JP2011038835A - Tunnel lining thickness measuring device, measuring method, and formwork - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tunnel lining thickness measuring device, a measuring method, and a formwork used therefor, measuring the thickness of a concrete lining when a tunnel is lined with concrete while the concrete is in unset state. <P>SOLUTION: The formwork 7 is used for lining the tunnel and the like. The formwork 7 is arranged so as to surround the existing concrete 5 and the ground 3, and a concrete supply part 8 is disposed on the ground 3 side of the formwork 7. In the formwork 7, a holder 9 which passes through the formwork 7 is provided. The holder 9 is detachably attached to the formwork and is a member for holding an oscillation section 11 consisting of a magnetostrictive element, and a receiving section 13. The oscillation section 11 and the receiving section 13 are exposed on the outer surface of the holder 9, which is composed of a surface almost flush with the outer surface (concrete casting side) of the formwork 7. The oscillation section 11 oscillates vibration (wave) to the casted unset concrete 10, and the receiving section 13 receives the reflected wave and the like of this vibration (wave). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tunnel lining thickness measuring device, a measuring method, and a formwork used therefor, which can measure the concrete lining thickness at the time of concrete lining in a tunnel in an unsolidified state of the concrete. is there.

  Conventionally, the lining thickness of lining concrete such as a tunnel is measured by oscillating ultrasonic waves from the surface of the concrete and measuring the thickness from the reflected waves.

  As such a concrete thickness measuring device, shock elastic waves are generated in the thickness direction of the concrete, vibrations in the thickness direction and the surface layer portion are detected, and the frequency component of the shock elastic waves propagating through the concrete, There is a concrete thickness measuring device that calculates a concrete thickness from the velocity of an elastic wave propagating through a surface layer (Patent Document 1).

  Moreover, at least one set of vibration generators is installed on the reinforcing bars in the formwork, and after placing the concrete, mechanical vibration is oscillated from one side, and this is received to calculate the elastic wave propagation velocity in the concrete. There is a concrete structure quality inspection method in which a vibration receiving element is installed on a concrete surface, mechanical vibration is generated from inside a mold, and the concrete thickness is calculated by receiving the vibration (Patent Document 2).

  Further, there is an exploration device that uses a resonator element with enhanced responsiveness of an excitation coil, receives a reflected signal from the inside of an object, and calculates a thickness and the like from the time from the oscillation signal to the received signal (Patent Document 3).

JP 2004-69495 A JP 2009-25022 A JP 07-218477 A

  However, the device of Patent Document 1 simply calculates the thickness by receiving the vibrations in the thickness direction and in the surface layer portion when the propagation speed of vibration in the concrete is unknown. The concrete thickness after hardening is measured. Therefore, the measurement when the concrete is unsolidified is not considered.

  Moreover, the apparatus described in Patent Document 2 needs to embed a sensor element in a mold in advance. Further, as in Patent Document 1, only the measurement after hardening of the concrete is considered.

  In addition, although the device described in Patent Document 3 is described as being capable of measuring a highly viscous material, it is necessary to install the device on the upper surface of the object because it is necessary to install it on the surface of the object. is there. As described above, Patent Documents 1 to 3 do not take into account the measurement of the unsolidified concrete lining thickness in the case of placing using a formwork such as tunnel lining.

  The present invention has been made in view of such a problem, a concrete lining thickness measuring apparatus capable of measuring the concrete lining thickness at the time of concrete lining such as a tunnel in an unsolidified state of the concrete, It aims at providing the measuring method and the formwork used for this.

  In order to achieve the above-described object, the first invention is a tunnel lining thickness measuring device, which is installed in a mold and oscillates to vibrate concrete placed in the mold And a receiving unit that receives the vibration started by the oscillating unit, and an analysis unit that analyzes a waveform received by the receiving unit, the oscillating unit is an oscillating device using a giant magnetostrictive element, The analysis unit includes a waveform separation unit that separates a direct wave propagating directly from the oscillation unit to the receiving unit and a reflected wave from the measurement target unit, and a lining that calculates a lining thickness of the concrete from the reflected wave. A tunnel lining thickness measuring device having a thickness calculating means.

