JPS63300944A - State detector for cutting blade part of shield drilling machine - Google Patents

Abstract

PURPOSE:To reduce the area of a notching part for antenna installation and to prevent a reflected wave from being masked owing to direct coupling by charging a dielectric which has a dielectric constant corresponding to the dielectric constant of pressurized drilling mud between an antenna and a notching blade part. CONSTITUTION:An antenna part 4 is constituted by embedding both a transmission antenna 4b and a reception antenna 4c in a metal case 4a above a radio wave absorber 4d. Further, the antennas 4b and 4c are connected to the pulse generator and amplifier of a measurement part through a balun 4e. Then the dielectric 4f is charged above the antennas 4b and 4c and the opening part of the metal case 4a is hermetically sealed with a plate material (g) made of rigide resin, etc. The thickness of the dielectric 4f is made larger than a distance (l) corresponding to the direct coupling by a direct wave. Consequently, even when a skin plate 3 and the cutting blade part is at a short distance, the state can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a face state detection device applied to a shield excavator.

[Prior Art] Radio pulse eco has been proposed and implemented as a method for detecting the state of a face portion applied to shield excavation n. In the apparatus related to this method, for example,
As shown in Publication No. 5, a plurality of notches for installing antennas are provided at the upper part of the skin play 1 tip of the shield excavator, and transmitting antennas and receiving antennas are installed in each of these notches. ” (embedded in. And,
The state of the face was detected by emitting electromagnetic wave pulses from the transmitting antenna toward the face and receiving the waves with the receiving antenna.

[Problems to be solved by the invention] By the way, shield excavation maintains the strength of
In order to make the device more compact, it is desirable to minimize the area of the above-mentioned cutout for installing the antenna and to reduce the number of cutouts.

However, in the above-mentioned conventional device, separate cutouts for antenna installation were provided for transmitting and receiving.
This was not sufficient to achieve the above objectives. Furthermore, g
In order to make the entire system more compact, transmitting and receiving antennas are installed close to each other. This has the disadvantage that detection becomes impossible.

(Means and effects for solving the problems) The present invention has the following features:
This was done in order to solve the above-mentioned problems of the conventional method. 9a is an electric body located in the upper part of the container and located above the transmitting antenna and the receiving antenna, which has a dielectric constant corresponding to the dielectric constant of pressurized mud water, and an electromagnetic wave pulse transmitted from the transmitting antenna. Therefore, the dielectric portions each have a dielectric portion having a thickness equal to or longer than the distance corresponding to the direct coupling R1.

As a result, the notch for installing the antenna can be filled with just one cutout, and its area can be made sufficiently small.Furthermore, by providing the above dielectric part together, the influence of the above-mentioned lζ direct wave can be suppressed.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 conceptually shows a device for detecting the state of a face portion in shield cutting according to the present invention.

In the figure, an ivy head 2 of a shield excavator 1 is rotatably supported by a skin plate 3. This head 2 is driven by the motor shown. The antenna section 4 is arranged above the tip of the skin plate 3.

FIG. 2 is a detailed view of this antenna section 4, and FIG.
), a transmitting antenna 4b and a receiving antenna 4C are both equipped with a radio wave absorbing material 4. It is buried at the top of the. And these antennas 4.4
is connected to the measuring unit 5 (Fig. 1), the pulse generator 5a, and the amplifier 5 via the balun 4 bce.
b, respectively.

A dielectric material c 4f is filled in the upper part of the antenna 4.4, and the metal case 4.4 is filled with dielectric material c4f. The frontage portion is sealed with a plate material 4 made of hard resin, hard urethane rubber, ceramics, or the like. Furthermore, Fig. 2(b)
As shown in FIG. 2, the opening of the metal case 4a may be sealed with the dielectric 4f.

The dielectric material 4f has a dielectric constant corresponding to the dielectric constant of pressurized mud, such as water or bentonite mud, and has a thickness e, which will be described later. Note that the upper surface of the antenna section 4 is the same as the upper surface of the skin plate 3.

FIG. 1(b) is an internal configuration diagram of the measurement unit 5. Electric pulses generated by R1 in the pulse generator 5 shown in the figure are transmitted as electromagnetic waves from the transmitting antenna 4b via the balun 4 of the antenna unit 4. It is oscillated as a pulse.

