JPH0932464A - Construction method for joining tunnel, and shield machine for use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and firmly join existing and new tunnels together. SOLUTION: A cutting and reinforcing ring 6 is provided inside the skin plate 2 of a shield machine 1 in such a way as to be free to move back and forth in the excavating direction, and a ring driving jack 10 for pushing out the cutting and reinforcing ring 6 is provided on the ring 6. As a new tunnel T2 is excavated using the shield machine 1, the cutting and reinforcing ring 6 is pushed out by the ring driving jack 10 at a position a predetermined distance away from an existing tunnel T1, after which the cutting and reinforcing ring 6 is pushed out while being rotated by transmitting the driving force of a cutter 11. The segments of the existing tunnel T1 are cut using a cutting bit 7 to form openings so as to join the existing T1 and new T2 tunnels together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, when connecting an existing tunnel and a new tunnel in the ground when newly constructing a tunnel for use in water and sewage, electricity, communication, or various kinds of traffic. The present invention relates to a suitable shield construction method and a shield excavator used therefor.

[0002]

2. Description of the Related Art Generally, when a new tunnel for water and sewerage, electricity, communication, or various types of traffic is installed,
In the ground, an existing tunnel and a new tunnel may be joined in a substantially T-shape.

Conventionally, when joining such a tunnel, a new tunnel is excavated by a shield excavator, and the excavation of the shield excavator is stopped near the existing tunnel.
After improving the ground around the junction of both tunnels, the shield excavator is further excavated to join the new tunnel and the existing tunnel.

However, in reality, the confluence of both tunnels joined by such a construction method is often under the road near a large-scale intersection. Due to the presence of various buried objects in such places, the conditions for ground improvement around the junction of the tunnel are very strict, making it difficult to perform the work and make sufficient ground improvement. There is a problem of becoming. In addition, after the ground improvement is completed, the ground that has been hardened by the improvement must be excavated by a shield excavator, which causes a problem of extremely poor excavation efficiency.

In recent years, as a tunnel joining method for solving such a problem, a cylindrical slide hood is provided outside the skin plate of the shield excavator so as to be movable back and forth along the excavation direction. When approaching the existing tunnel, the method of advancing the slide hood and abutting the tip of the slide hood on the side surface of the existing tunnel to stabilize the surrounding ground, and joining the tunnel in the slide hood in this state is possible. It has been implemented.

[0006]

However, the conventional tunnel joining method as described above and the shield excavator used therefor have the following problems. First of all, the slide hood provided in the shield excavator needs to have a concave end at the tip according to the external shape of the existing tunnel, but from the standpoint of workability, the existing tunnel will be deformed (flattened by external load). ), And in order to cope with the accuracy error of the arrival position of the shield excavator, some clearance is required between the tip of the slide hood and the existing tunnel. Contrary to this, from a safety point of view,
If the clearance is provided, the slide hood and the existing tunnel will not come into close contact with each other, so that it is not possible to sufficiently secure the waterproofness and the ground stability. In this way, it is difficult to achieve both workability and safety with the conventional technology.

Further, since the slide hood is on the outside of the shield excavator, friction with the surrounding ground during excavation causes
It is easily damaged by wear and deformation. For this reason, when the slide hood is damaged, especially when the tip of the slide hood is damaged while the new tunnel is being dug, when the slide hood is advanced to join the existing tunnel and the new tunnel, A situation occurs in which it cannot operate or cannot perform the required function. Moreover, even if the slide hood is replaced or maintained, it is very difficult or impossible to work in the ground. Such mechanical troubles are likely to occur particularly when the digging distance is long or when the gravel ground is dug.

Furthermore, with the slide hood in contact with the existing tunnel, an opening is formed in the existing tunnel,
A new tunnel is joined to this, but at this time, it is necessary to reinforce the opening of the existing tunnel, which also takes time and cost.

The present invention has been made in consideration of the above points, and provides a tunnel joining method and a shield excavator used therefor, which enables easy and reliable joining of an existing tunnel and a new tunnel. The purpose is to do.