  At least three of the vibration receiving units are installed at different distances from the oscillation unit with respect to one of the oscillation units, and the lining thickness calculating means is configured to receive vibration information received from each of the vibration receiving units. The wave process distance is calculated, and the reflection point trajectory for which the sum of the distances from the oscillation part and the vibration receiving part is the same as the process distance with the oscillation part and the vibration receiving part as a focal point is In this case, it is desirable that the point where the reflection point trajectories assumed for each vibration receiving unit intersect is specified as a common reflection point, and the distance to the common reflection point is calculated as the lining thickness.

  The waveform separation means separates the direct wave and the reflected wave by complex cepstrum analysis, and the lining thickness calculation means envelops the separated reflected wave by Hilbert analysis, and the maximum amplitude of the envelope It is desirable to analyze the time to be as the reflected wave travel time.

  According to the first invention, since the oscillating portion and the vibration receiving portion are directly provided on the formwork, when the concrete is placed using the formwork, the concrete is set before the concrete is hardened with the formwork installed. The lining thickness of can be measured. Moreover, although the concrete before hardening has a large attenuation of vibration propagating inside, the use of the giant magnetostrictive element can oscillate vibrations with a large amplitude (energy). Even the thickness can be measured. In this case, since the P wave, which is a longitudinal elastic wave having a high frequency, has a large attenuation tendency, an S wave, which is a transverse elastic wave, is used.

  In addition, three vibration receiving units are provided for one oscillation unit, and the respective vibration receiving units are arranged so as to have different distances from the oscillation unit, and a reflection point locus is provided for each vibration receiving unit. Since the common reflection point where the crossing points is specified and the thickness up to the common reflection point is specified as the tunnel lining thickness, the appropriate tunnel lining thickness is calculated even when the elastic wave reflection surface is uneven. be able to.

  In addition, since the direct wave and the reflected wave are separated by complex cepstrum analysis, the reflected wave group can be separated even if the reflected wave group is mixed in the direct wave group. The thickness can be calculated.

  The second invention is a tunnel lining thickness measuring method, comprising a step of installing a mold having an oscillating part using a giant magnetostrictive element capable of oscillating vibration and a receiving part capable of receiving vibration (a) And (b) placing concrete in the mold, (c) oscillating vibrations in the unsolidified concrete by the oscillating part, and receiving vibrations from the concrete by the vibration receiving part. (D), a step (e) of separating a direct wave propagating directly from the oscillating unit to the receiving unit and a reflected wave from the measuring unit from the information received by the receiving unit; And a step (f) of calculating a lining thickness of the concrete that has been solidified.

  The mold is provided with at least three of the vibration receiving units for each of the oscillation units at different distances from the oscillation unit, and the step (d) includes each of the vibration receiving units. The step (f) calculates the process distance of each wave from the information received for each vibration receiving unit, and the oscillation unit and the vibration receiving unit as a focal point. And a reflection point locus where the sum of the distances from the vibration receiving portion is the same as the process distance is assumed for each vibration receiving portion, and a point where the reflection point locus assumed for each vibration receiving portion intersects is a common reflection point The distance to the common reflection point is preferably calculated as the lining thickness.

  The step (e) is a step of separating the direct wave and the reflected wave by complex cepstrum analysis, and the step (f) envelops the separated reflected wave by Hilbert analysis, It is desirable to analyze the time when the maximum amplitude is as the reflected wave travel time.

  According to the second invention, since the oscillating portion is a giant magnetostrictive element and the oscillating portion and the vibration receiving portion are provided in the mold, the thickness of unsolidified concrete can be measured. In addition, three receiving parts are provided for one oscillation part, a reflection point locus is provided for each receiving part, a common reflection point where the three reflection point locus intersects is specified, and the thickness up to the common reflection point is determined by the thickness of the concrete. Since it is specified as the lining thickness, an appropriate concrete lining thickness can be calculated even when the elastic wave reflecting surface is uneven. In addition, since the direct wave and the reflected wave are separated by complex cepstrum analysis, the reflected wave group can be separated even if the reflected wave group is mixed in the direct wave group. The thickness can be calculated.

