KR200179851Y1 - Device to measure stress waves inside a core hole of tunnel lining - Google Patents

Abstract

This study aims to investigate the properties of tunnel concrete lining using seismic waves. The purpose of this paper is to enter into the core hole formed in the tunnel concrete lining and to concretely and efficiently measure the shear wave velocity around the core hole. By providing the seismic measuring device for core hole, it measures the shear wave (S-wave) deep inside the core section of the core hole, not the surface, under the field condition of concrete lining. In order to achieve this purpose, this proposal is to equip the core hole of the tunnel concrete lining with the oscillator, the first and second detectors and the airbag, and to make it into the core hole of the tunnel concrete lining. After grounding the first and second sensing rods of the first and second detectors, an oscillator generates an acoustic wave The hayeoseo detect the acoustic wave to turn on the first and second gamjingi that the ever delivered to the data acquisition system characterized by the technical configuration.

Description

Device to Measure Stress Waves inside a Core Hole of Tunnel Lining}

This study relates to understanding the properties of tunnel concrete lining using seismic waves, and especially the shear wave (S-wave) of concrete lining around the core hole that enters the core hole formed in the tunnel concrete lining to collect core specimens. The present invention relates to a seismic measuring device for core holes in a tunnel concrete lining, which is used for measuring the velocity and assessing the integrity of tunnel walls during the precise safety diagnosis of tunnels.

Due to the increase in the cultural space of modern society and the expansion of various indirect facilities, the demand and construction of underground spaces such as subway, high speed train, water tunnel are rapidly increasing. In addition, as the social concern is raised on the safety problem of the constructed underground space, the application of various techniques for diagnosing safety thereof is becoming active.

Recently, techniques for utilizing seismic waves have been widely applied in the ground survey and the soundness evaluation of concrete structures.

The seismic measurement is used for the calculation of the properties of the ground needed to analyze the mutual behavior of the ground and structures under dynamic loads such as earthquakes and vibrations. It is widely used as a method for earthwork quality management, such as quality and soundness evaluation of cast-in-place piles, tunnel linings, and rock grouting.

Conventionally, there are impact echo methods, impulse response techniques, SASW techniques, etc. as a method for grasping the properties of construction structures by measuring non-destructive seismic waves in the field. It has the advantage of being economically performed.

However, in the case of the non-destructive test method, it is good that the structure is not damaged. On the other hand, since the elastic wave is measured on the outer surface of the structure, there is a limit in accurately understanding the physical properties inside the structure.

On the other hand, crosshole test and downhole test are frequently used in the field to measure the linear behavior of soil under low strain.

The crosshole test method is to measure the propagation speed of waves by drilling two or more holes and installing oscillator in one hole, and installing the oscillator in the rest of the ball. It is a method to measure the wave propagation speed by installing at the planned station depth in the room.

Among these test methods, the downhole test has the advantage of being easily performed in the field. However, the accuracy of the test results is inferior because the error is large because it calculates the distance between the oscillator installed on the surface and the reducer installed in the space. have.

In addition, the cross hole test can obtain better test results than the down hole, but the configuration is complicated and costly. In particular, the cross-section thickness is thin because the structure is excessively damaged by drilling a large number of artificial holes. Tunnel concrete lining had a difficult problem in practical application.

On the other hand, when conducting precision safety diagnosis of road tunnels, in order to measure the compressive strength and other physical properties of concrete linings, the indoor test is conducted after collecting cores from concrete linings to a minimum number and used as data for soundness evaluation. Doing.

To harvest the core, a hole must be drilled in the tunnel concrete lining, which is usually refilled at the same time as the core is collected.

Before refilling the core hole, a simple seismic measuring device is placed in the core hole to measure the seismic velocity at the depth of the inner section, not the surface, under the condition of the concrete lining. Could be.

However, at present, no equipment for measuring seismic waves by inserting them into a core hole drilled in a tunnel concrete lining and an elastic wave irradiation technique using a core hole have been provided. It is because of the characteristics.

Accordingly, the author proposes a seismic wave irradiation technique using core holes drilled in the tunnel concrete lining for the precise safety diagnosis of the tunnel, and provides related equipment necessary to grasp the properties of the tunnel concrete lining using the seismic wave. In order to solve all the problems of the conventional test methods, this paper was devised.

