JPH0925786A - Block releasing device for mud discharging pipe of slurry shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely release the block of a mud discharging pipe by recognizing the block pattern of the mud discharging pipe, and controlling the by-pass operation and back-feed operation with a computer. SOLUTION: The block pattern of a mud discharging pipe D is recognized based on the pressure values detected by pressure sensors 1a, 1b and the current value of a slurry suction pump E, and the by-pass operation and back-feed operation are controlled by a computer 7. For the block release by the first relief circuit when the block of the mud discharging pipe D occurs, a relief valve 22 is opened as soon as the pressure sensors 1a, 1b detect the abnormal pressure, the mud feeding pressure applied to the working face is relieved to the mud discharging pipe D side, and a shield jack is stopped. When the normal pressure is detected, the relief valve 22 is closed. When the abnormal pressure is again detected, the relief valve 22 is opened and closed multiple times, the mud feeding pressure is intermittently applied to the working face, and the block in the mud discharging pipe D is released. After the block release, the pressure sensors 1a, 1b detect the normal pressure, and the excavation operation is restarted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mud pipe blocking release device for a muddy water shield machine.

[0002]

When the drainage pipe of the muddy water shield machine is clogged, conventionally, it was attempted to release the blockage by alternately sending and discharging mud. However, pressure fluctuation occurs in the face, The face could collapse.

Further, since the mud sending and discharging device of the conventional mud water shield machine is an open circuit, there is a risk that the mud water may be jetted into the mine due to the opening of the pressure release valve when the pressure is blocked and abnormal pressure is applied. A lot of labor is required for cleaning.

Further, the cavitation or water hammer may damage the muddy water suction pump, which requires cost and time for repair.

The present invention has been made in order to solve the above-mentioned problems, and does not cause collapse of a face, ejection of mud sending water into a mine, cavitation, water hammer, etc. An object of the present invention is to provide a mud pipe block releasing device for a muddy water shield machine, which can reliably release the blockage of the mud pipe.

[0006]

[Means for Solving the Problems]