[0010]

The invention according to claim 1 is
When excavating a new tunnel and joining it to an existing tunnel, a shield excavator for excavating the new tunnel is preliminarily rotatably attached to the inside of a cylindrical skin plate forming the outer shell of the shield excavator. A ring body which is provided so as to be movable back and forth along the axial direction of the plate and has a cylindrical shape and a cutting means at the tip peripheral edge; and a ring pushing means which is provided in the skin plate and pushes the ring body in the digging direction. A shield means provided inside the ring body for excavating the natural ground, and a drive force transmission means for transmitting the rotational driving force of the cutter means to the ring body. When excavating the natural ground by the cutter means and excavating a new tunnel, when the shield excavator reaches a position separated from the existing tunnel by a predetermined distance. The ring pushing means pushes out the ring body toward the existing tunnel, and thereafter, the driving force transmitting means transmits the rotational driving force of the cutter means to the ring body to rotate the ring body. Is further extruded and the lining body of the existing tunnel is cut by the cutting means to form an opening, thereby joining the existing tunnel and the new tunnel. In this way, the existing tunnel and the new tunnel are directly joined by the shield excavator by cutting the lining body of the existing tunnel with the cutting means of the ring body provided in the shield excavator to form the opening. You can Moreover, since the tip of the ring body bites into the existing tunnel instead of abutting it, it is possible to ensure high water shutoff and stability of the ground. Further, since the ring body is housed inside the skin plate, it is possible to prevent the ring body from being damaged by friction with the surrounding ground during the excavation of the new tunnel.

According to a second aspect of the invention, in the tunnel joining method according to the first aspect, after the existing tunnel and the new tunnel are joined, the ring body is left in the opening formed in the existing tunnel. It is characterized by that. Thereby, the opening of the existing tunnel can be reinforced by the remaining ring body.

The invention according to claim 3 is a shield excavator for excavating a new tunnel and joining the tunnel to an existing tunnel, wherein the shield excavator has a cylindrical skin plate forming an outer shell thereof. A cutter mechanism for excavating the natural ground is provided in the section, and a cylindrical cutting member is provided inside the skin plate and outside the cutter mechanism, and a cutting member is provided at the peripheral edge of the tip, and is rotationally driven in the axial direction. A ring body is provided so as to be movable back and forth along the axial direction of the skin plate, and the ring body is provided with a ring pushing mechanism for pushing the ring body in the digging direction. As a result, by rotating the ring body and pushing it out toward the existing tunnel by the ring pushing mechanism, the lining body of the existing tunnel is cut by the cutting member to form the opening, and the existing tunnel and the new tunnel are formed. And can be directly joined. Also, since the ring body is housed inside the skin plate, it is possible to prevent the ring body from being damaged by friction with the surrounding ground during the excavation of the new tunnel.

According to a fourth aspect of the present invention, in the shield excavator according to the third aspect, the ring pushing mechanism is provided independently of the cutter pushing mechanism provided for pushing the cutter mechanism. It is characterized by that.
In this way, by separately providing the ring pushing mechanism and the cutter pushing mechanism, it is possible to reduce the load applied to the cutter pushing mechanism, as compared with the configuration in which these are integrated.

[0014]

DETAILED DESCRIPTION OF THE INVENTION An example of an embodiment of the present invention will be described below with reference to FIGS. In these drawings, reference numeral T1 is an existing tunnel, T2 is a new tunnel to be excavated, 1 is a shield excavator, 2 is a shield excavator 1
2 shows a cylindrical skin plate that forms the outer shell of FIG.

As shown in FIG. 1, an annular ring girder 3 is integrally provided inside the skin plate 2 of the shield excavator 1 from the front end 2a of the skin plate 2 to the rear side of a certain size. And, in front of this ring girder 3 by a certain size,
A partition wall 4 located in a plane orthogonal to the axis of the skin plate 2 and having an outer diameter that is smaller than the inner diameter of the skin plate 2 by a certain size is provided integrally with the ring girder 3 via a support member 5.

Inside the skin plate 2 and outside the partition wall 4, there is a tubular shape in the axial direction of the skin plate 2 (hereinafter,
This has a certain length in the "digging direction")
A reinforcing ring (ring body) 6 is arranged.

