JP2931033B2 - Mud pressurization propulsion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to muddy water that excavates underground by forming a mud film between a front surface of a cutter portion and a face and between a shield cylinder and an outer ground. The present invention relates to a pressure propulsion device.

[Conventional technology]

2. Description of the Related Art Conventionally, a muddy water pressure propulsion method has been known as a method of excavating an underground lateral hole.

This construction method generally excavates a shaft for carrying an excavator and a buried pipe, and extrudes the excavator and the buried pipe in the horizontal direction while sequentially connecting a plurality of buried pipes behind the excavator. It excavates, pulls out the excavator from the reaching shaft provided at a predetermined location, and installs a buried pipe.

Here, the method of excavating the side hole is to inject muddy water from the excavator toward the ground side of the face and pressurize to form a mud film (mud film) on the ground side. Then, while the face is stably supported by the mud membrane normally pressurized to about 0.2 kg / cm ^{2 of} groundwater pressure, the cutter is rotated to excavate the earth and sand of the ground, and the propulsion is performed. As the cutter, a spoke type cutter or a face plate type cutter having a cutter face is usually used.

 FIG. 7 is a partial sectional view showing an example of a conventional excavator.

On the head side of the excavator 41 shown in the figure, the diameter of the cutter portion 8 is formed to be larger than the diameter of the shield tube 2, and the ground is slightly overcut from the shield tube 2, and A tail void C is formed between the ground pipe and the buried pipe connected rearward.

On the other hand, by sending muddy water a from the mud feed pipe 42 to the front surface of the cutter portion 8, a mud film is formed between the face A and the cutter portion 8, and the face A is stably supported. The earth and sand excavated by the cutter unit 8 is stirred and mixed with the muddy water in the excavation room 5 to be a high-concentration liquid material. By filling the tail void C part with this high-concentration liquid material in a pressurized state, the ground is brought into a pressure receiving state, the collapse of the ground, the tightening to the buried pipe is suppressed, and the excavator and the buried pipe and the ground are connected. To reduce the friction between the buried pipe and the ground. In addition,
In the figure, reference numeral 10 denotes a discharge port, reference numeral 11 denotes a discharge pipe, and reference numeral 43 denotes a valve.

As described above, the propulsion device using the excavator in which the cutter 8 has a diameter larger than that of the shield cylinder 2 enables long-distance propulsion with low thrust as compared with the conventional propulsion device without overcut. .

[Problems to be solved by the invention]

As described above, the muddy water pressure propulsion method employs a muddy water pressurization and injection from an excavator toward the ground side of the face to form a mud film between the cutter part and the face and between the shield cylinder and the outer ground. The cutter is rotated to excavate the earth and sand of the face while being stably supported by the pressing force via the mud film and the cutting face and the outer peripheral ground, thereby being propelled.

In this muddy water pressurized propulsion method, it is extremely important to keep the pressing force through the mud film within a certain range in order to stably support the face and the outer ground. The problem here is the pressure drop of the face due to the mud discharging operation. Naturally, excavation is not performed unless the excavated soil is discharged, so the excavation and the drainage work are repeatedly performed. In the conventional work, opening and closing of the valve on the mud pipe is performed by opening the valve when the pressure of the face is higher than the lower limit (groundwater pressure + 0.2 kg / cm ² ) and closing it at the lower limit. Although it was controlled, the pressure of the face was often below the lower limit of the setting, and it was difficult to stabilize the face and the tail void. On the other hand, if the face pressure at the time of opening the valve is set to a high value, the formed mud film is broken due to the high face pressure and is lost, the face pressure is reduced at once, and the face becomes unstable. Occurred.

Further, as a valve provided in the exhaust pipe, an air pinch valve 43 is provided, in which a rubber sleeve 43b is attached to a casing 43a as shown in FIG. 8, and the rubber sleeve 43b is opened and closed by supplying air at a predetermined pressure into the casing 43a. When the valve 43 is used, when the valve 43 is closed, it is in the state shown in FIG. 9A (front sectional view) and FIG. 10B (side sectional view) in a normal state. 44 is the same figure (c)
As shown in (side sectional view), when the rubber sleeve 43b is sandwiched, a large gap 45 is formed around the earth and sand 44 so that the valve 43
Muddy water may leak without being completely closed. For this reason, there is a problem that the operation of the valve 43 is not performed properly, causing pressure fluctuation in the excavation chamber.

