JPH05295989A - Shield machine - Google Patents

Abstract

PURPOSE:To secure a shield machine that is able to ensure the high sealability and suitable for use in large section tunneling work at superhigh depth and than under superhigh water pressure. CONSTITUTION:This shield machine is provided with a tail seal 10, being extended from a tail part 3 onto the outer peripheral surface of a segment 5 to be formed in ring form along an inner circumferential part of this tail part, and sliding on the outer peripheral surface of the segment in following after the tail part traveling in the cutting direction. A rear seal wall 20 is installed in a rear end of the tail part, constituting a rear tail seal 21, and a front seal wall 23 is installed in front of the rear tail seal, and water is filled up in a seal chamber 25 being formed in a gap between these seal walls as much as up to the specified height, while air pressure is taken into the upper space, making it counter to external pressure in the rear of a shield machine. In addition, plural pieces of the seal chambers are multiply installed there, whereby tunneling work under superhigh water pressure is made achievable in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield machine suitable for use in tunnel excavation under a super high water pressure such as a large cross section or a large depth.

[0002]

2. Description of the Related Art Generally, a tail seal is provided at a tail portion of a shield machine. This tail seal is a shield excavator that includes tail water from the rear of the shield machine, such as groundwater, and backfill injection agent injected on the outer peripheral surface of the segment formed along the inner circumference of the tail machine. It is a seal that prevents it from flowing into the machine body.

Conventionally, as a tail seal structure of this type of shield machine, a wire brush continuous in a ring shape is extended from the tail portion between the tail portion and the inner segment at the rear end portion of the tail portion. The seal chamber is defined between the front and rear wire brushes by providing two rows so that the tip of the lever slides on the outer peripheral surface of the segment and at predetermined intervals in the front-back direction of the shield machine. It is known that the structure is filled with grease to resist external pressure.

Further, a structure in which a plurality of seal chambers are defined between the wire brushes by providing three or more rows of the wire brushes continuous in the ring shape in the front-rear direction, and each seal chamber is filled with grease, respectively. Is also known.

[0005]

By the way, in a seal structure in which a seal chamber is defined between the wire brushes and the seal chamber is filled with grease, the external pressure of underground spring water or the like is the same as in the conventional case. In the case of level, it can be sufficiently counteracted, but when the depth of the tunnel to be excavated is extremely deep and the external pressure is very high, or the tunnel diameter is large and a very large water pressure is applied to the lower end of the tunnel compared to the water pressure at the top of the tunnel. In such a case, in the lower half part of the shield machine, it is not possible to withstand high external pressure, and when underground springs, etc. enter the shield machine, there is a problem that mud and backfill injection agent, etc., also enter at the same time. Occurs.

Further, as described above, since the underground spring water invading the shield machine includes a large amount of mud, it is very troublesome to treat the invading water in the shield machine body. Occurs.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to ensure a high sealing property and to perform under high water pressure such as tunnel excavation with a large cross section and a large depth. It is to provide a shield machine suitable for use in tunnel excavation.

[0008]

In order to achieve such an object, according to the present invention, the tail portion is extended along the inner peripheral portion of the tail portion onto the outer peripheral surface of a ring-shaped segment. In a shield machine having a tail seal that slides on the outer peripheral surface of the segment following the movement of the tail portion in the excavation direction, a rear seal wall is provided by providing a rear seal wall at the rear portion of the tail portion. Then, a front seal wall is provided in front of the rear tail seal at a predetermined interval, water is filled up to a predetermined height in a seal chamber formed between the seal walls, and air pressure is introduced into the upper space thereof. Characterize.

[0009]

The space formed between the rear tail seal at the rear part of the tail portion and the front seal wall provided at a predetermined distance in front of the tail portion is used as a seal chamber to fill the seal chamber with water to a predetermined height and to provide an upper portion thereof. It is configured to introduce air pressure into the space, and by appropriately adjusting the pressure of the seal chamber according to the external pressure such as the spring pressure or the backfill injection pressure, there is almost no pressure difference between the seal chamber and the external pressure. Can be done or reduced.

Therefore, the external pressure that fluctuates up and down does not directly act on the inside of the shield machine main body, and underground spring water, mud water, backfill injection agent, etc. are caused inside the shield machine by the influence of the external pressure. You can prevent intrusion.

