JPH0350992B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tunnel interior measurement device,
In particular, the present invention relates to a tunnel interior measurement device that measures the cross-sectional shape of a tunnel using ultrasonic waves.

When constructing tunnels, the so-called concrete lining method is generally adopted, in which a concrete wall of a predetermined thickness is cast on the excavated surface of the tunnel, which is excavated with a rock excavator. In order to form it, it was essential to measure the excavated surface.

In this case, most conventional tunnel interior measurement devices measure optically, and for example, a rotatable reflecting mirror is installed at a predetermined distance in front of a directional light source such as a laser. The light reflected by this reflecting mirror is irradiated onto the inner wall surface of the tunnel, and the reflecting mirror is rotated so that the light reflected from this inner wall surface is incident on the target position of a reference device installed near the light source. An apparatus is known in which the distance from the reference device to the inner wall surface is determined using trigonometric functions from the distance between the reference device and the reflecting mirror, which are known values, and the rotation angle of the reflecting mirror.

However, since such conventional devices are constructed based on purely optical means, measurements may become ineffective due to dust or moisture inside the tunnel, and the device itself must be kept clean at all times. This was extremely inconvenient as a device to be installed inside a tunnel. In addition, with conventional equipment, one section along the tunnel inner wall surface can be measured continuously, but other sections must be measured by moving the device little by little in the axial direction of the tunnel.
It was extremely inefficient to measure all cross sections.

This invention was made in view of these conventional problems, and its purpose is to provide a tunnel interior measurement device that can perform measurements over a wide range of conditions without being affected by the adverse conditions inside the tunnel. Our goal is to provide the following.

In order to achieve the above object, the present invention provides an ultrasonic sensor that transmits ultrasonic waves toward the inner wall of a tunnel and receives ultrasonic waves reflected from the inner wall surface, and a disc-shaped case that holds the ultrasonic sensor. a U-shaped arm that rotatably holds the case around the vertical cross-sectional direction of the tunnel; a first drive means that rotates the arm around the axial direction of the tunnel; a first angle detecting means for measuring a rotation angle caused by the driving means; and an electric means for driving the ultrasonic sensor to transmit and detect a time difference between ultrasonic waves transmitted and received by the ultrasonic sensor; A device for measuring the distance to the inner wall of the tunnel by sequentially determining the time difference while rotating the ultrasonic sensor by a driving means,
a second drive disposed on one end side of the rotating shaft of the case, rotating the case around the vertical cross-sectional direction of the tunnel, and changing the transmission direction of the ultrasonic sensor back and forth in the axial direction of the tunnel; and a second angle detection means provided on the other end side of the rotation axis of the case.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the tunnel interior measuring device according to the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 4 show an embodiment of the tunnel interior measuring device according to the present invention.

The measuring device shown in the figure includes a plurality of small-diameter disk-shaped ultrasonic sensors 10, 10 that transmit ultrasonic waves toward the inner wall surface of a tunnel and receive ultrasonic waves reflected from the inner wall surface. are embedded in an elastic body 12 such as rubber, and the ultrasonic sensor 10,
The ultrasonic sensors 10 are connected in parallel to a sensor case 14 formed in a dish shape that holds the transmitting and receiving surfaces of the ultrasonic sensors 10 so as to be exposed to the outside, and are electrically connected thereto.
0 and 10 respectively at specific frequencies,
It also includes an electric means 50 for detecting the time difference between the ultrasonic waves transmitted and received by the ultrasonic sensors 10 and 10.

A rotating shaft 20 extending through the center of the sensor case 12 projects from the outer periphery of the sensor case 12, and this rotating shaft 20 is rotatably supported by a substantially U-shaped arm portion 22.

One end of a horizontal support shaft 24 that supports the arm portion 22 is fixed to the base end of the arm portion 22.
4 is rotatably supported within a cylindrical support member 26 via a plurality of bearings 28, and a disc-shaped worm wheel 30 is fixed to the other end by screwing a nut. The worm wheel 30 meshes with the worm 32 and is rotationally driven by a drive motor 34 connected to the worm 32.

The rotation angle of the drive motor 34 is detected by the connected encoder 36 (first angle detection means), and the rotational force is detected by the worm 32 →
It is transmitted from the worm wheel 30 to the horizontal support shaft 24 to the arm portion 22, and rotates the ultrasonic sensors 10, 10 around the axial direction of the tunnel (Y-Y direction in each figure).

