JP5425855B2 - Muddy water type shield machine - Google Patents

Description

  The present invention relates to a muddy water shield machine, and more particularly to a muddy water shield machine that performs tunnel tunneling while stabilizing a face surface by the pressure of muddy water filled in a cutter chamber.

  The muddy water shield machine forms a cutter chamber partitioned by a partition wall behind the cutter head that is provided at the tip of the machine body and excavates the face, and fills the cutter chamber with muddy water. This is a shield excavator that excavates the tunnel while stabilizing the face with the pressure of the muddy water (muddy water pressure). The muddy water filled in the cutter chamber is circulated between the muddy water tank and muddy water tank, and excavated soil Is transported together with muddy water to a muddy water tank or muddy water tank, so that the tunnel can be dug while discharging excavated earth and sand excavated by the cutter head from the cutter chamber.

  In addition, as an improvement of the muddy water shield machine, an air chamber is formed behind the cutter chamber, and the cutter chamber and the air chamber are communicated with each other at the lower part thereof, so that the muddy water layer in the air chamber is located above the muddy water layer. A muddy water type shield excavator equipped with an air chamber has been developed in which a tunnel is dug in a state where an air layer is formed (see, for example, Patent Document 1 and Patent Document 2).

  In the muddy water type shield machine equipped with such an air chamber, for example, the height of the muddy water level, which is the boundary between the muddy water layer and the air layer in the air chamber, the air pressure of the air layer, the cutter chamber, Pressure fluctuations due to changes in water pressure from the ground surface on the face face are controlled by controlling the mud flow and mud discharge to the air chamber, and the air layer in the air chamber. The tunnel can be dug while being relaxed by the compressive and expansibility of air.

JP 2003-120175 A JP 2009-13702 A

  On the other hand, the soil quality of the natural ground excavated by the muddy water shield excavator changes with the tunnel excavation. In particular, in the case of a tunnel with a large section, the soil texture of the natural ground is not homogeneous in the cross-sectional direction. In many cases, for example, when a sand layer, a gravel layer, or a bedrock layer with a low uniformity coefficient is encountered, or when these layers are included in the face, there is a loss of water due to the eruption or release of muddy water. May cause trouble. When water loss or the like occurs, the pressure in the cutter chamber or the air chamber is also rapidly lowered by the pressurized muddy water in the cutter chamber being removed from the face to the ground. Further, for example, when a mud pipe for draining muddy water from the cutter chamber is blocked or cavitation occurs, the pressure in the cutter chamber or the air chamber will rise rapidly.

  Here, if there is water loss on the face, clogging of the sludge pipe, etc., if these can be detected and the pressure in the cutter chamber or air chamber can be recovered quickly, the face will be stabilized and digging will continue. It will be possible to do it. That is, for example, when a sudden drop in pressure due to water loss is detected, it is included in the muddy water adjusted to increase the specific gravity and viscosity through the pressure in the recovered cutter chamber and air chamber, for example, Due to bentonite components, mud pressure (impervious layer) is generated again on the ground surface of the face where water loss has occurred, so that the mud pressure of the desired magnitude can be obtained again and the face is stabilized. It is thought that it will be possible to continue drilling while

  On the other hand, in a mud shield shield machine equipped with a conventional air chamber, an accumulator or compressor is connected to a pipe that sends air to the air chamber so that the air pressure of the air layer in the air chamber can be adjusted. In addition, pressure reducing valves and air supply valves are installed in the pipes that send air, but these compressors and accumulators are used to prevent pressure fluctuations on the ground due to the collapse of small grounds. However, by supplying pressurized air to the air layer in the air chamber, it is possible to absorb these pressure fluctuations, while the capacity of the pressurized air that can be supplied to the air layer is limited. Therefore, when a sudden pressure drop due to water loss or the like occurs in the cutter chamber or air chamber, especially in the case of a tunnel with a large cross section, the volume of pressurized air is Added to, it is difficult to quickly recover the pressure of the cutter chamber and the air chamber. In addition, in a muddy water shield machine equipped with a conventional air chamber, if a sudden rise in pressure due to blockage of the mud pipe is detected, the pressure in the cutter chamber or air chamber can be quickly recovered. Have difficulty.