There is a slight difference between the pressure in the seal chamber and the internal pressure of the shield machine main body, but it is smaller than the direct pressure difference between the outside and the front seal wall. If it is set to a conventional tail seal or a seal wall such as that of the present embodiment or other type of seal wall so as to be able to counteract, it is possible to prevent water or air from entering and exiting between the seal chamber and the shield machine body. You can

If water enters the shield machine main body from the seal chamber, the water that enters the shield machine has a small amount of mud, and the treatment can be easily performed in the shield machine main body. In case of infiltration no harm occurs.

[0013]

Embodiments of the present invention will be described below with reference to FIGS.

First Embodiment FIGS. 1 to 6 show a first embodiment of the present invention. In the figure, reference numeral 1 is a shield machine main body which has a cutter portion 2 at the front end and which excavates the ground ahead in the excavation direction with the cutter portion 2.
Is a tail portion, 4 is a tail plate, 5 is a segment piece 6
Is a segment that is assembled into a ring.

In the tail portion 3 of the shield machine main body 1,
The segment 5 extends from the tail portion 3 along the inner peripheral portion thereof onto the outer peripheral surface 8 of the segment 5 and follows the movement of the tail portion 3 in the excavation direction. A tail seal 10 that slides on the outer peripheral surface 8 is provided.

Explaining the tail seal 10, a rear seal wall 20 is provided at a rear portion of the tail portion 3 to form a rear tail seal 21. A front seal wall 23 is provided in front of the rear tail seal 21 at a predetermined interval. A space is formed between the seal walls 20 and 23, the outer peripheral surface 8 of the segment 5 and the tail plate 4, and the space serves as a seal chamber 25. As will be described later, the seal chamber 25 is filled with water up to a predetermined height, and air pressure is introduced into the upper space thereof.

As shown in FIG. 2, a muddy water nozzle 27 is provided at the center of the lower portion of the seal chamber 25, and the muddy water nozzle 2 is also provided.
Mud washing nozzles 29 are arranged on both sides of the nozzle 7 at predetermined intervals. An air supply nozzle 31 is arranged at the center of the upper part of the seal chamber 25, and drainage nozzles 32, 32 are arranged at predetermined height positions on both sides of the air supply nozzle 31 at predetermined intervals. In FIG. 2, reference numeral 33 is a waterproof material injection nozzle arranged in a waterproof material chamber s described later. The nozzles 27, 29, 31, 32, and 33 are preferably arranged so as to be covered with a wire mesh or the like so that dust is not clogged.

The muddy water nozzle 27 is connected to a drain pipe 37a outside the tail plate 4 through a hole provided in the tail plate 4 as shown in FIG. Further, the mud washing nozzle 29, the air supply nozzle 31, and the drainage nozzle 32 are also provided with water supply pipes 39a, air supply pipes 41a, 41a outside the tail plate 4 through holes provided in the tail plate 4, respectively.
And the drainage pipe 42a.

The drain pipes 37a and 42a, the water supply pipe 3
9a and the air supply pipe 41a are formed along the longitudinal direction inside a rod-shaped member 43 having a substantially trapezoidal cross section fixed to the outside of the tail plate 4. The waterproof material injecting nozzle 33, like the mud washing nozzle 29 and the like, is waterproof through the holes formed in the tail plate 4 and the inside of the rod-shaped member 43 fixed to the outer peripheral surface of the tail plate 4. It is connected to the material pipe 45a.

The drainage pipes 37a and 42a, the water supply pipe 3
9a, the air supply pipe 41a, and the front end of the waterproof material pipe 45a are connected to the connecting portion 38 fixed to the inner peripheral surface of the tail plate 4 through holes provided in the tail plate 4 along the thickness direction. , 40, 44, 46, 48 are individually connected. Then, the ends of the drainage pipes 37b, 42b connected to the connecting portions 38, 40 are connected to the inlet side of the separation tank 47, and the water supply pipe 39b connected to the connecting portion 44.
Is connected to the outlet side of the separation tank 47. Moreover, the tip of the air supply pipe 41 connected to the connecting portion 46 is connected to the outlet side of the compressor 53.

In the separation tank 47, the muddy water or waste water in the seal chamber 25 is discharged into the drain pipes 37b and 42b.
The introduced wastewater is separated into a solid and a liquid by the supernatant water passing over a plurality of weir plates provided inside the separation tank 47. Then, the water separated by removing the mud is pumped to the water supply pipe 39b by the pump 49.

That is, the discharged sludge nozzles 27, 32,
The drainage nozzle 31, the drainage pipes 37a and 42a, the separation tank 47, the pump 49, the water supply pipes 39b and 39a, and the mud washing nozzle 29 constitute a circulation system 50 that circulates the mudwater in the seal chamber 25.