  3rd invention is a formwork used for the lining of a tunnel, Comprising: The oscillation part using the giant magnetostrictive element which can oscillate a vibration, The vibration receiving part which can receive the said vibration is provided, One said The mold is characterized in that at least three vibration receiving parts with respect to the oscillating part are provided with holders installed at different positions from the oscillating part.

  According to the third invention, the thickness of the unsolidified concrete can be measured at the time of tunnel lining.

  According to the present invention, there is provided a tunnel lining thickness measuring apparatus, a measuring method, and a formwork used for the tunnel lining thickness capable of measuring the concrete lining thickness at the time of tunnel concrete lining in an unsolidified state of the concrete. can do.

The figure which shows the installation state of the lining thickness measuring apparatus 1 at the time of concrete lining. The perspective view which shows the formwork 7 to which the oscillation part 11 and the vibration receiving part 13 were attached. 2A and 2B are diagrams showing the holder 9, in which FIG. 2A is a cross-sectional view taken along the line AA in FIG. 2 in the vicinity of the holder 9, and FIG. The figure which shows the structure of the oscillation part. The figure which shows the positional relationship and the reflection point locus | trajectory 37 of the oscillation part 11 and the receiving part 13. FIG. The figure which shows reflection point locus | trajectory 37a, 37b, 37c and the common reflection point 39. FIG. The flowchart of the lining thickness measuring method. The conceptual diagram which shows the process process of the waveform received by the vibration receiving part.

  Hereinafter, a concrete lining thickness measuring apparatus 1 according to an embodiment of the present invention will be described. FIG. 1 is a view showing a lining thickness measuring apparatus 1. The lining thickness measuring apparatus 1 mainly includes a mold 7, a holder 9, an oscillating unit 11, a vibration receiving unit 13, a control unit 15, an analysis unit 17, and the like.

  The molds 7 and 7a are used for tunnel lining and the like. The molds 7 and 7a are disposed so as to cover the concrete placement region, and the concrete supply unit 8 is installed in the molds 7 and 7a. The mold 7 is provided with a holder 9 that penetrates the mold 7. The holder 9 is a member that is detachably attached to the mold and holds the oscillation unit 11 and the vibration receiving unit 13. The oscillating portion 11 and the vibration receiving portion 13 are exposed on the outer surface (concrete placement side) of the holder 9, and are configured by the outer surface (concrete placement side) of the mold 7 and a substantially flat surface. That is, the outer surface of the holder 9, the oscillation part 11 and the vibration receiving part 13 are formed smoothly with the surface of the mold 7. The concrete supply unit 8 is a part for placing concrete in a range surrounded by the molds 7 and 7a, and is connected to a concrete supply device (not shown). The oscillating unit 11 oscillates vibration (wave) with respect to the placed unsolidified concrete 10, and the vibration receiving unit 13 receives a reflected wave or the like of the vibration (wave). In addition, you may install the formwork 7 so that a natural ground etc. may be covered, without providing the formwork 7a. That is, the concrete placement region can be a region surrounded by the formwork 7 and a natural ground.

  A control unit 15 and an analysis unit 17 are connected to the oscillation unit 11 and the vibration receiving unit 13. As the control unit 15 and the analysis unit 17, a computer having a calculation unit, a storage unit, a communication unit, an input / output unit, a display unit, and the like is used. The control unit 15 oscillates the oscillation unit 11 and receives vibrations at the vibration receiving unit. The control unit 15 also analyzes the waveform received by the analysis unit 17 and calculates the concrete lining thickness. The calculation means of the analysis unit 17 has at least a waveform separation means and a lining thickness calculation means. The storage means stores measurement data, various management values, an execution program, and the like. The communication means performs data communication with the oscillation unit 11, the vibration receiving unit 13, and the like. The input means inputs management values and conditions. The display means displays data such as measurement data and measurement results.

