Concrete pouring management method

Abstract

To provide a concrete pouring management method that enables actual progress of hardening of poured concrete to be grasped.SOLUTION: In a concrete C1 pouring management method, first, a sensor cable 20 is placed in a pouring area 3 between an inner surface 1S of a tunnel 1 and a formwork 2, and then concrete C1 is poured in the pouring area 3. Then, while the concrete C1 is hardening, a pulse wave is applied to the sensor cable 20 to acquire a TDR waveform during hardening. Based on a correlation between propagation speed of the pulse wave propagating through the sensor cable 20 and mechanical strength of the concrete C1, information regarding hardening status of the concrete C1 is output from the propagation speed of the pulse wave in the TDR waveform during hardening.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for controlling concrete pouring. [Background technology]

[0002] In tunnel lining, concrete is poured into a pouring area between the inner circumferential surface of the tunnel and the center (formwork). In tunnel lining, in order to manage the quality of the concrete filled into the pouring area, it is necessary to know whether the concrete has been filled reliably without creating voids or the like. For example, Patent Document 1 describes an unfilled portion detection device for identifying unfilled portions of a tunnel lining.

[0003] The detection device in Patent Document 1 includes a coated conductor wire and a measurement device main body. The coated conductor wire is arranged circumferentially around the inner surface of the tunnel. The measurement device main body applies a pulse wave to the coated conductor wire and detects a reflected pulse wave that is the pulse wave reflected. The detection device in Patent Document 1 detects air pockets by detecting the reflected pulse wave, which is a part of the pulse wave reflected due to a change in characteristic impedance caused by the difference in dielectric properties between concrete and air. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 3204605 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is difficult to check the progress of hardening of concrete poured in the pouring area from the outside. Therefore, in the past, in order to determine the timing of removing the form, the change in compressive strength of the poured concrete over time was measured in advance through laboratory tests, and the decision on whether to remove the form was made based on the measurement results of the change in compressive strength over time. However, this method does not take into account variations in hardening speed due to differences in actual pouring conditions. [Means for solving the problem]

[0006] A concrete management method that solves the above problem involves placing a sensor cable in the pouring area between the inner surface of the tunnel and the formwork, pouring concrete into the pouring area, applying a pulse wave to the sensor cable while the concrete is hardening to obtain a TDR waveform during hardening, and outputting information about the hardening status of the concrete from the propagation speed of the pulse wave in the TDR waveform during hardening, based on the correlation between the propagation speed of the pulse wave propagating through the sensor cable and the mechanical strength of the concrete. [Effects of the Invention]

[0007] According to the present invention, it is possible to grasp the actual progress of hardening of poured concrete. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a cross-sectional structure perpendicular to the axial direction of a tunnel with concrete poured in the pouring area. [Figure 2] FIG. 2 is a schematic diagram showing a cross-sectional structure perpendicular to the axial direction of the tunnel when concrete is being poured into the pouring area. [Figure 3] FIG. 3 is a cross-sectional view of the sensor cable. [Figure 4] FIG. 4 is a block diagram of the measurement system. [Figure 5] FIG. 5 is a graph showing the TDR waveform before concrete is poured. [Figure 6] FIG. 6 is a graph showing the TDR waveform during concrete pouring. [Figure 7] FIG. 7 is a graph showing the TDR waveform immediately after the concrete was poured. [Figure 8] FIG. 8 is a graph showing a TDR waveform in a state where concrete hardening has progressed since the concrete was poured. [Figure 9] FIG. 9 is a graph showing the correlation between the propagation velocity of the pulse wave propagating through the sensor cable and the uniaxial compressive strength of concrete depending on the hardening state of the concrete. [Figure 10] FIG. 10 is a schematic diagram showing an example of a screen displayed on the display unit. [Figure 11] FIG. 11 is a schematic diagram showing the axial configuration inside the tunnel. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, one embodiment of a concrete pouring management method will be described with reference to Figs. [Configuration of tunnel 1 and formwork 2] As shown in FIG. 1, in the concrete pouring management method of this embodiment, the progress of hardening of concrete C1 to be lined on the inner circumferential surface 1S of a tunnel 1 is evaluated.

[0010] The inner surface 1S of the tunnel 1 has any shape, such as a semicircular shape in cross section. Concrete C1 is poured in a pouring area 3 between the inner surface 1S of the tunnel 1 and a formwork 2. The formwork 2 is, for example, a center used in tunnel lining. The formwork 2 is positioned at a predetermined distance from the inner surface 1S of the tunnel 1. The shape of the formwork 2 is determined depending on the shape of the inner surface 1S of the tunnel 1 and the required thickness of the concrete C1 covering the inner surface 1S.

[0011] The pouring area 3 includes a first pouring area 3A and a second pouring area 3B. In a cross-sectional view perpendicular to the tunnel axis direction of the tunnel 1, the first pouring area 3A and the second pouring area 3B are two areas separated by the top end 1T of the tunnel 1. The first pouring area 3A is located on one side of the tunnel 1 in the width direction (left side of the paper) with the top end 1T of the tunnel 1 as the boundary. The second pouring area 3B is located on the other side of the tunnel 1 in the width direction (right side of the paper) with the top end 1T of the tunnel 1 as the boundary, i.e., on the opposite side from the first pouring area 3A.

[0012] The formwork 2 is provided with multiple injection ports 2A. Concrete C1 is poured into the casting area 3 through the injection ports 2A. For example, the multiple injection ports 2A are arranged at different positions in the vertical direction. Concrete C1 is poured into the casting area 3 through injection ports 2A at different heights. The formwork 2 is also provided with an injection port 2A facing the first casting area 3A and an injection port 2A facing the second casting area 3B. Therefore, concrete C1 can be poured into the first casting area 3A and the second casting area 3B simultaneously or separately. The formwork 2 may be provided with injection ports 2A at multiple locations not only in the vertical direction but also in the tunnel axis direction of the tunnel 1.

[0013] [Measurement System 10] In this embodiment, a measurement system 10 is used to evaluate the progress of hardening of concrete C1. The measurement system 10 includes a sensor cable 20, a connection cable 30, a switching unit 31, a measurement unit 40, and a control terminal 50.

[0014] As an example, the sensor cable 20 is a feeder cable. The sensor cable 20 is arranged from top to bottom along the inner circumferential surface 1S of the tunnel 1 in each of the first pouring area 3A and the second pouring area 3B. Hereinafter, the sensor cable 20 arranged in the first pouring area 3A will be referred to as the first sensor cable 20A, and the sensor cable 20 arranged in the second pouring area 3B will be referred to as the second sensor cable 20B. Furthermore, when there is no need to distinguish between the first sensor cable 20A and the second sensor cable 20B, they will simply be referred to as the sensor cables 20.