In this case, the drive motor 34, the worm 32, the worm wheel 30, the horizontal support shaft 24, the arm part 2
2 constitutes the first driving means.

Further, the support member 26 is rotatably supported by a tripod mount 40 via a hard shaft 38 that is vertically provided below.

Furthermore, a laser collimator 42 used for confirming the set position of the measuring device and a Cubic prism 42 used for axial distance measurement are arranged above the support 26.

On the other hand, the rotation shaft 20 of the sensor case 14 has a drive motor 16 attached to one end and an encoder 18 (second angle detection means) for detecting a rotation angle to the other end.

The drive motor 16 rotates the sensor case 14 to drive the ultrasonic sensors 10, 10.
Tunnel cross-sectional direction (X-X direction in each figure)
The rotation angle is also detected by the encoder 18, and the transmission direction of the ultrasonic sensor 10 is changed back and forth in the axial direction (Y-Y) of the tunnel. let

The above-mentioned ultrasonic sensors 10, 10 are made by molding an electrostrictive vibrator made of barium titanate or the like into a disc shape, and are usually commercially available.The directivity thereof is, for example, half an angle when the transmission frequency is 100 KHz. 0.5 degree, 70K
The same angle is about 0.8 degrees in Hz, so it can be used practically without any problems.

Note that the above-mentioned half-reduction half-angle is the angle at which the output of the sensor is reduced by half, and indicates that the smaller the angle, the better the directivity.

Further, the electrical means 50 performs electrical signal processing of the ultrasonic sensors 10, 10, and FIG. 4 shows an example thereof.

In the electric means 50 shown in the figure, first, the ultrasonic sensors 10, 10 are excited and emit pulsed ultrasonic waves by the pulse output of the pulse transmitter 50b based on a signal sent out by the synchronization controller 50a. At the same time as it is transmitted, it senses the ultrasonic waves that are reflected back from the tunnel's inner wall and converts them into electrical signals.

This electrical signal is amplified by a receiving amplifier 50c, then converted to direct current by an A/D converter 50d, and input to a counter circuit 50e.

The counter circuit 50e includes a pulse transmitter 50b that causes the ultrasonic sensors 10, 10 to transmit.
It is started almost simultaneously with the sending signal from the synchronous control unit 50a, and is stopped by the DC signal from the A/D converter 50d. This corresponds to the time it takes for the signal to be transmitted from the wall, reflected by the inner wall surface, and received again. Therefore, by measuring this, the distance from the ultrasonic sensors 10, 10 to the tunnel inner wall surface can be counted.

Note that 50f in FIG. 4 is a digital recording device that records the state of the circuit 50e, and
50g is a stabilized power supply that supplies power to the synchronization control section 50a and the like.

Next, a method of using the above-mentioned tunnel interior measuring device will be explained.

First, as shown in FIG.
0 is placed horizontally on the Sanya 46 and the rigid shaft 38 of the measuring device is rotated to align the Y-Y axis with the axis of the tunnel.

In this case, the distance can be easily measured by irradiating the Kubitsch prism 44 with the light beam L using a light wave distance meter 48 installed at the entrance of the tunnel, for example.

Next, drive the drive motors 16, 34,
The ultrasonic sensors 10, 10 are set so that their emission surfaces are horizontal, and the electric means 50 transmits ultrasonic waves to the inner wall surface 79 of the tunnel,
A distance R1 between the inner wall surface 49 and the ultrasonic sensors 10, 10 is measured based on the time difference between transmission and reception. Then, the drive motor 34 is driven, the ultrasonic sensors 10, 10 are rotated along the inner wall surface 49 by an arbitrary angle α, and the distance R2 is measured in the same manner as the measurement of R1 above. By repeating these operations, it is possible to continuously measure the interior space of one section of the inner wall surface 49 perpendicular to the tunnel axis direction, as shown in FIG.

Furthermore, when the inner space measurement of one cross section is completed as described above, the drive motor 16 is driven to move the transmitting surfaces of the ultrasonic sensors 10, 10 arbitrarily relative to the horizontal plane as shown in FIG. After that, the drive motor 34 is set to tilt by an angle β of
By repeating measurements while sequentially driving the measuring device, it is possible to measure the interior space of the inner wall surface that forms an angle α with respect to the vertical plane on which the measuring device is installed.