This electromagnetic wave pulse is reflected by the face portion 6 via the dielectric 3f, and is received by the receiving antenna 4°.

The strength of this reflection is generally determined by the difference in dielectric constant and conductivity. Therefore, the state of the face 6 can be detected from the moisture content of the face 6 and the difference in dielectric constant depending on the soil quality. The electromagnetic wave pulse received by the receiving antenna 4° passes through an amplifier 5, a sampler 5, and is subjected to signal processing by a signal processing device 7.

On the other hand, the excavation distance sensor 8 detects the excavation distance of the shield excavation pit 1, and the output of the excavation distance sensor 8 is inputted to a display device 9 such as a CRT together with the processed signal of the electromagnetic pulse. On the display device 9, the relationship between the excavation distance and the state of the face portion is displayed two-dimensionally.

Here, the apparent moisturizing effect of direct coupling will be explained.

First, considering the conventional case where the dielectric 4f described above does not exist, as shown in FIG. ), the reflected wave (b) in this vicinity is masked.

This masking phenomenon is shown in a time chart in Fig. 5, where the pulse signal transmitted from the transmitting antenna 4b shown in Fig. 5 (A) and the pulse signal received by the receiving antenna 4° shown in Fig. 5 (B) are shown. The pulse signal matches.

In the figure, tl is the convergence time of the direct wave (a) at the receiving antenna 4. Therefore, in this embodiment, the thickness of the dielectric 4f described above is set to a distance fift! corresponding to direct coupling by the direct wave (a). !
(=c1・tl) or more. However, C1 is the speed of electromagnetic waves in muddy water.

As mentioned above, the dielectric material 4. When the thickness of is set, the position corresponding to t1 on the time axis of the time chart is apparently at the same position as the surface of the skin plate 3. , the state of the face can be detected as shown by arrow (b) in FIG.

[Effect of light]

As explained above, in the present invention, the transmitting and receiving antennas are housed in one container. - A dielectric material having a dielectric constant corresponding to the dielectric constant of pressurized muddy water is filled between these antennas and the face portion.

Therefore, the area of the notch in the skin plate for installing the antenna can be reduced, and masking of reflected waves due to direct coupling can be prevented. As a result, the device can be made more compact, and the strength of the shield cutting machine can be significantly improved. It became possible to detect the state of the face at close range (0~53 degrees from the skin plate).

[Brief explanation of drawings]

Fig. 1 (a) is a diagram conceptually showing the state detection device of the working face in the shield detailing machine according to the present invention, and Fig. 1 (b)
2 is a block diagram showing the configuration of the measurement section shown in FIG. 2(a), FIG. 2(a) is a block diagram showing the configuration of the antenna section shown in FIG. 1, and FIG. Diagrams illustrating other configuration examples,
FIG. 3 is an explanatory diagram of direct coupling, FIG. 4 is a graph showing the effect of this embodiment, and FIG. 5 is a graph explaining the masking phenomenon according to the prior art. 1...Shield scraping, 3...Skin plate, 4
...Antenna part, 4 ...Metal case, 4b...
Transmitting antenna, 4o... Receiving antenna, 4f... dielectric, 5... Shooting section, 6... Face section, 7... Signal processing device, 8... Excavation distance sensor, 9. ...Display device. (a) (b) Figure 1 (a) (b) Figure 2 Figure 3

Claims (1)

[Claims] A transmitting antenna and a receiving antenna are respectively disposed above the tip of the skin plate of the shield excavator, and electromagnetic wave pulses oscillated from the transmitting antenna toward the face and reflected from the face are transmitted. The face state detection device detects the state of the face based on the electromagnetic wave pulses, which is disposed above the tip of the skin plate of the shield excavator, and the transmitting antenna and the receiving antenna are both internally installed. a dielectric part located in the upper part of the container facing the face and above the transmitting antenna and the receiving antenna, the dielectric part having a dielectric constant corresponding to the dielectric constant of pressurized mud water and a dielectric part located above the transmitting antenna and the receiving antenna. A state detection device for a face portion in a shield excavator, comprising: a dielectric portion having a thickness equal to or longer than a distance corresponding to direct coupling generated by electromagnetic wave pulses oscillated from the transmitting antenna.