As shown in FIG. 2, a cutting bit (cutting means, cutting member) 7 for cutting the existing tunnel T1 (see FIG. 1) is integrally provided at the front end of the cutting / reinforcing ring 6. There is. For the cutting bit 7, a cemented carbide bit, a water jet, or the like is appropriately applied according to the material of the segment (lining body) of the existing tunnel T1 to be cut, such as steel or concrete.

Further, at predetermined positions on the inner peripheral surface of the cutting / reinforcing ring 6, for example, four recesses 8, 8, ... Are formed in the circumferential direction.

The cutting / reinforcing ring 6 is formed on the partition wall 4
A substantially cylindrical holding member 9 which is provided integrally with the outer peripheral edge portion and has a constant length in the excavation direction is held so as to be movable back and forth in the axial direction and rotatable about the axis. The holding member 9 has a ring-shaped earth and sand sealing member on the front end side thereof in order to prevent intrusion of earth and sand between the partition wall 4 and the cutting / reinforcing ring 6 and between the cutting / reinforcing ring 6 and the skin plate 2. 9a, 9a are arranged, and support portions 9b, 9b for supporting the cutting / reinforcing ring 6 so as to move back and forth are formed on the rear end side.

Then, as shown in FIG.
The reinforcing ring 6 is normally housed in the skin plate 2 so that the cutting bit 7 at the front end thereof does not project further forward than the front end portion 2 a of the skin plate 2.

Inside the skin plate 2, a ring drive jack (ring pushing means, ring pushing mechanism) 1 which expands and contracts forward in the excavation direction at regular intervals in the circumferential direction thereof.
0, 10, ... Are held by the ring girder 3 and are extended from the front end 2a of the skin plate 2 by extending these ring drive jacks 10 and pushing the rear end of the cutting / reinforcing ring 6. It can be pushed out and projected.

On the partition wall 4, a cutter (cutter means, cutter mechanism) 11 for excavating the natural ground is rotatably provided via a drive shaft (cutter pushing mechanism) 12. As shown in FIGS. 3 and 4, the cutter 11 has
.. for excavating the natural ground are provided, and expandable and contractible cutters 14, 14, ... For expanding and contracting in the radial direction at a predetermined stroke are provided on the outer peripheral side.

As shown in FIG. The drive shaft 12 is connected to a drive device 15 arranged on the rear surface side of the partition wall 4, and the drive device 15 allows the drive shaft 12 to intervene through the cutter 11.
Is designed to be driven to rotate. Further, the drive shaft 12 has an expansion / contraction mechanism that expands / contracts in the excavation direction, and by driving the expansion / contraction to move the cutter 11 in the excavation direction with a predetermined stroke.

Such a cutter 11 is shown in FIG. 2 and FIG.
, The drive shaft 12 (see FIG. 5) is expanded / contracted and rotated so that the expansion / contraction cutters 14, 14, ...
After adjusting to the positions of the recesses 8, 8, ...
By extending 4, 4, ... To the outer peripheral side, the expansion and contraction cutter 14 is fitted in each recess 8. Then, in this state, the cutter 1 is driven by the drive device 15.
When 1 is rotationally driven, the rotational driving force is transmitted to the cutting / reinforcing ring 6 to rotate.

Further, inside the skin plate 2, there is provided an unillustrated slipping-out device for discharging the excavated slag to the rear, and an unillustrated segment assembly device for assembling the segment S constituting the new tunnel T2 to be constructed into a predetermined shape. A forward jack or the like for advancing the shield excavator 1 by applying a reaction force to the segments S, S, ... Is provided.

Further, the shield excavator 1 is provided with a waterproofing material injecting mechanism at a front portion thereof, so that the waterproofing material can be injected into the ground on the outer side of the skin plate 2 forward of the excavation direction. It is like this.

Next, the shield excavator 1 having the above structure.
A method of joining the new tunnel T2 and the existing tunnel T1 will be described with reference to FIG.