[0015] The sensor cable 20 is attached, for example, along the inner surface 1S of the tunnel 1, from the top 1T to the bottom 1B of the tunnel 1 in the pouring area 3. The sensor cable 20 has an upper end 20U and a lower end 20L. The upper end 20U is located near the top 1T of the tunnel 1 in the pouring area 3. The lower end 20L is located near the bottom 1B of the tunnel 1 in the pouring area 3.

[0016] The sensor cable 20 is connected to the connection cable 30 at its upper end 20U. A pulse wave is applied to the sensor cable 20 from the measurement unit 40 via the connection cable 30. The upper end 20U is the base end of the sensor cable 20. The lower end 20L is the tip end of the sensor cable 20.

[0017] The connection cable 30 is a power supply line that is less susceptible to changes in external dielectric constant than the sensor cable 20. The connection cable 30 is, for example, a coaxial cable. The connection cable 30 connects the sensor cable 20 and the measurement unit 40 via a switching unit 31. One end of the connection cable 30 is connected to the sensor cable 20 within the pouring area 3, and the other end is connected to the switching unit 31 outside the pouring area 3. Hereinafter, the connection cable 30 connected to the first sensor cable 20A will be referred to as the first connection cable 30A, and the connection cable 30 connected to the second sensor cable 20B will be referred to as the second connection cable 30B. Furthermore, when there is no need to distinguish between the first connection cable 30A and the second connection cable 30B, they will simply be referred to as the connection cable 30.

[0018] The first connection cable 30A, the second connection cable 30B, and the measurement unit 40 are connected to the switching unit 31. The switching unit 31 switches between a state in which a pulse wave from the measurement unit 40 is applied to the first connection cable 30A and a state in which a pulse wave from the measurement unit 40 is applied to the second connection cable 30B. The switching unit 31 is, for example, a high-frequency relay.

[0019] The measuring unit 40 is a TDR (Time Domain Reflectometry) measuring device. The measuring unit 40 applies a pulse wave to the sensor cable 20 via the switching unit 31 and the connection cable 30, and detects a reflected pulse wave that is the pulse wave reflected by the sensor cable 20. The pulse wave from the measuring unit 40 is applied from the upper end 20U, which is the base end side of the sensor cable 20, toward the lower end 20L, which is the tip end side.

[0020] The control terminal 50 is, for example, a laptop computer, but may be another portable terminal such as a tablet. The control terminal 50 acquires a TDR waveform from the intensity of the reflected pulse wave detected by the measurement unit 40.

[0021] The control terminal 50 outputs information about the hardening state of the concrete C1 based on changes in the propagation speed of the pulse wave in the TDR waveform as the hardening progresses. The information about the hardening state is, for example, an estimated value of the mechanical strength of the concrete C1. The information about the hardening state is displayed on a display unit 54 provided in the control terminal 50.

[0022] As shown in FIG. 2, the measurement system 10 can also measure the pouring height H1 when pouring concrete C1 into the pouring area 3. In other words, the measurement system 10 can measure both the pouring height H1 of the concrete C1 during pouring and the strength of the concrete C1 during hardening. The pouring height H1 of the concrete C1 is the vertical distance from the bottom 1B of the tunnel 1 to the pouring surface CS1 of the concrete C1. While the concrete C1 is being poured, a portion of the sensor cable 20 corresponding to the length L1 from the lower end 20L to the pouring surface CS1 is embedded in the concrete C1.

[0023] When measuring the pouring height H1, the measuring unit 40 applies a pulse wave to the sensor cable 20 while pouring concrete C1 into the pouring area 3, and detects a reflected pulse wave that is the pulse wave reflected by the sensor cable 20. The control terminal 50 detects a local reflected pulse wave that is generated when the pulse wave passes through the pouring surface CS1 of the concrete C1 between the upper end 20U and the lower end 20L.

[0024] The control terminal 50 acquires a TDR waveform while pouring concrete C1 into the pouring area 3, and measures a pouring height H1 of the concrete C1 based on the TDR waveform acquired during pouring. In the control terminal 50, the measurement of the pouring height H1 is performed in parallel with the acquisition of the TDR waveform during pouring. The control terminal 50 is equipped with a display unit 54 that displays the measured pouring height H1. The control terminal 50 displays the measured pouring height H1 on the display unit 54 in real time.

[0025] [Sensor Cable 20] 3, the sensor cable 20 is a long, ribbon-shaped electric wire. As an example, the sensor cable 20 is a feeder cable having a characteristic impedance of 300 Ω. The sensor cable 20 includes a pair of core wires 21, a pair of coating portions 22 that cover the core wires 21, and a connecting portion 23 that connects the coating portions 22 together.

[0026] The core wires 21 are metal wires such as copper wires. The pair of core wires 21 are arranged parallel to each other and spaced apart at a fixed distance W1. The sensor cable 20 is configured so that the pair of core wires 21 are not connected to each other at the lower end 20L, which is the tip of the sensor cable 20, and are open ends. For example, insulating tape or the like is provided at the lower end 20L of the sensor cable 20 to prevent the pair of core wires 21 from being electrically connected to each other.

[0027] The covering portion 22 and the connecting portion 23 are integrally formed from, for example, an insulating resin. The covering portion 22 has a cylindrical shape with a substantially uniform thickness in the radial direction. The covering portion 22 suppresses attenuation of the pulse wave passing through the core wire 21. The connecting portion 23 has, for example, a flat band shape with a thickness smaller than the outer diameter of the covering portion 22. Note that the connecting portion 23 may be omitted and the covering portions 22 may be directly connected to each other.

[0028] When a predetermined pulse wave is applied to the sensor cable 20, an electromagnetic field region is formed around the sensor cable 20. The strongest electromagnetic field region is formed inside the sheath 22. Therefore, most of the pulse wave energy propagates within the sheath 22, thereby suppressing attenuation of the energy of the pulse wave. When the pulse wave applied to the sensor cable 20 reaches the lower end 20L, a reflected pulse wave is generated by terminal reflection.

[0029] A first electromagnetic field region 24 is formed near the outside of the covering portion 22. A second electromagnetic field region 25 having a weaker electromagnetic force than the first electromagnetic field region 24 is formed outside the first electromagnetic field region 24. As an example, the second electromagnetic field region 25 is distributed over a range approximately twice the distance W1 between the pair of core wires 21.