  The control unit 15 may further control the concrete supply unit 9. The control unit 15 and the analysis unit 17 may be an integrated computer. Further, as the unsolidified concrete 10, a secondary lining concrete of a NATM (New Australian Tunneling Method) method, a lining concrete of a SENS (Shield machine expanded NATM System) method, or the like can be used.

  Next, the mold 7 will be described. FIG. 2 is a perspective view showing the mold 7. The mold 7 is mainly composed of four side plates 19 and a skin plate 21. The skin plate 21 is curved with a curvature corresponding to the curvature of the tunnel to be installed, and the side plates 19 are joined along the curvature of the skin plate 21. For example, steel can be used as the mold 7.

  A holder 9 is attached to the approximate center of the mold 7 from the inner surface side. FIG. 3A is a cross-sectional view showing the vicinity of the holder 9 in the cross section along the line AA in FIG. As shown in FIG. 3, the holder 9 is joined to the skin plate 21 with a bolt or the like. The holder 9 holds the oscillating portion 11 and the vibration receiving portion 13 so as to be exposed on substantially the same surface as the outer surface of the skin plate 21.

  FIG. 3B is a schematic view showing the holder 9 viewed from the outer surface side of the skin plate 21. As shown in FIG. 3B, the holder 9 is provided with one oscillating portion 11 and three vibration receiving portions 13 (13a, 13b, 13c). Here, BD which is the distance from the oscillation part 11 to each receiving part 13a, 13b, 13c differs. That is, the vibration receiving units 13a, 13b, and 13c are arranged on the same plane as the oscillation unit 11 so as to have different distances.

  Next, the oscillation unit 11 will be described. FIG. 4 is a cross-sectional view showing the oscillating unit 11. The oscillating unit 11 mainly includes a head 23, a rod 25, a permanent magnet 29, a giant magnetostrictive element 31, a coil 33, and the like.

The giant magnetostrictive element 31 is made of a Tb _0.3 Dy _0.7 Fe _2.0 compound. The giant magnetostrictive element 31 can extend by 0.1% or more in the major axis direction next time around the surroundings, and can return to its original length by disappearance of the magnetic field. The giant magnetostrictive element 31 is disposed in the coil 33. A permanent magnet 29 is disposed around the coil 31 so as to cover the coil 31.

  The rod 25 is connected to the end of the giant magnetostrictive element 31. The rod 25 is provided with a flange 27, and a spring 35 is provided so as to urge the rod 25 toward the axial direction rearward (downward in the drawing) with respect to the flange 27. A head 23 is provided at the tip of the rod 25. The head 23 is a part that directly applies vibration to the concrete.

  Normally, the spring 25 applies a force to the rod 25 behind the giant magnetostrictive element 31 in the long axis direction. In this state, when a current is supplied to the coil 33 by a power supply (not shown), a magnetic field is generated by the coil 33 and the giant magnetostrictive element 31 extends. As the giant magnetostrictive element 31 extends, the rod 25 moves forward in the long axis direction of the giant magnetostrictive element 31 against the force of the spring 35. That is, the head 23 moves forward.

  When the current to the coil 33 is stopped from this state, the giant magnetostrictive element 31 returns to its original length, and the rod 25 is pushed back by the spring 35. That is, the head 23 moves backward. By repeating the above operation, the head 23 can be reciprocated in the major axis direction of the giant magnetostrictive element 31 (in the direction of arrow E in the figure). That is, vibration (elastic wave) can be generated in the direction of arrow E in the figure by the reciprocating motion of the head 23.

  Although details of the vibration receiving unit 13 are omitted, it is only necessary that the vibration (wave) in the axial direction can be received and converted into an electric signal or the like at the tip of the vibration receiving unit, and a piezoelectric element or an accelerometer can be used.

  Next, a vibration propagation process when the vibration generated from the oscillating unit 11 is received by the receiving unit 13 will be described. FIG. 5 is a schematic diagram illustrating a state where the vibration oscillated from the oscillating unit 11 is reflected by the measurement target unit and the reflected wave is received by the vibration receiving unit 13.