By performing the above-mentioned operations in sequence, it becomes possible to measure the inner space of the inner wall surface by cutting the inner wall surface 49 of the tunnel into rings at predetermined intervals, and to measure the inner space of the inner wall surface by cutting the inner wall surface 49 of the tunnel into rings at predetermined intervals.
When the measurement is completed, the measurement device is moved to another location and the inside of the tunnel is measured in the same way.

When moving this measurement installation, it is necessary to align the Y-Y axes of the device before and after the movement, but in this case, for example, a plane mirror is suspended near the axis of the tunnel, and the laser collimator 42 can be easily matched by projecting a laser beam and observing the reflected light.

It is also possible to interpose a plurality of flat plates with small holes in the optical path of the laser beam of the laser collimator 42 and install the device so that all the laser beams pass through these small holes. can be specified.

The drive motors 16 and 34 are, for example, stepper motors that are rotated intermittently at a predetermined angle by a pulse power source, and these rotation angles are converted into electrical signals by the encoders 18 and 36. Since it can be extracted as
In addition to programming the rotation control of the encoders 18 and 36 in advance, the electrical signals from the encoders 18 and 36 and the time information from the electrical means 50 are integrated and counted, and the measured value of the tunnel interior can be graphically displayed on a CRT etc. It is also possible to automatically measure the interior space over a predetermined distance l after the device has been installed.

Now, since the tunnel interior measurement device with the above-mentioned configuration uses ultrasonic waves, it can perform measurements without being affected by dust or moisture inside the tunnel. It can be measured regardless of the surface.

In addition, by changing the wavelength of the ultrasonic waves transmitted from the ultrasonic sensor, it is possible to, for example, lengthen the wavelength to expand the directivity and accurately measure the most protruding part of the tunnel inner wall, or conversely, shorten the wavelength. This makes it possible to accurately measure the detailed unevenness of the tunnel inner wall. Furthermore, by combining a plurality of ultrasonic sensors, it is possible to provide the same resolution as a large sensor, thereby avoiding high costs.

Furthermore, since the ultrasonic sensor can freely rotate around the rotation axes in directions orthogonal to each other by the first and second driving means, it can measure not only one cross section but also each cross section within a predetermined range. This can be done without changing the location of the device, greatly improving measurement efficiency.

[Brief explanation of drawings]

1 to 4 show an embodiment of the tunnel interior measurement device according to the present invention, in which FIG. 1 is a plan view, FIG. 2 is a front view, FIG. 3 is a sectional view, and FIG.
The figure is a block diagram of the electrical configuration. Figures 5 to 7 show the measurement conditions, with Figure 5 being an explanatory diagram of the installed state of the device, Figure 6 being an explanatory diagram of measuring the inner space of a section of a tunnel, and Figure 7 FIG. 2 is an explanatory diagram when measuring by moving the device in the axial direction of the tunnel. 10... Ultrasonic sensor, 12... Elastic body, 1
4...Sensor case, 16...Drive motor, 1
8... Encoder, 20... Rotation axis, 22...
Arm portion, 34... Drive motor, 36... Encoder, 49... Inner wall surface.

Claims (1)

[Claims] 1. An ultrasonic sensor that transmits ultrasonic waves toward the inner wall of a tunnel and receives ultrasonic waves reflected from the inner wall surface, a disc-shaped case that holds the ultrasonic sensor, and a vertical cross section of the tunnel. A U-shaped arm that is rotatably held around a direction, a first drive means that rotates the arm around an axial direction of the tunnel, and a rotation angle by the first drive means is measured. The ultrasonic sensor is rotated by the first driving means, comprising a first angle detection means and an electric means for driving the ultrasonic sensor to transmit and detect a time difference between the ultrasonic waves transmitted and received by the ultrasonic sensor. A device that measures the distance to the inner wall of the tunnel by sequentially determining the time difference while moving the case, and is disposed at one end side of the rotating shaft of the case, and the device rotates the case about the vertical cross-sectional direction of the tunnel. and a second driving means for changing the transmission direction of the ultrasonic sensor back and forth in the axial direction of the tunnel, and a second angle detecting means provided on the other end side of the rotation axis of the case. A tunnel interior measurement device featuring: