the above-described embodiment, and can be applied based on the technical idea shown in the claims, and many embodiments can be obtained.

For example, in the above description, the striking rod 30 is inserted into the small diameter hole 101 so that the lower end portion 30a abuts on the bottom portion 101a, the upper end portion 30b is impacted with the iron ball H, and the small diameter hole 101 is formed through the lower end portion 30a. An elastic wave was input from the bottom portion 101a into the inside of the concrete member 100, but the lower end portion 30a was brought into contact with a predetermined portion on the inner peripheral surface in the middle of the small diameter hole 101, and the elastic wave was input from the abutting portion of the lower end portion 30a. You may. In this case, the small-diameter hole 101 may have a bottom portion 101a, or may be a small-diameter hole 101 penetrating the concrete member 100 having no bottom portion.

Further, for example, in the above description, the upper end portion 30b of the striking rod 30 inserted into the small diameter hole 101 is impacted by the iron ball H, and an elastic wave is generated from the bottom portion 101a of the small diameter hole 101 to the inside of the concrete member 100 via the lower end portion 30a. Is input, but a small-diameter hole 101 is drilled with a drilling device such as a hammer drill to which an impact is applied, and an elastic wave is input to the inside of the concrete member 100 by the impact at the time of drilling, so that the concrete member 100 The internal elastic wave velocity distribution may be calculated to evaluate the internal quality of the concrete member 100.

Further, in the above description, although the position of the small-diameter hole 101 to be drilled and the position of the concrete member 100 to be drilled are known, the vibration generated when the small-diameter hole 101 is drilled and the impact during the drilling are performed. The elastic wave generated by the concrete member 100 may be received by the receiving side sensor 22 arranged on the surface of the concrete member 100 to obtain the position where the small diameter hole 101 is formed.

Specifically, the receiving side sensor 22 is arranged on the surface of the concrete member 100, and the small-diameter hole 101 is drilled to a predetermined length with a drilling device such as a pneumatic vibration drill to which an impact is applied. To form.
In a drilling device such as a pneumatic vibration drill to which an impact is applied, a blow is applied at a predetermined rotation speed during drilling.

Therefore, during drilling by the drilling device, that is, from the drilling start time to the drilling end time at which the drilling of a predetermined depth is completed, the vibration due to the propagated drilling is continuously received by the receiving sensor 22 as reception information. Once acquired, the received information acquired by the receiving side sensor 22 will show a waveform due to elastic waves generated by the impact at regular intervals corresponding to each predetermined rotation to which the impact is applied.

Then, the interval of the impact waveform can be calculated based on the drilling time from the drilling start time to the drilling end time and the number of waveforms due to impact in the received information acquired by the receiving side sensor 22. Since the calculated striking waveform interval is proportional to the distance between the striking point and the receiving side sensor 22, the distance between the striking point and the receiving side sensor 22 can be obtained from the calculated striking waveform interval.

By analyzing this based on the received information received by the plurality of receiving side sensors 22 arranged on the surface of the concrete member 100, the position of the small diameter hole 101 formed by drilling with the drilling device can be obtained. .. In this way, the quality inside the concrete member 100 may be evaluated based on the position information calculated from the received information during drilling.

Furthermore, a plurality of small-diameter holes 101 are provided in the concrete member 100, a receiving side sensor 22 is arranged on the inner surface of the small-diameter hole 101, and a plurality of predetermined locations (elastic wave input locations) on the surface 100a of the concrete member 100 are formed by iron balls H. The elastic wave may be input by hitting with, and the receiving side sensor 22 provided in the small diameter hole 101 may receive the elastic wave propagating inside the concrete member 100 to evaluate the quality inside the concrete member 100.

In this case, a plurality of receiving side sensors 22 may be arranged on the inner peripheral surface of the small diameter hole 101 at predetermined intervals in the depth direction, and elastic waves may be input at a plurality of locations in the depth direction.
Further, the receiving side sensor 22 is arranged on both the surface 100a of the concrete member 100 and the inner peripheral surface of the small diameter hole 101, and elastic waves are input from both the bottom 101a of the small diameter hole 101 and the surface 100a of the concrete member 100. You may.

Furthermore, in the above description, the internal quality of the concrete member 100 was evaluated as the evaluation target member evaluated by the elastic wave velocity distribution analysis system 1, but the evaluation target member evaluated by the elastic wave velocity distribution analysis system 1 is The quality of not only the concrete member 100 but also a steel member or a synthetic member composed of the steel member and the concrete member may be evaluated by the elastic wave velocity distribution analysis system 1.