Further, when the rubber sleeve 43b is damaged, there is a problem that the muddy water flows out and the face pressure is reduced, and the face is collapsed.

Therefore, the present invention suppresses the pressure fluctuation in the excavation chamber in the muddy water pressurization propulsion method, and also appropriately operates the sludge discharge valve to form a stable mud film between the excavator and the ground at all times. The aim is to perform long-distance excavation smoothly.

[Means for solving the problem]

In order to achieve the object, the muddy water pressurizing propulsion device of the present invention forms a mud film between the front surface of the cutter part having a diameter larger than the shield cylinder and the face and between the shield cylinder and the outer peripheral ground. In a muddy water pressurizing propulsion device that excavates underground, a valve provided in the middle of a mud exhaust pipe connected to the excavation room of an excavator was an air pinch valve having a rubber sleeve mounted in a casing, and the rubber sleeve was closed. Sometimes, in a muddy water pressurized propulsion device provided with air supply ports at three or more locations in the circumferential direction of the casing so that the rubber sleeve cross-sectional shape is radial,
A plurality of the air pinch valves are connected in series.

Further, the casing of the air pinch valve may be a casing made of hard rubber, and the casing may have a structure capable of being pressed from the outside.

Further, a partition provided at a rear portion of the cutter unit for forming an excavating chamber of the excavator, and a pressure adjusting body which is elastically deformed according to a pressure change in the excavating chamber are provided, and the pressure adjusting body and the air pinch valve are provided. May be provided in the excavator in combination.

[Action]

In the muddy water pressurizing propulsion device of the present invention, the pressure adjuster provided on the partition wall forming the excavation chamber has a pressure adjuster against a pressure increase in the excavation chamber when a large lump of excavated soil enters the excavation chamber. In response to the contraction and the pressure drop at the start of the sludge discharge, the pressure regulator expands to absorb the pressure fluctuation in the excavation chamber, and always keeps the excavation chamber at a predetermined pressure.

The air pinch valve provided in the mud pipe does not form a gap due to the rubber sleeve being deformed by being fitted to the earth and sand even when the rubber sleeve sandwiches a lump of earth and sand. In addition, when a plurality of the air pinch valves are connected in series, by appropriately setting the supply air pressure of the valves, the pressure in the excavation chamber can be reliably maintained at a predetermined pressure. Also,
When the casing of the air pinch valve is made of a hard rubber casing and the casing can be pressed from the outside, when the rubber sleeve in the casing is broken, the casing can be pressed to close the valve.

FIG. 1 is a sectional view showing a main part of an excavator provided with a pressure adjusting body used in the present invention.

In FIG. 1, the excavator 1 has a cylindrical shape as a whole,
A plurality of buried pipes (not shown) are sequentially connected behind the excavator 1.

A partition 3 is provided in a shield cylinder 2 of the excavator 1. A mud feed pipe 4 is connected to the rear side of the partition wall 3.
The mud pipe 4 is connected to a mud storage tank (not shown) via a pump for pumping mud a. On the front side of the partition wall 3, a rotating shaft 7 to which a rotating force is applied by a driving device 6 such as a motor, and an outer diameter which is connected to the rotating shaft 7 and which is larger than the outer diameter of the shield cylinder 2 of the excavator 1. A cutter unit 8 is provided. A cutting blade 81 is radially disposed on the front surface of the cutter portion 8, and the outermost cutting blade 81 is located outside the shield tube 2, and a tail void is formed in a gap between the shield tube 2 and the outer peripheral ground B. A part C is formed.

The space surrounded by the bulkhead 3, the cutter part 8, and the shield tube 2 of the excavator 1 is a drilling room 5 in which muddy water and excavated earth and sand are mixed and stirred.
It has become.

In the excavation room 5, a scraper 9 is protruded from the back of the cutter unit 8 in parallel with the axis of the rotating shaft 7. The scraper 9 scrapes off the earth and sand that tends to remain on the inner surface side of the shield tube 2 and stirs and mixes the excavated earth and sand with the muddy water a.

Then, in the excavation section and the excavation chamber 5 in front of the cutter section 8, the liquid mixture formed by uniformly stirring and mixing the muddy water a and the excavated earth and sand forms a mud film on the face A side in front of the cutter section 8. At the same time, a tail void portion C is formed between the shield cylinder 2 and the outer peripheral ground B. A mud film is also formed on the tail void portion C.