<A> The present invention relates to the discharge of a muddy water shield machine having a mud pipe for sending muddy water or fresh water to a face, a muddy pipe for extracting muddy water from the face, and a muddy water suction pump provided on the way of the muddy pipe. In the mud pipe blockage release device, a pressure sensor provided on the face of the shield machine and on the way of the mud pipe, downstream of the pressure sensor of the mud pipe, and upstream of the mud suction pump of the mud pipe. Mud shield machine, characterized in that it comprises a relief circuit which communicates with the side by a relief path and which is provided with a relief valve and a check valve in order from the upstream on the way of the relief path. It is a device for releasing the blockage of the mud pipe. <B> Further, in the mud pipe blocking release device of the mud shield machine described in <A> above, in the mud suction of the mud pipe, between the pressure sensor of the mud pipe and the branch portion of the relief passage, and the mud suction of the mud pipe. Pump and release
The bypass passage communicates with the branch part of the bypass and a switching valve is provided on the way of the bypass to attach a bypass circuit.The downstream side of the bypass valve and the downstream side of the mud suction pump for the mud pipe. And a relief valve provided on the way of the relief passage, and a relief circuit is attached between the branch portion of the bypass passage of the mud pipe and the branch portion of the relief passage. A mud pipe blockage release device for a muddy water shield machine, characterized in that a switching valve is provided on the mud pipe and a switching valve is provided between the branch portion of the bypass path of the mud pipe and the branch portion of the relief path. . <C> Further, in the mud pipe blockage releasing device of the muddy water shield machine according to <A> above, between the pressure sensor of the mud pipe and the branch portion of the relief path,
The mud suction pump of the mud discharge pipe and the branch portion of the relief passage are connected by the first switching passage, a switching valve is provided on the way of the first switching passage, and a first switching circuit is attached to the mud suction pipe. The downstream side of the branch portion of the relief path, the mud suction pump of the mud pipe and the branch portion of the first switching path are connected by a second switching path, and a switching valve is provided on the way of this second switching path. And a second switching circuit, and a switching valve is installed between the branch part of the first switching path of the mud pipe and the branch part of the relief path, and the branch part of the first switching path of the mud pipe and the second switching. A mud discharge pipe blockage release device for a muddy water shield machine, characterized in that a switching valve is provided between branch portions of the passage. <D> Further, in the mud pipe blockage releasing device of the mud shield machine described in <B> above, a mud suction pump for the mud pipe and a downstream side of the branch portion of the relief line of the mud pipe. A switching path is used to connect between the branch section of the bypass path and a switching valve is provided on the way of this switching path, and a switching valve is installed between the branch section of the mud pipe switching path and the bypass section. The device is a device for releasing the blockage of the sludge discharge pipe of a muddy water shield machine. <E> In the drainage mud pipe blockage releasing device of the muddy water shield machine described in <C> above, a means for removing the blockages is provided at the face opening of the sludge pipe, and the relief line of the sludge pipe is provided. Between the branch part of the first switching path and the branch part of the second switching path of the sludge discharge pipe and the switching valve on the way of the sludge discharge pipe by a relief path, and the release path is in progress. A mud pipe blockage release device for a muddy water shield machine, characterized by being provided with a relief valve and a relief circuit. <F> Further, in the device for removing mud pipe blockage of a muddy water shield machine according to the above <d>, means for removing obstruction is provided at a face opening of the mud pipe, and a relief line for the mud pipe is provided. And a switching valve upstream of the branch portion of the bypass passage and a switching valve downstream of the branch portion of the mud pipe and the bypass portion of the bypass passage are connected by a relief passage, Lily on the way to the road
A mud pipe blockage release device for a muddy water shield machine, characterized in that a relief valve is provided and a relief circuit is additionally provided. <G> Also, a mud pipe that sends muddy water or clear water to the face,
In the drainage pipe blockage release device of a muddy water shield machine having a drainage pipe for extracting muddy water from a face and a muddy water suction pump provided on the way of the drainage pipe, the face portion of the shield machine and the muddy pipe A pressure sensor provided on the way, a downstream side of the pressure sensor of the mud pipe, and an upstream side of the mud suction pump of the mud pipe are connected by a bypass path, and a switching valve is provided on the way of the bypass path. The bypass circuit, the downstream side of the switching valve of the bypass path, and the downstream side of the mud suction pump of the mud pipe are connected by a relief path,
A relief valve provided with a relief valve on the way of the relief passage, a switching valve provided downstream of the branch portion of the bypass passage of the mud pipe, and an upstream side of the branch portion of the bypass passage of the mud pipe. A mud pipe blockage release device for a muddy water shield machine, which is characterized by comprising a switching valve provided on the side. <H> Further, in the sludge discharge pipe blockage releasing device of the muddy water shield machine according to the above <to>, the downstream side of the switching valve of the mud pipe, the muddy water suction pump of the sludge pipe, and the branch portion of the bypass passage. And a switching circuit are provided along the switching path, and a switching circuit is attached, and a switching valve is provided between the branch part of the bypass path of the sludge discharge pipe and the branch part of the switching path. This is a device for releasing the blockage of a sludge discharge pipe of a muddy water shield machine. <L> Further, in the sludge discharge pipe blockage releasing device of the muddy water shield machine according to <C>, a means for removing blockages is provided at the face opening of the sludge pipe, and the bypass line of the sludge pipe is branched. The upstream side of the switching valve on the upstream side of the section and the switching valve on the downstream side of the branch portion of the bypass path of the sludge pipe and the branch portion of the switching path are connected by a relief path, and the relief path is on the way. A mud pipe blockage release device for a muddy water shield machine, characterized by being provided with a relief valve and a relief circuit. <Nu> Also, a mud pipe that sends muddy water or clear water to the face,
In the drainage pipe blockage release device of a muddy water shield machine having a drainage pipe for extracting muddy water from a face and a muddy water suction pump provided on the way of the drainage pipe, the face of the shield machine and the muddy pipe The pressure sensor provided on the way, the downstream side of the pressure sensor of the mud pipe, and the upstream side of the mud suction pump of the sludge pipe are connected by the first switching path, and switched to the middle of the first switching path. A first switching circuit provided with a valve, a switching valve provided on the downstream side of the branch of the first switching path of the mud pipe, and a branch of the first switching path of the mud pipe and the mud suction pump The switching valve, the downstream side of the switching valve for the mud pipe, and the switching valve for the mud pipe and the mud suction pump are connected by a second switching path, and a switching valve is provided on the way of this second switching path. This is a device for releasing the blockage of the mud pipe in a muddy water shield machine, which is characterized by comprising two switching circuits. <Lu> In addition, in the sludge discharge pipe blockage release device of the muddy water shield machine described in <N>, a means for removing blockages is provided at the face opening of the sludge pipe, and the first switching path for the sludge pipe. The upstream side of the branch part of the, the branch part of the second switching path of the sludge pipe and the switching valve in the middle of the sludge are connected by a relief path, and a relief valve is installed in the middle of the relief path. It is a device for releasing the blockage of a sludge discharge pipe of a muddy water shield machine, which is provided with a relief circuit. <Wo> Furthermore, in the sludge discharge pipe blockage release device of the muddy water shield machine according to any one of the above <e>, <f>, <li>, and <le>, the sludge is removed as a means for removing blockages. A mud discharge pipe blockage release device for a muddy water shield machine, characterized in that a jack capable of projecting is used at a face opening portion of the pipe.