[0030] As the pulse wave travels, if there are locations with different dielectric properties in the first electromagnetic field region 24 or the second electromagnetic field region 25, a reflected pulse wave will be generated at those locations. There is a large difference in dielectric properties between the poured concrete C1 and the air. Therefore, when a pulse wave is applied to the sensor cable 20 while the concrete C1 is being poured, a reflected pulse wave will be generated as the pulse wave passes near the pouring surface CS1, which is the boundary between the concrete C1 and the air.

[0031] In the sensor cable 20, the lower the moisture content of the surrounding concrete C1, the faster the propagation speed of the pulse wave. In other words, the propagation speed of the pulse wave in the sensor cable 20 increases as the hydration reaction progresses during hardening of the surrounding concrete C1. Therefore, when the mechanical strength of the concrete C1 increases as hardening progresses, the propagation speed of the pulse wave in the sensor cable 20 also increases.

[0032] [Measurement section 40] 4, the measurement unit 40 includes an application unit 41 and a detection unit 42. The application unit 41 applies a voltage to the connection cable 30 that generates a pulse wave at the upper end 20U of the sensor cable 20. The detection unit 42 detects the intensity of the reflected pulse wave reflected between the upper end 20U and the lower end 20L of the sensor cable 20.

[0033] The application unit 41 applies a pulse wave to each of the first sensor cable 20A and the second sensor cable 20B via the switching unit 31. When the application unit 41 applies a pulse wave to the first sensor cable 20A via the first connection cable 30A, the detection unit 42 detects the intensity of the reflected pulse wave generated by the first sensor cable 20A on the time axis. When the application unit 41 applies a pulse wave to the second sensor cable 20B via the second connection cable 30B, the detection unit 42 detects the intensity of the reflected pulse wave generated by the second sensor cable 20B on the time axis.

[0034] [Control terminal 50] As shown in FIG. 4, the control terminal 50 includes a control unit 51, a storage unit 52, an operation unit 53, a display unit 54, and a communication unit 55.

[0035] The control unit 51 controls, for example, the operation of each unit included in the control terminal 50. Furthermore, the control unit 51 controls the switching of the switching unit 31 and the operation of the application unit 41 and detection unit 42 of the measurement unit 40. The control unit 51 includes, for example, a processor such as a CPU or MPU that executes various processes using software.

[0036] The storage unit 52 includes a temporary memory and a non-volatile memory. The temporary memory temporarily stores data processed by the control terminal 50. The temporary memory is, for example, a RAM. The non-volatile memory is, for example, a flash memory, an HDD, or an SSD.

[0037] The nonvolatile memory stores, for example, tunnel cross-section information, which is data on the cross-sectional shape of the tunnel 1. The nonvolatile memory also stores, in advance, for example, the propagation speed of the pulse wave that propagates through the sensor cable 20 before the concrete C1 is poured, i.e., when air is present around the sensor cable 20. The nonvolatile memory also stores a pouring height acquisition program and a hardening status acquisition program. The control unit 51 controls the operation of the switching unit 31 and the measurement unit 40 by executing the pouring height acquisition program and the hardening status acquisition program.

[0038] The control unit 51 executes a pouring height acquisition program to function as a pouring height acquisition unit 51A. The pouring height acquisition unit 51A applies a pulse wave to the sensor cable 20 while pouring the concrete C1, and controls the measurement unit 40 to detect the reflected pulse wave reflected by the sensor cable 20. The pouring height acquisition unit 51A acquires a TDR waveform based on the intensity of the reflected pulse wave detected by the measurement unit 40 while pouring the concrete C1 into the pouring area 3. The pouring height acquisition unit 51A measures the pouring height H1 based on a change in the intensity of the reflected pulse wave due to a difference in dielectric properties between the air at the pouring surface CS1 and the concrete C1 in the TDR waveform acquired while pouring the concrete C1.

[0039] The control unit 51 executes a hardening status acquisition program to function as a hardening status acquisition unit 51B. The hardening status acquisition unit 51B applies a pulse wave to the sensor cable 20 while the concrete C1 poured in the pouring area 3 is hardening, and controls the measurement unit 40 to detect the reflected pulse wave reflected by the sensor cable 20. The hardening status acquisition unit 51B acquires a TDR waveform based on the intensity of the reflected pulse wave detected by the measurement unit 40 while the concrete C1 is hardening in the pouring area 3. The control terminal 50 outputs the mechanical strength of the concrete C1 from the propagation velocity of the pulse wave in the TDR waveform acquired while the concrete C1 is hardening, based on the correlation between the propagation velocity of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1.

[0040] The operation unit 53 is an input device such as a keyboard or pointing device that allows the operator to operate the control terminal 50. The display unit 54 is a display that displays various information. As an example, the control terminal 50 may be provided with a touch panel that integrates the operation unit 53 and the display unit 54. The communication unit 55 is responsible for communication with the switching unit 31 and the measurement unit 40 via wired or wireless communication.

[0041] [TDR waveform] The TDR waveforms acquired in the casting area 3 will be described with reference to FIGS. 5, a waveform 101 in a graph 100 is an example of a TDR waveform acquired by applying a pulse wave to the sensor cable 20 before concrete C1 is poured into the pouring area 3. The vertical axis of the graph 100 represents the reflection coefficient ρ, which is the ratio of the amplitude of the reflected pulse wave to the amplitude of the incident pulse wave. The horizontal axis of the graph 100 represents time T (propagation time).

[0042] The time T on the horizontal axis can be converted into the distance from the measurement unit 40 based on the propagation speed of the pulse wave in each of the sensor cable 20 and the connection cable 30. By converting the time T on the horizontal axis into the distance from the measurement unit 40, the reflection coefficient ρ in the TDR waveform can be associated with the positions of each part of the connection cable 30 and the sensor cable 20.

[0043] The portion of waveform 101 from point P0 to point P1 represents the reflection coefficient ρ within connection cable 30. The portion of waveform 101 from point P1 to point P2 represents the reflection coefficient ρ within sensor cable 20. Point P0 corresponds to the connection point between connection cable 30 and switching unit 31. Point P1 corresponds to the connection point between connection cable 30 and upper end 20U of sensor cable 20. Point P2 corresponds to lower end 20L, which is the tip of sensor cable 20. Before concrete C1 is poured, air is present in the electromagnetic field region of sensor cable 20 between point P1 and point P2.