First, as shown in FIG. 1, in the shield excavator 1, the new tunnel T2 is constructed toward the existing tunnel T1 in the same manner as the ordinary shield construction method. At this time, the cutting / reinforcing ring 6 is stored in the skin plate 2. Then, the expandable cutter 14 of the cutter 11,
.. are extended to the outer peripheral side, and the cutter 11 is rotationally driven by the drive device 15 in this state, whereby the ground is excavated by the cutter bits 13, 13 ,. And the skin plate 2 behind it
In the inside, while the segment S is assembled into a predetermined shape by the segment assembly device (not shown) and the primary lining is performed, the shield excavator 1 is moved forward by taking a reaction force to the segment S assembled by the forward jack (not shown). To go.

In this way, the new tunnel T2 is constructed, and when the shield excavator 1 approaches the existing tunnel T1 up to a predetermined distance, the excavation is stopped. When the cutting / reinforcing ring 6 is pushed out from the skin plate 2, the predetermined distance is slightly separated without the cutting bit 7 coming into contact with the existing tunnel T1, and the recess 8 (see FIG.
It is desirable to set so that the reference) corresponds to the expansion / contraction cutter 14.

Then, as shown in FIG. 5, with a water-stopping material injection mechanism (not shown) provided in the front part of the shield excavator 1,
A water blocking material is injected into the surrounding ground A in the forward direction of the excavation.

After this, first, each expansion and contraction cutter 1 of the cutter 11 is
After contracting 4, the ring driving jacks 10, 10, ... Are extended to push the cutting / reinforcing ring 6 forward.

Then, as shown in FIGS. 2 and 4,
Extend each telescopic cutter 14 to the outer peripheral side and cut each
It is fitted into the recesses 8, 8, ... Of the reinforcing ring 6.

Then, as shown in FIG.
Thus, while driving the cutting / reinforcing ring 6 integrally with the cutter 11, the drive shaft 12 is extended to press the cutting / reinforcing ring 6 against the existing tunnel T1. Then, the segment which is the lining body of the existing tunnel T1 is cut by the cutting bit 7, and the ground inside thereof is excavated by the cutter 11. Then, when the opening is formed in the existing tunnel T1, the advancement and rotation of the cutting / reinforcing ring 6 are stopped.

After that, the shield excavator 1 is disassembled except for the skin plate 2 and the cutting / reinforcing ring 6, and the other parts are disassembled. In this state, the waterproofing material and the cutting / reinforcing ring 6 ensure the waterproofness and the stability of the surrounding ground. The opening formed in the existing tunnel T1 is
It is reinforced by the tip of the cutting / reinforcing ring 6.

Then, after that, the assembled segment S, the skin plate 2, the cutting / reinforcing ring 6, and the inner peripheral surface of the existing tunnel T1 are laid with concrete to carry out a secondary lining, whereby a new tunnel T2 is formed. And the joining of the existing tunnel T1 is completed.

As described above, the cutting / reinforcing ring 6 is provided inside the skin plate 2 of the shield excavator 1 so as to be movable back and forth in the excavation direction. The ring driving jack 10 for pushing the cutting / reinforcing ring 6 is provided. Is provided. Then, the shield tunneling machine 1 is used to excavate the new tunnel T2, and the cutting / reinforcing ring 6 is pushed out by the ring drive jack 10 at a position separated from the existing tunnel T1 by a predetermined distance. , The driving force of the cutter 11 is transmitted to rotate and push the cutter 11, thereby cutting the segment of the existing tunnel T1 with the cutting bit 7 to form an opening,
1 and the new tunnel T2 are joined. Thereby, the existing tunnel T1 and the new tunnel T2 can be directly joined by the shield excavator 1. Therefore, compared with the conventional method, it is possible to reduce the number of auxiliary construction methods such as the improvement of the ground around the junction between the existing tunnel T1 and the new tunnel T2, which saves labor and reduces the construction period. Can be planned.

Further, since the existing tunnel T1 is directly cut by the cutting / reinforcing ring 6, the cutting / reinforcing ring 6 bites into the existing tunnel T1 instead of merely abutting it. Therefore, it is possible to secure high water stoppage and stability of the ground, and it is also possible to deal with the deformation of the existing tunnel T1 and the error of the arrival position of the shield excavator 1, which is conventionally required. The cost that was used can be suppressed.