[0007]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. <B> Outline of the muddy water shield machine The muddy water shield machine is equipped with a bulkhead in front of the mechanical shield machine, pressurizing the muddy water on the ground of the cutting face to suppress the water flow and stabilize the ground. It is a machine that excavates with a rotary cutter head while aiming for.

To send muddy water or fresh water to the face, see FIG.
As shown in FIG. 3, the mud pipe C is installed in the mine and has one end opened to the cutting face B of the muddy water shield machine A. The mud pipe D is used to extract the muddy water from the cutting face. Further, a mud suction pump E provided on the way of the mud discharge pipe D is used for extracting the mud water. In the following description, the right side of FIG. 1 is the upstream side of the mud sending pipe C, the left side is the downstream side, and the mud discharging pipe D is the opposite.

<B> Pressure sensor-In the middle of the face portion B of the muddy water shield machine A and the mud pipe C,
Known pressure sensors-1a and 1b are arranged and used to detect the face pressure and the muddy water pressure in the mud pipe C.

<C> First Relief Circuit The first relief circuit 2 relieves the downstream side of the pressure sensor-1b of the mud pipe C and the upstream side of the mud suction pump E of the mud pipe D. A relief valve 22 and a check valve 23 are provided in this order from the upstream side on the way of the relief passage 21.
The relief valve 22 is a safety valve capable of instantaneously responding to an abnormal pressure (the same applies to relief valves 34 and 53 described later).

<D> Bypass Circuit The bypass circuit 3 is provided between the pressure sensor-1b of the mud pipe C and the branch portion of the relief passage 21, and the mud suction pump E of the mud pipe D.
The bypass passage 31 communicates with the branch portion of the relief passage 21, and a switching valve is provided on the way of the bypass passage 31.

A second relief circuit is also included in the bypass circuit 3, and the second relief circuit is provided in the bypass passage 31 on the downstream side of the switching valve 32 and in the mud pipe D. The downstream side of the muddy water suction pump E is connected by a relief path 33,
A relief valve 34 is provided on the way of the relief passage 33.

Further, in order to configure the bypass circuit 3, a switching valve 35 is provided between the branch portion of the bypass passage 31 of the mud feeding pipe C and the branch portion of the relief passage 21. Further, a switching valve 36 is also provided between the branch portion of the bypass passage 31 of the sludge discharge pipe D and the branch portion of the relief passage 21.

<E> Reverse feed circuit The reverse feed circuit 4 comprises a first switching circuit and a second switching circuit. Since the first switching circuit can also serve as the bypass passage 31 and the switching valve 32 described above, There is no particular need to provide in.

The second switching circuit is a mud suction pump E for the mud pipe C and the downstream side of the branch portion of the relief passage 21 and the mud suction pipe D.
The switching path 41 communicates with the branch portion of the bypass path 31, and a switching valve 42 is provided on the way of the switching path 41. Further, a switching valve 43 is provided between the branch portion of the switching passage 41 of the sludge discharge pipe D and the branch portion of the bypass passage 31.

Further, means for removing the blockage is provided at the face opening of the sludge discharge pipe D. As an example of this removing means, a jack 5 as shown in FIG. 2 is used. The jack 5 is configured such that a telescopic rod 51 having a sharp tip can be projected at the face opening of the mud discharge pipe D.

