JP3364032B2 - Forward monitoring device for shield machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forward monitoring device for a sealed shield machine of earth pressure type or muddy type.

[0002]

2. Description of the Related Art If it is possible to nondestructively search for existing structures such as metal and concrete buried in the ground, and obstacles such as piles, damage to the cutter bit of the shield machine due to these obstacles during shield excavation. It can be prevented. There is a ground radar as one of the methods for nondestructively searching for an obstacle buried in the ground. The ground radar uses electromagnetic waves, and when electromagnetic waves are radiated into the ground from a transmitting antenna, they are reflected at the boundary between soil and obstacles having different electrical properties. This reflected wave is received by the receiving antenna, and the distance from the arrival time to the obstacle can be calculated. Further, the presence or absence of an obstacle can be confirmed by comparing the levels of the received signals. conventionally,
As shown in FIGS. 8 and 9, a part of the front surface of the cutter head 2 is cut out, an antenna unit 3 having a transmitting antenna 9 and a receiving antenna 10 therein is attached, and an obstacle is searched.

[0003]

In the conventional method, it was not possible to achieve both a distant search and a wide range search for the following reasons. That is, the directivity of the antenna must be improved in order to improve the accuracy of obstacle search. Therefore, the range that can be searched by one antenna is only the range of the circular locus 4 drawn by the antenna unit 3 when the cutter head rotates, and if the wide range search in front of the cutter head is performed, the number of antennas must be increased. I have to.

On the other hand, the shape of the antenna must be made large in order to carry out distant exploration. If the shape of the antenna is increased, the mounting space is limited and the number of antennas cannot be increased. Therefore, it is difficult to explore a wide area. Further, if the search range is widened, the shape of the antenna must be made small, and the search at a distance cannot be performed.

[0005]

The present invention has the following means in order to solve the above problems. (1) A plurality of antennas are arranged in a straight line in the radial direction from the center of the cutter head of the shield machine. (2) Approximately half of the plurality of antennas are dedicated antennas for transmission, and the other half are antennas for both transmission and reception. (3) The transmitting antenna and the transmitting / receiving antenna are arranged alternately. (4) A synchronization control device for controlling the timing of radiating the transmission wave from the plurality of antennas is provided.

[0006]

As described below, by controlling the timing of radiating the transmission wave from the plurality of antennas, it is possible to perform both wide-range search near the cutter head and distant search. That is, when performing a remote search, the transmitted waves are simultaneously radiated from all the plurality of antennas. Since the emitted transmitted waves overlap each other in the same phase, the amplitude of the transmitted waves becomes large. Therefore, it reaches a distance farther than the transmission wave from one antenna, and it becomes possible to search a distance.

On the other hand, when conducting a wide-range search, two adjacent antennas are set as one set, one of which is a transmitting antenna and the other is a receiving antenna. Each set emits a transmitted wave and receives a reflected wave. However, the transmission and reception in each group are sequentially performed at different timings. This is to eliminate the influence of transmission waves from other antennas. This allows
It is possible to accurately perform a search in the vicinity of each antenna, and it is possible to perform a wide range search for the entire antenna.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an overall view of a shield machine 1 equipped with a front monitoring device according to an embodiment of the present invention. As shown in the figure, the shield machine 1 has a cutter head 2 which is rotationally driven on the front surface to excavate the natural ground. The cutter head 2 is electrically connected to the inside of the shield machine 1 in a fixed state via a slip ring 6. The rotary shaft portion of the cutter head 2 is provided with a rotary encoder 5 for obtaining a rotation angle. The rotary encoder 5 is connected to the analysis display device 8.

On the front surface of the cutter head 2, antenna parts 13 to 18 are arranged substantially straight from the center of the cutter head. Each antenna unit 13 to 18 has a dipole antenna 13a to 18a that radiates a high frequency electromagnetic pulse into the ground and can receive the reflected wave. The dipole antennas 13a to 18a are, as shown in FIG.
In order to prevent the influence of earth pressure and water pressure during excavation, and to transmit electromagnetic waves to the electromagnetic wave emission surface, and having sufficient strength and watertightness against earth pressure and water pressure, for example, to the protective plate 11 made of FRP resin. It is protected by the protection box 21 and is entirely housed in the protection box 21. Further, in this embodiment, in order to improve the water tightness, the protection box 21 is filled with silicon 23.

