A system and method for measuring axial deformation of a tunnel

Abstract

The present invention provides a system and method for measuring the axial deformation of a tunnel, comprising two reflective plates arranged at intervals along the axial direction of the tunnel, the two reflective plates are parallel to each other and perpendicular to the axial direction of the tunnel, laser reflectors and photoelectric display boards are arranged at the upper and lower ends of the reflective plates, a tube beam emitted by a laser emitter is irradiated on the photoelectric display board after multiple reflections, and then according to the distance between the imaging position of the light spot and the starting point of the light source, the number of refracted lines of the light beam, and the reflection angle of the light beam, the light path is equivalent to a triangle and the axial deformation of the tunnel is calculated. The device has a simple structure and is easy to operate, and at the same time, the light beam line is used as a calculation parameter to improve the measurement accuracy.

Description

Technical Field

[0001] The invention relates to the field of tunnel construction, and in particular to a system and method for measuring the axial deformation of a tunnel. Background Art

[0002] Tunnels are engineering structures buried in the ground and are a form of human utilization of underground space. In order to ensure the safe operation of tunnels, people need to conduct regular safety inspections of tunnels, which includes determining whether there are cracks on the tunnel walls and detecting the axial deformation of the tunnel.

[0003] Currently, vibrating-wire sensors and resistance strain gauges are used to monitor cracks in subway tunnels. The data measured by the above equipment needs to be converted to identify the deformation of the tunnel, and the data processing is complex and difficult to be accurate. If optical fiber sensor monitoring technology is used, this method is too costly and the elongation of the sensor system is limited.

[0004] In view of the above problems, it is necessary to design a new measurement system to realize fast and accurate detection of tunnel deformation. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a system and method for measuring the axial deformation of a tunnel, which adopts optical principles to measure the axial deformation of the tunnel, thereby improving the measurement efficiency and accuracy.

[0006] The present invention is achieved through the following technical solutions:

[0007] A system for measuring the axial deformation of a tunnel comprises a laser emitter, a photoelectric display panel, and two reflective plates arranged at intervals along the axis of the tunnel, wherein the two reflective plates are symmetrically arranged and perpendicular to the axis of the tunnel, and the axis is a straight line;

[0008] The laser emitter and the photoelectric display board are arranged on one of the reflective boards, or respectively on the two reflective boards. The laser emitter and the photoelectric display board are respectively arranged at the upper and lower ends of the reflective board. The light beam emitted by the laser emitter can be irradiated on the photoelectric display board after multiple reflections.

[0009] Preferably, the reflector is connected to the base via an adjusting device, the base is fixed on the side wall of the tunnel, and the adjusting device is used to adjust the angle of the reflector.

[0010] Preferably, the reflective plate is fixed to the guard plate, and the guard plate is connected to the base through an adjustment device.

[0011] Preferably, the adjusting device includes a sleeve, a rotating shaft and a locking device. The sleeve is arranged on the side wall of the guard plate and extends toward one side of the base. The rotating shaft is arranged on the base, and the end of the rotating shaft is fitted in the sleeve. The locking device is used to limit the rotation direction of the sleeve.

[0012] Preferably, the limiting device is a nut, the sleeve is connected to the rotating shaft through threads, and the nut is arranged on the rotating shaft.

[0013] Preferably, a supporting device is provided between the guard plate and the base, and includes a supporting rod and a slide groove;

[0014] The support rod is arranged parallel to the rotating shaft, one end of the support rod is fixedly connected to the guard plate, the slide groove is arranged on the surface of the bottom plate, the end of the support rod is fitted in the slide groove and can move along the slide groove.

[0015] Preferably, the slide groove is an arc-shaped groove, the center of which is concentric with the rotation axis.

[0016] Preferably, a bearing is provided at the end of the support rod, and the bearing is located in the slide groove.

[0017] Preferably, a calibration point is provided on the reflective plate directly facing the laser emitter, and the laser beam is irradiated on the calibration point to calibrate the parallelism of the two reflective plates.