[0044] The pulse wave applied from the measuring unit 40 to the connection cable 30 propagates toward the upper end 20U of the sensor cable 20 between points P0 and P1 corresponding to the connection cable 30, with almost no reflected pulse wave. When the pulse wave propagating through the connection cable 30 reaches the upper end 20U (point P1) of the sensor cable 20, the reflection coefficient ρ increases due to the difference in dielectric properties between the sensor cable 20 and the connection cable 30. After showing a steep rise near point P1, the reflection coefficient ρ gradually increases as the waveform 101 approaches point P2. Then, because the lower end 20L of the sensor cable 20 is an open end, a reflected pulse wave is generated due to terminal reflection when the pulse wave reaches the lower end 20L (point P2), and the reflection coefficient ρ increases from point P2 onwards.

[0045] As shown in Figure 6, waveform 201 of graph 200 is an example of a TDR waveform during pouring obtained by applying a pulse wave to sensor cable 20 while concrete C1 is being poured into pouring area 3.

[0046] Points P0 to P2 of waveform 201 correspond to the same locations on sensor cable 20 and connection cable 30 as those on waveform 101. Point P3 of waveform 201 corresponds to a portion of sensor cable 20 that is at the same height as pouring surface CS1 of concrete C1.

[0047] The portion of waveform 201 from point P1 to point P3 represents the reflection coefficient ρ of the portion of sensor cable 20 located above pouring surface CS1 of concrete C1. Between point P1 and point P3, air exists in the electromagnetic field region of sensor cable 20. The portion of waveform 201 from point P3 to point P2 represents the reflection coefficient ρ of the portion of sensor cable 20 located below pouring surface CS1 of concrete C1. Between point P3 and point P2, concrete C1 exists in the electromagnetic field region of sensor cable 20.

[0048] Waveform 201 shows the same tendency as waveform 101 in the portion from point P0 to point P3. When the pulse wave propagating through sensor cable 20 reaches pouring surface CS1, which is the boundary between concrete C1 and air, the reflection coefficient ρ decreases due to a change in characteristic impedance caused by the difference in dielectric properties between air and concrete C1.

[0049] The waveform 201 shows a steep fall near point P3, and then reaches point P2 while maintaining a substantially constant reflection coefficient ρ. When the pulse wave reaches the lower end 20L (point P2), a reflected pulse wave occurs due to terminal reflection, and the reflection coefficient ρ increases from point P2 onwards.

[0050] The pouring height acquisition unit 51A calculates the position of the pouring surface CS1 within the pouring area 3, i.e., the pouring height H1 of the concrete C1, by identifying the value of time T at point P3 in the waveform 201 where the reflection coefficient ρ decreases in the sensor cable 20.

[0051] For example, the pouring height acquisition unit 51A calculates the distance from the upper end 20U of the sensor cable 20 to the pouring surface CS1 based on the time T required for the pulse wave to travel from point P1 to point P3 and the propagation speed of the pulse wave through the sensor cable 20. Next, the pouring height acquisition unit 51A calculates the length L1 from the lower end 20L of the sensor cable 20 to the pouring surface CS1 by subtracting the calculated distance from the upper end 20U of the sensor cable 20 to the pouring surface CS1 from the total length of the sensor cable 20. Then, the pouring height acquisition unit 51A identifies the pouring height H1 corresponding to the length L1 of the sensor cable 20 based on the correspondence between the total length of the sensor cable 20 and the tunnel cross-section information. Through the above procedure, the pouring height acquisition unit 51A calculates the pouring height H1 of the concrete C1.

[0052] Point P3 corresponds to a downward inflection point where the tendency of the change in the reflection coefficient ρ per propagation time, which is the value on the vertical axis of the TDR waveform, changes. Specifically, the portion of waveform 201 from point P1 to point P3 has an upward convex shape. The portion of waveform 201 from point P3 to point P2 has a downward convex shape. That is, waveform 201 switches from an upward convex shape to a downward convex shape at point P3.

[0053] The pouring height acquisition unit 51A can identify the value of time T when the pulse wave reaches the pouring surface CS1 of the concrete C1 by detecting the downward inflection point of the waveform 201. For example, when the reflection coefficient ρ of the waveform 201 is differentiated with respect to time T, the value of time T at which dρ / dT takes the minimum value corresponds to the value of time T at point P3. Therefore, by differentiating the TDR waveform acquired during pouring, the pouring height acquisition unit 51A can detect the downward inflection point in the TDR waveform when the pulse wave passes through the pouring surface CS1.

[0054] 7, waveform 301 of graph 300 is an example of a TDR waveform acquired by applying a pulse wave to sensor cable 20 immediately after concrete C1 is poured into pouring area 3. After concrete C1 is poured, concrete C1 is present in the electromagnetic field region of sensor cable 20 between point P1 and point P2.

[0055] The portion of waveform 301 from point P0 to point P1 shows the same tendency as waveform 101 and waveform 201. When the pulse wave propagating through connection cable 30 reaches upper end 20U (point P1) of sensor cable 20, the reflection coefficient ρ increases due to the difference in dielectric properties between sensor cable 20 and connection cable 30. Waveform 301 shows a steep rise near point P1 and near point P2. Note that after concrete C1 has been poured into pouring area 3, there is no pouring surface CS1, and therefore point P3 seen in waveform 201 is not observed in waveform 301 unless there is an unintended void or the like.

[0056] For comparison, graph 300 shows waveform 101 with a two-dot chain line. In waveform 301, the reflection coefficient ρ from point P1 to point P2 is smaller than in waveform 101 due to the difference in dielectric properties between air and concrete C1. Furthermore, in waveform 301, the time T required for the pulse wave to travel from point P1 to point P2 is longer than in waveform 101. Therefore, the propagation speed of the pulse wave traveling through the sensor cable 20 is slower when concrete C1 is present around the sensor cable 20 than when air is present around the sensor cable 20.

[0057] For example, when the frequency of the pulse wave is set to 2.5 GHz or higher and 3.0 GHz or lower, the relative permittivity (εr) of each substance is 1 for air, 2.3 for polyethylene, about 6 to 8 for polyvinyl chloride, and about 77 for water. Furthermore, the relative permittivity (εr) of other substances is 2.25 for dry sand, 19.4 for sand with a moisture content of 20%, 2.27 for dry clay, 2.88 for clay with a moisture content of 4%, and 19.2% for clay with a moisture content of 20%.

[0058] As shown in FIG. 8, a waveform 401 in a graph 400 is an example of a TDR waveform during hardening that is acquired by applying a pulse wave to the sensor cable 20 while the concrete C1 is hardening.