Further, since the cutting / reinforcing ring 6 is left as it is, it can be used as a reinforcing body of the existing tunnel T1, and in the ordinary case, the reinforcing work of the opening which needs to be separately constructed. It can be omitted or minimized, and also in this respect, the cost can be reduced and the construction period can be shortened. Then, by reducing the reinforcement construction method such as the reinforcement of the opening of the existing tunnel T1 and the improvement of the surrounding ground, the work from the side of the existing tunnel T1 is reduced, so that the new tunnel can be used even when the existing tunnel T1 is in service. It becomes possible to carry out a joining operation with T1.

Further, the cutting / reinforcing ring 6 is provided inside the skin plate 2. This prevents the cutting / reinforcing ring 6 from being damaged by the friction with the surrounding ground during the digging of the new tunnel T1 even when the digging distance is long or when digging the gravel ground. Thus, it becomes possible to smoothly carry out the joining work between the existing tunnel T1 and the new tunnel T2.

By providing the cutting / reinforcing ring 6 inside the skin plate 2, the diameter of the cutting / reinforcing ring 6 can be made smaller than in the case where it is provided outside the skin plate 2. . Therefore, cutting
Since the driving force for rotating the reinforcing ring 6 can be suppressed, the size of the drive device 15 can be reduced and the cost can be suppressed. On the other hand, since the force (energy) applied to the existing tunnel T2 side to be cut becomes small,
Problems such as breakage of the existing tunnel T2 can be avoided. This effect becomes more remarkable as the diameter of the new tunnel T2 to be excavated is larger.

In addition, the ring drive jack 10 for pushing out the cutting / reinforcing ring 6 is provided separately from the expansion / contraction mechanism provided on the drive shaft 12 for pushing out the cutter 11. And the cutting and reinforcing ring 6
Is driven toward the existing tunnel T1, the ring drive jack 10 is used. Of course, it is also conceivable to extend the drive shaft 12 at this time to push out the cutting / reinforcing ring 6. However, in the case of such a configuration, the drive shaft 1
The expansion / contraction stroke of 2 must be increased. The larger the expansion / contraction stroke of the drive shaft 12, the larger the moment due to the reaction force that the cutting / reinforcing ring 6 and the cutter 11 receive from the existing tunnel T1 and the ground in the extended state of the drive shaft 12. Drive shaft 1 to
2 must be strengthened, which causes a problem that the manufacturing cost of the shield excavator 1 increases. In order to avoid this problem, the recesses 8 of the cutting / reinforcing ring 6 are formed at a plurality of positions at intervals without increasing the expansion / contraction stroke of the drive shaft 12, and the expansion / contraction of the drive shaft 12 is repeated to perform cutting / cutting. It is also possible to push out the reinforcing ring 6, but in this case, the expansion and contraction cutter 14 of the cutter 11 has to be replaced with the recess 8 many times, which causes a problem that it takes a lot of time and effort. On the other hand, as described above, the ring drive jack 10 for pushing out the cutting / reinforcing ring 6 is provided separately from the expansion / contraction mechanism provided on the drive shaft 12, so that the above-mentioned problems are not caused. It does not occur, the manufacturing cost of the shield excavator 1 can be suppressed, and the construction can be performed easily and smoothly.

In the above example, before the cutting / reinforcing ring 6 is extruded, the waterproof material is injected into the surrounding ground in front of the cutting / reinforcing ring 6. Since the stability of the ground can be ensured, it may be possible to omit the injection of the waterproofing material depending on the geological conditions. Further, the tunnel joining method and the application of the tunnel constructed by applying the shield excavator 1 used therefor are not questioned at all.

