JPH10142343A - Muddy water propagation wave measuring sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high sensitivity muddy water propagation wave measuring sensor excellent in abrasion resistance and durability. SOLUTION: The muddy water propagation wave measuring sensor 13 comprises a diaphragm 2 being set in a recess of a cutter head 1 and receiving the reflected wave of a transmitter an acceleration sensor 3 bonded to the back face of the diaphragm 2, a box member 5 having open front for holding the diaphragm 2 oscillatory through a butter member 4 while covering the front face, a member 7 for supporting the diaphragm holding member 5 while defining an airtight space (airtight chamber 6) between the back face of the diaphragm holding member 5 and the recess in the cutter head 1, and a diaphragm guard 8 covering the front face of the recess in the cutter head 1 in order to block intrusion of rubbish. A pressure release hole 10 through which a space (water chamber 9) defined in the back face of the diaphragm 2 communicates the outside is made in the circumferential wall of the diaphragm holding member 5 so that a reflected wave can be measured while balancing the pressure on the surface and rear of the diaphragm 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for measuring a muddy water propagation wave for performing an underground forward exploration in a shield method.

[0002]

2. Description of the Related Art The shield construction method is to construct a tunnel while safely excavating and lining work inside a shield excavator having a face on the front surface while propelling it underground to prevent collapse of the surrounding ground. It is a construction method. In recent years, underground space has been actively used, especially in underground urban areas. Therefore, tunnels must be constructed so as not to damage these underground structures. Therefore, recent shield excavators are equipped with an underground forward exploration device including a transmitter and a receiver for exploring obstacles ahead of the face. As the underground forward exploration device, an electromagnetic wave type and a sound wave type are generally adopted. However, in order to avoid the overcrowded part mentioned above, the depth of the tunnel is deeper than the groundwater level, and drilling is often performed in muddy water containing a large amount of water or seawater. It is not suitable for the electromagnetic wave type that performs On the other hand, the sonic wave type is suitable for excavating muddy water containing a large amount of water because sound waves do not propagate without water. As this sound wave type underground forward exploration device, a hydrophone in which a piezoelectric element is molded with urethane rubber is used, like a so-called sonar or fish finder, and a sound wave is transmitted and reflected by obstacles etc. The time to return is measured by a plurality of sensors, and its position and size are known.

[0003]

As described above, the hydrophone has poor abrasion resistance and durability because the piezoelectric element is simply molded of urethane rubber, and furthermore,
Because it is provided on the cutter head in front of the shield machine,
The muddy water comes into direct contact with the gravel, which may cause abrasion or breakage of the piezoelectric element. Furthermore, hydrophones convert sound waves into distortions of piezoelectric elements for detection, and require high sensitivity to detect small signals under the ground because sound waves are greatly attenuated. The phone itself could not be strengthened.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a muddy water propagation wave measurement sensor that is excellent in wear resistance and durability and is high in sensitivity.

[0005]

According to the present invention, a transmitted sound wave is mounted on a shield machine which excavates underground while rotating a cutter head having a plurality of cutter bits on a front surface facing a face. In the muddy water propagation wave measuring sensor for receiving the reflected wave, the diaphragm provided in the concave portion of the cutter head and receiving the reflected wave, the acceleration sensor fixed to the rear surface of the diaphragm, and the front surface opened. A box member, wherein a diaphragm holding member for vibrating the diaphragm via a cushioning material so as to cover the front surface thereof, and a hermetic seal between a back surface of the diaphragm holding member and a concave portion of the cutter head. A supporting member that supports the diaphragm holding member so as to form a suitable space, and a diaphragm guard that covers the front surface of the concave portion of the cutter head and prevents intrusion of gravel, and a peripheral wall of the diaphragm holding member includes , A pressure release hole communicating the space formed on the back surface of the diaphragm with the outside is provided, and the reflected wave is measured while maintaining the pressure balance between the front and back of the diaphragm. Provided.

The present invention described above is intended to measure a muddy water propagation wave as a reflected wave using a high-sensitivity acceleration sensor instead of a piezoelectric element. For this purpose, muddy water propagation waves are received by a diaphragm having excellent wear resistance and durability, and the vibration of the diaphragm can be converted into an electric signal by an acceleration sensor. Since this acceleration sensor is provided on the back surface of the diaphragm, it does not come into direct contact with muddy water, gravel, or the like, can be used in a stable environment, and has little risk of failure. Therefore, it is possible to provide a muddy water propagation wave measuring sensor that is excellent in wear resistance and durability and is highly sensitive.

Further, according to the embodiment of the present invention, it is preferable that a filter for preventing sand from entering is provided in the pressure release hole. It is preferable that a flange portion is provided, and that the flange portion be supported by the support member inserted over the entire periphery of the concave side surface of the cutter head.

According to the configuration of the embodiment of the present invention described above, the filter is provided in the pressure release hole, so that mud and gravel do not enter the space formed on the back surface of the diaphragm, and the acceleration sensor Can be protected, and the space formed on the back surface of the pressure release hole and the diaphragm can be prevented from being clogged. In addition, the provision of the flange portion on the diaphragm holding member facilitates the support and the sealing.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side sectional view showing a muddy water propagation wave measuring sensor of the present invention, and FIG.
1 is a front view of a shield machine equipped with a muddy water propagation wave measurement sensor of the present invention.

The muddy water propagation wave measuring sensor 13 of the present invention shown in FIG.
The vibration plate 2 receives a reflected wave (muddy water propagation wave) of a sound wave transmitted from the vibration plate 2 (see FIG. 2), an acceleration sensor 3 fixed to the rear surface of the vibration plate 2, and a box member having an open front surface. The diaphragm 2 so as to cover the front surface thereof.
And a diaphragm holding member 5 that holds the diaphragm so as to be able to vibrate therethrough, and forms an airtight space (airtight chamber 6) between the back surface of the diaphragm holding member 5 and the concave portion of the cutter head 1. And a diaphragm guard 8 that covers the front surface of the concave portion of the cutter head 1 and prevents the intrusion of gravel. The peripheral wall of the diaphragm holding member 5 is formed on the rear surface of the diaphragm 2. Pressure release hole 10 that connects the open space (water chamber 9) with the outside.
Are provided to measure the reflected wave while maintaining the pressure balance between the front and back surfaces of the diaphragm 2.

The diaphragm 2 is preferably a tough member because it directly faces the face, and is preferably lightweight to improve the response (sensitivity). Therefore, a light and strong member such as titanium or aluminum is used for the diaphragm 2. Then, the shape, the shape, and the like must be set so as to have strength, durability and wear resistance enough to withstand the excavation work of the shield machine, and to have a sensitivity capable of receiving a small signal of a reflected wave. Various conditions such as size and thickness are determined.

The acceleration sensor 3 is fixed to the rear surface of the diaphragm 2 by molding with a resin together with an amplifier board (not shown). By molding in this manner, the acceleration sensor 3 and the like can be reliably waterproofed, and the largest cause of failure can be eliminated. Note that the signal line of the acceleration sensor 3 is connected to a measuring device (not shown) in the shield machine through the airtight chamber 6 or the support member 7 from the diaphragm holding member 5.

The diaphragm holding member 5 holds the diaphragm 2 so that it can vibrate, and forms a water chamber 9 filled with water on the back surface of the diaphragm 2 so as to balance the pressure between the front and back of the diaphragm 2. Is what you take. As described above, the diaphragm 2 is supported by the diaphragm (metal frame) 4 in the peripheral direction, so that the impact given to the diaphragm 2 during excavation can be reduced, and the roll of the diaphragm 2 can be prevented. Thus, the response can be improved.

