JP7294025B2 - Protective container, measurement system and measurement method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a protective container, a measuring system, and a measuring method for obtaining measured values in steel shoring used in construction of tunnels and the like.

In mountain tunnel construction, in order to confirm the stability of the ground during excavation, measurements such as inner space displacement measurement and ground subsidence measurement are carried out as daily observation and measurement items (A measurement). When it becomes necessary to judge the suitability of steel shoring according to ground conditions, underground displacement measurement, rock bolt axial force measurement, etc. are carried out (B measurement). If the soil cover is small and the ground strength ratio is small, or if the ground is expansive, there is a possibility that a large earth pressure will be generated on the steel shoring. For this reason, strain measurement (stress measurement) of steel shoring is sometimes carried out for the purpose of confirming the stability and validity of steel shoring in terms of dimensions, pitch, etc.

For example, a technique for measuring the inner space displacement of a structure such as a tunnel and monitoring the deformation of the structure has been studied (see, for example, Patent Document 1). In the technique disclosed in this document, one end of a beam, which is a hollow displacement sensor, is fixed inside the structure, a device capable of measuring strain is installed on the surface of the beam, and the measured strain is used to determine the structure. Calculate the vertical and horizontal displacements of Then, the strain measuring device acquires the signal of the strain detecting device attached to the hollow displacement sensor.

Also, a measurement system for grasping the behavior of the tunnel lining during an earthquake in real time is being studied (see, for example, Patent Document 2). In the tunnel lining behavior measurement system disclosed in this document, a sensor having a strain gauge on the surface of the tunnel lining and a wireless transmitter connected to the sensor are arranged. Then, the tunnel lining surface deformation information from the wireless transmitting device is received by the wireless receiving device outside the tunnel, and the tunnel lining surface deformation information is analyzed by the tunnel lining deformation information analyzing device.

JP 2013-047629 A JP 2009-300323 A

When measuring the strain of steel shoring, the strain gauge installed on the steel shoring is connected to the data logger. When starting strain measurement immediately after erecting a steel shoring, it is necessary to extend the wiring while curing it to the rear where it will not be affected by excavation, and connect it to the data logger. In this case, labor and cost are required. In addition, since the work will be done in the face immediately after excavation, measures such as skin fall-off are required. Immediately after the erection of the steel shoring, a large strain may occur, and if the measurement of the strain is delayed, it is difficult to quickly take countermeasures such as installing additional rock bolts. In addition, since deformation of the steel shoring is difficult to determine visually, measures such as emergency evacuation from the pit were also difficult.

A protective container for solving the above problem houses a communication device that acquires measurements from sensors attached to the steel shoring. Then, a protective side that supports the underground space and can be in close contact with the steel shoring embedded in the shotcrete, an internal space that is surrounded by the protective side and can accommodate the communication device, and a space that is integrated with the protective side. a lid portion to which a portion is connected and which allows the communication device to be taken out from the internal space.

A measurement system for solving the above problems outputs measurement values from a sensor attached to a steel shoring. Then, a protective side that supports the underground space and is in close contact with the steel shoring embedded in the shotcrete, an internal space that is surrounded by the protective side and can accommodate a communication device, and a part of the protective side The protective container is connected to the protective container and includes a cover that allows the communication device to be taken out from the internal space, and an evaluation device that outputs information acquired from the communication device.

A measurement method for solving the above problems uses a measurement system that outputs measurement values from sensors attached to the steel shoring. Then, a protective side that supports the underground space and can be in close contact with the steel shoring embedded in the shotcrete, an internal space that is surrounded by the protective side and can accommodate communication equipment, and a part of the protective side is connected, and a protective container having a lid that allows the communication device to be taken out from the internal space is inserted into the gap of the steel shoring, the sensor transmits the measured value to the communication device, and the After the measurement value is measured, the lid is opened, the communication device is taken out from the internal space, and a filler material is inserted into the internal space.

ADVANTAGE OF THE INVENTION According to this invention, the measured value in steel shoring can be acquired efficiently and safely.

The perspective view of the protective container of this embodiment. 6A and 6B are six views of the protective container of the present embodiment, in which (a) is a front view, (b) is a left side view, (c) is a right side view, (d) is a top view, and (e) is a rear view. , (f) is a bottom view, and (g) is a sectional view taken along line AA. FIG. 4 is an explanatory diagram of how to use the protective container of the present embodiment, where (a) is before insertion into H-shaped steel and (b) is after insertion. Explanatory drawing of the steel shoring to which the protective container of this embodiment was attached. Explanatory drawing of the measurement system of this embodiment. FIG. 4 is an explanatory diagram of the measurement work of the present embodiment, where (a) is an explanatory diagram of mounting a strain gauge, (b) is an explanatory diagram of housing a strain measuring device, and (c) is an explanatory diagram of mounting a protective container. It is an explanatory diagram of the measurement work of this embodiment, (a) is the opening of the protective container after measurement, (b) is the removal of the strain measuring device and the storage of the stuffing block, and (c) is the state after the completion of the work. Illustration of .