  The present invention detects and detects pressure when a sudden drop or rise in the pressure in the cutter chamber or air chamber occurs due to water leakage on the face or clogging of the sludge pipe during tunnel excavation. The purpose is to provide a muddy water type shield excavator equipped with an air chamber that can restore the face face to a stable state by muddy water pressure and recover the tunnel surface continuously by recovering it quickly. And

  The present invention is provided by a cutter head provided at the tip of the excavator main body for excavating the face, and a cutter-side partition disposed behind the cutter head, and the cutter-side partition and the cutter head A cutter chamber formed between the main body side partition wall and the cutter side partition wall, and is partitioned by a main body side partition wall disposed behind the cutter chamber. In the muddy water type shield excavator that excavates the tunnel while stabilizing the face by the pressure of the muddy water filled in the cutter chamber, the air chamber and the cutter chamber are provided below the partition wall on the cutter side. As a result, the muddy water layer is formed in the lower part of the air chamber and the air layer is formed in the upper part. The tunnel excavation can be carried out while mitigating the pressure fluctuation on the ground surface on the face surface by the compressibility of the air in the air layer in the air chamber, and the air is pumped to the air layer. The air supply pipe and the exhaust pipe that discharges air from the air layer are provided with an air supply side air control valve and an exhaust side air control valve, respectively, and are connected to the air supply pipe to store compressed air. An air tank is provided, and the air supply side air control valve and the exhaust side air control valve are connected to a control device, and the muddy water pressure in the cutter chamber and / or the air in the air chamber. The opening degree of these valves is controlled in response to the detection result of the air pressure of the layer, and the air supply side air compressor is controlled. The trawl valve and the exhaust side air control valve are in an open state during tunnel excavation, and continue to pump air from the air tank and continue to exhaust air from the air layer, The opening degree of each valve is controlled by the control device such that the air pressure of the cutter chamber is maintained at a predetermined pressure, and the muddy water pressure in the cutter chamber and / or the air layer in the air chamber A muddy water type in which the opening degree of each valve is controlled by the control device so that the air pressure of the air layer is restored to the predetermined pressure when a sudden drop or rise in the air pressure is detected. The above object is achieved by providing a shield machine.

  And the muddy water type shield machine according to the present invention is provided with an air compressor that is connected to the air tank via a storage pipe to generate compressed air, and a storage pressure reducing adjustment valve is provided in the storage pipe. It is preferable that

  In the mud shield shield machine of the present invention, it is preferable that the predetermined pressure of the air layer held in the chamber is a management pressure set based on a groundwater level at a construction site.

  Furthermore, in the muddy water type shield machine according to the present invention, the air pressure of the compressed air stored in the air tank is preferably 2 to 10 times the predetermined pressure of the air layer.

  Furthermore, in the muddy water type shield machine according to the present invention, it is preferable that a supply air pressure reducing adjustment valve is provided downstream of the supply air control valve of the supply pipe.

  According to the mud shield shield machine equipped with the air chamber of the present invention, sudden pressure drop or rise in the cutter chamber or the air chamber due to the water loss on the face and the clogging of the mud pipe while the tunnel is dug. When this occurs, it is detected and the pressure is quickly recovered, so that the face surface can be returned to a stable state by the muddy water pressure and the tunnel can be continuously dug.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view illustrating a configuration of a muddy water shield machine according to a preferred embodiment of the present invention. It is sectional drawing along AA of FIG.