Therefore, the purpose of this paper is to enter the core hole formed in the tunnel concrete lining to collect core specimens and to measure the shear wave (S-wave) velocity of the concrete lining around the core hole reliably and efficiently. By providing a measuring device, it is possible to measure the shear wave (S-wave) deep inside the internal section, not the surface, under the site condition of the concrete lining. have.

1 is an external perspective view of a seismic measuring device of the present invention

Figure 2 is an external perspective view showing the acoustic wave measuring device of the present invention

Figure 3 is a longitudinal cross-sectional view of the acoustic wave measuring device of the present disclosure

Figure 4 is a schematic diagram showing the state of measuring the seismic wave inside the core hole using the seismic measuring device of the present invention

Fig. 5 is a partial view of a state in which the acoustic wave measuring device of the present invention acts inside the hole

<Explanation of symbols for main parts of the drawings>

1: Measuring device 2: Core hole 3: Lining

4: power supply 5: data acquisition system 6: air supply pump

10: housing 11: top 12: side wall

13: Bottom 14: Nipple 15: Connector

16: Support wall plate 17: Handle bar 18: Connection port

19: Bracket 20: Oscillator 21: Strike bar

22: solenoid 23: support frame 24: buffer material

30a: first detector 30b: second detector 31: first sensing rod

32: first accelerometer 33: second sensing rod 34: second accelerometer

35: Teflon resin 36: Coupling sphere 40: Airbag

41: jacket 42: tube A: point 1

B: 2nd point e: Power line h: Air transfer hose

Hereinafter, the technical configuration of the present invention will be described in detail with reference to the accompanying drawings shown in FIGS. 1 to 5.

The core acoustic acoustic wave measuring device of the tunnel concrete lining of the present invention comprises: a housing (10) manufactured as a cylindrical body surrounded by an upper plate (11), a side wall (12) and a lower plate (13) to receive components therein;

It is mounted to the upper end of the side wall 12 of the housing 10, the striking rod 21 of the distal end is advanced by the operation of the solenoid 22 while applying a physical shock to the inspected object by applying an acoustic wave to the inspected object. An oscillator 20 for generating;

Located in the lower portion of the vertical line of the oscillator 20 is mounted on the upper half of the side wall of the housing 10, the first sensing rod 31 provided in the front end is in close contact with the object to be inspected by the oscillator 20 A first senser (30a) for receiving the generated acoustic wave to be transmitted to the first accelerometer (32) connected to the rear end thereof to sense the acoustic wave of the inspected object;

The oscillator 20 and the first senser (30a) is positioned below the vertical line of the first senser (30a) at a predetermined interval, mounted on the lower end of the side wall (12) of the housing, the second sensing provided at the tip The second rod 33 is in close contact with the object to be inspected, and is generated by the oscillator 20. The second sensing rod is received after passing through the point where the first sensing rod 31 is in close contact. A second detector 30b which is transmitted to the accelerometer 34 and senses an acoustic wave of the object to be inspected;

It is mounted on the side wall 12 of the housing located on the rear side of the first and second transducers 30a and 30b, and is inflated by the air injected into the first and the second and second regulators. An air bag 40 for tightly fixing the sensing rods 31 and 33 to the inside surface of the hole to be inspected; What is configured is a basic feature of technical configuration.

The seismic measuring apparatus of the present invention configured as described above is miniaturized to a size that can be installed into the core hole 2 formed to collect the cores, and the first and second accelerometers 32 of the first and second reducers ( 34) is electrically connected to the data acquisition system to transmit the seismic waves they detect to the data acquisition system outside the hall.

The housing 10 is made of stainless steel, and accommodates various components therein.

The housing 10 is manufactured in a form in which the upper plate 11 and the lower plate 13 are separated from the side wall 12. The upper plate 11 is fastened to the upper side wall 12 by fastening with a separate screw bolt, the lower plate 13 is assembled in the form of being screwed to the female screw formed on the lower side wall 12 by processing a male screw portion on its outer peripheral surface. .