[0043]

As described above, according to the tunnel joining method of the first aspect, a new tunnel is excavated by a shield excavator, and the skin plate is separated from the existing tunnel by a predetermined distance. The ring body provided on the inside of the is pushed out toward the existing tunnel by the ring pushing means, and thereafter, the rotational driving force of the cutter means is transmitted by the driving force transmitting means to push the ring body while rotating the ring body and the cutting means is used. The opening is formed by cutting the existing tunnel to join the existing tunnel and the new tunnel. In this way, the existing tunnel and the new tunnel can be directly joined by the shield excavator, so auxiliary construction methods such as improvement of the ground around the junction of the existing tunnel and the new tunnel can be reduced compared to the conventional method. As a result, the cost and the construction period can be shortened. Moreover, since the tip of the ring body bites into the existing tunnel instead of abutting it, it is possible to ensure high water shutoff and stability of the ground. Therefore, it is possible to cope with the deformation of the existing tunnel and the position error of the shield excavator, and to suppress the cost for manufacturing the ring body and the cost for improving the excavation accuracy, which have been conventionally required to cope with this. You can Furthermore, since the ring body is stored inside the skin plate, it is possible to prevent the ring body from being damaged by friction with the surrounding ground during the excavation of the new tunnel, and it is possible to join the existing tunnel and the new tunnel. Can be done smoothly.

According to the tunnel joining method of the second aspect, after joining the existing tunnel and the new tunnel, the ring body provided for the shield excavator is left in the opening formed in the existing tunnel. As a result, it is possible to reinforce the opening of the existing tunnel with the remaining ring body, and it is possible to omit or minimize the reinforcement work of the opening that normally needs to be separately constructed,
From this point as well, it is possible to reduce the cost and the construction period.

According to the shield excavator of claim 3,
A ring member provided with a cutting member on the peripheral edge of the tip end so as to be capable of advancing and retracting inside the skin plate, and a ring pushing mechanism for pushing the ring member in the excavation direction are configured. With this, by rotating the ring body and pushing it out toward the existing tunnel by the ring pushing mechanism,
The lining body of the existing tunnel is cut with the cutting member to form the opening, and the existing tunnel and the new tunnel can be directly joined, and the tunnel joining method according to claim 1 can be realized. Also, because the ring body is contained inside the skin plate, it prevents the ring body from being damaged by friction with the surrounding ground during the excavation of the new tunnel, thus facilitating the joint work between the existing tunnel and the new tunnel. Can be done. Moreover, as compared with the case where the ring body is provided outside the skin plate, the driving force for rotationally driving the ring body can be suppressed,
The production cost of the shield excavator can be suppressed.

According to the shield excavator of claim 4,
The ring push-out mechanism for pushing out the ring body is provided separately from the cutter push-out mechanism for pushing out the cutter mechanism provided inside the ring body. In this way,
By separately providing the ring pushing mechanism and the cutter pushing mechanism, the load applied to the cutter pushing mechanism can be reduced as compared with the configuration in which these are integrated, so that the manufacturing cost of the shield excavator is suppressed. In addition to supporting, <construction can be performed easily and smoothly.

[Brief description of drawings]

FIG. 1 is a view showing an example of a tunnel joining method according to the present invention and a shield excavator used therefor, showing a state in which a new tunnel is constructed from the existing tunnel to a position separated from a predetermined distance by the shield excavator. FIG.

FIG. 2 is a vertical cross-sectional view showing a main part of the shield excavator.

FIG. 3 is a front view of the shield excavator showing a state when excavating the natural ground by the cutter mechanism of the shield excavator.

FIG. 4 is a diagram showing a state when the ring body is rotationally driven by the cutter mechanism of the shield excavator.

FIG. 5 is a view showing a method of joining the tunnel, and is a vertical cross-sectional view showing a state in which a ring body provided in a shield excavator is pushed out toward an existing tunnel.

FIG. 6 is a view showing the same construction method, and is a vertical cross-sectional view showing a state in which a lining body of an existing tunnel is cut by the ring body.