  A muddy-water shield machine 10 according to a preferred embodiment of the present invention shown in FIG. 1 is for roads and subways, for example, on the ground where groundwater exists, for example, the diameter of the tunnel cross section is about 6 to 20 m. In the construction of the tunnel, it was adopted as a shield machine for digging the tunnel while stabilizing the face 20 by mud pressure (muddy water pressure) without affecting the surrounding ground. . Further, the muddy water type shield machine 10 of the present embodiment is further provided with an air chamber 14 behind the cutter chamber 13 formed behind the cutter head 12 excavating the face 20, so that the ground on the face 20 It has a function of enabling tunnel excavation while mitigating the pressure fluctuation on the mountain side by the compressibility of the air in the air layer 15 formed in the air chamber 14, and the water loss on the face during the tunnel excavation. When the pressure in the cutter chamber 13 or the air chamber 14 suddenly drops or rises due to the clogging of the mud pipe 34 or the like, the pressure in the cutter chamber 13 or the air chamber 14 that has fallen or rises immediately. A machine that makes it possible to easily return the face 20 to a stable state by muddy water pressure by restoring the pressure to the original pressure. It is equipped with a.

  That is, the muddy water type shield machine 10 of the present embodiment is partitioned by a cutter head 12 provided at the tip of the machine 11 and excavating the face surface, and a cutter-side partition wall 16 disposed behind the cutter head 12. The main body side partition wall 17 and the cutter side partition wall 16 are partitioned by a cutter chamber 13 formed between the cutter side partition wall 16 and the cutter head 12 and a main body side partition wall 17 disposed behind the cutter chamber 13. In the shield machine that digs the tunnel while stabilizing the face surface 20 by the pressure of the muddy water 21 filled in the cutter chamber 12, the air chamber 14 The cutter chamber 13 is a communication port 18 provided in the lower part of the cutter side partition wall 16. As a result, the muddy water layer 19 is formed in the lower part of the air chamber 14 and the air layer 15 is formed in the upper part, and the pressure fluctuation on the ground surface side in the face 20 is caused by the air layer 15 in the air chamber 14. The tunnel can be dug while being relaxed by the compressibility of air.

  The supply side air control valves 26 and 26a and the exhaust side air control valves 38a and 38b are respectively provided in the supply pipe 24 for pumping air to the air layer 15 and the exhaust pipe 35 for discharging air from the air layer 15. In addition, an air tank 22 for storing compressed air is provided in connection with the air supply pipe 24. The air supply side air control valves 26 and 26a and the exhaust side air control valves 38a and 38b are provided with a control device ( The cutter chamber 13 includes a muddy water pressure detector 50 that detects the muddy water pressure in the cutter chamber 13 and a chamber air pressure detector 27 that detects the air pressure of the air layer 15 in the air chamber 14. In response to detection results of the muddy water pressure and / or the air pressure of the air layer 15 in the air chamber 14, Valve 26, 26a, 38a, opening degree of 38b is adapted to be controlled. The supply-side air control valves 26 and 26a and the exhaust-side air control valves 38a and 38b are in an open state when the tunnel is being dug, and continue to pump air from the air tank 22 and air from the air layer 15. The degree of opening of the valves 26, 26a, 38a, 38b is controlled by the control device so that the air pressure of the air layer 15 is maintained at a predetermined pressure while the air is being discharged, and the cutter chamber 13 When a sudden drop or rise in the air pressure of the muddy water pressure and / or the air layer 15 in the air chamber 14 is detected, the air pumping amount is increased more than the air discharging amount, or the air discharging amount is exceeded. Each valve 26, 26a, 38a, etc. is controlled by the control device so that the air pumping amount is reduced and the air pressure of the air layer 15 returns to a predetermined pressure. Opening degree of 8b is adapted to be controlled.

  Further, in the present embodiment, an air compressor 23 that is connected to the air tank 22 via the storage pipe 28 and generates compressed air is provided, and a storage decompression adjustment valve 29 is provided in the storage pipe 28. Yes.

  In this embodiment, the excavator main body 11 of the muddy water shield machine 10 has a configuration substantially similar to that of the conventional muddy water shield machine equipped with an air chamber. That is, the excavator main body 11 is disposed at the outer shell 30 formed in a cylindrical shape (cylindrical shape) and the distal end portion of the excavator main body 11, and by a known cutter rotation drive mechanism (not shown). The cutter head 12 that is rotated and excavates the face, the cutter-side partition wall 16 formed in the outer shell 30 so as to be separated from the cutter head 12 in the direction opposite to the digging direction, and the digging direction from the cutter-side partition wall 16 The main body side partition wall 17 is formed in the outer shell 30 so as to be spaced apart in the opposite direction.