In order to prevent electromagnetic waves radiated from the antennas 13a to 18a from leaking not only on the front surface of the cutter head but also on the rear surface of the cutter head and reflected inside the protective box 21 to be received as noise, An electromagnetic wave absorber 22 such as ferrite is attached to the inner surface of the protective box 21. Further, as shown in FIG. 3, a plurality of dipole antennas 1
Dipole antennas 13a and 15 among 3a to 18a
a and 17a are used as transmission-only antennas, and dipole antennas 14a, 16a, and 18a are used as transmission antennas and reception antennas.

That is, the dipole antennas 13a, 15
a and 17a are connected to the transmitters 13b, 15b and 17b, respectively. The transmitters 13a, 15b, 17b generate extremely short pulsed electric power having a pulse width of 1 ns.
This pulsed power is applied to the dipole antennas 13a, 15
In addition to a and 17a, pulsed electromagnetic waves are emitted (transmitted). On the other hand, the dipole antennas 14a and 16
a and 18a are transmission / reception switching units 14d and 16 respectively.
The transmitters 14b, 16b, 18b and the receivers 14c, 16c, 18c are connected via d and 18d.

Transmission / reception switching units 14d, 16d, 18d
Radiates (transmits) an electromagnetic wave by the dipole antennas 14a, 16a, 18a according to a command from the synchronization control device 12.
In this case, the pulsed power generated by the transmitters 14b, 16b, 18b is supplied to the dipole antenna 14 respectively.
a, 16a, 18a, and when receiving an electromagnetic wave returning from the excavation direction, the dipole antenna 14
The signals from a, 16a, and 18a are received by the receiving unit 14 respectively.
Tell c, 16c, 18c.

The receivers 14c, 16c and 18c are internally provided with a high frequency amplifier and a sampling circuit for frequency conversion, and a weak high frequency signal received by the dipole antennas 14a, 16a and 18a is amplified and converted into a low frequency. .
The transmitting units 13b to 18b, the receiving units 14c, 16c, and 18c of the antenna units 13 to 18 and the transmission / reception switching unit 14d,
16d and 18d are connected to the synchronous control device 12 via the slip ring 6.

As described above, the synchronization control device 12 transmits the transmission / reception switching command to the transmission / reception switching units 14d, 16.
d, 18d, dipole antenna 13a ~
Adjust the timing of radiating electromagnetic waves from 18a,
A transmission command is sent to the transmission units 14b, 16b, 18b. The synchronization control device 12 is connected to the analysis display device 8, and the analysis display device 8 is connected to the rotary encoder 5.

The analysis display device 8 is an A / D converter 8 for converting an analog signal, which is a radar reception signal, into a digital signal.
and a counter 8b for converting the rotation angle signal (pulse signal) of the rotary encoder 5 into a cutter head rotation angle. After the data input by the A / D converter 8a and the counter 8b are extracted, calculation processing is performed and the result is displayed.

In the forward monitoring apparatus of the present embodiment having the above-mentioned configuration, when searching for a distant obstacle as shown in FIG. 4, it is performed as follows. First, the transmission / reception switching units 14d, 16d, 18d
The transmitters 14b, 16b and 18b are connected to the dipole antennas 14a, 16a and 18a, respectively. At the same time, the transmitters 13b14b, 15b, 16b, 17
Pulsed electric power is generated from b and 18b.

As a result, as shown in FIG. 5, the dipole antennas 13a, 14a, 15a, 16a, 17a,
Pulsed electromagnetic waves are emitted from 18a. Since the electromagnetic waves (transmitted waves) radiated from the dipole antennas 13a to 18a overlap each other in the same phase, the amplitude of the transmitted wave becomes large. Therefore, the transmitted wave reaches the obstacle 20 located farther away. Continuously, the transmission / reception switching units 14d, 16d, 18d
Respectively connect the receivers 14c, 16c, 18c and the dipole antennas 14a, 16a, 18a.

The reflected wave from the obstacle 20 is received by the dipole antennas 14a, 16a and 18a as shown in FIG. 5, and the received signals are received by the receivers 14c, 16c and 18c.
Amplify in and perform low frequency conversion processing. The processed signal,
It is sent to the analysis display device 8 via the synchronization control device 12. The operations of to are repeated at a constant cycle. The above control is performed by the synchronous control device 12. The analysis display device 8 calculates the data of the cutter head rotation angle by the rotary encoder 5 and the received signal received as described above, and displays the result.