In the lower part of the excavation chamber 5, a part of the partition wall 3 is opened, and a mud outlet 10 is formed. The exhaust port 10 is provided with an exhaust pipe 11 and a valve 12, and a mud storage tank (not shown) is installed at an end of the valve 12 on the exhaust side.

In such an excavator 1, the partition 3 is provided with a pressure adjusting body 13 which is elastically deformed in accordance with a pressure change in the excavating chamber 5. The pressure adjusting body 13 has an elastic body 13a made of rubber or the like on the side of the excavation chamber 5 and a rear side 3a formed integrally with the partition wall 3 as a rigid body. A gas such as air at a pressure of is enclosed.

Next, the operation of the excavator 1 shown in FIG. 1 will be described.

First, muddy water a is pumped through the mud pipe 4 by a pump (not shown). The pumped mud a fills the excavation chamber 5 and is sent to the face A in a pressurized state. Then drive 6
, The excavation is performed by the cutter unit 8 while the muddy water a is continuously injected. The excavated earth and sand are mixed with the muddy water a, and the face A is pressed by the liquid mixture, and a mud film is formed between the cutter portion 8 and the face A, so that the face A is stabilized.

Further, since the outer diameter of the cutter portion 8 is set to be larger than the outer diameter of the shield tube 2, a tail void portion C is formed between the outer periphery of the shield tube 2 and the buried pipe and the outer peripheral ground B after excavation. . A mud film is also formed between the tail void portion C and the outer peripheral ground mountain B.

The pressure applied to the mud film is the same as the pressure of the liquid mixture in the excavating chamber 5, for example, the groundwater pressure +0.2 kg / cm ^2, and the pressing force suppresses the collapse of the face A and the outer peripheral ground B, and loosens. The occurrence of earth pressure is prevented, and the required propulsive power of the excavator is reduced by eliminating the tightening of the outer peripheral ground B to a buried pipe or the like. Therefore, the excavator can be propelled with a small propulsion,
Suitable for long-distance propulsion.

The liquid mixture of earth and sand and mud water a in the excavation chamber 5
Through the mud pipe 11 and the valve 12 to be discharged to a mud storage tank (not shown). By appropriately adjusting the opening / closing operation pressure of the valve 12, it is possible to maintain the pressure of the liquid mixture in the excavation chamber 5 for performing good excavation.

In the above-described excavation work, when a relatively large lump of excavated soil enters the excavation chamber 5, the pressure in the excavation chamber 5 temporarily increases by an amount corresponding to the volume of the lump, and the excavation chamber 5 Fluctuation of pressure inside the mud causes unstable mud film. However, since the pressure adjusting body 13 that is elastically deformed is attached to the partition wall 3, the volume of gas such as air in the pressure adjusting body 13 is reduced by an amount corresponding to the pressure increase, and the pressure in the excavation chamber 5 is reduced. It does not rise. After the lump is discharged from the discharge port 10, the lump returns to the original state, so that a stable mud film is maintained. In addition, when the pressure of the face is reduced due to the sludge, or when the pressure is reduced in an abnormal state, the pressure adjusting body 13 expands,
Following the volume change, the pressure of the face is prevented from dropping, and the pressure returns to its original state when the pressure becomes normal.

FIG. 2 is a diagram showing a different configuration example of a pressure adjusting body that elastically deforms. In this example, the pressure adjusting body 14 is provided with a bag-shaped portion 14a made of an elastic material such as rubber and a pipe 14b connected to the bag-shaped portion 14a, a pressure adjusting gauge 14c, and a valve 14d. It consists of.

In this configuration, the valve 14d is operated by the pressure adjusting gauge 14c so that the pressure of gas such as air in the bag-shaped portion 14a is constant. When the excavation chamber 5 is in a relatively large lump of excavated earth and sand, the bag-shaped portion 14a is elastically deformed as shown in FIG. To absorb the pressure rise in the excavation chamber 5. At this time, a part of the gas in the bag-like portion 14a is released via the valve 14d. When a lump of earth and sand is discharged from the excavation chamber 5, the valve 14
After d, the gas is supplied to the bag-like portion 14a and returns to the state shown in FIG.