[0059] In this state, concrete C1 is present in the electromagnetic field region of sensor cable 20 between points P1 and P2, but the amount of moisture contained in concrete C1 has decreased due to a hydration reaction as concrete C1 hardens. Therefore, in waveform 401, the propagation speed of the pulse wave increases as the amount of moisture contained in concrete C1 decreases, and the time T required for the pulse wave to travel from point P1 to point P2 is shorter than in waveform 301. That is, in waveform 401, the position of point P2 is shifted to the left compared to waveform 301, and the entire waveform is shortened to the left between points P1 and P2. For comparison, waveform 301 is shown in graph 400 by a two-dot chain line.

[0060] As shown in FIG. 9, an approximate curve 501 of a graph 500 represents the change in the propagation velocity (m / ns) of the pulse wave propagating through the sensor cable 20 with respect to the number of days elapsed since the start of hardening after pouring of the concrete C1. The propagation velocity of the pulse wave in the approximate curve 501 is calculated by dividing the total length of the sensor cable 20 by the time T required for the pulse wave to reach point P2 from point P1 at any time point after the start of hardening. A plurality of data points 502 of the graph 500 represent the change in the unconfined compressive strength (N / mm 2 ) represents the change in unconfined compressive strength. Note that the unconfined compressive strength is an example of the mechanical strength of concrete C1.

[0061] In the approximation curve 501, as the hardening of the concrete C1 progresses, the propagation velocity of the pulse wave increases due to a decrease in the water content caused by a hydration reaction when the concrete C1 hardens. Furthermore, at multiple data points 502, the mechanical strength of the concrete C1 increases as the hardening of the concrete C1 progresses. In other words, the graph 500 represents the correlation between the propagation velocity of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1 depending on the hardening state of the concrete C1. A correlation such as that shown in the graph 500 is pre-stored in the memory unit 52 of the control terminal 50.

[0062] For example, a correlation such as that shown in graph 500 may be obtained in advance by a laboratory test or the like before the concrete C1 is lined. In the laboratory test, a first correspondence relationship between the hardening time of the concrete C1 and the propagation velocity of the pulse wave propagating through the sensor cable 20 is obtained, and a second correspondence relationship between the hardening time of the concrete C1 and the mechanical strength of the concrete C1 is obtained. Then, based on the first correspondence relationship and the second correspondence relationship having the hardening time of the concrete C1 as a common variable, the correlation between the propagation velocity of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1 may be derived. Note that the approximation curve 501 is an example of the first correspondence relationship. Furthermore, the multiple data points 502 are an example of the second correspondence relationship.

[0063] The hardening status acquisition unit 51B acquires a TDR waveform such as waveform 401 in graph 400 while the concrete C1 is hardening, and measures the propagation speed of a pulse wave propagating through the sensor cable 20 based on the acquired TDR waveform. Based on the correlation between the propagation speed of the pulse wave propagating through the sensor cable 20 and the strength of the concrete C1, the hardening status acquisition unit 51B can output the mechanical strength of the concrete C1 from the propagation speed of the pulse wave in the TDR waveform acquired while the concrete C1 is hardening.

[0064] For example, concrete C1 can be determined to be able to be removed from the formwork if its uniaxial compressive strength is equal to or greater than the strength threshold value σ1. In other words, the strength threshold value σ1 is the value of uniaxial compressive strength that serves as a threshold for determining whether or not the formwork 2 can be removed. Furthermore, when the concrete C1 has hardened to such an extent that it exhibits the strength threshold value σ1 as its uniaxial compressive strength, the propagation speed when a pulse wave is applied to the sensor cable 20 is set to the velocity threshold value V1.

[0065] In this case, the hardening status acquisition unit 51B may determine that the uniaxial compressive strength of the concrete C1 is equal to the strength threshold value σ1 if the propagation velocity of the pulse wave propagating through the sensor cable 20 is equal to or greater than the velocity threshold value V1. The determination result that the formwork 2 can be removed may then be displayed on the display unit 54. For example, the velocity threshold value V1 may be stored in the storage unit 52. Such a correspondence relationship between the strength threshold value σ1 and the velocity threshold value V1 is also an example of the correlation between the propagation velocity of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1.

[0066] [Concrete C1 pouring management method] Hereinafter, a description will be given of a pouring control method for concrete C1 using the measurement system 10. The pouring control method of this embodiment includes a method for measuring the pouring height H1 of concrete C1 and a method for evaluating the hardening state of concrete C1.

[0067] First, the sensor cable 20 is placed from above to below in the pouring area 3. More specifically, the first sensor cable 20A connected to the first connection cable 30A is placed from above to below in the first pouring area 3A. Then, the second sensor cable 20B connected to the second connection cable 30B is placed from above to below in the second pouring area 3B.

[0068] The sensor cable 20 is attached to the inner surface 1S of the tunnel 1 so that the upper end 20U connected to the connection cable 30 is located near the top end 1T. The connection cable 30 is led out from near the top end 1T along the tunnel axis direction of the tunnel 1 to the outside of the pouring area 3 and is connected to a switching unit 31 located outside the pouring area 3. In the pouring area 3, the inner surface 1S of the tunnel 1 may be covered with a resin covering sheet. In this case, the sensor cable 20 is attached to the covering sheet that covers the inner surface 1S.

[0069] Next, while pouring concrete C1 in the pouring area 3, the measurement system 10 is used to measure the pouring height H1. Specifically, in both the first pouring area 3A and the second pouring area 3B, the concrete C1 is poured in order starting from the injection port 2A located at the bottom. For example, the concrete C1 is poured simultaneously in the first pouring area 3A and the second pouring area 3B. The pouring height acquisition unit 51A measures the pouring height H1 in each of the first pouring area 3A and the second pouring area 3B.

[0070] The pouring height acquisition unit 51A applies a pulse wave to either the first sensor cable 20A or the second sensor cable 20B by controlling the switching unit 31 and the application unit 41. The pouring height acquisition unit 51A acquires a TDR waveform such as waveform 201 in graph 200 based on the intensity of the reflected pulse wave detected by the detection unit 42. In parallel with acquiring the TDR waveform, the pouring height acquisition unit 51A measures the pouring height H1 by detecting a descending inflection point in the TDR waveform. The pouring height acquisition unit 51A immediately displays the measured pouring height H1 on the display unit 54.

