JPH094380A - Tail seal structure for shield machine and tail seal replacing method - Google Patents

Abstract

PURPOSE: To apply high fastening force to the segment of the rearmost tail seal by fitting a spongy packing to the inner face of the tail plate behind the rearmost tail seal. CONSTITUTION: A spongy elastic body 3 brought into contact with the outer face of a segment 8 and pressing the rearmost tail seal 6 to the segment 8 is fitted to the inner face of a tail plate 2 behind the rearmost tail seal 6. When a back-filling material is injected behind a shield machine 1 during an advance after the elastic body 3 is fitted, the pressure of the back-filling material is applied to the back face of the rearmost tail seal 6 via the elastic body 3 to press it to the outer face of the segment 8. The tip of the rearmost tail seal 6 can be prevented from being separated from the segment 8 backward, and the back-filling material is prevented from infiltrating between the tail seals 5, 6 to solidify a filler 10. The differential pressure between the front and rear of the rearmost tail seal 6 is increased by the injection of the back-filling material, and higher fastening force to the segment 8 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tail seal structure for a shield machine and a method for replacing the tail seal, which improves the sealing performance of the tail seal of the shield machine and facilitates replacement thereof.

[0002]

2. Description of the Related Art Generally, the tail of a shield machine has
A tail seal structure as shown in FIG. 4 is provided.

As shown in the figure, a is a shield machine main body, and a cutter portion d for excavating the natural ground is formed at the front portion of the shield machine main body a in the excavation direction and at the rear end portion in the excavation direction. A tail portion b is formed. The tail portion b is defined by a tubular tail plate c, and a ring-shaped segment e is assembled inside the tail portion b.

The segment is formed of arc-shaped segment pieces, and the shield body a is advanced by receiving a reaction force when the shield jack f pushes the front end portion of the assembled segment e.

The backing agent h is sequentially introduced between the inner surface of the drilled hole g and the outer surface of the segment e. The backing agent, such as cement milk, solidifies to form a tunnel with the segment. A tail seal i is provided to prevent the backing agent h from flowing out into the tail portion b.

The tail seal i is an annular brush formed by bundling wires, and its root portion is fixed to the inner surface of the tail plate, and its tip is in sliding contact with the segment e. The tail seal i is provided in at least two stages, and a supply hole j for supplying a filler such as petroleum-based grease or resin is bored between each tail seal i of the tail plate c, and a supply pipe is connected to the tail seal i.

With such a tail seal structure, the backing agent h and the earth and sand injected on the outer peripheral surface of the segment e formed along the inner peripheral portion of the tail portion b include the tail portion b. It is sealed so that it does not leak to the side.

[0008] In such a tail seal structure, the tail seal is worn or damaged when the excavation is carried out over a long distance, or the backing agent adheres and loses its flexibility to deteriorate the sealing property. Therefore, the tail seal is replaced. You may have to do it. Conventionally, when replacing the tail seal, the ground has been solidified by a chemical injection or freezing method and then replaced, but it takes many days to freeze the ground and the cost is high.

Therefore, for example, Japanese Patent Laid-Open No. 3-244793 has been proposed as a method for easily replacing the tail seal. FIG. 5 is a schematic diagram showing such a tail seal replacement method, and the steps of the tail seal replacement will be described below with reference to the drawings. It should be noted that (a) in the figure shows a state in which the excavation is stopped after the usual excavation and the shield jack f is retracted for the following steps.

(1) First step: A special segment 9 equipped with a pressure-expandable hollow seal 7 on the outer periphery is assembled in front of a normal segment 8 (FIG. 5 (b)). (2) Second step: After completing the assembly of the special segment 9, the excavation and the assembly of the subsequent segment 8 are repeated as usual,
The shield machine 1 is advanced to a position where the pressure-expandable hollow seal 7 mounted on the special segment 9 faces the rear end portion 2a of the tail plate 2 (FIG. 5 (c)). (3) Third step: The pressure-expandable hollow seal 7 mounted on the special segment 9 is expanded at this position by injecting a fluid (water or air), and the expanded pressure-expandable hollow seal 7 is tail plate. By making contact with the vicinity 2a of the rear end portion of 2, the water between the tail seal 5 and the natural ground is stopped (FIG. 5 (d)). (4) Fourth step: After that, the segment 8 in contact with the tail seal 5 is disassembled and the tail seal 5 is replaced (not shown).

[0011]

In the shield machine, the rear end of the tail plate is extended rearward from the tail seal at the rearmost portion in order to stop the water by contacting the expanded hollow seal. However, since this extended portion is exposed to a backing agent such as cement milk that hardens over time, the backing agent adheres to the inner surface and solidifies, and part of the solidified backing agent is further advanced by the shield machine. It may be peeled off at the same time.