In the forward monitoring apparatus of the present embodiment having the above-mentioned structure, when an obstacle which spreads over a wide area in the vicinity of the cutter head 2 as shown in FIG. 6 is searched, it is carried out as follows. First, the transmission / reception switching units 14d, 16d, 18d
The receivers 14c, 16c, 18c are connected to the dipole antennas 14a, 16a, 18a, respectively. Next, pulse-shaped power is generated from the transmitter 13b. As a result, as shown in FIG.
Pulsed electromagnetic waves are radiated from 3a.

The radiated electromagnetic wave (transmitted wave) is, as shown in FIG. 6, an obstacle 20a near the antenna unit 13.
Reflect on. The reflected wave is received by the dipole antenna 14a as shown in FIG. 7, the reception unit 15c amplifies the received signal, performs low frequency conversion processing, and analyzes the processed signal through the synchronization control device 12. Send to the display device 12. As shown in FIG. 7, the antenna units 15 and 16 also perform the same operations as above to search for the obstacle 20b.

Also in the antenna units 17 and 18, FIG.
As shown in FIG.
Explore c. The above operations (1) to (5) are repeated at regular intervals. The above control is performed by the synchronous control device 12 as in the case of searching for a remote obstacle. By such an operation, it is possible to accurately grasp the position and the like of the obstacle near each antenna unit. The operation of the analysis display device 12 is the same as that in the case of searching for a distant obstacle.

[0022]

As described above in detail with reference to the embodiments, the present invention has the following effects. (1) It is possible to search far beyond the limit that can be searched with one radar antenna. (2) It is possible to accurately perform a wide range of exploration near the cutter head.

[Brief description of drawings]

FIG. 1 is a sectional view of a front monitoring device for a shield machine according to an embodiment of the present invention.

FIG. 2 is a structural diagram of a radar antenna according to an embodiment of the present invention.

FIG. 3 is a block diagram of a front monitoring device.

FIG. 4 is an explanatory diagram of a case where a remote monitoring is performed by a front monitoring device.

FIG. 5 is a time chart when performing a remote survey.

FIG. 6 is an explanatory diagram when a wide area search is performed by a front monitoring device.

FIG. 7 is a time chart when performing wide area exploration.

FIG. 8 is a sectional view of a conventional shield machine.

FIG. 9 is a structural diagram of a conventional radar antenna.

[Explanation of symbols]

1 shield machine 2 cutter head 3 antenna 4 Trajectory drawn by the radar antenna 5 rotary encoder 6 slip rings 7 Antenna control device 8 Analysis display device 8a A / D converter 8b counter 9 Transmit antenna (dipole antenna) 10 Receiving antenna (dipole antenna) 11 Protective plate 12 Synchronous control device 13-18 Antenna part 13a to 18a dipole antenna 13b-18b transmitter 14c, 16c, 18c receiver 14d, 16d, 18d transmission / reception switching unit 20,20a, 20b, 20c Obstacle 21 Protective box 22 Radio wave absorber 23 Silicon

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-2-28586 (JP, A) JP-A-1-274092 (JP, A) JP-A-8-94737 (JP, A) JP-A-7- 43461 (JP, A) Actual Kaihei 4-97996 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01V 3/12 E21D 9/06 301 G01S 13/88

Claims (2)

(57) [Claims] 1. A shield machine having a cutter head which is rotationally driven to excavate the natural ground, wherein a plurality of radar antennas are arranged in a straight line in a radial direction from a center of the cutter head on a front surface of the cutter, and a synchronous control device is used. A forward monitoring device in a shield machine, which is capable of distant exploration by simultaneously radiating transmission waves from all of the plurality of radar antennas. 2. A shield machine having a cutter head which is rotationally driven to excavate the natural ground, wherein a plurality of radar antennas are arranged in a straight line in a radial direction from a center of the cutter head on a front surface of the cutter, and the plurality of radar antennas are arranged. Two radar antennas are set as one set, one set as a transmission antenna and the other as a reception antenna, and the radiation timing of the transmission wave of each set of radar antennas is shifted to enable wide-area exploration in the vicinity of the antenna. Forward monitoring device for shield machine.