  The cutter-side partition wall 16 is composed of a disk-shaped partition plate formed so as to partition the inside of the outer shell body 30 in the front and rear direction in the digging direction. As shown in FIG. 2, the main body-side partition wall 17 disposed behind the cutter-side partition wall 16 has a substantially annular donor plate shape with a central portion cut out in a circular shape and a lower end portion cut out in an arcuate shape. It consists of a partition plate. A cylindrical inner cylinder 31 is fitted inside the central portion of the main body-side partition wall 17 cut into a circle. The inner cylinder 31 is joined to the main body-side partition wall 17 in a state of extending to the back surface of the cutter-side partition wall 16 and being in close contact therewith. A bottom plate 32 is provided at the lower end portion of the main body-side partition wall 17 that is notched in an arcuate shape. The bottom plate 32 forms a flat bottom portion inclined toward the cutter chamber 13 in the air chamber 14. The bottom plate 32 extends to the back surface of the cutter side partition wall 16 and is in close contact with the main body side partition wall 17 while being in close contact therewith.

  As a result, between the cutter side partition wall 16 and the main body side partition wall 17, a substantially annular donor-shaped air chamber 14 with a lower end portion cut out is formed, similar to the conventional muddy shield shield machine having an air chamber. Is done. The air chamber 14 communicates with the cutter chamber 13 through a communication port 18 formed in the lower portion of the cutter-side partition wall 16 at a portion directly above the bottom plate 32 that covers the bottom. Thus, muddy water is sent from the cutter chamber 13 to the air chamber 14, and a muddy water layer 19 is formed in a substantially lower half portion below the air layer 15. Further, the inner chamber 31 provided in the central portion of the air chamber 14 in the radial direction is provided with gears, motors, and the like, similar to the muddy water shield machine equipped with the conventional air chamber. A known cutter rotation drive mechanism (not shown) is provided.

  Moreover, in this embodiment, the mud pipe 33 which sends mud to the cutter chamber 13 in the excavator main body 11 of the mud type shield machine 10 and the mud pipe 34 which discharges mud together with excavated soil from the cutter chamber 13. With.

  The mud pipe 33 is attached to the upper part of the main body side partition wall 17 and the cutter side partition wall 16 so as to pass through these from the rear side of the main body side partition wall 17 so that the tip opening is opened at the upper part of the cutter chamber 13. The mud feeding pipe 33 feeds mud water toward the cutter chamber 13 by driving a mud feeding pump (not shown), for example, from a mud tank or mud tank (not shown) installed in a shaft or tunnel. Mud can be used.

  The mud discharge pipe 34 is attached below the bottom of the air chamber 14 partitioned by the bottom plate 32 so as to penetrate the cutter side partition wall 16 and open at the bottom of the cutter chamber 13 at the rear end. The drainage pipe 34 drives a drainage pump (not shown), for example, for mud tanks and mud tanks (not shown) installed in shafts or tunnels to mix mud mixed with excavated soil. It can be discharged from the cutter chamber 13.

  Then, mud is sent to the cutter chamber 13 through the mud pipe 33, and the mud is discharged from the cutter chamber 13 together with the excavated soil through the mud pipe 34, and then a mud tank or mud tank (shown). The tunnel is dug while the face 20 is excavated by the cutter head 12 while mud is circulated between them. The mud pump and the mud pump are connected to a known control device (not shown) for controlling the amount of mud and the amount of mud discharged in the same manner as the conventional mud shield shield machine equipped with an air chamber. For example, based on the detection result by the muddy water pressure detector 50 provided in the cutter chamber 13, the amount of mud and the amount of muddy water can be controlled so that the muddy water pressure in the cutter chamber 13 becomes a predetermined value. ing.