[0018] A system for measuring axial deformation of a tunnel comprises the following steps:

[0019] Step 1, setting marking points at intervals along the axial direction of the undeformed tunnel;

[0020] Step 2: After the tunnel is deformed, a base is installed at two marking points on both sides of the deformation area, and a guard plate with a reflector is installed on the base, so that the reflector is perpendicular to the axial direction of the tunnel and the surface of the reflector is flush with the marking points;

[0021] Step 3: Adjust the emission angle of the laser transmitter to emit a laser beam toward the reflector facing the reflector. After multiple reflections, the laser beam is irradiated onto the photoelectric display board.

[0022] Step 4, obtaining the number of light rays n that are reflected between the two planes during the period from the laser emission to the irradiation on the photoelectric display panel, as well as the laser emission angle θ, the initial distance L between the two marking points, and calculating the axial deformation l according to the obtained parameters;

[0023]

[0024] Among them, △L is the side length of the laser emitter, H1 is the height of the reflector on the same guard plate as the laser emitter, and h is the scale value of the light spot on the light spot display board.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The present invention provides a system for measuring the axial deformation of a tunnel, comprising two reflective plates arranged at intervals along the axial direction of the tunnel, the two reflective plates are parallel to each other and perpendicular to the axial direction of the tunnel, laser reflectors and photoelectric display boards are arranged at the upper and lower ends of the reflective plates, a tube beam emitted by a laser emitter is irradiated on the photoelectric display board after multiple reflections, and then according to the distance between the imaging position of the light spot and the starting point of the light source, the number of refracted lines of the light beam, and the reflection angle of the light beam, the light path is equivalent to a triangle and the axial deformation of the tunnel is calculated. The device has a simple structure and is easy to operate, and at the same time, the light beam line is used as a calculation parameter to improve the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a front view of the measuring system of the present invention;

[0028] Figure 2 is a top view of the measurement system of the present invention;

[0029] Figure 3 is a side view of the measuring system of the present invention;

[0030] Figure 4 is a side view of the guard plate of the present invention;

[0031] Figure 5 It is a front view of the base plate of the present invention.

[0032] In the figure: 1. guard plate; 2. reflector; 3. photoelectric display board; 4. laser transmitter; 5. base; 6. support rod; 7. bearing; 8. bushing; 9. rotating shaft; 10. locking nut. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings, which are intended to explain the present invention rather than to limit it.

[0034] See also Figure 1-5 , a system for measuring the axial deformation of a tunnel, comprising a laser emitter 4, a photoelectric display board 3, and two reflectors spaced apart along the axis of the tunnel, the two reflectors being symmetrically arranged and perpendicular to the axis of the tunnel, the axis being a straight line;

[0035] The laser emitter 4 and the photoelectric display board 3 are arranged on one of the reflective plates 2, or respectively on two reflective plates 2. The laser emitter 4 and the photoelectric display board 3 are respectively arranged at the upper and lower ends of the reflective plate. The light beam emitted by the laser emitter 4 can be irradiated on the photoelectric display board 3 after multiple reflections.

[0036] The reflector 2 is fixedly hung on the side wall of the tunnel through the base 5. The hanging setting makes it easy to adjust the angle of the reflector. At the same time, since the reflector is made of glass, it is easy to break and is not conducive to hanging installation. The reflector is fixed on the guard plate, and the guard plate 1 is connected to the base 5.

[0037] Specifically, the base 5 is fixed on the side wall of the tunnel, and the guard plate 1 is connected to the base through an adjusting device, and the adjusting device is used to control the light reflection angle of the reflective plate 2.

[0038] The adjusting device includes a sleeve 8, a rotating shaft 9 and a locking device. The sleeve 8 is arranged on the side wall of the guard plate 1 and extends to one side of the base. The rotating shaft is arranged at the center of the base, and the end of the rotating shaft is mounted in the sleeve 8. The sleeve and the rotating shaft are connected by threads. The locking device is used to limit the circumferential position of the sleeve, that is, to position the angle of the reflector.