The nipple 14 is penetrated to one side of the upper plate 11 so that the air transfer hose h of the airbag 40 is connected to the lower end of the nipple 14. This nipple 14 is used to blow air into the airbag 40 by connecting an air supply pump 6 outside the hole to the upper end thereof.

The connector 15 is penetrated to the other side of the upper plate 11 so that the conducting lines e of the solenoid 22 and the first and second accelerometers 32 and 34 are connected. This connector 15 is used to connect the solenoid 22 to the power supply 4 outside the hole and to connect the first and second accelerometers 32 and 34 to the data acquisition system 5 outside the hole. .

The back surface of the side wall 12 is provided with a supporting wall plate 16 which is bent inward to support the airbag 40.

The upper part of the housing 10 is provided with a handle bar 17 for use when inserting or removing the measuring device in the core hole (2) inside.

The handle bar 17 is provided in such a manner as to form a connector 18 having a female threaded portion in the center of the upper plate 11 of the housing and to screw the connector 18 to the connector 18. And, the handle bar is provided with a ruler (not shown), when installing the device in the interior of the core hole, can accurately grasp the measuring point.

The oscillator 20 is a device that generates a seismic wave by applying a physical impact to the object to be inspected.

The oscillator is mounted on the upper end of the side wall 12 of the housing, and the solenoid 22 and the support frame 23 holding the solenoid 22 enter the inside of the housing 10 and the impact rod 21 A tip portion is exposed out of the side wall.

The oscillator 20 is provided with a bracket 19 whose upper and lower surfaces of the support frame 23 holding the solenoid 22 and the striking rod 21 are horizontally protruded inwardly from the side wall 12 of the housing. It is fixed.

A technical configuration is provided in which a cushioning material 24 is sandwiched between the support frame 23 and the surface where the bracket 19 is in contact so that the elastic waves generated in the oscillator 20 do not propagate along the body of the housing 10. .

In addition, the solenoid 22 was operated at 27V using a small battery to simplify the use at the tunnel site.

The first and second transducers 30a and 30b are devices for sensing a signal reached by propagation of an acoustic wave.

The first and second retarders 30a and 30b are vertically positioned to be spaced apart from each other. In the example of this paper, in order to facilitate the calculation of the seismic velocity, a distance of 10 cm was installed.

The first and second sensing units 30a and 30b are largely divided into sensing rods and accelerometers, and they are connected by screwing, so that the seismic waves are transmitted reliably.

The first and second detectors surround the first and second sensing rods 31 and 33 with Teflon resin frames 35, bolt the sensing rods as shown in FIG. They are joined together in the form of nuts. Then, the Teflon resin frame 35 is inserted into the coupler 36 protruding inwardly from the side wall 12 of the housing, and the screw bolt is filled and fixed.

Such first and second transducers are generated by the oscillator 20 so that the acoustic waves transmitted along the sidewalls are attenuated by the Teflon resin frame 35 so that the first and second accelerometers 32 and 34 are not affected by unnecessary acoustic waves. To make more accurate measurements.

The first and second sensing rods 31 and 33 are rounded at their tip part in a spherical shape. The tip configuration of the sensing rods allows the tip to be completely grounded on the curved surface of the inspected object.

The airbag 40 is a device for pushing and fixing the sensing rods of the reducer to the wall of the core hole 2.

The airbag 40 is composed of an outer shell 41 fixed to the backing wall plate 16 side of the housing and a tube 42 inside the outer shell 41.

The outer shell 41 is preferably made of a fabric tube (materials such as fire hoses and weaving structure) excellent in tensile strength and tear strength. Such a fabric tube is wrapped in a woven fabric, which is not only resistant to abrasion and less likely to be broken, but also is inexpensive and maintenance free.

The airbag 40 is provided on the side of the support wall plate 16 formed on the rear portion of the side wall 12 of the housing. In addition, the tube 42 is provided with an air transfer hose h connected to the inside of the housing to blow air.

Hereinafter, a method of measuring elastic waves of a core hole formed in a tunnel concrete lining using the elastic wave measuring apparatus of the present disclosure will be described.