  Further, in the present embodiment, a liquid level gauge installation chamber 40 is formed on the bottom of the main body side partition wall 17 forming the air chamber 14 so as to project from the main body side partition wall 17 to the cutter side partition wall side 16. The measurement opening 41 is disposed in the portion directly above the liquid level of the muddy water layer 19, and a ball valve that opens and closes the hollow measurement path between the measurement opening 41 and the measurement opening 41 in a liquid level gauge installation chamber 40. A liquid level gauge 44 for detecting the reflected wave from the liquid surface 19a of the muddy water layer 19 in the air chamber 14 and measuring the water level of the muddy water layer 19 is detachably attached via a valve mechanism 43 composed of, for example. ing. The liquid level gauge 44 is connected to a known control device (not shown) that controls the amount of mud fed through the mud pipe 33 and the amount of mud discharged through the mud pipe 34. Based on the measurement result of the water level of the liquid level 19a of the measured mud layer 19, the amount of mud and the amount of mud discharged can be controlled so that the level of the mud layer 19 in the air chamber 14 becomes a predetermined level. It has become.

  Further, in the present embodiment, the excavator body 11 of the muddy water type shield excavator 10 includes an air supply pipe 24 that pumps air to the air layer 15 in the air chamber 14 and an exhaust pipe that discharges air from the air layer 15. 35 is provided in the upper part of the main body side partition wall 17 so as to penetrate the main body side partition wall 17. An air tank 22, an air compressor 23, an air supply decompression adjustment valve 25, and an air supply side air control valve 26 are connected to the air supply pipe 24.

  As the air tank 22, for example, a known air tank having a capacity of about 1000 to 6000 L, which is used for various works such as a pressurized air construction method capable of storing compressed air of about 0.1 to 1 MPa, for example, is used. Can do. The air tank 22 is provided with an air pressure detector 22a.

  Here, the pressure of the compressed air stored in the air tank 22 is preferably a management pressure set based on the groundwater level at the construction site, and the pressure of the air layer 15 to be held in the air chamber 14 during tunnel excavation. The predetermined pressure is preferably 2 to 10 times the predetermined pressure, and more preferably 5 to 10 times the pressure. If the pressure of the compressed air stored in the air tank 22 is too high, for example, when a sudden drop in pressure in the cutter chamber 13 or the air chamber 14 is detected, the degree of opening of the air supply side air control valves 26 and 26a is detected. After increasing the required amount of compressed air from the air tank 22 to the air layer 15 by increasing the pressure, the opening degree of the air supply side air control valves 26, 26a is narrowed to return the compressed air pressure to the original state. When returning, excessive compressed air is pumped to the air layer 15 while the opening degree of the air supply side air control valves 26 and 26a is being reduced, so that the pressure in the cutter chamber 13 and the air chamber 14 is increased. There is a disadvantage that rebound, which is a phenomenon that becomes higher than necessary, becomes excessively large. If the pressure of the compressed air stored in the air tank 22 is too low, a sufficient amount of compressed air necessary to quickly recover the reduced pressure in the cutter chamber 13 and the air chamber 14 is supplied to the air layer 15. There is a disadvantage that it becomes difficult to pump.

  As the air compressor 23 that generates compressed air, for example, various known compressed air generators that can generate compressed air of about 0.1 to 1 MPa can be used.

  In the present embodiment, the pressure feed pipe 24 is connected to the air tank 22 via two branch air supply pipes 24a and 24b branched on the upstream side thereof, and the first branch air supply pipe 24a includes: A manual gate valve 36, an air supply pressure reducing adjustment valve 25, an air supply side air control valve 26, and a check valve 37 are provided in this order from the air tank 22 side. In other words, in the present embodiment, the supply air pressure reducing adjustment valve 25 is provided on the downstream side of the supply air control valve 26 in the first branch supply air pipe 24a constituting the upstream side portion of the supply air pipe 24. Yes.

  Here, the manual gate valve 36 is used for, for example, when the equipment constituting the muddy water shield machine 10 breaks down or the air supply side air control valve 26 breaks down, the air through the first branch air supply pipe 24a. It is provided to block pumping. The air supply decompression adjustment valve 25 is provided in order to prevent unnecessary high-pressure compressed air from being pumped to the air layer 15 in the air chamber 14 via the first branch air supply pipe 24a. The air supply side air control valve 26 is connected from the air tank 22 via the first branch air supply pipe 24a so that the air pressure of the air layer 15 in the air chamber 14 is maintained at a predetermined pressure during normal tunnel excavation. And adjusting so that a desired amount of compressed air is pumped to the air layer 15, and when a sudden drop or rise in the muddy water pressure in the cutter chamber 13 or the air pressure of the air layer 15 in the air chamber 14 is detected. In order to quickly recover the air pressure of the air layer 15 to a predetermined pressure, the amount of compressed air pumped from the air tank 22 to the air layer 15 via the first branch air supply pipe 24a is adjusted. It is provided for.