[0071] The pouring height acquisition unit 51A continues to measure the pouring height H1 from the start of pouring the concrete C1 into the pouring area 3 until the concrete C1 has been poured into the entire pouring area 3. The pouring height acquisition unit 51A updates the measurement result of the pouring height H1 displayed on the display unit 54 every time the measurement result of the pouring height H1 is updated.

[0072] The pouring height acquisition unit 51A controls the switching unit 31 to alternately measure the pouring height H1 of the first pouring zone 3A and the pouring height H1 of the second pouring zone 3B at predetermined time intervals. In other words, the pouring height acquisition unit 51A controls the switching unit 31 to switch between measuring the pouring height H1 of the first pouring zone 3A and measuring the pouring height H1 of the second pouring zone 3B at predetermined time intervals. This allows the pouring height H1 of both the first pouring zone 3A and the second pouring zone 3B to be measured while pouring concrete C1 in both the first pouring zone 3A and the second pouring zone 3B.

[0073] For example, first, the pouring height acquisition unit 51A controls the switching unit 31 to measure the pouring height H1 of the first pouring area 3A based on the first TDR waveform acquired by applying a pulse wave to the first sensor cable 20A. Next, the pouring height acquisition unit 51A measures the pouring height H1 of the second pouring area 3B based on the second TDR waveform acquired by applying a pulse wave to the second sensor cable 20B. By repeating this process, the pouring heights H1 of both the first pouring area 3A and the second pouring area 3B can be measured using a single measurement unit 40.

[0074] 10 shows an example of an image displayed on the display unit 54 while concrete C1 is being poured. The image displayed on the display unit 54 includes, for example, a measurement time display area 54A, a pouring height display area 54B, and a tunnel cross section display area 54C.

[0075] The measurement time display area 54A displays the time when the pouring height H1 was measured. The pouring height display area 54B displays the pouring height H1 of the first pouring area 3A and the second pouring area 3B separately. The tunnel cross section display area 54C displays the cross-sectional shape of the tunnel 1 based on the tunnel cross section information. In addition to the cross-sectional shape of the tunnel 1, the tunnel cross section display area 54C displays a pouring surface display section 54D that shows the position of the pouring surface CS1 within the cross section of the tunnel 1. When the measurement result of the pouring height H1 is updated, the image displayed on the display unit 54 is also updated. Therefore, the measurement result of the pouring height H1 is displayed on the display unit 54 in real time.

[0076] Next, at any timing after the concrete C1 has been poured into the pouring area 3, the measurement system 10 is used to evaluate the progress of hardening of the concrete C1. For example, the hardening status acquisition unit 51B evaluates the progress of hardening of the concrete C1 in each of the first pouring area 3A and the second pouring area 3B.

[0077] In detail, the hardening status acquisition unit 51B applies a pulse wave to either the first sensor cable 20A or the second sensor cable 20B by controlling the switching unit 31 and the application unit 41. The hardening status acquisition unit 51B acquires a TDR waveform such as waveform 401 in graph 400 based on the intensity of the reflected pulse wave detected by the detection unit 42. The hardening status acquisition unit 51B measures the propagation speed of the pulse wave propagating through the sensor cable 20 in the TDR waveform acquired while the concrete C1 is hardening. The hardening status acquisition unit 51B outputs information regarding the hardening status of the concrete C1 from the acquired propagation speed based on the correlation between the propagation speed of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1.

[0078] For example, the hardening status acquisition unit 51B controls the switching unit 31 and the application unit 41 to output information about the hardening status of the concrete C1 poured in the first pouring area 3A from the propagation speed of a first TDR waveform acquired by applying a pulse wave to the first sensor cable 20A. Next, the hardening status acquisition unit 51B controls the switching unit 31 and the application unit 41 to output information about the hardening status of the concrete C1 poured in the second pouring area 3B from the propagation speed of a second TDR waveform acquired by applying a pulse wave to the second sensor cable 20B.

[0079] For example, the hardening status acquisition unit 51B outputs an estimated value of the mechanical strength of the concrete C1 as information relating to the hardening status of the concrete C1. Alternatively, or in addition, the hardening status acquisition unit 51B outputs, as information relating to the hardening status of the concrete C1, a determination result as to whether the concrete C1 has a mechanical strength sufficient to allow removal of the formwork 2. The hardening status acquisition unit 51B displays information relating to the hardening status of the concrete C1 on the display unit 54.

[0080] As shown in Figure 11, the lining of tunnel 1 is carried out in pouring sections, which are sections of the tunnel 1 separated by a predetermined length in the tunnel axis direction. Figure 11 illustrates a first pouring section S1 in which the concrete C1 has completely hardened, and a second pouring section S2 in which the concrete C1 is being poured in the pouring area 3. Note that Figure 11 also shows a schematic representation of the positions of the concrete C1, sensor cable 20, and connection cable 30 in the tunnel axis direction within the pouring area 3. In each pouring section, the sensor cable 20 is positioned in the center of the pouring area 3 in the tunnel axis direction.

[0081] In the first pouring section S1 where the concrete C1 has completely hardened, the sensor cable 20 and the connection cable 30 are buried inside the concrete C1. The portion of the connection cable 30 that extends from the pouring area 3 to the outside is cut off after the concrete C1 has completely hardened. Therefore, in the method for managing pouring of the concrete C1 using the measurement system 10, a new sensor cable 20 and connection cable 30 are used for each pouring section.

[0082] [Effects of the embodiment] (1) As the hardening of the concrete C1 located around the sensor cable 20 progresses, the amount of water contained in the concrete C1 decreases due to a hydration reaction, and the propagation speed of the pulse wave propagating through the sensor cable 20 increases. Therefore, by measuring the propagation speed of the pulse wave in the TDR waveform acquired while the concrete C1 is hardening, the actual progress of the hydration reaction in the concrete C1 can be quantitatively evaluated. As described above, by outputting information regarding the hardening status of the concrete C1 from the propagation speed of the pulse wave in the TDR waveform acquired while the concrete C1 is hardening based on the correlation shown in graph 500, the actual hardening status of the concrete C1 can be quantitatively grasped.

[0083] (2) In this embodiment, a first correspondence relationship representing a change in the propagation time of the pulse wave propagating through the sensor cable 20 relative to the hardening time of the concrete C1, and a second correspondence relationship representing a change in the mechanical strength of the concrete C1 relative to the hardening time of the concrete C1 are obtained in advance. Then, based on the first correspondence relationship and the second correspondence relationship, a correlation between the propagation speed of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1 is obtained in advance before the concrete C1 is poured into the pouring area 3. This method allows the correlation between the propagation speed of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1 to be optimized in accordance with the type and composition of the concrete C1.