Therefore, since the surface of the solidified backing material has irregularities and the peeled portion has a step, the pressure-expandable hollow seal is expanded and brought into contact with the tail plate extension. However, there was a problem that a gap was created and water could not be stopped sufficiently. Further, there is a problem that the pressure-expansion type hollow seal is damaged and damaged due to the unevenness and the steps.

Further, since the tail seal at the rearmost portion does not have a shape restriction, the tail seal is gradually moved backward as the digging proceeds, the tip of the tail seal is separated from the segment, and the backing agent enters between the tail seals and is filled. The agent sticks. Therefore, there is a problem that the tail seal at the rearmost portion loses flexibility, and since the pressure difference before and after the tail seal is lost, the tightening force to the segment is reduced and the sealing property is lost.

The present invention was devised to solve such problems. That is, an object of the present invention is to maintain the sealing property by preventing a decrease in the tightening force of the tail seal at the rearmost part, and to easily replace the tail seal. A seal replacement method is provided.

[0015]

According to the present invention, an annular tail seal, which is in the shape of a wire brush and contacts the outer surface of a segment, is provided on the inner surface of the tail plate of a shield machine in a plurality of stages in the axial direction. In the tail seal structure of the shield machine with the filler filled between the tail seals,
Provided is a tail seal structure for a shield machine, wherein an elastic body that comes into contact with an outer surface of a segment and presses the tail seal at the rearmost portion is attached to an inner surface of the tail plate rearward of the tail seal at the rearmost portion.

Further, the sponge-like elastic body is compressed by a special segment having a diameter expanding device to improve the water stopping performance.

Further, the water stopping effect may be confirmed by a hole penetrating in the radial direction provided in the special segment and a valve communicating with the hole.

Further, according to the present invention, an annular tail seal, which is in the shape of a wire brush and is in contact with the outer surface of the segment, is provided on the inner surface of the tail plate of the shield machine in a plurality of stages in the axial direction, and the space between the tail seals is filled. The tail of a shield machine with a tail seal structure that is filled with agent and has a sponge-like elastic body that contacts the outer surface of the segment on the inner surface of the tail plate behind the rear tail seal and presses the rear tail seal against the segment. In the seal replacement method, during the excavation of the shield machine,
A first step of assembling the special segment for compressing the elastic body to improve the waterproof performance, a second step of repeating the excavation and the subsequent segment assembly until the elastic body reaches the position of the special segment, and the special segment Of the shield machine, comprising: a third step of compressing the elastic body to improve water-stopping performance, and a fourth step of disassembling the segment in contact with the tail seal and replacing the tail seal. A tail seal replacement method is provided.

Further, on the outer peripheral surface of the special segment,
A front end of an annular flexible member surrounding this is fixed, and a diameter expanding device that expands the rear end of the flexible member radially outward is provided.

Further, after the completion of the third step, there may be provided a step of confirming the water stopping effect by a hole penetrating in the special segment in the radial direction and a valve communicating with the hole.

[0021]

According to the tail seal structure and the method of replacing the tail seal of the present invention described above, a sponge-like member that contacts the outer surface of the segment and presses the tail seal at the rearmost portion against the inner surface of the tail plate rearward of the tail seal at the rearmost portion is pressed against the segment. By attaching the elastic body, the shape of the tail seal at the rearmost portion can be regulated, the tightening force of the tail seal at the rearmost portion can be prevented from decreasing, and the sealing performance can be maintained.

Further, since the rear end of the flexible member provided in the special segment is expanded and pressed against the elastic body by the diameter expanding device, sufficient water can be stopped and the tail seal can be easily replaced. You can Further, the water blocking effect can be confirmed by the hole penetrating in the radial direction provided in the special segment and the valve communicating with the hole.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. In each figure, the same parts as those in the related art are designated by the same reference numerals, and a duplicate description will be omitted.

FIG. 1 is an explanatory view of the tail seal replacement method of the present invention. In the tail seal structure of the shield machine 1 shown in FIG. 1, annular tail seals 5 and 6 that are in the shape of a wire brush and contact the outer surface of the segment 8 are provided on the inner surface of the tail plate 2 of the shield machine 1 in the axial direction. In the tail seal structure of the shield machine 1 in which the filler 10 is filled between the tail seals 5 and 6 provided in a step,
It is characterized in that a sponge-like elastic body 3 is attached to the inner surface of the tail plate 2 behind the rearmost tail seal 6 so as to contact the outer surface of the segment 8 and press the rearmost tail seal 6 against the segment 8. .

