JP2611153B2 - Underground joining type different diameter shield machine and its joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground junction type different diameter shield excavator (hereinafter, simply referred to as an excavator), an underground joining method of the excavator, and a method of communicating with different diameter tunnels. More specifically, in order to excavate and connect tunnels having different diameters, an excavator including a large-diameter shield machine and a small-diameter shield machine, whose front ends can be joined to each other, an underground joining method for the excavator, and the excavation On the communication method of tunnels using machines.

[0002]

2. Description of the Related Art In recent years, the construction of tunnels, common grooves, and the like is often performed by a shield method. However, in this case, there is a limit to the construction period and the distance that can be excavated by a single shield machine.Therefore, a plurality of shafts are provided, and these shafts are excavated with shield machines, and so to speak, tunnels communicate with each other. Forming a tunnel.

On the other hand, even when tunnels are excavated with this shield machine, for example, in sewerage works, a small-diameter so-called branch pipe is provided on the upstream side, and a large-diameter so-called main pipe is provided on the downstream side to connect them. In some cases, continuous sewers may be formed, and in the construction of electricity, telephone lines, etc.
There is a case where a continuous wiring path is formed by providing a so-called branch pipe having a small diameter at a demand destination and connecting them. Therefore, it is necessary to form tunnels for providing such sewers and wiring paths having different diameters, so-called tunnels having different diameters.

However, particularly in urban areas, construction of underground buildings and transportation networks as well as the ground are congested, so that it is often difficult to construct shafts. Therefore, it is not necessary to provide an intermediate shaft or a reaching shaft, for example, two tunnel machines having different diameters are used to excavate a tunnel or the like from a separation point, and finally the two shield machines are joined to penetrate the tunnel. Technology is being developed.

As an underground joining method for such tunnels having different diameters, there is a technique described in Japanese Patent Publication No. 6-6865. This technology uses a large-diameter shield machine 5 as shown in FIG.
1 and the small-diameter shield machine 52 are moved so that a movable outer shell 51a provided in front of the large-diameter shield machine 51 at the joining point is positioned on the outer periphery of the small-diameter shield machine 52, and the movable outer shell 51a and the small-diameter shield machine are moved. After the soil E between the outer shell 52a and the outer shell 52a is solidified by freezing or injection of a chemical solution, the internal structures of both shield machines 51 and 52 are dismantled.

However, such an underground joining method requires a large-scale auxiliary method for improving the ground so that the joint is frozen or the groundwater does not pass through by injecting a chemical solution. I do. In addition, in this case, since many areas are frozen or improved ground, if frozen, frozen soil may expand during freezing and land subsidence during thawing, etc. Needs time chemical injection.

Furthermore, in the case of the construction method in which the joint is sealed only by freezing, the frozen soil is often thawed due to the heat insulation of the disassembly part generated during the disassembly work of the shield machine after freezing, and water leakage is caused. There is a problem that management of frozen soil is difficult. As described above, it is extremely difficult to excavate a different diameter tunnel and join it underground by the conventional method.

The present invention has been made to solve such a problem, and does not require an auxiliary construction method, or
One object is to provide an excavator for excavating and communicating with a different diameter tunnel that efficiently achieves water stoppage at a tunnel junction by a local small-scale auxiliary construction method, and can easily join even in an eccentric state, It is another object of the present invention to provide an underground joining method and a tunnel communication method of different diameters which can shorten the construction period and reduce the construction cost.

[0009]

According to a first aspect of the present invention, there is provided an excavating machine comprising: a large-diameter shield machine; and a small-diameter shield machine including a large-diameter shield machine and a small-diameter shield machine whose front ends can be joined to each other. An excavator, wherein the large-diameter shield machine includes a ring-shaped joining member having a diameter substantially equal to the skin plate of the small-diameter shield machine and a width equal to or greater than the thickness of the skin plate on the front surface of the cutter disk, further,
It has a closing means for closing a slit formed between the cutter spokes on the front surface of the cutter disk from the inside, and in the small-diameter shield machine, the skin plate and the structure inside the skin plate are axially aligned. It is configured to be able to relatively move, the front edge of the skin plate of the small-diameter shield machine after the structure is retracted by the relative movement can be joined to the joining member of the large-diameter shield machine. It is characterized by becoming.