The method for measuring the seismic wave using the present design will be described schematically, and the seismic wave measuring device 1 is inserted into the core hole 2 of the tunnel concrete lining and the first and second transducers 30a and 30b are formed on the wall surface of the core hole 2. A step of installing an acoustic wave measuring device for grounding the first and second sensing rods 31 and 33;

An elastic wave generating step of generating elastic waves in the tunnel concrete lining 3 around the core hole 2 by hitting the wall surface of the core hole 2 with the striking rod 21 of the oscillator 20;

Receiving the oscillated acoustic wave by the first sensing rod 31 grounded at the first point A of the core hole wall surface and sensing the acceleration of the elastic wave by the first accelerometer 32;

Seismic wave detection at the second point that receives the elastic wave propagated to the second point B after passing through the first point A and measures the acceleration of the acoustic wave with the second accelerometer 34 Steps;

A first point that obtains the seismic wave information of the first and second points A and B from the data acquisition system 5 and obtains a time for the leading shear wave to pass between the first and second points A and B; Calculating a shear wave transit time between the second points;

A shear wave velocity calculating step of obtaining a shear wave velocity by dividing the shear wave passing time obtained in the step by the distance between the first point and the second branch; Is done.

In more detail with respect to the above steps, the acoustic wave measuring device of the present invention is connected to the external power supply device 4, the data acquisition system 5 and the air supply pump 6 before entering into the core hole.

Next, the acoustic wave measuring device 1 is inserted into the core hole 2 of the tunnel concrete lining, and the correct measuring position is set. Then, the air supply pump 6 is operated to blow air into the air bag. The first and second sensing rods 31 and 33 of the first and second sensing units 30a and 30b are stably grounded on the wall surface of (2).

When the installation of the acoustic wave measuring device is completed as described above, the acoustic wave is generated on the core hole wall.

In the seismic wave generation step, the power switch of the power supply device 4 is turned on to apply power to the solenoid 22 of the oscillator 20 to operate the solenoid 22 to strike the rod connected to the solenoid 22. By hitting the wall surface of the core hole (2) with 21 to generate a seismic wave in the tunnel concrete lining (3) around the core hole (2).

The seismic waves thus oscillated are spread around the hall in a tunnel concrete lining.

In the seismic wave detection step of the first point, the first point A of the wall surface of the core hole (2), which is oscillated in the seismic wave generation step, is mounted on the tunnel concrete lining, and the first sensing rod 31 of the first detector 30a is grounded. Receives the elastic wave passing through the first sensing rod 31 and measures the acceleration of the elastic wave with the first accelerometer 32 connected to the rear end and sends it to the data acquisition system (5).

The elastic wave passing through the first point A continues to propagate to the point where the second sensing rod 33 is grounded.

In the seismic wave detection step of the second point, the second point of the wall surface of the core hole 2 where the second sensing rod 33 of the second detector 30b is grounded after passing through the first point A and then in a concrete lining. (B) receives the seismic wave through the second sensing rod 33, detects the acceleration of the seismic wave with the second accelerometer 34 connected to the rear end, and sends the seismic wave to the data acquisition system 5. do.

In the step of calculating the shear wave passing time between the first point and the second point, the seismic wave information transmitted through the seismic wave detection step of the first and second points is obtained from the data acquisition system 5 and analyzed, and then the first and second points ( A first shear wave (previously SV wave) that arrives at A) (B) is picked up, and the time that this leading shear wave passes between the first and second points A and B is determined.

Next, the shear wave velocity obtained by dividing the shear wave transit time obtained in the shear wave transit time calculation step between the first point and the second point by the distance between the first point and the second point in the shear wave rate calculation step is obtained. All seismic measurements are completed using.

In this way, the shear wave velocity of the seismic wave measured at the core hole of the tunnel site is compared with the existing physical properties and core specimen properties, and is used as a soundness evaluation data of the tunnel wall during the precision safety diagnosis of the tunnel.

As described above, according to the present proposal, a seismic measuring device that can reliably and efficiently measure the shear wave (S-wave) velocity of the concrete lining around the core hole into the core hole formed in the tunnel concrete lining to collect core specimens In addition to complementing other seismic techniques that are nondestructive in the practice of contraindication to damaging the waterproof membranes on the back of concrete linings, the internal surface, not the surface, under field conditions of the surrounding concrete lining Shear waves (S-waves) deep in the cross section can be measured.