Further, a relief passage 52 connects the branch portion of the relief passage 21 of the sludge discharge pipe D and the switching valve 36, and the branch portion of the switching passage 41 of the sludge discharge pipe D and the switching valve 43 by a relief passage 52. Then, a relief valve 53 is provided on the way of the relief passage 52 to provide a third relief.
A circuit is additionally provided so that the pressure in the sludge discharge pipe D is released when the jack 5 is operated.

<F> Control means As described above, the blockage release device of the present invention has a closed circuit structure, and the circuit group is mounted on the valve carriage 6 and moves as the shield advances. Further, the blockage pattern of the sludge discharge pipe D is recognized from the pressure value detected by the pressure sensors-1a and 1b and the current value of the muddy water suction pump E, and controlled by the personal computer 7 or the like. Bypass operation, reverse feed operation, etc. are performed.

In the above embodiment, the structure including all of the first relief circuit 2, the bypass circuit 3 and the reverse feed circuit 4 is covered, but one of them may be used as a blockage releasing device. Further, it is also possible to configure the blocking device by appropriately selecting and combining a plurality of combinations.

[0020]

With the device configured as described above, the blockage can be released as follows. <B> Release of blockage by the first relief circuit As shown in FIGS. 3 and 4, when the blockage of the sludge discharge pipe D occurs,
The pressure sensors-1a and 1b detect an abnormal pressure, the relief valve 22 is opened instantly, and the mud sending pressure acting on the face escapes to the mud discharge pipe D side. At the same time, the shield jack stops.

When the pressure sensor-1b detects a normal pressure value by opening the relief valve 22, the relief valve 22 is closed. After that, when the pressure sensors-1a and 1b again detect an abnormal pressure, the relief valve 22 is opened and closed a plurality of times. As a result, the pressure of the mud sending water intermittently acts on the face, so that the blockage in the mud discharge pipe D can be released. When the blockage is released, the pressure sensors-1a and 1b detect a normal pressure value, and the excavation operation is restarted.

<B> Release of Blockage by Bypass Circuit As shown in FIG. 3, when the relief valve 22 is opened and the shield jack is stopped and the pressure sensor-1b still detects an abnormal pressure, the bypass operation is performed. I do. In the bypass operation, as shown in FIG. 5, the switching valves 35 and 36 are closed, the switching valve 32 is opened, and the mud water is fed through the bypass passage 31.
Turn it so that it does not reach the face.

When the pressure sensor-1b detects a normal pressure value by this bypass operation, the switching valve 36
Since it is found that the mud pipe D and the mud suction pump E on the further downstream side are not blocked, the excavation operation is restarted after cleaning the inside of the mud pipe D between the face and the switching valve 36.

However, if the pressure sensor-1b detects an abnormal pressure even when the bypass operation is performed, the relief valve 34 is instantly opened as shown in FIG. The mud sending pressure escapes to the downstream side of the mud suction pump E.
If the current value of the muddy water suction pump E is abnormal in this state,
Since the muddy water suction pump E is blocked, the operation is stopped and cleaned, and then the excavation operation is restarted.

By opening the relief valve 34, the pressure sensor
When 1b detects a normal pressure value, the relief valve 34
Close and restart the excavation operation after performing bypass operation.

<C> Release of Blockage by Reverse Feed Circuit As shown in FIG. 3, when the pressure sensors -1a and 1b further detect abnormal pressure after the relief valve 22 is opened and closed a plurality of times, the reverse feed operation is performed. I do. In the reverse feed operation, as shown in FIG. 7, the switching valves 35, 43 are closed and the switching valves 32,
Mud is fed with 42 being opened, the mud feeding route is switched by the bypass passage 31, and mud water is supplied to the face through the mud discharge pipe D.

When the muddy water is to be extracted from the face, the muddy pipe C extracts the muddy water, and the drainage pipe D again through the switching path 41.
Return to and discharge. By performing the reverse feed operation in this manner, the blockage in the sludge discharge pipe D can be pushed out to the face and the blockage can be released. When the blockage is released and the pressure sensors-1a and 1b detect normal pressure values, the excavation operation is restarted.

If the pressure sensor-1b detects an abnormal pressure even after performing the reverse feed operation as described above, the relief valve 53 is opened for about 15 seconds as shown in FIG. 8, and the relief passage 5 is opened.
In the state where 2 is opened, the telescopic rod 51 of the jack 5 is extended to remove the blockage that blocks the face opening of the mud discharge pipe D. As a result, when the pressure sensors-1a and 1b detect a normal pressure value, the relief valve 53 is closed and the excavation is restarted by the normal progressive operation.