[0039] The locking device is a locking nut, which is sleeved on the rotating shaft 9. After the angle adjustment of the reflector is completed, the locking nut is rotated to abut against the end of the sleeve, so that the circumferential positioning of the sleeve can be achieved.

[0040] In another embodiment, the locking device is a top screw, which is arranged on the sleeve. When the sleeve is positioned circumferentially, the top screw is rotated so that its end passes through the sleeve and abuts against the rotating shaft, thereby completing the circumferential positioning of the sleeve.

[0041] Similarly, the shaft sleeve and the rotating shaft can also be arranged in a transposed manner, with the shaft sleeve being arranged at the center of the base plate and the rotating shaft being arranged at the center of the side wall of the guard plate.

[0042] Furthermore, a supporting device is provided between the guard plate and the base to provide stability for the reflector, the supporting device comprises a supporting rod 6 and a bearing 7, the supporting rod is provided in parallel with the rotating shaft, one end of the supporting rod is fixedly connected to the guard plate, the bearing 7 is provided at the other end of the supporting rod, a sliding groove is provided on the surface of the base opposite to the guard plate, the bearing is fitted in the sliding groove, when the angle of the reflector is adjusted, the bearing can slide in the sliding groove, the sliding groove is an arc groove, the guard plate is supported on the sliding groove of the base through the supporting plate, which will greatly reduce the force on the rotating shaft and make the adjustment of the reflector more convenient.

[0043] The guard plate is provided with a plurality of supporting devices, preferably two, which are respectively provided at the upper and lower ends of the guard plate.

[0044] The laser emitter 4 and the photoelectric display board 3 are arranged on the same reflective board. The photoelectric display board is located on the top of the reflective board 2 and fixed on the guard plate. The laser reflector is located at the bottom of the reflective board and is also connected to the guard plate.

[0045] The laser emitter 4 includes a shell and a rotatable light source arranged inside the shell. A dividing plate is arranged on the surface of the shell, and the dividing plate is transparent. The light source is connected to an adjustment handle, and the handle extends out of the shell. The emission angle of the light source can be adjusted by rotating the handle.

[0046] A calibration point is arranged on the reflective plate facing the laser emitter 4, and when the laser beam is irradiated on the calibration point, the two reflective plates are parallel to each other.

[0047] Preferably, the width of the base is the same as the total width of the guard plate and the reflector, and the width is the dimension along the extension direction of the tunnel.

[0048] The scale plate is provided with scale lines from bottom to top for observing the position of the received laser point.

[0049] The following is a description of a measurement method of a tunnel axial deformation measurement system provided by the present invention. It should be noted that when the measurement system measures the deformation, it needs to use the axial data of the tunnel when it is not deformed. Therefore, it is necessary to establish at least two marked measurement points after the tunnel is built and record the distance between the two marked measurement points.

[0050] The specific steps include:

[0051] Step 1: After the tunnel construction is completed, a plurality of marking points are carved on the side wall of the tunnel at fixed intervals along the axial direction of the tunnel, and the marking points are arranged in a straight line along the axial direction of the tunnel.

[0052] Step 2: When the tunnel has been in use for a long time and cracks appear on the inner wall of the tunnel, select the two nearest marking points on both sides of the cracks, install bases at the two marking points respectively, and install a guard plate with a reflector on the base, so that the reflector is perpendicular to the axis of the tunnel and the surface of the reflector is flush with the marking points.

[0053] During the installation process, the angle of the guard plate is adjusted by adjusting the rotating shaft, thereby adjusting the angle of the reflector so that the reflector is perpendicular to the axis of the tunnel.

[0054] Adjust the reflector to be perpendicular to the tunnel axis: rotate the guard plate around the middle axis and observe with a laser level until the reflector is perpendicular to the tunnel axis.