  In the second branch air supply pipe 24b, a second manual gate valve 36a, a second air supply side air control valve 26a, and a second check valve 37a are provided in this order from the air tank 22 side. Here, the second manual gate valve 36a is provided with the second branch air supply pipe 24b when, for example, a device constituting the muddy water type shield machine 10 breaks down or the second air supply side air control valve 26a breaks down. It is provided in order to cut off the air pumping. The second air supply side air control valve 26a is connected to the second branch air supply pipe 24b from the air tank 22 so that the air pressure of the air layer 15 in the air chamber 14 is maintained at a predetermined pressure during normal tunnel excavation. Is adjusted so that a desired amount of compressed air is pumped to the air layer 15, and a sudden drop or rise in the muddy water pressure in the cutter chamber 13 or the air pressure of the air layer 15 in the air chamber 14 is detected. In this case, the amount of compressed air pumped from the air tank 22 to the air layer 15 via the second branch air supply pipe 24b is adjusted so that the air pressure of the air layer 15 is quickly recovered to a predetermined pressure. Provided to adjust.

  In the present embodiment, the storage pipe 28 that connects the air compressor 23 and the air tank 24 includes a third manual gate valve 36b and a storage pressure reducing adjustment valve 29 in this order from the air compressor 23 side. Is provided. Here, the third manual gate valve 36b blocks, for example, the pumping of compressed air through the storage pipe 28 when a device constituting the muddy water shield machine 10 fails or when the storage decompression adjustment valve 29 fails. Is provided to do. The storage decompression adjustment valve 29 is provided to prevent the unnecessary high pressure compressed air generated by the air compressor 23 from being stored in the air tank 24 via the storage pipe 28.

  Furthermore, in this embodiment, the exhaust pipe 35 provided in the upper part of the main body side partition wall 17 includes two branch exhaust pipes 35a and 35b branched on the downstream side thereof, and each branch exhaust pipe 35a, 35b is provided with exhaust side air control valves 38a, 38b and check valves 39a, 39b, respectively.

  Here, the exhaust-side air control valves 38a and 38b are arranged so that the air pressure of the air layer 15 in the air chamber 14 is maintained at a predetermined pressure during normal tunnel tunneling. 2 In conjunction with the air supply side air control valve 26a, the air layer 15 is adjusted so that a desired amount of air is discharged through the branch exhaust pipes 35a and 35b, and the muddy water pressure in the cutter chamber 13 When a sudden drop or rise in the air pressure of the air layer 15 in the air chamber 14 is detected, the air layer 15 is linked with the air supply side air control valve 26 or the second air supply side air control valve 26a. A desired amount of air is supplied from the air layer 15 through the branch exhaust pipes 35a and 35b so that the air pressure is quickly recovered to a predetermined pressure. It is provided for adjusting to be discharged.

  Furthermore, in the present embodiment, a chamber air pressure detector 27 is provided at the upper part of the main body side partition wall 17 so as to face the air layer 15 of the air chamber 14, and is detected by the chamber air pressure detector 27. The detection result of the pressure of the air layer 15 is connected to the air supply side air control valves 26, 26a and the exhaust side air control valves 38a, 38b, and the opening degree of these valves 26, 26a, 38a, 38b is adjusted. Thus, it can be sent to a known control device (not shown) that controls the pressure in the air chamber 14.