Here, the circulation system 50 is provided with a pressure adjusting means so that the pressure in the seal chamber 25 becomes equal to the external pressure near the rear end of the shield machine main body 1 (pressure of spring water or muddy water or back pressure). The pressure is adjusted to the same level as or slightly higher than the pressure of the injection agent.

As the pressure adjusting control means, for example, the compressor 53 is constantly operated to introduce compressed air into the seal chamber 25 through the air supply pipes 41b and 41a and the air supply nozzle 31, while the drainage pipes 39b and 42b are separated. Tank 4
It is conceivable that the pressure adjusting valves 52, 52 are provided in the vicinity of the connecting portion to 7, and the spool position of the pressure adjusting valve 52 is adjusted. The pump 49 is always operated while the shield machine is operating. This is to prevent mud from clogging the lower part of the seal chamber 25.

At the rear end of the shield machine body 1, a pressure sensor for measuring the external pressure behind the machine body is arranged, and in the seal chamber 25, a pressure sensor for measuring the pressure inside the seal machine body. (Both not shown) are arranged.
Further, 54 is an air vent provided in the drainage pipes 37b, 42b.

As shown in FIG. 4, the rear sealing wall 20 is surrounded by a tail waterproof plate 61 arranged at the rear end of the tail plate 4 and a shape retaining plate 62 arranged on the front side of the tail waterproof plate 61. Wire brush 63, a wire brush 64 arranged at a predetermined distance in front of the wire brush 63, and a petroleum grease filled in a space s formed between the wire brushes 63, 64. Alternatively, it is composed of a seal waterproof material 71 such as resin.

The tail waterproof plate 61 is formed of a rubber plate or a urethane plate which is waterproof and elastic. Further, the wire brushes 63 and 64 are used in a broad sense here including a brush made of bias wire mesh as well as a wire brush in a narrow sense. As a material, a stainless steel wire which is excellent in rust prevention and strength is preferable, but a simple steel wire or a synthetic fiber wire may be used.

The shape-retaining plate 62 holds and protects the shapes of the wire brushes 63 and 64 as described above, and a stainless steel plate or a Teflon-treated steel plate having appropriate elasticity is used.

Shape retaining plate 62 and the tail waterproofing plate 61
Are formed by being divided in the circumferential direction. In particular, the tail waterproof plates 61 are arranged in a scale shape so as to overlap with each other at the joints of the ends in the circumferential direction. Also, the tail waterproof plate 61
The tip portion of is provided so as to slide in contact with the segment.

On the other hand, the front seal wall 23 has substantially the same structure as the rear seal wall 20. That is, the wire brush 6 is provided at a predetermined distance in front of the wire brush 64.
7 is arranged, a wire brush 69 is arranged further in front of the wire brush 67 at a predetermined interval, and a seal made of petroleum-based grease or resin is provided in a space s formed between the wire brushes 67 and 69. The waterproof material 71 is filled and comprised.

A sealing material is mixed in the seal waterproof material 71 if necessary. As the sealing material, in addition to the fiber material, a sheet-shaped piece or a granular material is used. Further, the sealing material is preferably made of a material having high water absorption, flexibility and elasticity and oil resistance. In the case of a sheet-like piece, for example, a cut piece such as a cloth-like material or a paper-like material, etc. Is used. As a more specific material for the sealing material, a starch-based material,
A highly water-absorbent resin material such as a cellulose-based material or a synthetic polymer-based material can be used.

The wire brushes 67 and 69 are also surrounded by the shape retaining plate 62. Further, reference numeral 73 is a fitting for fixing a wire brush or the like.

The relationship between the wire brushes 63, 64, 67 and 69 arranged at the rear end, the center and the front side will be described. The rear end wire brush 63 is the front side wire brushes 64, 67 and 69. It is preferable that they are arranged relatively densely as compared with. This is because the improvement of the sealing property due to the entanglement of the sealing material mixed in the seal waterproof material 71 is more important than the strength.

Further, it is preferable that the central wire brushes 64 and 67 are arranged more coarsely than the rear end wire brush 63 and that the diameter of each wire is set larger. The coarse arrangement is that the sealing material mixed in the seal waterproof material 71 facilitates the backward flow through the wire brushes 64 and 67, so that the sealing material is positively attached to the rear end wire brush 63. This is for clogging, and the reason why the diameter of each wire is set to be large is to increase the repulsive force that opposes the water pressure in the seal chamber 25.