Further, in the above description, the receiving side sensor 22 receives the elastic wave, and the received elastic wave is used for three-dimensional elastic wave tomography analysis to obtain the three-dimensional velocity distribution of the elastic wave inside the concrete member 100. The internal quality of the concrete member 100 as an evaluation target member was evaluated based on the calculated and calculated elastic wave three-dimensional velocity distribution. However, the elastic wave two-dimensional velocity distribution was calculated and the calculated elastic wave two-dimensional velocity distribution was used. Based on this, the internal quality of the concrete member 100 as the evaluation target member may be evaluated. Further, the internal quality of the member to be evaluated may be evaluated by analyzing based on an appropriate factor such as the amplitude of the received elastic wave, the attenuation factor of the amplitude, or the Q value.

1 ... Elastic wave velocity distribution analysis system 11 ... Control / analysis device 14 ... Display unit 22 ... Receiving side sensor 30 ... Strike rod 30a ... Lower end 30b ... Upper end 100 ... Concrete member 100a ... Surface 101 ... Small diameter hole 101a ... Bottom K … Analysis element

Claims (6)

The striking rod is inserted into a small-diameter hole which is a bottomed small-diameter hole having a bottom while opening to one main surface of the member to be evaluated so that the tip abuts on the bottom, and is exposed from the one main surface. By striking the end of the striking rod, an elastic wave is input from a predetermined elastic wave input location on the bottom through the tip.
The elastic wave propagated by the receiving side sensor arranged at a predetermined elastic wave receiving point on the main surface is received, and the elastic wave is received.
The quality inside the evaluation target member is evaluated based on the calculation result obtained by calculating the reception information received by the receiving side sensor for a predetermined element.
The measurement arrival time is obtained by subtracting the propagation time of the elastic wave propagating from the striking rod from the arrival time of the elastic wave from the transmitting side sensor attached near the upper end of the striking rod to the receiving side sensor .
The calculation result is
Based on the measurement arrival time of the elastic wave to the receiving side sensor and the relative positional relationship between the receiving side sensor and the elastic wave input location, the elastic wave velocity distribution inside the evaluation target member is analyzed and analyzed. Internal quality evaluation method which is the elastic wave velocity distribution. The difference between the measurement arrival time of the elastic wave received by the receiving sensor and the analysis arrival time of the analysis considering the detour in which the elastic wave propagates is reduced.
The internal quality evaluation method according to claim 1 , wherein the elastic wave velocity distribution is calculated by adjusting the reciprocal of the velocity in the analysis. An AE sensor is used as the receiving sensor.
The analysis is a three-dimensional elastic wave tomography analysis using the elastic wave received by the AE sensor.
The internal quality evaluation method according to claim 2 , wherein the elastic wave velocity distribution is an elastic wave three-dimensional velocity distribution. A transmitting side sensor attached to the vicinity of the upper end of the striking rod inserted into the small-diameter hole which is a bottomed small-diameter hole having a bottom while opening to one main surface of the member to be evaluated so that the tip abuts on the bottom. ,
The end portion of the striking rod exposed from the one main surface is impacted, and an elastic wave input from a predetermined elastic wave input location on the bottom portion via the tip end and propagates inside the evaluation target member is received. At the same time, a receiving side sensor arranged at a predetermined elastic wave receiving point on the main surface, and
It is provided with an analysis unit that evaluates the quality inside the evaluation target member based on the calculation result obtained by calculating the received information received by the receiving side sensor for a predetermined element.
The measurement arrival time is obtained by subtracting the propagation time of the elastic wave propagating from the striking rod from the arrival time of the elastic wave from the transmitting side sensor attached near the upper end of the striking rod to the receiving side sensor .
The analysis unit determines the elastic wave velocity distribution inside the evaluation target member based on the measurement arrival time of the elastic wave to the receiving side sensor and the relative positional relationship between the receiving side sensor and the elastic wave input location. It is a configuration to analyze
An internal quality analysis system further provided with a display unit for displaying the results of the analyzed elastic wave velocity distribution. The analysis unit
The inverse of the velocity in the analysis is adjusted so that the difference between the measurement arrival time of the elastic wave received by the receiving sensor and the analysis arrival time of the analysis considering the detour in which the elastic wave propagates is reduced. The internal quality analysis system according to claim 4 , which is configured to calculate the elastic wave velocity distribution. The receiving side sensor is an AE sensor.
The analysis is a three-dimensional elastic wave tomography analysis using the elastic wave received by the AE sensor.
The internal quality analysis system according to claim 5 , wherein the elastic wave velocity distribution is an elastic wave three-dimensional velocity distribution.

Images