The sponge-like elastic body 3 is an impermeable elastic body (for example, a sponge having closed cells) that does not allow liquid such as water to pass therethrough, and the rear surface of the tail seal 6 and the outer surface of the segment 8 at the rearmost portion. Is fixed to the inner surface of the tail plate 2 behind the tail seal 6 at the rearmost portion by an adhesive or the like so as to come into contact with.

By attaching the sponge-like elastic body 3, when the backfill agent is injected to the rear of the shield machine 1 during excavation, the pressure of the backfill agent via the elastic body 3 causes the tail seal at the rearmost portion. It is applied to the back surface of 6 and pressed against the outer surface of the segment 8. Therefore, the tail seal 6 at the rearmost part
Can be prevented from moving away from the segment 8 and the backing agent is added to the tail seals 5, 6
There is no possibility that the filler 10 will enter into the space and become fixed.

That is, since the pressure difference before and after the tail seal 6 at the rearmost portion increases due to the injection of the back-filling agent, a higher tightening force for the segment can be obtained and the sealing performance can be improved.

In the figure, 4 is a shield jack of the shield machine 1 and 9 is a special segment used in the tail seal replacement method of the present invention.

FIG. 2 is a side sectional view of the special segment 9, and FIG. 3 is a sectional view taken along the line III-III in FIG.
A front end of an annular flexible member 11 that surrounds the outer peripheral surface of the special segment 9 is fixed, and a diameter expansion device 21 that expands the rear end of the flexible member 11 radially outward is provided. ing.

A hole 17 penetrating in the radial direction and a valve 18 communicating with the hole 17 are also provided.

The diameter expansion device 21 has a hole 14 penetrating in the radial direction of the special segment 9 and a part of which is threaded, and a hole 14 at one end and a hole 14 at the other end.
A handle 16 is provided for screwing into the rod member, and a rod-shaped member 13 provided with a connecting pin 19 for connecting to the flexible member 11 at the tip of the threaded side, and an O-ring for sealing the hole 14. It is composed of 15 and.

The flexible member 11 is a rubber-based elastic body or the like, and is provided with connection fittings 12 provided with flanges at both ends of the cylindrical member so that it can be connected to the connection pins 19 of the diameter expanding device 21. There is.

The hole 17 is provided so as to be located in front of the shield machine 1 with respect to the diameter expanding device 21 when the special segment 9 is assembled.

The diameter expanding device 21, the hole 17 and the valve 18 are different in the number provided depending on the construction conditions and the like, and several special segments 9 are assembled to form one ring (see FIG. 3). ), And the special segment 9 may not have the hole 17 and the valve 18.

Returning to FIG. 1, a method of replacing the tail seal of the shield machine 1 according to the present invention will be described. In addition,
FIG. 1A shows a state in which the excavation is stopped after the usual excavation and the shield jack 4 is retracted for the following steps.

FIG. 1 (b) shows a first step of assembling the special segment 9 for compressing the sponge-like elastic body 3 to enhance the water blocking performance during the excavation of the shield machine 1.

The special segment 9 is a normal segment 8
Since the width is narrower than that of, the ring can be formed in a horizontal state within one shield machine. Therefore, the flexible member 11 is fixed to the outer peripheral surface of the special segment 9 after forming the ring in the shield excavator 1 with the special segment 9 in a horizontal state. Further, the rod-shaped member 13 is screwed into the hole 14 by the handle 16, the connection pin 19 is passed through the connection fitting 12 of the flexible member 11, and a snap ring or the like is fitted and fixed to the protruding portion of the connection pin 19. There is.

Thereafter, the special segment 9 is erected and connected to the other segments 8 to complete the assembly of the special segment 9.

FIG. 1C shows a second step in which the excavation and the assembling of the succeeding segment 8 are repeated until the elastic body 3 reaches the position of the special segment 9.

FIG. 1 (d) shows a third step of expanding the flexible member 11 radially outward by the diameter expanding device 21 of the special segment 9 to compress the elastic body 3 and improve the water stopping performance. Shows. Since the elastic body 3 is fixed to the inner surface of the tail plate 2 and is in contact with the rear surface of the tail seal 6 at the rearmost portion, if the flexible member 11 is expanded outward in the radial direction,
The contact force of the elastic body 3 can be completely stopped by the elastic force of the elastic body 3.

Thereafter, as a fourth step (not shown), the segment 8 in contact with the tail seals 5, 6 is disassembled and the tail seals 5, 6 are replaced.