  In the present embodiment, the air supply pressure detector 22a provided in the air tank 22 described above, the supply air pressure reduction adjustment valve 25 provided in the first branch supply air pipe 24a, the supply air control valve 26, and Check valve 37, second air supply side air control valve 26a and second check valve 37a provided in the second branch air supply pipe 24b, storage decompression adjustment valve 29 provided in the storage pipe 28, exhaust gas Exhaust air control valves 38a, 38b and check valves 39a, 39b, etc. provided in the branch exhaust pipes 35a, 35b of the pipe 35 are a mud pressure detector 50 provided in the cutter chamber 13 and a mud feed pipe. In addition to the mud pump provided in 33, the mud pump provided in the mud pipe 34, and the like, the pressure in the cutter chamber 13 and the air chamber 14 is controlled. It is connected to the control unit. These devices receive the detection result of the muddy water pressure in the cutter chamber 13 and the air pressure of the air layer 15 detected by the muddy water pressure detector 50 and the in-chamber air pressure detector 27, and compressed air is supplied from the air tank 22 to the air. It can be controlled automatically or manually through a control device so that the air is fed to the layer 15 at a predetermined pressure and flow rate, and the air pressure of the air layer 15 in the air chamber 14 is a predetermined pressure. .

  And according to the muddy water type shield excavator 10 of the present embodiment having the above-described configuration, for example, there is no water flow on the face 20 and small pressure fluctuation on the ground due to the collapse of a small ground During normal tunnel excavation, the air supply side air control valves 26 and 26a and the exhaust side air control valves 38a and 38b are opened by adjusting the degree of opening of these valves 26, 26a, 38a and 38b. The air pressure of the air layer 15 is maintained at a predetermined pressure while continuing to pump air from the air tank 22 and continuously discharging air from the air layer 15, and the pressure fluctuation on the ground surface in the face 20 is reduced. The tunnel is dug while being relaxed by the compressibility of the air in the air layer 15 formed in the air chamber 14.

  On the other hand, due to the water flow on the face 20 or the clogging of the mud discharge pipe 34, the mud pressure or air pressure in the cutter chamber 13 or the air chamber 14 is detected by the mud pressure detector 50 or the chamber pressure detector 27. If a sudden drop or rise is detected, for example, the degree of opening of the air supply side air control valves 26, 26a is controlled to increase or decrease the amount of air pumped from the air tank 22 to the air layer 15. At the same time, by controlling the opening degree of the exhaust side air control valves 38a and 38b to reduce or increase the amount of air exhausted from the air layer 15, the air pressure of the air layer 15 that has suddenly decreased or increased is controlled. It is possible to quickly return to a predetermined pressure.

  Here, in the present embodiment, the air supply side air control valves 26 and 26a and the exhaust side air control valves 38a and 38b are in an open state when the tunnel is dug, and air is always supplied to the air layer 15. Since air pressure is exhausted and air is exhausted from the air layer 15 so that the air pressure of the air layer 15 is maintained at a predetermined pressure, the muddy water pressure and air pressure in the cutter chamber 13 and the air chamber 14 are rapidly increased. When a drop or rise is detected, the amount of air staying in the air layer 15 is increased or decreased by controlling the degree of opening of these valves 26, 26a, 38a, 38b. The air pressure of the layer 15 can be restored immediately. This reduces the time delay when opening and closing the valve compared to opening and closing the valve after a sudden drop in air pressure in the air chamber 14 is detected, making it smoother and faster. It is possible to restore the air pressure of the air layer 15 to a predetermined pressure.

  In the present embodiment, an air tank 22 is provided that is connected to the air layer 15 in the air chamber 14 via an air supply pipe 24 and stores compressed air. Since a considerable amount of compressed air sent from the air compressor 23 that generates compressed air can be always stored, the air pressure in the air layer 15 in the air chamber 14 is maintained at a predetermined pressure. When the compressed air continues to be pumped to the layer 15 or when a sudden drop in the air pressure of the air layer 15 is detected, a sufficient amount of compressed air is secured to increase the pumped amount of the compressed air. It is possible to easily hold or restore the air pressure so that the air pressure becomes a predetermined pressure.