In general, during excavation by a shield machine, a pressure of about 5 kg / cm ² is applied to prevent the face from collapsing. Therefore, the pressure balance between the front and back of the diaphragm 2 must be maintained. This makes it difficult to receive the reflected wave, which is a minute signal, so that accurate measurement cannot be performed. Therefore, as described above, the water chamber 9 is provided to maintain the pressure balance between the front and back of the diaphragm 2. The water chamber 9 is a space surrounded by the diaphragm holding member 5, the diaphragm 2, and the diaphragm 4, and a plurality of pressure relief holes 10 are formed from the peripheral wall of the diaphragm holding member 5 toward the front face on the face side. And communicates with the outside on the face side. Therefore, the water filled in the water chamber 9 and the water in the muddy water in front of the cutter head 1 can flow, and the pressure on the front and back of the diaphragm 2 can be maintained uniformly. At this time, if sand or mud flows into the water chamber 9 or the pressure release hole 10, there is a risk of clogging.
Is provided. By providing the filter 11, the influence of the dynamic pressure can be reduced. Note that a labyrinth may be provided instead of the filter 11.

Further, a flange portion 5f is provided on the outer peripheral surface of the diaphragm holding member 5, and the flange portion 5f is inserted into the support member 7. Therefore, an airtight chamber 6 that is an airtight space can be formed between the back surface of the diaphragm holding member 5 and the recess of the cutter head 1. The airtight chamber 6 uses the difference in acoustic impedance between the shield machine and the air to transmit the solid waves of the shield machine to the diaphragm 2.
To prevent transmission to the user. Further, in order to improve the shielding property of the airtight chamber 6, a foamed urethane resin may be filled.

The support member 7 is a damper and seal member for supporting the diaphragm holding member 5, and supports the flange portion 5f of the diaphragm holding member 5 so as to support the entire periphery of the concave side surface of the cutter head 1. It is inserted across. The support member 7 maintains the airtightness of the airtight chamber 6, and absorbs the vibration of the shield machine and prevents the vibration from being transmitted to the diaphragm 2. The support member 7 is made of a so-called anti-vibration rubber.

The vibrating plate guard 8 is made of wire mesh, resin, FR
P, etc., and the gravels form the diaphragm 2 and the diaphragm 4
The cutter head 1 is stretched on the front surface of the concave portion of the cutter head 1 in order to prevent collision of the cutter head 4 and clogging of the gap of the diaphragm 4 and the pressure release hole 10. As described above, although the diaphragm 2 itself has sufficient strength,
It is necessary to design with emphasis on the response (sensitivity). Frequent collision of gravel with the diaphragm 2 is inconvenient in terms of durability and measurement of minute signals. For this reason, the diaphragm guard 8 is provided with a porosity that allows the passage of particles having a particle size as small as that of sand and the removal of particles having a particle size larger than that of sand. Although not shown, 2
The diaphragm guard 8 may be provided three times or more. By providing the diaphragm guard 8, the response of the diaphragm 2 can be designed with priority.

The above-described muddy water propagation wave measuring sensor of the present invention is arranged, for example, as shown in FIG. Here, two transmitters 12 are provided, and six muddy water propagation wave measuring sensors 13 of the present invention are provided in an array. A plurality of muddy water propagation wave measurement sensors 13 are provided to reliably receive the reflected wave, which is a small signal, and to obtain the resolution required to determine the direction of an obstacle or the like, and measure while rotating the cutter head 1 during measurement. Therefore, they are arranged in a line in the radial direction.
When the underground forward exploration is performed using the muddy water propagation wave measurement sensor 13 of the present invention, for example, a sound wave is transmitted from the transmitter 12 while the cutter head 1 is stopped as shown in FIG. The reflected wave is received by the muddy water propagation wave measurement sensor 13. Next, the cutter head 1 is rotated and stopped by a certain angle, a sound wave is transmitted from the transmitter 12, and the reflected wave is received by the muddy water propagation wave measurement sensor 13. One round (36
0 °) to complete one underground exploration. In general, in tunnel excavation using a shield excavator, a single excavation operation advances about 2 m and assembles segments for one ring in one hour. Therefore, it is a condition that an obstacle at least 2 m away can be found and one round (360 °) can be measured in one hour. Mud water propagation wave measuring sensor 1 of the present invention
No. 3 can detect an obstacle having a size of about 30 cm, which is about 5 m away, by a single underground exploration, and sufficiently satisfies the conditions described above.