For the relative movement between the skin plate and the internal structure, the small-diameter shield machine can be moved axially forward with respect to the internal structure by a driving device mounted on the internal structure. It is possible to provide a structured skin plate or to mount a drive on the skin plate, by means of which the internal structure can be moved axially forward with respect to the skin plate.

In the above-mentioned small-diameter shield machine, the main body of the propulsion jack is connected to a fixed portion formed on the internal structure, and the rear end of the spreader of the propulsion jack is configured to be detachable from the assembled segment. The fixing portion is configured to be detachable from the skin plate, whereby the fixing portion and the skin plate are connected and the excavator is excavated in a state where the rear end and the segment are separated, and the connection between the fixing portion and the skin plate is established. The inner structure can be moved in the axial direction with respect to the skin plate in a state where the inner structure is released and the rear end of the spreader is connected to the segment. This is preferable because no special driving device is required.

An excavator according to a second aspect of the present invention is a large-diameter shield machine that can be joined to a small-diameter shield machine at its front end, and a front surface of the cutter disk is substantially the same as the skin plate of the small-diameter shield machine. With a joining member having a width equal to or greater than the diameter and the thickness of the skin plate,
It has a closing means for closing the slit formed between the cutter spokes on the front surface of the cutter disc from the inside, and the closing means can be pushed out by the driving device so as to close the slit by the driving device. It is characterized by comprising a closing plate.

An excavator according to a third aspect of the present invention is a large-diameter shield machine which can be joined to a small-diameter shield machine at a front end thereof, and a front surface of the cutter disk is substantially equivalent to a skin plate of the small-diameter shield machine. With a joining member having a width equal to or greater than the diameter and the thickness of the skin plate,
The cutter disk has a closing means for closing a slit formed between the cutter spokes on the front surface of the cutter disk from the inside, and the closing means fixes the rotation drive device and the output shaft of the rotation drive device to the concave side thereof. A closing plate having a partially cylindrical shape, wherein the closing plate can be rotated so as to substantially fit into the slit and close the slit by the rotation driving device.

[0014] The excavator joining method of the present invention comprises:
A method of joining front ends of a large-diameter shield machine and a small-diameter shield machine that have come close to each other, and (1) accommodating a side-over cutter around a cutter disk of a small-diameter shield machine in the cutter disk, including the cutter disk (2) moving the inner structure closer to the skin plate and housing it in the skin plate; (3) joining to an annular joining member provided on the front surface of the cutter disc;
Closing the slit on the front surface of the cutter disk of the large-diameter shield machine, which is exposed to the outside from the small-diameter shield machine, with a closing member provided inside the cutter disk of the large-diameter shield machine. .

According to the tunnel communication method of the present invention, (1) a side over cutter on the outer periphery of a cutter disk of a small-diameter shield machine is accommodated in the cutter disk, and an internal structure including the cutter disk is relatively moved with respect to the skin plate. Retreating and storing it in the skin plate, and (2) an annular joint member mounted on the front surface of the cutter disk of the large-diameter shield machine so that the front edges of the skin plate of the small-diameter shield machine are brought closer to each other. Joining to the
(3) closing the slit on the front surface of the cutter disk of the large-diameter shield machine, which is exposed to the outside from the small-diameter shield machine, by a closing member provided inside the cutter disk of the large-diameter shield machine; A step of injecting the solidifying filler into the cutter chamber while discharging the soil and the like in the cutter chambers of both shield machines and solidifying the same; (5) excavating and removing the solidified filler and removing both shields; Cutting and removing the internal structure at the joint of the machine.

The terms "front" and "rear" in the claims refer to the forward direction as "front" and the opposite direction as "rear" for each shield machine.

[0017]

According to the excavator of the present invention, first, the small-diameter shield machine can make the skin plate protrude forward relative to the internal structure. The front edge of the skin plate projecting from the front end of the skin plate can be joined. Therefore, earth and sand do not enter the inside of the shield machine from where the front end surfaces of both shield machines overlap. Further, outside the overlapping portion on the front end face of the large-diameter shield machine, the opening such as the slit portion is closed by the closing means from the inside of the large-diameter shield machine, so that the inflow of earth and sand is prevented. In this way, effective shield machine joining becomes possible without requiring a large-scale auxiliary construction method such as ground improvement.