Therefore, this proposal not only can more accurately derive the data for the soundness evaluation of tunnel walls during the precise safety diagnosis of the tunnel, but also the quality control and soundness evaluation of various basic civil works such as site casting piles and concrete structures. Edo is a very useful design and can be widely used.

Claims (6)

A housing (10) manufactured as a cylindrical body surrounded by the upper plate (11), the side wall (12), and the lower plate (13) to receive components therein; It is mounted on the upper end of the side wall 12 of the housing 10, the striking rod 21 of the front end is advanced by the operation of the solenoid 22, while applying a physical shock to the object to be inspected by the seismic wave An oscillator 20 for generating; Located in the lower portion of the vertical line of the oscillator 20 is mounted on the upper half of the side wall of the housing 10, the first sensing rod 31 provided in the front end is in close contact with the object to be inspected by the oscillator 20 A first senser (30a) for receiving the generated acoustic wave to be transmitted to the first accelerometer (32) connected to the rear end thereof to sense the acoustic wave of the inspected object; The oscillator 20 and the first senser (30a) is positioned below the vertical line of the first senser (30a) at a predetermined interval, mounted on the lower end of the side wall (12) of the housing, the second sensing provided at the tip The second rod 33 is in close contact with the object to be inspected, and is generated by the oscillator 20. The second sensing rod is received after passing through the point where the first sensing rod 31 is in close contact. A second detector 30b which is transmitted to the accelerometer 34 and senses an acoustic wave of the object to be inspected; It is mounted on the side wall 12 of the housing located on the rear side of the first and second transducers 30a and 30b, and is inflated by the air injected into the first and the second and second regulators. An air bag 40 which tightly fixes the sensing rods 31 and 33 to the inside surface of the hole to be inspected; Tunnel concrete, characterized in that the first and second accelerometers (32, 34) of the first and second reducers are electrically connected to the data acquisition system to transmit the acoustic waves sensed by them to the data acquisition system outside the hall. Acoustic wave measuring device for core hole of lining. According to claim 1, wherein the nipple 14 is penetrated to one side of the housing upper plate 11, the air transfer hose (h) of the air bag 40 is connected, the connector 15 is penetrated to the other side The solenoid 22 and the conducting wires e of the first and second accelerometers 32 and 34 are connected to each other so that the air supply pump of the airbag 40 outside the hole, the power switch of the solenoid, and the first, 2. A seismic measuring device for core holes in a tunnel concrete lining, characterized in that it is connected to the data acquisition system of the accelerometer (32) (34). The core of the tunnel concrete lining according to claim 1, wherein the housing 10 is provided with a handle bar 17 extending upwardly in a vertical line to be used when it is inserted into or removed from the measurement point inside the hole. Hall acoustic wave measuring device. The oscillator (20) of claim 1, wherein the upper and lower surfaces of the support frame (23) holding the solenoid (22) and the striking rod (21) protrude horizontally inwardly from the side wall (12) of the housing. It is fixed to the bracket 19, the cushioning material 24 is sandwiched between the support frame 23 and the contact surface of the bracket 19, the elastic wave generated from the oscillator 20 is the body of the housing 10 Elastic wave measuring device for the core hole of the tunnel concrete lining, characterized in that not to propagate along. According to claim 1, wherein the first and second detectors (30a, 30b) is the first sensing rod 31 and the second sensing rod 33 is surrounded by a Teflon resin frame 35 is fixed, the Teflon The resin frame 35 is fixed to the side wall 12 of the housing so that the elastic waves generated by the oscillator 20 and transmitted along the side wall are attenuated by the Teflon resin frame 35 so that the first and second accelerometers 32 ( 34. A seismic measuring device for core holes in a tunnel concrete lining, characterized in that it does not affect 34). The tunnel concrete lining according to claim 1 or 3, wherein the first and second sensing rods (31) and (33) have rounded ends of the first and second sensing rods (31, 33) so as to be perfectly grounded to the curved surface of the inspection object. Acoustic wave measuring device for core hole.