[0055] Step 3: Verify that the two plane reflectors remain parallel. Adjust the emission angle of the laser emitter to 0. At this time, the emitted light is perpendicular to the reflector. Turn on the laser emitter to emit the laser. If the light beam shines on the calibration point facing the reflector, the two reflectors are parallel to each other.

[0056] Since the two reflectors are parallel, the reflected light coincides with the incident light, and the laser returns along the original path. No light spot will appear on the final light spot presentation board. Therefore, as long as no light spot appears on the photoelectric display board, it can be proved that the left and right plane reflectors remain parallel.

[0057] Step 4: Adjust the emission angle of the laser transmitter and emit the laser toward the opposite reflector. After multiple reflections, the laser is irradiated onto the photoelectric display board.

[0058] The range of the emission angle θ is 0°﹤θ﹤90°.

[0059] Step 5: Obtain the number of light rays n that are reflected between the two planes during the period from the laser emission to the irradiation on the photoelectric display board, the height H2 of the light spot display board, the laser emission angle θ, and the initial distance L between the two marking points. Calculate the axial deformation l based on the obtained parameters.

[0060] According to the imaging characteristics of the plane reflector, the original light path is equivalent to a right triangle:

[0061] As long as there is a light spot on the photoelectric display board, there must be:

[0062]

[0063] According to mathematical relations

[0064] Solve ① and we get

[0065] Among them, △L is the side length of the laser emitter, H1 is the height of the reflector on the same guard plate as the laser emitter, the height of the light spot display board is H2, h is the scale value of the light spot on the light spot display board, and the 0 scale of the light spot display board is located at the joint of the light spot display board and the reflector.

[0066] The measurement results of the measurement method of the tunnel axial deformation measurement system of the present invention are analyzed below.

[0067] Depend on It is known that there are two errors in the measurement using this system and method. One is the error from the manual reading of h, and the other is the error caused by rounding in scientific calculations. The latter is difficult to avoid, but efforts can be made to reduce the error caused by the former. The specific analysis is as follows

[0068] Taking the derivative of both sides with respect to l, we can simplify to get Due to the natural defects of manual readings, dh cannot be effectively reduced within a certain range. In order to minimize dl, we can only hope to increase ntanθ, which can effectively improve the accuracy of the measurement.

[0069] According to the expression It can be seen that θ is negatively correlated with n.

[0070] Its practical guiding significance includes: when manufacturing equipment, the distance H1 from the lower edge of the guard plate to the intersection of the right plane reflector and the photoelectric display board should be increased as much as possible; when selecting the bonding position of the bottom plate, the distance between the left and right bottom plates should be appropriately reduced, thereby reducing the distance L between the two plane reflectors. When the equipment manufacturing industry has been formed and the location of the marking point on the inner wall of the tunnel has been determined, H1, H2, △L and L are all fixed values, and θ is negatively correlated with n. In actual measurement, each time a θ is determined, according to the expression A unique n value can be obtained. In actual measurement, the angle θ of the high-precision angle head can be adjusted to control ntanθ to maximize it. Therefore, exploring the range of θ that can make the accuracy reach the maximum value under the allowable conditions is more practical and significant for improving measurement accuracy. The following is an experiment designed for this purpose and some of the data obtained:

[0071]

[0072]

[0073] From the data in the table, we can get: under the conditions of △L=100, H1=600mm, H2=100mm, l=1mm, L=200mm, when the laser emission angle θ=19°, the maximum value of ntanθ is 3.44. This set of measuring device relies on the core idea of ​​the micro-magnification method to magnify the micro-axial deformation of the tunnel into several times the radial deformation, so as to reduce the large error caused by manual reading during measurement.

[0074] Compared with the traditional laser direct distance measurement, this method can eliminate the error caused by the final manual reading due to the presence of a certain angle θ when the laser is emitted, so that the light can be reflected dozens or even hundreds of times in the two plane reflectors. In addition, the device can also be fixed on the inner wall of the tunnel without disassembly, and the dynamic measurement of the axial deformation of the tunnel can be achieved through relevant calculations by observing the position movement of the light spot on the light spot display board.