Even if the jack 5 is operated, the pressure sensor-1
If a and 1b are still detecting the abnormal pressure, the reverse feed operation is stopped and the switching valve 3 from the bulkhead of the sludge pipe D is stopped.
The space between 6 is cleaned, and then excavation operation is performed. Since the operation of each circuit described above is controlled by the personal computer 7, all the causes of blockage can be automatically and continuously eliminated, and the blockage can be quickly released.

[0030]

Since the present invention has been described above,
The following effects can be obtained. <A> Since the blockage releasing device of the present invention is a closed circuit, there is no risk of face collapsing even if the blockage releasing operation does not change.

<B> Since there is no possibility of muddy water spouting into the mine, it is not necessary to spend much labor for cleaning.

<C> Since the mud suction pump can be prevented from being damaged by cavitation or water hammer, the cost for repair can be reduced.

<D> Blocking release work can be performed safely, reliably and easily by controlling a personal computer.

[Brief description of drawings]

FIG. 1 is an explanatory view of a blockage releasing device of the present invention.

FIG. 2 is an explanatory diagram of an obstruction removal jack.

FIG. 3 is an explanatory diagram of a blockage releasing method.

FIG. 4 is an explanatory diagram showing the occurrence of blockage.

FIG. 5 is an explanatory diagram showing a bypass operation.

FIG. 6 is an explanatory diagram showing bypass operation.

FIG. 7 is an explanatory diagram showing reverse feed operation.

FIG. 8 is an explanatory diagram showing the operation of the plug removal jack.

Claims (12)