FIG. 3 is a view showing still another configuration example of the pressure adjusting body. In this example, the pressure adjusting body 15 is connected to a disk 15a that slides in a piston shape on the inner surface of the convex portion 3c in which the partition wall 3 is formed in a cylindrical shape, a rod 15b connected to the disk 15a, and a rod 15b connected to the disk 15a. Piston head 1 reciprocating in the fluid pressure cylinder 15d
5c. The left side of the fluid pressure cylinder 15d in the drawing communicates with the outside air, and the right side of the drawing communicates with the liquid tank 15e. Air of a predetermined pressure is sealed in the liquid tank 15e, and is always in a state shown in FIG. When a relatively large lump of excavated soil enters the excavation chamber 5, the disk 15a, the rod 15b, and the piston head 15c move rightward in the figure as shown in FIG. Absorb pressure rise. When the lump of earth and sand is discharged from the excavation chamber 5, the disk 15a, the rod 15b, and the piston head 15c return to the state shown in FIG.

FIG. 4 is a view showing the structure of the valve 12 provided in the drainage pipe 11 in FIG. In this embodiment, as shown in the examples of FIGS. 4A, 4B and 4C, the valve 12 has three or more air supply ports 12c into the casing 12a, and closes the valve 12. In this state, the cross-sectional shape of the rubber sleeve 12b is made radial. Because of this, the rubber sleeve
Even if 12b sandwiches the earth and sand mass 20, the rubber sleeve 1
2b does not adapt to the lump 20 and deform, creating no gap,
No mud leaks. At this time, the rubber sleeve 12b
The casing 12a in advance so that
If the rubber sleeve 12b is fixed at three or more points, the rubber sleeve 12b does not separate from the casing 12a at the fixed point, and the rubber sleeve 12b can be reliably closed in a radial cross-sectional shape. .

FIG. 5 is a view showing an embodiment of the present invention in which the valve provided in the exhaust pipe is a double valve. In this example, the first
The second valve 16 and the second valve 17 are connected in series, and the first valve 16
Supplying air pressure P ₁ from the supply port 16c is in, the second valve 17 for supplying the pressure P ₂ air from the supply port 17c. 1 in the figure
6a, 17a is a casing, 16b, 17b is a rubber sleeve, 16d, 17d
Is a pressure gauge. In this dual valve, valve 16
1, the air pressure of the valve 17 is made slightly higher than the air pressure of the valve 16, as in the case of FIG.

In FIG. 5, FIG. 5 (a) shows a state in which both valves are closed, and FIGS. 5 (b) to 5 (c) show a valve operation procedure at the time of discharging the mud. When the excavation proceeds and the pressure in the excavation chamber 5 becomes higher than a predetermined pressure, the first valve 16 is automatically opened (the state of FIG. 2B). At this time, the operator looks at the increase in the display pressure of the pressure gauge 16d, and lowers the air pressure supplied to the second valve 17 to open the second valve 17 (the state of FIG. 3C). In this state, the liquid mixture in the excavation chamber 5 is discharged. As the mud proceeds, the pressure in the excavation chamber 5 decreases, and when the pressure falls below a predetermined pressure, the first valve 16 is automatically closed, and the mud stops (the state of FIG. 3D). Thereafter, the operator closes the second valve 17 and returns to the state shown in FIG. As described above, by operating the second valve 17 by monitoring the display pressure of the pressure gauge of the first valve 16 using the double-draining valve as a double valve, the timing of closing the second valve 17 can be adjusted. Even if there is a delay, the pressure in the excavation chamber 5 does not become lower than the predetermined pressure, whereby the face can be stably supported, and the face can be prevented from collapsing.

FIG. 6 is a view showing an embodiment of the present invention in which a casing provided with hard rubber is formed as a valve provided in the exhaust pipe, and the casing is configured to be able to be pressed from the outside. FIG. FIG. 3B is a side sectional view, and FIG. 3C is a side sectional view showing a state where the casing is pressed. In this example, the main body of the valve 21 includes a hard rubber casing 22 and a rubber sleeve 23, and a fluid pressure cylinder 24 for pressing the casing 22 from the outside against the main body is provided. In a normal operation state, the rubber sleeve 23 is opened and closed by supplying air at a predetermined pressure between the casing 22 and the rubber sleeve 23. If the rubber sleeve 23 is damaged during operation for some reason, the hydraulic cylinder 24 is operated and the casing 22 is pressed by the presser 25 at the tip of the cylinder rod to release the valve.
The entire 21 is kept in close contact to prevent muddy water from flowing out.

〔The invention's effect〕

As described above, according to the muddy water pressurizing propulsion device of the present invention, the pressure of the mixture of the muddy water and the excavated earth and sand between the excavation room and the shield tube and the outer ground is maintained in a predetermined range,
Fluctuation of the pressure applied to the mud film formed on the front surface of the cutter portion and the outer periphery of the shield tube becomes minute, and the face and the outer ground are stably supported. Thereby, stable long-distance excavation work can be performed. Further, each means that can be employed in the device of the present invention has the following individual effects.