Further, the above-described muddy water propagation wave measuring sensor of the present invention can measure in a frequency range from 100 Hz to 5000 Hz. The frequency range of the reflected wave from the obstacle is from 500 Hz to 1000 Hz, and the muddy water propagation wave measuring sensor of the present invention has sufficient performance required for underground forward exploration.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0021]

As described above, according to the muddy water propagation wave measuring sensor of the present invention, the following excellent effects can be obtained. (1) Since the reflected wave is received by the diaphragm, the range of material selection is expanded, and the durability and wear resistance can be improved. (2) Since the vibration of the diaphragm is processed by the acceleration sensor, the reflected wave can be measured with high sensitivity. (3) Since the electronic components such as the acceleration sensor and the amplifier board are molded with resin on the back surface of the diaphragm, it can be completely waterproofed, and the largest cause of failure such as the acceleration sensor can be eliminated. . (4) Since a water chamber is provided on the back surface of the diaphragm to maintain the pressure balance between the front and back surfaces of the diaphragm, the vibration of the diaphragm is not restricted even in a pressurized atmosphere, and a small signal is received. be able to. (5) By supporting the diaphragm holding member with a highly elastic supporting member and providing an airtight chamber, the influence of the vibration of the shield machine can be suppressed, and a small signal can be received. Measurement accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a muddy water propagation wave measuring sensor of the present invention.

FIG. 2 is a front view of a shield machine equipped with the muddy water propagation wave measurement sensor of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cutter head 2 diaphragm 3 acceleration sensor 4 cushioning material (diaphragm) 5 diaphragm holding member 5 f flange 6 airtight chamber 7 support member 8 diaphragm guard 9 water chamber 10 depressurization hole 11 filter 12 transmitter 13 muddy water propagation wave measurement sensor

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeki Murayama 3-1-1-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd.Higashiji Technical Center (72) Inventor Hitoshi Kitayama 11 Kitahama-cho, Chita City, Aichi Prefecture No. 1 Ishikawajima Harima Heavy Industries Co., Ltd. Aichi Factory

Claims (3)

[Claims] 1. A muddy water propagation wave measurement mounted on a shield machine for excavating underground while rotating a cutter head having a plurality of cutter bits on a front surface facing a face and receiving a reflected wave of a transmitted sound wave. In the sensor, a diaphragm provided in the recess of the cutter head and receiving the reflected wave, an acceleration sensor fixed to a back surface of the diaphragm, and a box member having an open front surface, covering the front surface And a diaphragm holding member for holding the diaphragm so as to be able to vibrate via a cushioning material, and an airtight space between a back surface of the diaphragm holding member and a recess of the cutter head. A supporting member for supporting the member; and a diaphragm guard for covering the front surface of the concave portion of the cutter head and preventing intrusion of gravel. The peripheral wall of the diaphragm holding member is provided on the rear surface of the diaphragm. During the pressure release hole communicating it is provided an external, while keeping the pressure balance on the front and back the diaphragm to measure the reflected wave, mud propagating wave measuring sensor, characterized in that. 2. The muddy water propagation wave measuring sensor according to claim 1, wherein a filter for preventing intrusion of sand is provided in the pressure release hole. 3. A flange portion is provided on an outer peripheral surface of the diaphragm holding member, and the flange portion is supported by the support member inserted around the entire periphery of a concave side surface of the cutter head. The muddy water propagation wave measurement sensor according to claim 1 or claim 2.