  By these, according to the muddy water type shield machine 10 having the air chamber 14 of the present embodiment, the inside of the cutter chamber 13 and the air chamber 14 due to water leakage on the face surface, blockage of the mud pipe, etc. during tunnel excavation. When a sudden pressure drop or rise occurs, this can be detected and recovered quickly so that the face can be stabilized by mud pressure and the tunnel can continue to be dug. It becomes possible to.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the pressure feeding pipe does not necessarily have to include two branch air supply pipes branched on the upstream side thereof, and the air layer and the air tank may be connected by one pressure feeding pipe. The exhaust pipe is not necessarily provided with two branch exhaust pipes branched on the downstream side thereof, and air may be exhausted from the air layer through one exhaust pipe. In addition, it is not always necessary to provide the supply air pressure reducing adjustment valve on the downstream side of the supply air control valve of the supply piping. Furthermore, it can be controlled in consideration of fluctuations in the water level in the air chamber.

DESCRIPTION OF SYMBOLS 10 Muddy water type shield machine 11 Engraver machine body 12 Cutter head 13 Cutter chamber 14 Air chamber 15 Air layer 16 Cutter side partition wall 17 Body side partition wall 18 Communication port 19 Muddy water layer 20 Face face 21 Muddy water 22 Air tank 23 Air compressor 24 Supply Air pipe 24a First branch air supply pipe 24b Second branch air supply pipe 25 Supply air pressure reduction adjustment valve 26, 26a Supply air control valve 27 Chamber air pressure detector 28 Storage pipe 29 Storage pressure reduction adjustment valve 33 Mud pipe 34 Exhaust Mud pipe 35 Exhaust piping 35a, 35b Branch exhaust piping 38a, 38b Exhaust air control valve 40 Level gauge installation chamber 43 Valve mechanism 44 Level gauge 50 Mud pressure detector

Claims (5)

A cutter head provided at the tip of the excavator main body for excavating the face, and partitioned by a cutter-side partition disposed behind the cutter head, and formed between the cutter-side partition and the utter head. The cutter chamber and the air chamber formed between the main body-side partition wall and the cutter-side partition wall are partitioned by a main body-side partition wall disposed behind the cutter chamber. In a muddy water type shield excavator that tunnels while stabilizing the face by the pressure of the filled muddy water,
The air chamber and the cutter chamber communicate with each other through a communication port provided in the lower part of the cutter-side partition wall so that a muddy water layer is formed in the lower part of the air chamber and an air layer is formed in the upper part. In addition, tunnel excavation can be performed while mitigating pressure fluctuation on the ground surface on the face surface by compressive expansion of air in the air layer in the air chamber,
An air supply pipe that pumps air to the air layer and an exhaust pipe that discharges air from the air layer are each provided with an air supply side air control valve and an exhaust side air control valve, and are connected to the air supply pipe. And an air tank for storing compressed air is provided,
The supply side air control valve and the exhaust side air control valve are connected to a control device, and receive the detection result of the muddy water pressure in the cutter chamber and / or the air pressure of the air layer in the air chamber. , The degree of opening of these valves is controlled,
The air supply side air control valve and the air supply side air control valve are in an open state during tunnel excavation, and continue to pump air from the air tank and continue to discharge air from the air layer. However, the opening degree of each valve is controlled by the control device so that the air pressure of the air layer is maintained at a predetermined pressure, and the muddy water pressure in the cutter chamber and / or the air chamber The degree of opening of each valve is controlled by the control device so that the air pressure of the air layer returns to the predetermined pressure when a sudden drop or rise in the air pressure of the air layer is detected. A muddy water shield machine. The muddy water type shield digging according to claim 1, wherein an air compressor is provided that is connected to the air tank via a storage pipe to generate compressed air, and a storage decompression adjustment valve is provided in the storage pipe. Machine. The muddy water type shield machine according to claim 1 or 2, wherein the predetermined pressure of the air layer held in the chamber is a management pressure set based on a groundwater level at a construction site. The muddy water shield machine according to claim 3, wherein the air pressure of the compressed air stored in the air tank is 2 to 10 times the predetermined pressure of the air layer. The muddy water type shield machine according to any one of claims 1 to 4, wherein a supply air pressure reducing adjustment valve is provided downstream of the supply air control valve of the supply pipe.

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