An embodiment embodying a protective container, a measurement system, and a measurement method will be described below with reference to FIGS. 1 to 7. FIG. In this embodiment, a protective container, a measuring system, and a measuring method for measuring the strain of a steel shoring used in construction of a tunnel as an underground space will be described.

As shown in FIG. 1, in this embodiment, a protective container 10 is used when strain is measured. The protective container 10 is composed of a housing (made of concrete material, for example) having the same strength as shotcrete, and includes side portions 11 and 12, a bottom portion 13, a lid portion 14, and a rear portion 15 as protective side surfaces. An internal space 16 is formed by the side surface portion 11 to the rear surface portion 15 .

2 is a six-sided view of the protective container 10, FIG. 2(a) is a front view, FIG. 2(b) is a left side view, FIG. 2(c) is a right side view, and FIG. 2(d) is a top view. 2(e) is a rear view, and FIG. 2(f) is a bottom view.
The side portions 11 and 12 have a height of approximately 140 mm, a depth of approximately 180.5 mm, and a thickness of approximately 50 mm.

The bottom portion 13 is provided between the side portions 11 and 12 and has a width of approximately 160 mm, a depth of approximately 100 mm, and a thickness of approximately 20 mm.
The lid portion 14 is provided between the side portions 11 and 12 and connected to the back portion 15 . The size of the lid portion 14 is approximately 150 mm in width, approximately 60 mm in depth, and approximately 10 mm in thickness. Slits 14 a having a width of about 5 mm are provided along both sides of the internal space 16 between the lid portion 14 and the side portions 11 and 12 .

FIG. 2(g) is a cross-sectional view taken along line AA. A notch 14b is provided on the rear surface portion 15 side of the lid portion 14 .
The back portion 15 is connected to the side portions 11 and 12 and has a height of approximately 140 mm, a width of approximately 160 mm, and a thickness of approximately 50 mm.

As shown in FIG. 3(a), this protective container 10 is used for a steel shoring made of H-section steel 40 with a height of 150 mm. A strain measuring device 20 is housed in the inner space 16 of the protective container 10 . This strain measuring device 20 is connected by wiring to a strain gauge 30 attached to a web of H-shaped steel 40 (steel shoring). The strain gauge 30 is a sensor whose physical property value (resistance value in this embodiment) changes according to the applied stress (strain) on the surface of the H-section steel 40 .

Since the strain measuring device 20 is housed in the inner space 16 of the protective container 10 , the height h1 of the inner space 16 is slightly higher than the height of the strain measuring device 20 . Also, the depth d1 of the lid portion 14 is longer than the depth of the strain measuring device 20 . Further, in the side portions 11 and 12, the depth d2 on the front side of the lid portion 14 is slightly shorter than the one-side length d4 of the flange of the H-section steel 40. As shown in FIG. Moreover, in the side portions 11 and 12 , the height h3 on the front side of the lid portion 14 is slightly lower than the height h4 of the web of the H-section steel 40 . This shape allows the protective container 10 to be substantially adhered to the upper and lower flanges and webs of the H-beam.

Then, as shown in FIG. 3(b), when the protective container 10 containing the strain measuring device 20 is inserted between the flanges of the H-section steel 40, the tips of the side portions 11 and 12 are the webs of the H-section steel 40. abut. Further, when the bottom surface portion 13 is brought into contact with the inner surface of the flange, the tip surface of the lid portion 14 is brought into contact with the side surface of one of the flanges.

As shown in FIG. 4, the H-shaped steel 40 is arranged according to the shape of the tunnel in order to support the earth pressure so that the excavated surface does not collapse until it is lined with concrete. Then, the protective container 10 containing the strain measuring device 20 is arranged at a plurality of locations on the H-section steel 40 provided in the tunnel. For example, three locations, one on the ceiling side and the other on both sides, are used as the placement locations. In this case, in FIG. 4, the protective container 10 is inserted so that the lid portion 14 is arranged in the direction of the arrow. The protective container 10 is arranged on the opposite side (entrance side) of the face of the tunnel construction.

(measurement system)
A measuring system S1 using the strain measuring device 20 will be described with reference to FIG. The measurement system S1 includes a strain measuring device 20, a strain gauge 30, and an evaluation device 50.

The strain measuring device 20 includes a bridge 21 , an amplifier 22 , a communication control unit 23 , a radio unit 24 and a battery 25 .
The bridge 21 is a circuit (for example, a Wheatstone bridge) that uses the strain gauge 30 as one resistor to measure a resistance value according to changes in strain.