[Explanation of symbols]

1 shield excavator 2 skin plate 6 cutting / reinforcing ring (ring body) 7 cutting bit (cutting means, cutting member) 10 ring drive jack (ring pushing means, ring pushing mechanism) 11 cutter (cutter means, cutter mechanism) 12 driving Shaft (cutter extrusion mechanism)

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 000195971 Nishimatsu Construction Co., Ltd. 1-20-10 Toranomon, Minato-ku, Tokyo (71) Applicant 000140982 Mazumagumi Co., Ltd. 2-5-8 Kita-Aoyama, Minato-ku, Tokyo (71) ) Applicant 000230010 Geostar Co., Ltd. 4-3-3 Shiba, Minato-ku, Tokyo (72) Inventor Kazuo Takahashi 2-6-2 Otemachi, Chiyoda-ku, Tokyo Tokyo Sewer Service Co., Ltd. (72) Inventor Yabe Toshiyuki 2-6-2 Otemachi, Chiyoda-ku, Tokyo Within Tokyo Sewer Service Co., Ltd. (72) Inventor Shigeto Aoki 2-6-2 Otemachi, Chiyoda-ku, Tokyo Within Tokyo Sewer Service Co., Ltd. (72) Inventor Minoru 1-3 2-3 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Shinji Seki 1-chome, Shibaura, Minato-ku, Tokyo No. 3 in Shimizu Corporation (72) Inventor Yoshikazu Kido No. 2 Tsukudo-cho, Shinjuku-ku, Tokyo Kumagai Gumi Co., Ltd. Tokyo Head Office (72) Noriyama Yamamori No. 2 Tsukudo-cho, Shinjuku-ku, Tokyo Kumagai Gumi Tokyo Head Office (72) Inventor Toru Watanabe 2570-4 Shimotsuruma, Yamato-shi, Kanagawa Nishimatsu Construction Co., Ltd. Technical Research Institute (72) Yoshio Iso Iso 2570-4 Shimotsuruma, Yamato-shi, Kanagawa Nishimatsu Construction Technical Research Institute Co., Ltd. (72) Inventor Masahiko Hayakawa 2-5-8 Kita-Aoyama, Minato-ku, Tokyo In-house company group (72) Inventor Tsutomu Hagiwara 2-5-8 Kita-Aoyama, Minato-ku, Tokyo In-house company group (72) Inventor Yutaka Fujino 4-3 Shiba 4-3 Shiba, Minato-ku, Tokyo Geostar Co., Ltd. (72) Inventor Hideki Tanaka 2-3-4 Shiba Shiba, Minato-ku, Tokyo Geostar, Inc.

Claims (4)

[Claims] 1. When excavating a new tunnel and joining it to an existing tunnel, a shield excavator for excavating the new tunnel is previously installed inside a cylindrical skin plate forming an outer shell thereof. A ring body which is rotatably and capable of advancing and retracting along the axial direction of the skin plate, and has a cylindrical shape and is provided with a cutting means at the tip peripheral edge portion; and the ring body provided in the skin plate in the excavation direction A ring pushing out means for pushing out, a cutter means provided inside the ring body for excavating the natural ground,
The rotary driving force of the cutter means is provided to the ring body, and the drive force transmitting means is transmitted to the ring body. The cutter means of the shield excavator excavates the natural ground to advance a new tunnel. When the shield excavator reaches a position separated from the existing tunnel by a predetermined distance, the ring pushing means pushes out the ring body toward the existing tunnel, and thereafter, the driving force transmitting means causes the cutter to move. By rotating the ring body by transmitting the rotational driving force of the means to the ring body, the ring body is further pushed out, and the lining body of the existing tunnel is cut by the cutting means to form an opening. A tunnel joining method characterized by joining a tunnel and a new tunnel. 2. The tunnel joining method according to claim 1, wherein after joining the existing tunnel and the new tunnel, the ring body is left in the opening formed in the existing tunnel. Joining method. 3. A shield excavator for excavating a new tunnel and joining it to an existing tunnel, wherein the shield excavator excavates a rock mass in front of a cylindrical skin plate forming an outer shell of the shield excavator. A cutter mechanism for doing so is provided, inside the skin plate and outside the cutter mechanism, a cylindrical body is provided with a cutting member at the tip peripheral edge portion, and a ring body that is rotationally driven in the axial direction thereof is A shield excavator, which is provided so as to be movable back and forth along an axial direction of a skin plate, and the ring body is provided with a ring pushing mechanism for pushing the ring body in the excavating direction. 4. The shield excavator according to claim 3, wherein the ring pushing mechanism is provided independently of a cutter pushing mechanism provided for pushing the cutter mechanism. Excavator.