  In FIG. 5, the upper side of the oscillation unit 11 and the vibration receiving unit 13 is a measurement target, for example, concrete. The vibration oscillated from the oscillating unit 11 propagates in the measurement target unit and is reflected at a boundary such as a natural ground. The reflected vibration is transmitted to the vibration receiving unit 13 and received by the vibration receiving unit 13. The process distance from the oscillation unit 11 to the reflection point to the vibration receiving unit 13 can be calculated by measuring the time from when the vibration is generated by the oscillation unit 11 to when the vibration receiving unit 13 receives the vibration. In addition, what is necessary is just to preset the propagation speed of the vibration in concrete.

  In this case, as a process of transmitting vibration, the oscillation unit 11 to the reflection point to the vibration receiving unit 13 are reflected at any reflection point that is the calculated process distance. For example, in FIG. 5, it is conceivable that the reflected wave reflected from the oscillation unit 11 at the point F is received by the vibration receiving unit 13 or the reflected wave reflected at the point G is received by the vibration receiving unit 13. In this case, the sum of the distance r1 from the oscillation unit 11 to the point F and the distance r2 from the point F to the vibration receiving unit 13 should be the same as the calculated process distance. Similarly, r3 + r4 is the same as the process distance.

  Thus, when the vibration process distance is calculated from the reflected wave, the reflection point that is the process distance is the sum of the distances from the oscillation unit 11 and the vibration receiving unit 13 with the oscillation unit 11 and the vibration reception unit 13 as the focal point. Is positioned on an ellipse that is the process distance. Such a reflection point locus is referred to as a reflection point locus 37.

  That is, the reflection point locus 37 can be assumed from the vibration process distance from the oscillation unit 11 to the vibration receiving unit 13, and the reflected wave received by the vibration receiving unit 13 is reflected at any position on the reflection point locus. Can be treated as Although the reflection point locus is shown two-dimensionally in FIG. 5, the reflection point locus 37 is a three-dimensional locus having a set of reflection points as a surface.

  FIG. 6 is a diagram illustrating the reflection point loci 37a, 37b, and 37c when three vibration receiving units 13a, 13b, and 13c are installed for one oscillating unit 11. In FIG. In FIG. 6, for the sake of simplicity, the oscillation unit 11 and the vibration receiving units 13a, 13b, and 13c are arranged on the same line, but the present invention is not limited to this. FIG. 6 shows a case where the reflection side is the natural ground 3.

  The distances from the oscillation unit 11 to the vibration receiving units 13a, 13b, and 13c are different as described above. For this reason, the time until the vibrations oscillated from the oscillating units 11 are received by the respective receiving units 13 is different. Therefore, the vibration process distance calculated for each vibration receiving unit 13 is different. That is, reflection point trajectories 37a, 37b, and 37c can be assumed for the vibration receiving units 13a, 13b, and 13c, respectively.

  A portion where the respective reflection point loci 37a, 37b, and 37c intersect is referred to as a common reflection point 39. That is, the common reflection point 39 is a common point of reflection points assumed in the respective reflection point loci 37a, 37b, and 37c. Therefore, it can be considered that the reflected waves reflected by the common reflection point 39 are received by the respective receiving portions 13a, 13b, and 13c. When the position of the common reflection point 39 is specified, the depth to the position (H in the figure) can be calculated as the concrete lining thickness. If there are two receiving parts 13, there may be two common reflection points 39. However, by providing three receiving parts 13, the common reflection point 39 must be specified as one point. Can do.

  Next, the concrete lining thickness measuring method in the present invention will be described. FIG. 7 is a flowchart showing the steps. First, the mold 7 in which the oscillation unit 11 and the vibration receiving unit 13 are installed in advance is installed in a concrete lining part (step 101). After installing the formwork 7, concrete is cast (step 102).

  Start the measurement of the concrete lining thickness during concrete placement or before hardening starts after concrete placement. First, the control unit 15 vibrates the oscillation unit 11 to generate vibration (step 103). Further, the control unit 15 receives the vibration at the vibration receiving unit 13 and causes the analysis unit 17 to analyze the waveform (step 104).