Amplifier 22 amplifies the strength of the output signal of bridge 21 .
The communication control unit 23 converts the output signal into a radio signal.
Radio unit 24 transmits radio signals via an antenna. In this embodiment, a communication distance of about 20 m is ensured by using a frequency of 920 MHz band.

A battery 25 supplies power to the amplifier 22 , the communication control unit 23 and the wireless unit 24 . In this embodiment, the wireless signal is transmitted at 1-minute intervals until 24 hours after installation of the strain measuring device 20, and at 10-minute intervals after 24 hours.
It should be noted that the housing of the strain measuring device 20 is IP67 compliant in terms of dustproof performance and waterproof performance.

The evaluation device 50 comprises a radio unit 51 , a communication control unit 52 and an analysis unit 53 . This evaluation device 50 is installed, for example, in a drilling device such as a tunnel construction machine such as a drill jumbo (registered trademark).

A wireless signal transmitted from the strain measuring device 20 is received by the wireless unit 51 of the evaluation device 50 . This wireless unit 51 is provided within 20 m from the wireless unit 24 of the strain measuring device 20 . The communication control unit 52 then converts the radio signal into an output signal related to strain intensity.

The analysis unit 53 is a computer terminal that analyzes the strain condition of the steel shoring (H-section steel 40) based on the output signal. The analysis unit 53 outputs an alarm if the strain situation exceeds the reference value.

(Measurement method)
First, as shown in FIG. 6(a), the strain gauge 30 is attached to the desired position of the H-section steel 40 before erecting the steel shoring. Then, the wiring from the strain gauge 30 is connected to the strain measuring device 20 .

Next, as shown in FIG. 6(b), the strain measuring device 20 is housed in the internal space 16 of the protective container 10. Next, as shown in FIG. In this case, the strain measuring device 20 is turned on and activated.
Next, as shown in FIG. 6(c), the side portions 11 and 12 are inserted between the flanges of the H-shaped steel 40. Then, as shown in FIG. Then, the tip portions of the side portions 11 and 12 are brought into contact with the web of the H-section steel 40 . In this case, the tip of the lid portion 14 is brought into contact with the flange of the H-section steel 40 . Furthermore, in order to prevent the protective container 10 from falling off, the protective container 10 is fixed to the H-section steel 40 using a binding band or the like.

In tunnel construction, drilling, charging, blasting, sliding, erection of shoring, shotcrete, and concrete lining are carried out in sequence. Then, the H-section steel 40 to which the strain measuring device 20 is fixed is built into the pit as a steel support. From this erection stage, measurement of strain is started by the measurement system S1. In this case, the strain measuring device 20 is embedded in concrete except for the surface of the lid portion 14 by shotcrete.

When the measurement for the predetermined period is finished, the strain measuring device 20 is collected. In this case, the lid portion 14 is hit with a hammer or the like to break the notch 14b.
As shown in FIG. 7A, the lid 14 is separated from the protective container 10 by the slit 14a and the broken notch 14b. .

As shown in FIG. 7(b), the strain measuring device 20 is taken out from the internal space 16. As shown in FIG. Next, the stuffing block 60 is inserted into the internal space 16 . This interfilling block 60 has the same strength as shotcrete. The height h5 of the interstitial block 60 is such that when the interstitial block 60 is inserted, the upper surface is from the bottom surface portion 13 of the protective container 10 to the upper end of the lid portion 14 (the upper surface of the flange of the H-shaped steel 40), and the height h2 (Fig. 3) is configured to be the same. The depth of the interstitial blocks 60 is the same as the depth of the lid portion 14 . The stuffing block 60 has a return portion 61 that rises from the front end to the rear end.

As shown in FIG. 7( c ), when the interstitial block 60 is inserted into the internal space 16 , the return portion 61 is hooked to the flange of the H-section steel 40 and fixed. The upper surface of the interstitial block 60, the upper surfaces of the side portions 11 and 12 of the protective container 10, and the upper surface of the rear portion 15 are at the same height as the shotcrete.

According to this embodiment, the following effects can be obtained.
(1) In this embodiment, the protective container 10 containing the strain measuring device 20 is inserted between the flanges of the H-section steel 40 . As a result, the strain measuring device 20 can be protected from explosions during blasting, protection from heavy machinery, and protection from shotcrete. Since the protective container 10 is made of the same material as the shotcrete, it has a strength equivalent to that of the shotcrete and is easily compatible with the shotcrete.