[0084] (3) According to the pouring management method of this embodiment, the sensor cable 20 arranged in the pouring area 3 can both measure the pouring height H1 when pouring the concrete C1 and evaluate the hardening status of the concrete C1 during hardening.

[0085] (4) The hardening status acquisition unit 51B controls the switching unit 31 and the application unit 41 to separately output information regarding the hardening status of the concrete C1 poured in the first pouring zone 3A and information regarding the hardening status of the concrete C1 poured in the second pouring zone 3B. This allows the hardening status of the concrete C1 to be individually evaluated for each of the first pouring zone 3A and the second pouring zone 3B that make up the pouring zone 3. Furthermore, by placing the first sensor cable 20A in the first pouring zone 3A and the second sensor cable 20B in the second pouring zone 3B, the pouring height H1 of the concrete C1 can be measured in both the first pouring zone 3A and the second pouring zone 3B.

[0086] (5) By using a feeder cable as the sensor cable 20, the decrease in the moisture content of the concrete C1 due to the hydration reaction as the concrete C1 hardens can be detected by the electromagnetic field area formed around the feeder cable. In addition, the difference in the dielectric properties between the air and the concrete C1 at the pouring surface CS1 of the concrete C1 can be detected by the electromagnetic field area formed around the feeder cable.

[0087] (6) By acquiring a TDR waveform using the sensor cable 20 arranged from the top 1T to the bottom 1B of the tunnel 1, the overall trend in the vertical direction of the concrete C1 poured in the pouring area 3 is reflected in the TDR waveform. By outputting information on the hardening status of the concrete C1 from the propagation speed of the pulse wave in the TDR waveform acquired in this way, it is possible to output information that reflects the overall hardening status in the vertical direction of the concrete C1 poured in the pouring area 3.

[0088] (7) In the pouring area 3, the sensor cable 20 is arranged from top to bottom, so that the pulse wave from the application unit 41 is input from top to bottom to the sensor cable 20. Therefore, during the pouring of the concrete C1, the pulse wave propagates with little attenuation in the sensor cable 20 from the air side, where the loss coefficient of the pulse wave is small, to the concrete C1 side, where the loss coefficient of the pulse wave is large. In other words, by acquiring a TDR waveform during the pouring of the concrete C1 using the sensor cable 20 arranged from top to bottom in the pouring area 3, it is possible to reduce the attenuation of the pulse wave until it reaches the pouring surface CS1 of the concrete C1. Therefore, in the TDR waveform acquired during pouring, it is easy to capture the change in the TDR waveform when the pulse wave reaches the pouring surface CS1 of the concrete C1.

[0089] (8) The sensor cable 20 is attached downward from the top 1T of the tunnel 1 along the inner surface 1S of the tunnel 1. By measuring the pouring height H1 from the TDR waveform acquired using the sensor cable 20 arranged in this manner, it can be confirmed that the concrete C1 has been sufficiently filled up to the inner surface 1S of the tunnel 1, even near the top 1T.

[0090] (9) By detecting the downward inflection point in the TDR waveform acquired during the pouring of concrete C1, it is possible to more accurately capture the change in the TDR waveform when the pulse wave reaches the pouring surface CS1 of concrete C1. In addition, by detecting the downward inflection point in the TDR waveform in parallel with the acquisition of the TDR waveform, it is possible to display the pouring height H1 in real time.

[0091] (10) By providing the switching unit 31, it is possible to acquire TDR waveforms of multiple sensor cables 20 using a single measurement unit 40. As a result, even when concrete C1 is poured simultaneously in the first pouring area 3A and the second pouring area 3B, the pouring height H1 of the concrete C1 in each of the first pouring area 3A and the second pouring area 3B can be measured using a single measurement unit 40. Furthermore, the hardening status of the concrete C1 in the first pouring area 3A and the second pouring area 3B can be evaluated separately using a single measurement unit 40.

[0092] (11) By providing a connection cable 30 between the sensor cable 20 and the measuring unit 40, the intensity of the pulse wave applied from the measuring unit 40 can be prevented from attenuating before it reaches the pouring area 3.

[0093] [Example of change] The above embodiment can be modified as follows: The following modifications can be implemented in combination with each other within the scope of technical compatibility.

[0094] The sensor cable 20 is not limited to a feeder cable, but may be any cable that can detect changes in the moisture content of the concrete C1 as it hardens. The measurement system 10 may omit the switching unit 31. In this case, instead of pouring concrete C1 into both the first pouring zone 3A and the second pouring zone 3B simultaneously, concrete C1 may be poured into one of the first pouring zone 3A and the second pouring zone 3B and then poured into the other pouring zone. In this case, the connection cable 30 connected to the sensor cable 20 located in the pouring zone 3 between the first pouring zone 3A and the second pouring zone 3B where concrete C1 is poured may be connected directly to the measurement unit 40 without using the switching unit 31. Furthermore, the connection cable 30 connected to the sensor cable 20 located in the pouring zone 3 between the first pouring zone 3A and the second pouring zone 3B where the hardening state of the concrete C1 is to be evaluated may be connected directly to the measurement unit 40 without using the switching unit 31.

[0095] Instead of connecting the first connection cable 30A and the second connection cable 30B to one measurement unit 40 via the switching unit 31, the first connection cable 30A and the second connection cable 30B may be connected to separate measurement units 40. In this case, it is not necessary to alternately measure the pouring height H1 of the first pouring area 3A and the pouring height H1 of the second pouring area 3B. In other words, it is possible to measure the pouring height H1 throughout the entire process, from the start of pouring to the end of pouring, in each of the first pouring area 3A and the second pouring area 3B.

[0096] Although an example has been given in which the sensor cable 20 is placed in both the first pouring area 3A and the second pouring area 3B, the sensor cable 20 may be placed in only one of the first pouring area 3A and the second pouring area 3B.

[0097] In measuring the pouring height H1, a method for identifying the downward inflection point (point P3) in the TDR waveform by differentiating the TDR waveform was exemplified, but this is not limited to this, and the time T of point P3 in the TDR waveform can be identified by any method.