Since the water between the tail plate 2 and the segment 9 can be completely stopped by the third step, even if the segment 8 in contact with the tail seals 5 and 6 is disassembled, the shield machine 1 The tail seals 5 and 6 can be easily replaced without water flowing into the machine.

After the third step, the special segment 9
If the valve 18 communicating with the hole 17 penetrating in the radial direction provided in the is opened and the water blocking effect is confirmed and then the process proceeds to the fourth step, the tail seals 5, 6 can be more reliably stopped.
Can be replaced. In addition, as a result of confirming the water blocking effect, when the water blocking is not sufficiently performed, it is possible to improve the ground level by injecting a chemical solution or the like and then shift to the fourth step.

The present invention is not limited to the above embodiment,
Of course, various changes can be made without departing from the spirit of the present invention.

[0045]

According to the above-described tail seal structure and tail seal exchanging method for a shield machine of the present invention, by attaching a sponge-like packing to the inner surface of the tail plate rearward of the rearmost tail seal, A high tightening force for the tail seal segment can be obtained, the sealing performance can be improved, and the tail seal will not be damaged or the backing agent will stick and lose its flexibility. The number of times the tail seals are replaced can be reduced and the construction period can be shortened.

Further, since water can be stopped easily by using a special segment having a flexible member and a diameter expanding device, it is possible to reduce the time and effort required to replace the tail seal.

Further, since the water-stopping effect can be confirmed only by providing the special segment with the hole penetrating in the radial direction and the valve communicating with the hole, the breakage of the elastic body or the flexible member can be confirmed. When the water is not stopped sufficiently,
It is possible to reliably and easily prevent groundwater, backfilling agent, and the like from flowing into the shield machine by replacing the tail seal.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a tail seal replacement method of the present invention.

FIG. 2 is a side sectional view of a special segment.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a side sectional view of a tail portion of a conventional shield machine.

FIG. 5 is an explanatory diagram of a conventional tail seal replacement method.

[Explanation of symbols]

 1 shield machine 2 tail plate 3 sponge-like elastic body 4 shield jack 5, 6 tail seal 7 pressure expansion hollow seal 8 segment 9 special segment 10 filler 11 flexible member 12 connecting member 13 rod-shaped member 14, 17 Hole 15 O-ring 16 Handle 18 Valve 19 Connection pin 21 Expander

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Waji 11-11 Kitahamacho, Chita City, Aichi Prefecture Ishikawajima Harima Heavy Industries Co., Ltd. Aichi Factory

Claims (6)

[Claims] 1. A shield in which an annular tail seal, which is in the shape of a wire brush and contacts the outer surface of a segment, is provided in a plurality of stages in the axial direction on the inner surface of the tail plate of the shield machine, and a filler is filled between the tail seals. In the tail seal structure of an excavator, a shield characterized by attaching a sponge-like elastic body that contacts the outer surface of the segment and presses the tail seal at the rear end to the inner surface of the tail plate behind the tail seal at the rear end. Excavator tail seal structure. 2. The tail seal structure for a shield machine according to claim 1, wherein the sponge-like elastic body is compressed by a special segment having a diameter expanding device to enhance water blocking performance. 3. The tail seal structure for a shield machine according to claim 2, wherein the water blocking effect is confirmed by a hole penetrating in the radial direction provided in the special segment and a valve communicating with the hole. 4. An inner surface of a tail plate of the shield machine is provided with annular tail seals, which are in the shape of a wire brush and are in contact with the outer surface of the segment, in a plurality of stages in the axial direction, and a filler is filled between the respective tail seals. In the tail seal replacement method of the shield machine having a tail seal structure in which a sponge-like elastic body that contacts the outer surface of the segment with the inner surface of the tail plate rearward of the tail seal of the rearmost portion is pressed against the segment, Assembling a special segment for compressing the elastic body to improve water stopping performance during the excavation of the shield machine 1
The second step of repeating the process, the excavation and the assembling of the subsequent segment until the elastic body comes to the position of the special segment, the third step of compressing the elastic body by the special segment to improve the waterproof performance, and the tail seal A tail seal replacement method for a shield machine, comprising: a fourth step of disassembling a segment in contact with the tail seal and replacing the tail seal. 5. A diameter expansion device for fixing the front end of an annular flexible member surrounding the special segment to the outer peripheral surface of the special segment, and further expanding the rear end of the flexible member outward in the radial direction. The method of replacing a tail seal of a shield machine according to claim 4, further comprising: 6. The shield according to claim 4, further comprising a step of confirming a water stopping effect by a hole penetrating in the radial direction provided in the special segment and a valve communicating with the hole after the completion of the third step. Excavator tail seal replacement method.