(2) In this embodiment, the strain measuring device 20 wirelessly transmits information about strain measured by the strain gauge 30 attached to the web of the H-section steel 40 . As a result, strain measurement can be started immediately after erecting the steel shoring. Since wiring from the strain measuring device 20 to the evaluation device 50 is unnecessary, measurement can be performed efficiently. In addition, it is possible to prevent the skin from falling off during installation of the strain measuring device 20 and wiring work. Therefore, the adequacy of steel shoring can be judged early. If it is determined that the steel shoring will become unstable, countermeasures such as driving additional rock bolts can be taken.

(3) In the present embodiment, slits 14 a are provided along both sides of the internal space 16 between the lid portion 14 and the side portions 11 and 12 . This makes it easier to transmit radio waves from the strain measuring device 20 .

(4) In the present embodiment, the notch 14b is provided on the back portion 15 side of the lid portion 14 . Accordingly, since there is no protrusion for fixing the lid portion 14, the concrete spraying work can be efficiently performed.

Furthermore, after the measurement is completed, the lid portion 14 can be easily opened by the slit 14a and the notch 14b. If the cover 14 is closed by bolting or the like, the bolt may not be able to turn if the shotcrete adheres. Cost can be reduced.

(5) In this embodiment, the strain gauge 30 is attached to the H-shaped steel 40 and the protective container 10 containing the strain measuring device 20 is fixed before the steel shoring is erected. As a result, high-place work can be reduced even when strain is measured near the ceiling.

(6) In this embodiment, the strain measuring device 20 is taken out from the internal space 16 of the protective container 10 and the stuffing block 60 is inserted into the internal space 16 . Thereby, it is possible to secure the winding thickness at the time of lining. Furthermore, since the interstitial block 60 has the return portion 61, it can be firmly fixed.

This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- In the above embodiment, the underground structure is not limited to a tunnel. Any structure using steel shoring embedded in concrete may be used.

- In the above embodiment, the H-shaped steel 40 is used as the shoring, but the shape of the shoring is not limited to the H-shaped steel, and can be applied to a steel shoring embedded in concrete. For example, it may be used for channel steel.
• In the above embodiments, the radio unit 24 transmits radio signals via an antenna. Alternatively, steel shoring may be used as a communication medium. In this case, the output signal output section of the strain measuring device 20 is electrically connected to the steel shoring, and the output signal is output to the outside via this steel shoring.

- In the above embodiment, the object to be measured is not limited to strain as long as it is information that can be measured during construction.
- In the above embodiment, the protective container 10 consists of a housing (for example, made of a concrete material) having the same strength as shotcrete. The housing is not limited to concrete as long as it is made of a material having strength equal to or greater than that of shotcrete. For example, it is possible to use a steel or resin housing.

DESCRIPTION OF SYMBOLS 10... Protective container, 11, 12... Side part, 13... Bottom part, 14... Lid part, 14a... Slit, 14b... Notch, 15... Back part, 16... Internal space, 20... Strain measuring device, 21... Bridge , 22... amplifier, 23... communication control unit, 24... wireless unit, 25... battery, 30... strain gauge, 40... H-shaped steel, 50... evaluation device, 51... wireless unit, 52... communication control unit, 53... analysis Unit, 60 -- Stuffing block, 61 -- Return part, S1 -- Measuring system.

Claims (6)

A protective container containing a communication device that acquires measurements from sensors attached to steel shoring,
a protective side supporting the underground space and capable of close contact with said steel shoring embedded in shotcrete;
an internal space surrounded by the protective side and capable of accommodating the communication device;
A protective container, comprising: a lid part that is partially connected to the protective side surface and that allows the communication device to be taken out from the internal space. 2. The protective container according to claim 1, wherein the side portion of the protective side has a height corresponding to the distance between the flanges of the steel shoring made of H-section steel. 3. The protective container according to claim 1, wherein the lid has a notch, and the inner space can be opened by breaking the notch. The protective container according to any one of claims 1 to 3, wherein the protective side surface is made of a concrete material having a strength equal to or higher than that of the shotcrete. A measurement system that outputs measurements from sensors attached to steel shoring,
a protective flank capable of supporting the underground space and close to the steel shoring embedded in the shotcrete;
an internal space surrounded by the protective side and capable of accommodating a communication device;
a protective container including a lid portion partially connected to the protective side surface and capable of taking out the communication device from the internal space;
and an evaluation device that outputs information acquired from the communication device. A measurement method using a measurement system that outputs a measurement value from a sensor attached to a steel shoring,
A protective side that supports an underground space and can be in close contact with a steel shoring embedded in shotcrete, an internal space that is surrounded by the protective side and that can accommodate a communication device, and a part of which is connected to the protective side. and inserting a protective container having a lid that allows the communication device to be taken out from the internal space into the gap of the steel shoring,
causing the sensor to transmit a measured value to the communication device;
After measuring the measured value, opening the lid and taking out the communication device from the internal space;
A measuring method characterized by inserting a filling material into the internal space.

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