The wire brush 69 at the front end is preferably a wire brush having the same structure as that 63 used at the rear end. This is because the sealability is important here.

Next, the operation of the first embodiment will be described.

As shown in FIGS. 1 and 4, the rear seal wall 20 is formed by filling the seal waterproof material 71 between the wire brushes 63 and 64, and the seal waterproof material 71 is filled between the wire brushes 67 and 69. The seal chamber 25 formed between the front seal wall 23 and the front seal wall 23 is filled with water up to a predetermined height and air pressure is introduced into the upper space, and this air pressure tends to fluctuate outside the shield machine main body 1, that is, the spring pressure. Adjust and control so that the pressure is approximately the same as the pressure of the backfill injection material.

That is, the pump 49 is operated to supply the seal chamber 2 through the water supply pipes 39b and 39a and the mud washing nozzle 29.
5 is supplied with water, and the waste mud water that has entered the seal chamber 25 is separated into the separation tank 4 through the waste mud water nozzle 27, the drain nozzle 32, and the drain pipes 37a, 37b, 42a, 42b.
Form a series of flows back to 7.

Further, the compressor 53 is operated to pressurize the inside of the seal chamber 25 to a predetermined pressure. Further, in the waterproof material chamber s, a seal waterproof material is pumped by operating a waterproof material injection pump (not shown), and the seal waterproof material is supplied to the upper part of the seal chamber 25 through the waterproof material pipe 45 a and the waterproof material inflow nozzle 33. Inject at a pressure similar to atmospheric pressure. At this time, the injection is performed mainly when the injection of the backfill injection material is stopped. This is because if the seal waterproof material is injected during the injection, the seal waterproof material easily leaks to the outside of the rear, so that wasteful consumption is avoided.

The pressure in the sealing chamber 25 is the same as the drainage pipe 39.
The spool positions of the pressure adjusting valves 52, 52 provided at b, 42b are adjusted and controlled in accordance with the external pressure detected by the pressure sensor attached to the rear end of the shield machine main body 1.
However, this is not the case when the injection pressure of the backfill injection material is preset.

For example, when the backfill injection material is injected into the rear end of the shield machine main body 1, the external pressure behind the shield machine main body 1 temporarily rises. At this time, based on the signal from the pressure sensor that detects the external pressure, the pressure regulating valve 5
Move the spool of No. 2 and raise the setting of the pressure control valve.
Along with this, the atmospheric pressure of the seal chamber 25 rises and becomes approximately the same as the external pressure behind the shield machine body.

FIG. 5 shows the pressure state at that time.
That is, the underground pressure (Pb) of the shield machine 1
And the external pressure (Pa-Pd) behind the shield machine body,
The comparison with the pressure (Pc-Pd) in the seal chamber 25 is shown. The external pressure behind the shield machine main body and the internal pressure of the seal chamber 25 both increase as water pressure is applied downward, but both are equally balanced.

As shown in this figure, the pressure (Pc-Pd) in the seal chamber 25 is maintained by adjusting the pressure adjusting valve 52 so that the pressure is substantially equal to the external pressure behind the shield machine main body 1. ing.

However, in the vicinity of the upper portion, the pressure inside the seal chamber is slightly higher than the external pressure. That is, at the top of the tail portion of the shield machine, a slight pressure difference is generated by the pressure difference between Pc and Pa, and the inside of the seal chamber is higher.
Be done.

Therefore, outside underground spring water, backfill injection material, etc. do not enter the shield machine main body, and the air in the seal chamber 25 tries to flow out to the rear outside. Because it is small, both wire brushes 63, 64
The rear seal wall 20 composed of the seal waterproof material 71 and the seal waterproof material 71 prevents air from being blown out against the rear seal wall 20.
The air and water in 5 never flow out.

Further, the pressure in the sealing chamber 25 (Pc-Pd)
Is higher than the underground pressure (Pb) of the shield machine main body, the air or water in the seal chamber 25 tries to enter the inside of the shield machine main body, but the front seal wall 23 is set to oppose it. Therefore, air or the like does not enter the mine of the shield machine body 1 from the seal chamber 25. Further, when a pressure difference is expected such that the front seal wall cannot oppose it, the seal chambers of the present invention may be provided in multiple stages further forward.