[0098] While the example shown here illustrates the placement of the sensor cable 20 along the inner circumferential surface 1S of the tunnel 1, the sensor cable 20 may alternatively be attached from the top of the formwork 2 downward along the outer circumferential surface of the formwork 2. In this case, a portion of the formwork 2 may be made of resin to prevent the metal portion of the formwork 2 from entering the electromagnetic field region of the sensor cable 20, or another member may be interposed between the formwork 2 and the sensor cable 20. In this case, when the formwork 2 is removed, the sensor cable 20 can be removed from the concrete C1 along with the formwork 2, making it possible to reuse the sensor cable 20. Furthermore, because the sensor cable 20 is not placed between the inner circumferential surface 1S of the tunnel 1 and the concrete C1, the adhesion of the concrete C1 to the inner circumferential surface 1S of the tunnel 1 can be improved.

[0099] The sensor cable 20 and the measuring unit 40 (or the switching unit 31) may be directly connected without providing the connection cable 30. In each concrete pouring section, multiple sensor cables 20 may be arranged in the tunnel axial direction. In this case, multiple measurement units 40 may be used depending on the number of sensor cables 20, or multiple sensor cables 20 may be connected to the measurement units 40 via the switching unit 31.

[0100] The pouring height H1 of the concrete C1 may be the circumferential length L1 of the tunnel 1 instead of the vertical distance from the bottom of the pouring area 3 to the pouring surface CS1. The circumferential length L1 of the tunnel 1 may be the distance along the inner surface 1S of the tunnel 1 between the bottom 1B of the tunnel 1 and the pouring surface CS1, or may be the distance along the outer surface of the formwork 2.

[0101] The sensor cable 20 may be arranged in an upward direction in the pouring area 3. In other words, the pulse wave from the application unit 41 may be input to the sensor cable 20 in an upward direction from below.

[0102] In the method for managing the pouring of concrete C1, measurement of the pouring height H1 during pouring of concrete C1 may be omitted. The sensor cable 20 is not limited to being arranged in the pouring area 3 from the top 1T to the bottom 1B of the tunnel 1, but may be arranged, for example, in any part between the top 1T and the bottom 1B of the tunnel 1. Even in this case, the hardening condition of the concrete C1 in the entire pouring area 3 can be inferred from the hardening condition of the concrete C1 in the part of the pouring area 3 where the sensor cable 20 is arranged.

[0103] A single sensor cable 20 may be arranged to span both the first pouring area 3A and the second pouring area 3B. In this case, the single sensor cable 20 can acquire TDR waveforms that reflect the hardening conditions of both the first pouring area 3A and the second pouring area 3B.

[0104] The procedure for acquiring the correlation between the propagation velocity of the pulse wave propagating through the sensor cable 20 and the mechanical strength of the concrete C1 is not limited. For example, the correlation between the propagation velocity of the pulse wave and the mechanical strength of the concrete C1 may be acquired directly without using the setting time of the concrete C1, which is a common variable in the first and second correspondence relationships. Furthermore, it is not necessary to acquire the correlation every time the concrete C1 is poured into the pouring area 3. For example, if the concrete C1 has the same moisture content as another concrete C1 for which a correlation has been acquired, the procedure for acquiring the correlation may be omitted and the correlation for the other concrete C1 may be used instead. Alternatively, if the concrete C1 has the same composition or is from the same lot as another concrete C1 for which a correlation has been acquired, the procedure for acquiring the correlation may be omitted and the correlation for the other concrete C1 may be used instead.

[0105] The correlation between the propagation velocity of the pulse wave in the TDR waveform acquired during hardening of the concrete C1 and the mechanical strength of the concrete C1 may be stored in the storage unit 52 in the form of a graph 500, or in the form of a table or a relational expression. The mechanical strength of the concrete C1 may be a physical property value for any mechanical strength other than the unconfined compressive strength.

[0106] [Note] According to the above embodiment and its modifications, the following technical ideas can be further derived. (Appendix 1) The sensor cable is a feeder cable including a pair of core wires arranged parallel to each other and spaced apart at a fixed interval, and a covering portion covering the pair of core wires. 2. The method for controlling concrete pouring according to claim 1.

[0107] (Appendix 2) The sensor cable is arranged in the pouring area from the top to the bottom of the tunnel. 2. The method for controlling concrete pouring according to claim 1. [Explanation of symbols]

[0108] ρ...reflection coefficient, C1...concrete, CS1...casting surface, D...distance, H1...casting height, L1...length, P0~P3...point, S1...first casting section, S2...second casting section, W1...spacing, 1...tunnel, 1B...bottom, 1S...inner surface, 1T...top, 2...formwork, 2A...pressure inlet, 3...casting area, 3A...first casting area, 3B...second casting area, 10...measurement system, 20...sensor cable, 20A...first sensor cable, 20B...second sensor cable, 20L...bottom end, 20U...top end, 21...core wire, 22...coating part, 23...connecting part, 24...first electromagnetic field area, 25...second electromagnetic Boundary area, 30...connection cable, 30A...first connection cable, 30B...second connection cable, 31...switching unit, 40...measuring unit, 41...application unit, 42...detection unit, 50...control terminal, 51...control unit, 51A...pouring height acquisition unit, 51B...hardening status acquisition unit, 52...memory unit, 53...operation unit, 54...display unit, 54A...measurement time display area, 54B...pouring height display area, 54C...tunnel cross section display area, 54D...pouring surface display unit, 55...communication unit, 100,200,300,400,500...graph, 101,201,301,401...waveform, 501...approximate curve, 502...data point.

Claims

1. A sensor cable is placed in the pouring area between the inner surface of the tunnel and the formwork, Pouring concrete into the pouring area; While the concrete is hardening, a pulse wave is applied to the sensor cable to acquire a TDR waveform during hardening; Based on the correlation between the propagation speed of the pulse wave propagating through the sensor cable and the mechanical strength of the concrete, information regarding the hardening state of the concrete is output from the propagation speed of the pulse wave in the TDR waveform during hardening. A concrete pouring management method characterized by the above.

2. Before pouring the concrete into the pouring area, obtaining a first correspondence relationship between a hardening time of the concrete and a propagation velocity of a pulse wave propagating through the sensor cable; obtaining a second correspondence relationship between the hardening time of the concrete and the mechanical strength of the concrete; The correlation between the propagation velocity of the pulse wave propagating through the sensor cable and the mechanical strength of the concrete is acquired in advance based on the first correspondence relationship and the second correspondence relationship.

2. The method for controlling concrete pouring according to claim 1.

3. When pouring the concrete into the pouring area, a TDR waveform during pouring is acquired using the sensor cable while pouring the concrete; The concrete pouring height is measured based on a change in the intensity of the reflected pulse wave due to a difference in dielectric properties between the air at the concrete pouring surface and the concrete in the TDR waveform during pouring.

3. The method for controlling concrete pouring according to claim 1 or 2.

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