  FIG. 8 is a conceptual diagram showing a waveform received by the receiving unit, and a waveform as shown in FIG. The elastic wave measured in the present invention is an S wave which is a transverse wave. This is because the P wave, which is a longitudinal wave, has a high frequency and is difficult to measure because the attenuation is large in unsolidified concrete. The analysis unit 17 first performs filtering processing on the received waveform (step 105). The filtering process is set according to the situation at the site. For example, an amplitude recovery process, a frequency filter process, a white deconvolution process, and the like are performed. The frequency band of vibration directly transmitted through the holder 9 can be removed by various filtering processes. FIG. 8B is a conceptual diagram of waveforms subjected to various filtering processes.

  Next, the analysis unit 17 separates the vibration waveform received by the waveform separation unit into a direct wave and a reflected wave group (step 106). The direct wave is a wave that propagates directly from the oscillating unit 11 toward the vibration receiving unit 13 on the concrete surface or the like without being reflected by the target unit. Complex cepstrum analysis is performed as the waveform separation means. By performing cepstrum analysis, the influence of direct waves can be reduced. FIG. 8C is a conceptual diagram showing a waveform obtained by removing the influence of a direct wave by cepstrum analysis.

  Next, the analysis unit 17 converts the reflected wave group into an envelope using the lining thickness calculation means (step 107). The Hilbert transform is used for enveloping. FIG. 8D is a conceptual diagram showing a waveform after the Hilbert transform is performed.

  Next, the analysis unit 17 reads the time of the maximum amplitude from the waveform that has been enveloped by the lining thickness calculation means (step 108). In FIG. 8D, for example, the T point is read as the time of the maximum amplitude.

  Next, the analysis unit 17 calculates the process distance of the vibration from the obtained maximum amplitude time and the propagation speed of the wave (S wave) in the concrete by the lining thickness calculation means, and based on this Then, a reflection point locus as shown in FIG. 5 is calculated (step 109).

  Next, the analysis part 17 specifies the common reflection point 39 from three reflection point locus | trajectories by a lining thickness calculation means (step 110). Further, the lining thickness of the concrete is calculated from the position of the common reflection point 39 (step 111). Thus, the concrete lining thickness is measured. After the concrete is hardened, the mold 7 is removed, and the same measurement is repeated by placing the mold 7 in the next concrete placement site.

  In addition, if necessary, the control unit 15 may manage the calculated lining thickness, and may control to finish placing concrete when the lining thickness is equal to or greater than a preset management value, You may make it give a pass determination, when lining thickness is more than a management value. Moreover, the filling pressure of the concrete when it is determined that the lining thickness is acceptable may be stored and used as a reference value when placing concrete at the next position.

  According to the concrete lining thickness measuring method according to the present embodiment, the oscillating unit 11 and the receiving unit 13 are attached to the mold 7, and the super magnetostrictive element 31 is used for the oscillating unit 11 for management. Since the S wave is used as the elastic wave, the lining thickness of the unsolidified concrete can be measured. Further, the concrete lining thickness is calculated from the reflection point trajectory obtained by at least the three receiving portions 13. Therefore, the lining thickness can be reliably calculated even when the reflective surface has irregularities.

  Further, since the obtained received wave is analyzed by complex cepstrum analysis, the initial position of the reflected wave having a correlation with the direct wave can be obtained even when the direct wave and the reflection group are mixed. For this reason, it is possible to quickly perform on-site from reading the reflected wave initial motion to calculating the lining thickness.

  In addition, since it is possible to quickly measure the lining thickness of unsolidified concrete, it becomes easy to manage the lining thickness during or after concrete placement. For this reason, the placement pressure can be handled as a management reference value at the next placement, and for example, even when there is an unfilling or an abnormality at the placement, it is possible to respond quickly.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, in the embodiment, one holder 9 is attached to the center of the mold 7, but the attachment position and the number of attachments of the holder 9 to the mold 7 are not limited thereto. Further, the shape of the holder 9 and the arrangement and the number of the oscillation unit 11 and the vibration receiving unit 13 are not limited thereto.