Further, even if air, water, or the like enters the mine of the shield machine main body 1 from the seal chamber 25,
Air intrusion does not cause any trouble, and the water in the seal chamber 25 contains almost no mud compared to external underground springs, etc. Therefore, the treatment inside the shield machine main body is normally performed outside the mine. It is only necessary to carry out the waste water treatment, and it can be performed very easily and without difficulty compared with the conventional treatment of underground spring water containing a large amount of mud.

Even in this state, the pressure (Pg-Pi) in the seal chamber 25 is maintained so as to be slightly higher than the external pressure (Pf-Ph) behind the shield machine body 1, and the rear seal wall 20 is opposed. In combination with the force, external underground spring water, backfill injection material, etc., will be generated inside the shield machine 1 (seal chamber 25
Inside) can be prevented.

Further, the pressure in the sealing chamber 25 (Pg-Pi)
Is slightly higher than the underground pressure (Pb) at the upper position of the shield machine main body 1 and higher at the lower position of the shield machine main body. Therefore,
Inflow or outflow of air or water tends to occur between the seal chamber 25 and the mine of the shield machine main body, but since the front seal wall 23 opposes it, the inflow or outflow of air or seal water is small.

The muddy water circulation system 50 in the sealing chamber 25
In the above, if the pressure in the seal chamber 25 is temporarily reduced with respect to the external pressure due to a time delay in adjusting the pressure in the seal chamber 25, underground spring water or muddy water may enter the seal chamber 25 from the outside. Even in such a case, after the intrusion, the pressure in the seal chamber 25 rises due to the intruding underground spring water or the like to balance with the external pressure. Therefore, there is no further intrusion of underground spring water from the outside.

When underground spring water or the like enters the seal chamber 25 as described above, the water level in the seal chamber 25 rises temporarily, but the increased muddy water is drained at a predetermined height in the seal chamber 25. The water is rapidly transferred from the nozzle 32 to the separation tank 47, whereby the water level in the seal chamber 25 is kept substantially constant. When the amount of muddy water in the separation tank 47 increases due to the external underground spring or the like passing through the rear seal wall 20 and entering the seal chamber 25, a normal type installed in the rear of the shield machine main body 1 is used. It is discharged to the outside and treated through the wastewater treatment facility outside the mine. Further, when the mud is deposited on the bottom of the seal chamber, it is sucked from the sludge drainage nozzle 27 to be drained and drained, so that the treatment is extremely simple.

Further, in this embodiment, an air layer is provided above the seal chamber 25 to introduce air pressure into the air chamber. However, as compared with the case where all the seal chamber 25 is filled with seal water, Since the air layer of FIG. 6 functions to absorb the pressure fluctuation of the seal chamber 25, even if underground spring water or the like intrudes into the seal chamber 25 from the outside due to some cause, the seal walls 20 and 23 are damaged. There is also an advantage that problems such as damage and destruction can be prevented in advance.

Second Embodiment FIG. 7 shows a second embodiment of the present invention. In this embodiment, the rear and front seal walls 20 and 23 are configured by filling the seal waterproof material 71 between the front and rear wire brushes 63, 64, 67 and 69, and the rear and front seal walls thus configured. A seal wall 9 formed by a wire brush having shape-retaining plates on both front and rear sides with seal chambers 91 and 93 interposed between 20 and 23.
Two seal chambers are continuously provided through the unit 5.

Here, the pressure in the rear seal chamber 91 is
The inside of the shield chamber 93 is set to a value that is intermediate between the pressure inside the shield machine main body 1 and the external pressure and close to the external pressure.
The pressure is set to a value intermediate between the pressure inside the shield machine main body 1 and the external pressure and close to the pressure inside the shield machine main body 1. That is, the pressure inside the shield machine main body and the external pressure are sealed in stages.

With such a structure, the pressure resistance of the seal required for the rear seal wall 20 and the front seal wall 23 can be lowered. On the contrary, if the rear and front seal walls 20 and 23 have the structure of the seal wall having the same degree of pressure resistance as in the first embodiment, the high-pressure underground spring water from the outside, the injectant, etc. It is possible to more strongly prevent the invasion of.

In the first and second embodiments, the rear seal wall 20 and the front seal wall 23 are provided between the two wire brushes provided on the front and rear surfaces of the seal waterproof material 71.
Is configured by filling, but is not limited to this,
Provide three or more wire brushes at a predetermined interval, and seal waterproof material 7 between the wire brushes.
1 may be used for the filling structure, or may be formed by a tail seal structure that is simply a wire brush and seal wall structure, or may be formed by another type of tail seal structure.