When a pressure regulating body that elastically deforms according to the pressure change in the drilling chamber is provided in the partition wall that forms the drilling chamber, the pressure regulating body responds to a pressure rise when a large lump of excavated soil enters the drilling chamber. It shrinks to absorb the rise in pressure in the excavation chamber, and constantly maintains the excavation chamber at a predetermined pressure to stabilize the support of the face. Conversely, with respect to the pressure drop at the start of the sludge discharge, the pressure adjusting body expands to prevent the pressure drop in the excavation chamber and prevent the face and the tail void from collapsing.

When the valve provided on the mud pipe is an air pinch valve whose rubber sleeve has a radial cross-sectional shape when the rubber sleeve is closed, the rubber sleeve fits into the sand even when the rubber sleeve sandwiches a lump of earth and sand. There is no gap due to deformation and no leakage of muddy water.

When two air pinch valves are provided in series as a valve provided in the mud pipe, by appropriately setting the supply air pressure of each valve, the pressure in the excavation chamber can be reliably maintained at a predetermined pressure. Can be prevented from collapsing.

When the casing is made of hard rubber, and the casing is made of a structure that can be pressed by fluid pressure, the outflow of muddy water can be prevented even when the rubber sleeve in the casing is broken, and the face collapses. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an excavator equipped with a pressure adjusting body used in the present invention, FIGS. 2 and 3 are diagrams showing different constitution examples of a pressure adjusting body which elastically deforms, and FIG. Fig. 5 is a view showing a structure of a valve provided in a mud pipe, Fig. 5 is a view showing the double valve, and Fig. 6 is a view showing another structural example of the valve.
On the other hand, FIG. 7 is a sectional view showing an example of a conventional excavator,
FIG. 8 is a view for explaining a problem of the conventional exhaust pipe valve. 1,41: excavator, 2: shield cylinder 3: bulkhead, 3a: rear side of bulkhead 3b, 3c: convex part of bulkhead, 4,42: mud pipe 5: drilling room, 6: drive machine 7: rotary shaft , 8: cutter part 81: cutting blade, 9: scraper 10: drain port, 11: drain pipe 12, 16, 17, 43: valve 12a, 16a, 17a, 43a: casing 12b, 16b, 17b, 43b: Rubber sleeves 12c, 16c, 17c: Air supply ports 13, 14, 15: Pressure adjusting body, 13a: Elastic body 14a: Bag-shaped part, 14b: Piping 14c: Pressure adjusting gauge, 14d: Valve 15a: Disk, 15b: Rod 15c: Piston head, 15d: Fluid pressure cylinder 15e: Liquid tank, 16d, 17d: Pressure gauge 20,44: Mass of earth and sand, 21: Valve 22: Casing, 23: Rubber sleeve 24: Fluid pressure cylinder, 25: Hold down Tool 45: Clearance A: Face, B: Outer ground C: Tail void, a: Muddy water

Claims (3)

(57) [Claims] 1. A muddy water pressurizing propulsion device which excavates underground by forming a mud film between a front surface of a cutter portion having a diameter larger than a shield cylinder and a face and between a shield cylinder and an outer ground. The valve installed in the middle of the mud pipe connected to the excavation room of the machine,
A muddy water pressurization propulsion device having an air pinch valve having a rubber sleeve mounted in a casing, and having air supply ports provided at three or more positions in the circumferential direction of the casing so that the rubber sleeve has a radial cross section when the rubber sleeve is closed. 3. The muddy water pressure propulsion device according to claim 1, wherein a plurality of the air pinch valves are connected in series. 2. A muddy water pressurizing propulsion device according to claim 1, wherein the casing of the air pinch valve according to claim 1 is a casing made of hard rubber, and the casing has a structure capable of being pressed from the outside. 3. A muddy water pressurizing propulsion device which excavates underground by forming a mud film between a front surface of a cutter portion having a diameter larger than a shield cylinder and a face and between a shield cylinder and an outer ground. A pressure regulating body which is elastically deformed in accordance with a pressure change in the excavating chamber is provided on a partition wall provided at a rear portion of the cutter unit to form an excavating chamber of the drilling machine. A muddy water pressurizing propulsion device characterized by being provided in an excavator in combination with the air pinch valve described in the crab.