1 ......... Thickness measuring device 3 ......... Mt 5 ......... Concrete 7 ......... Formwork 8 ......... Concrete supply unit 9 ......... Holder 10 ......... Unsolidified concrete 11 ......... Oscillators 13, 13 a, 13 b, 13 c... Vibration receiving unit 15... Control unit 17... Analyzing unit 19... Side plate 21 ... skin plate 23 ... head 25. ... Flange 29 ... Permanent magnet 31 ... Giant magnetostrictive element 33 ... Coil 35 ... Spring 37, 37a, 37b, 37c ... Reflection point locus 39 ... Common reflection point

Claims (7)

Tunnel lining thickness measuring device,
An oscillating portion that is installed in a mold and oscillates vibration with respect to the concrete placed in the mold;
A vibration receiving portion for receiving the vibration started by the oscillation portion;
An analysis unit for analyzing the waveform received by the vibration receiving unit;
Comprising
The oscillation unit is an oscillation device using a giant magnetostrictive element,
The analysis unit includes a waveform separation unit that separates a direct wave propagating directly from the oscillation unit to the receiving unit and a reflected wave from the measurement target unit, and a lining that calculates a lining thickness of the concrete from the reflected wave. A tunnel lining thickness measuring device, comprising: a thickness calculating means. At least three of the vibration receiving units are installed at different distances from the oscillation unit with respect to one oscillation unit,
The lining thickness calculation means includes
The process distance of each wave is calculated from the received vibration information received for each of the vibration receiving parts, and the sum of the distances from the oscillating part and the vibration receiving part with the oscillation part and the vibration receiving part as a focus is the process distance. Assuming the same reflection point trajectory for each of the receiving parts, specifying the point where the reflection point trajectory assumed for each of the receiving parts intersects as a common reflection point, the distance to the common reflection point is the lining thickness The tunnel lining thickness measuring apparatus according to claim 1, wherein:   The waveform separation means separates the direct wave and the reflected wave by complex cepstrum analysis, and the lining thickness calculation means envelops the separated reflected wave by Hilbert analysis, and the maximum amplitude of the envelope The tunnel lining thickness measuring device according to claim 1, wherein the time when the reflected wave travels is analyzed as reflected wave travel time. A method for measuring the lining thickness of a tunnel,
(A) installing a mold having an oscillating part using a giant magnetostrictive element capable of oscillating vibration and a receiving part capable of receiving vibration;
Placing the concrete in the mold (b);
A step (c) of oscillating vibrations in the unsolidified concrete by the oscillating unit;
Receiving the vibration from the concrete in the vibration receiving portion (d),
A step (e) of separating a direct wave propagating directly from the oscillating unit to the receiving unit and a reflected wave from the measuring unit from the information received by the receiving unit;
Calculating the lining thickness of the unsolidified concrete from the reflected wave;
A tunnel lining thickness measuring method, comprising: In the mold, at least three of the vibration receiving parts for one oscillating part are installed at different positions from the oscillating part,
The step (d) is a step of receiving vibration at each of the receiving portions.
In the step (f), the process distance of each wave is calculated from the information received for each vibration receiving unit, and the distances from the oscillation unit and the vibration receiving unit are calculated with the oscillation unit and the vibration receiving unit as a focal point. A reflection point trajectory whose sum is the same as the process distance is assumed for each vibration receiving unit, a point where the reflection point locus assumed for each vibration receiving unit intersects is specified as a common reflection point, and up to the common reflection point 5. The tunnel lining thickness measuring method according to claim 4, wherein the distance is a step of calculating the lining thickness. The step (e) is a step of separating the direct wave and the reflected wave by complex cepstrum analysis,
6. The step (f) is characterized in that the separated reflected wave is enveloped by Hilbert analysis, and the time when the maximum amplitude of the envelope is obtained is analyzed as reflected wave travel time. Tunnel lining thickness measuring device as described in 1. A formwork used for tunnel lining,
An oscillating unit using a giant magnetostrictive element capable of oscillating vibration;
A receiving part capable of receiving the vibration;
Comprising
A formwork characterized in that at least three vibration receiving units for one oscillating unit are provided with holders installed at different distances from the oscillating unit.

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