[0075] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A system for measuring axial deformation of a tunnel, characterized in that: It comprises a laser emitter (4), a photoelectric display panel (3), and two reflective panels spaced apart along the axial direction of the tunnel, the two reflective panels being symmetrically arranged along the radial direction of the tunnel and perpendicular to the axis of the tunnel, the axis being a straight line; The laser emitter (4) and the photoelectric display board (3) are arranged on one of the reflective boards (2), or respectively on the two reflective boards (2); the laser emitter (4) and the photoelectric display board (3) are respectively arranged at the upper and lower ends of the reflective board; the light beam emitted by the laser emitter (4) can be irradiated on the photoelectric display board (3) after multiple reflections; The measuring method of the tunnel axial deformation measuring system comprises the following steps: Step 1, setting marking points at intervals along the axial direction of the undeformed tunnel; Step 2: After the tunnel is deformed, a base is installed at two marking points on both sides of the deformation area, and a guard plate with a reflector is installed on the base, so that the reflector is perpendicular to the axial direction of the tunnel and the surface of the reflector is flush with the marking points; Step 3: Adjust the emission angle of the laser transmitter to emit a laser beam toward the reflector facing the reflector. After multiple reflections, the laser beam is irradiated onto the photoelectric display board. Step 4: Obtain the number of light rays n that are reflected between the two planes during the period from the laser emission to the irradiation on the photoelectric display panel, as well as the laser emission angle θ and the initial distance L between the two marking points. Calculate the axial deformation based on the obtained parameters: l ; l Among them, △L is the side length of the laser emitter, H1 is the height of the reflector on the same guard plate as the laser emitter, and h is the scale value of the light spot on the light spot display board.

2. A system for measuring tunnel axial deformation according to claim 1, characterized in that: The reflective plate (2) is connected to a base (5) via an adjusting device, the base is fixed on the side wall of the tunnel, and the adjusting device is used to adjust the angle of the reflective plate.

3. A system for measuring tunnel axial deformation according to claim 2, characterized in that: The reflective plate is fixedly connected to the guard plate (1), and the guard plate is connected to the base via an adjustment device.

4. A system for measuring tunnel axial deformation according to claim 3, characterized in that: The adjusting device comprises a shaft sleeve (8), a rotating shaft (9) and a locking device, wherein the shaft sleeve (8) is arranged on the side wall of the guard plate (1) and extends toward one side of the base, the rotating shaft is arranged on the base, and the end of the rotating shaft is fitted in the shaft sleeve (8), and the locking device is used to limit the rotation direction of the shaft sleeve.

5. A system for measuring tunnel axial deformation according to claim 4, characterized in that: The locking device is a nut, the sleeve is connected to the rotating shaft through threads, and the nut is arranged on the rotating shaft.

6. A system for measuring tunnel axial deformation according to claim 3, characterized in that: A supporting device is provided between the guard plate and the base, comprising a supporting rod (6) and a slide groove; The support rod (6) is arranged parallel to the rotating shaft, one end of the support rod is fixedly connected to the guard plate, a slide groove is arranged on the surface of the bottom plate, and the end of the support rod is fitted in the slide groove and can move along the slide groove.

7. A system for measuring tunnel axial deformation according to claim 6, characterized in that: The slide groove is an arc groove, and the center of the circle is concentric with the rotation axis.

8. The system for measuring the axial deformation of a tunnel according to claim 6, characterized in that: A bearing is arranged at the end of the support rod, and the bearing is located in the slide groove.

9. The system for measuring the axial deformation of a tunnel according to claim 1, characterized in that: A calibration point is provided on the reflective plate directly facing the laser emitter (4), and the laser beam is irradiated on the calibration point to calibrate the parallelism of the two reflective plates.

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