When two or more front seal walls are provided in front of the rear tail wall and a total of three or more seal walls are provided and a plurality of seal chambers are continuously provided between them, the shield machine main body It is preferable to set the pressure so that the pressure gradually decreases in order from the rear to the front in a pressure range that does not change much from the underground pressure of 1.

Further, the structures of the rear and front seal walls 20 and 23 are not limited to those shown in the first embodiment or the second embodiment, and various design changes are possible. The position of the drainage nozzle 32 provided in the upper part of the seal chamber 25 is set to an appropriate value depending on the excavation depth of the tunnel or the diameter of the shield machine. Further, the drain nozzle 32 may be configured to be vertically adjustable by a cylinder or the like, and the height of the drain nozzle may be adjusted according to the excavation depth of the tunnel or the like. Further, a water level detection sensor is attached to the drainage nozzle 32, and when the position of the drainage nozzle 32 is exceeded, the seal chamber 25
Regardless of whether the internal pressure is high or low, the structure may be such that the pressure adjusting valve 52 is opened to forcibly transfer muddy water and the like above the drainage nozzle 32 to the separation tank 47.

[0059]

As described above, according to the present invention, the rear seal wall is provided at the rear portion of the tail portion to form the rear tail seal, and the front seal wall is provided at a predetermined interval in front of the rear tail seal. The space formed between the seal walls is used as a seal chamber, and the seal chamber is filled with water up to a predetermined height and air pressure is introduced into the upper space of the seal chamber. The pressure difference between the seal chamber and the external pressure can be almost eliminated by properly adjusting and controlling the external pressure such as the pressure of the back-filling agent and the back-filling agent. It does not affect the opening of the shield machine and can prevent underground spring water, mud water, backfill injection material, etc. from entering the shield machine body due to the effect of external water pressure. In tunnel excavation under high pressure it can be suitably used. Further, by providing a plurality of stages of sealing chambers, it is possible to provide a shield machine capable of withstanding ultrahigh pressure of external water.

Therefore, even under a slightly high pressure, a large-scale underground pressure equipment or the like as in the conventional case is unnecessary. In addition, since the pressure in the mine can be kept to a minimum even under ultra-high pressure, the equipment can be small compared to the conventional one, so the economic effect is large.

Further, air pressure is introduced into the upper part of the seal chamber, but since this upper air layer acts to absorb fluctuations in the pressure of the seal chamber, it has some cause as compared with the case where the entire seal chamber is filled with the seal water. From outside the seal room 25
Even if underground spring water or the like intrudes into the interior with a large pressure, it is possible to prevent problems such as damage or destruction of the seal wall.

Further, if water enters the shield machine body from the seal chamber, the invading water has a small amount of mud, and the treatment is carried out in the shield machine body as conventional wastewater treatment. Since it suffices, it has an excellent effect that it can be performed extremely easily as compared with the conventional treatment of mud accompanying the intrusion of underground spring water containing a large amount of mud.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a shield machine according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the shield machine according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a lower portion of the shield machine according to the first embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a lower portion of the shield machine according to the first embodiment of the present invention.

FIG. 5 is an explanatory view showing the operation of the first embodiment of the present invention.

FIG. 6 is an explanatory view showing the operation of the first embodiment of the present invention.

FIG. 7 is an enlarged sectional view of an essential part showing a second embodiment of the present invention.

[Explanation of symbols]

 1 Shield Excavator Main Body 3 Tail 5 Segment 20 Rear Seal Wall 21 Rear Tail Seal 23 Front Seal Wall 25 Seal Chamber 27 Drain Muddy Water Nozzle 29 Wash Muddy Nozzle 31 Air Supply Nozzle 32 Drainage Nozzle 33 Waterproof Material Injection Nozzle 47 Separation Tank 49 Pump 52a Pressure adjustment valve 52b Pressure adjustment valve 53 Compressor 71 Seal waterproof material

Claims (1)

[Claims] 1. A segment extending from the tail portion to an outer peripheral surface of a segment formed in a ring shape along an inner peripheral portion of the tail portion and following the movement of the tail portion in the excavation direction. In a shield machine having a tail seal that slides on the outer peripheral surface of the rear tail seal, a rear seal wall is provided at a rear portion of the tail portion to form a rear tail seal, and a front seal is provided at a predetermined interval in front of the rear tail seal. A wall is provided, and the seal chamber formed between the seal walls is filled with water to a predetermined height, and
A shield machine with air pressure introduced into its upper space.