[Claims] 1. A mud pipe of a mud shield machine having a mud pipe for sending muddy water or fresh water to a face, a muddy pipe for drawing muddy water from the face, and a muddy water suction pump provided on the way of the muddy pipe. In the blockage release device, the pressure sensor provided on the face of the shield machine and on the way of the mud pipe, the downstream side of the pressure sensor of the mud pipe, and the upstream side of the mud suction pump of the mud pipe. Through a relief passage, and a relief circuit in which a relief valve and a check valve are provided in this order from upstream on the way of the relief passage. Mud pipe blockage release device. 2. The muddy water blockage release device for a muddy water shield machine according to claim 1, wherein the pressure sensor of the muddy water pipe and the branch portion of the relief passage, and the muddy water suction pump of the muddy water pipe. A bypass valve is provided on the way of the bypass path to connect between the branch section of the relief path and the branch section of the relief path, and a bypass circuit is attached to the bypass path. It is connected to the downstream side by a relief path, a relief valve is installed on the way of the relief path and a relief circuit is attached, and the bypass section of the mud pipe and the relief path are connected. A switching valve is provided between the branch parts, and a switching valve is provided between the branch part of the bypass line of the mud discharge pipe and the branch part of the relief line. apparatus. 3. The mud pipe blockage releasing device for a mud shield machine according to claim 1, wherein a pressure sensor of the mud pipe and a branch portion of the relief passage, and a mud suction pump for the mud pipe. And the branch portion of the relief path are connected by the first switching path, a switching valve is provided on the way of the first switching path and a first switching circuit is attached, and the branch portion of the relief path of the mud pipe is connected. The downstream side of the, the mud suction pump of the mud pipe and the branch part of the first switching path are connected by a second switching path, and a switching valve is provided along the second switching path with a second switching circuit. A switching valve is installed between the branch part of the first switching path of the mud pipe and the branch part of the relief line to switch between the branch part of the first switching path of the mud pipe and the branch part of the second switching path. A mud shield blocking device for a mud shield machine, which is characterized by being provided with a valve. 4. A mud pipe blockage release device for a mud shield machine according to claim 2, wherein the mud pipe suction pump and bypass are located downstream of the branch portion of the relief line of the mud pipe. The switching path is connected to the branch part of the path, and a switching valve is installed along the switching path, and a switching valve is installed between the branch part of the switching path of the sludge pipe and the branch part of the bypass path. A device for removing the blockage of a mud pipe in a muddy water shield machine, which is characterized by being provided. 5. The mud pipe blockage release device for a muddy water shield machine according to claim 3, wherein a means for removing blockages is provided at the face opening of the mud pipe, The branch section and the branch section of the first switching path, and the branch section of the second switching path of the sludge discharge pipe and the switching valve in the middle of the sludge discharge pipe are connected by a relief path so that they are on the way of the relief path. A mud pipe blockage release device for a muddy water shield machine, which is provided with a relief valve and a relief circuit. 6. The mud pipe blockage releasing device for a muddy water shield machine according to claim 4, wherein a means for removing blockages is provided at a face opening portion of the mud pipe, The branch valve and the switching valve on the upstream side of the branch portion of the bypass passage and the branch valve of the switching passage of the sludge pipe and the switching valve on the downstream side of the branch portion of the bypass passage are connected by a relief passage, and the -A relief valve is installed on the way of the relief path.
A mud shield blocking device for a mud shield machine, which is equipped with a circuit. 7. A mud pipe of a muddy water shield machine having a mud pipe for sending muddy water or fresh water to the face, a drain pipe for extracting the muddy water from the face, and a muddy water suction pump provided on the way of the mud pipe. In the blockage release device, the pressure sensor provided on the face of the shield machine and on the way of the mud pipe, the downstream side of the pressure sensor of the mud pipe, and the upstream side of the mud suction pump of the mud pipe. Through a bypass path, and a bypass circuit with a switching valve in the middle of the bypass path, the downstream side of the switching valve in the bypass path, and the downstream side of the mud suction pump in the mud pipe are connected by a relief path. , A relief valve provided with a relief valve in the middle of the relief passage, a switching valve provided downstream of the branch portion of the bypass passage of the mud pipe, and a branch portion of the bypass passage of the mud pipe. A mud shield blocking solution for a mud shield machine, which is characterized by a switching valve provided on the upstream side. Removal device. 8. The mud pipe closing release device for a muddy water shield machine according to claim 7, wherein the mud pipe suction valve downstream of the switching valve of the mud pipe and the branch portion of the bypass passage. And a switching path, a switching valve is provided on the way of this switching path, a switching circuit is attached, and a switching valve is provided between the branch part of the bypass path of the mud pipe and the branch part of the switching path. A device for releasing the blockage of the mud pipe in a muddy water shield machine. 9. The mud pipe blockage release device for a muddy water shield machine according to claim 8, wherein a means for removing blockages is provided at a face opening of the mud pipe, and a branch portion of a bypass passage of the mud pipe. The upstream side of the switching valve on the upstream side of, and the switching valve on the downstream side of the branch portion of the bypass path of the sludge pipe and the branch portion of the switching path are connected by a relief path,
A mud pipe blockage release device for a muddy water shield machine, which is characterized in that a relief valve is provided along the free passage and a relief circuit is additionally provided. 10. A mud pipe of a mud shield machine having a mud pipe for sending muddy water or fresh water to a face, a muddy pipe for drawing muddy water from the face, and a muddy water suction pump provided on the way of the muddy pipe. In the blockage release device, the pressure sensor provided on the face of the shield machine and on the way of the mud pipe, the downstream side of the pressure sensor of the mud pipe, and the upstream side of the mud suction pump of the mud pipe. Through the first switching path, a first switching circuit having a switching valve on the way of the first switching path, a switching valve provided downstream of the branch portion of the first switching path of the mud pipe, and the sludge The switching valve provided between the branch part of the first switching path of the pipe and the mud suction pump, the downstream side of the switching valve of the mud pipe, and the second switching path between the switching valve of the mud pipe and the mud suction pump. It is characterized in that it comprises a second switching circuit which is in communication with and provided with a switching valve on the way of the second switching path. Mud sheet - ejecting mud pipe unblocking device field machine. 11. The mud pipe blockage releasing device for a muddy water shield machine according to claim 10, wherein a means for removing blockages is provided at a face opening of the mud pipe, and the first switching path of the mud pipe is provided. A relief valve connects the upstream side of the branch, the branch of the second switching path of the sludge pipe, and the switching valve in the middle of the sludge, and a relief valve is provided in the middle of the relief path. A release circuit for the muddy water shield machine, which is equipped with a relief circuit. 12. The mud pipe block releasing device for a muddy water shield machine according to any one of claims 5, 6, 9 and 11, wherein the mud pipe is projected at a face opening of the mud pipe as means for removing the blockage. A mud pipe blockage release device for a muddy water shield machine, which uses a jack that can be used.