In addition, when the inside of the cutter chamber of both shield machines is filled with a solidifying filler such as poorly mixed mortar or the like, such mortar does not flow out of the slit section or the like. Can be easily replaced with cutting sand. As a result, the removal of the internal structure of both shield machines becomes easier, and the communication of the tunnels of different diameters becomes easier as compared with the related art.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an excavator according to the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view showing a joining state of an excavator according to an embodiment of the present invention, FIG. 2 is a front view of a large-diameter shield machine in the excavator of FIG. 1, and FIG. 3B is a perspective view showing an embodiment of a closing member in the large-diameter shield machine of FIG. 3, FIG. 3B is a cross-sectional view taken along line AA of FIG. 3A, and FIG. FIG. 5A is a cross-sectional view illustrating another embodiment of the member, and FIG. 5A is a cross-sectional view illustrating a non-operating state of still another embodiment of the closing member in the large-diameter shield machine in FIG. 1, and FIG. FIG. 6 is a sectional view showing an operation state.
(A) to (d) are explanatory views showing an embodiment of a tunnel communication method performed by using the excavator of FIG. 1, and FIG. 7 is a side view showing a joined state of an excavator according to another embodiment of the present invention. It is sectional drawing.

FIG. 1 shows a joining state between the large-diameter shield machine 1 and the small-diameter shield machine 2.

As is apparent from the figure, the right side is the large-diameter shield machine 1 and the left side is the small-diameter shield machine 2. In this embodiment, the small-diameter shield machine 2 is joined to the large-diameter shield machine 1 so as to be eccentric upward. In actual tunnel construction, such eccentric joints are illustrated because they are many. However, the present invention is not particularly limited to upper eccentric joints. For example, the small-diameter shield machine 2 may be replaced with a large-diameter shield machine. It may be eccentric downward, laterally or obliquely with respect to 1, and further includes one in which both shield machines are coaxially joined.

As shown in FIGS. 1 and 2, reference numeral 3 denotes a joining member formed of a rubber material or a metal circular plate, which is mounted so as to be exposed on the front surface of the cutter disk 4 of the large-diameter shield machine 1. ing. The joining member 3 has substantially the same diameter as the skin plate 2a of the small-diameter shield machine 2, and is wider than the thickness of the skin plate 2a. The front edge of the skin plate 2a of the small-diameter shield machine 2 is pressed against the outer surface of the joining member 3 to prevent the inflow of earth and sand from that portion.

Incidentally, the joining between the large-diameter shield machine 1 and the small-diameter shield machine 2 is based on recent sensor technology and surveying technology. This can be performed within an error range of about to several tens mm. Therefore, the width of the joining member 3 may be, for example, about 50 mm wider than the thickness of the skin plate 2a of the small-diameter shield machine 2. Note that this dimension may be set to an optimum value depending on the size of the shield machine, excavation conditions, and the like, and is not particularly limited to the above example.

In this embodiment, as shown in FIG. 1, both the large-diameter shield machine 1 and the small-diameter shield machine 2 add water from the water pipes 6 and 8 to the cut soil in the cutter chambers 4 and 5 to form muddy water. Although a muddy excavator that discharges this from the mud pipes 7 and 9 is illustrated, the present invention is not particularly limited to the muddy excavator, and the present invention provides an earth pressure type excavator that discharges cutting soil as it is by a carrying-out means such as a screw conveyor. It is also applicable to excavators.

In the small-diameter shield machine 2, reference numeral 10 denotes a propulsion jack for propelling the shield machine, and reference numeral 11 denotes a drive jack for retracting the internal structure integrally with the skin plate 2a. Here, the internal structures are the cutter disk 12, the bulkhead 13, the pipes 8, 9 and the like. Reference numeral 14 denotes a side over cutter which is disposed so as to be able to radially enter and exit from the outer periphery of the cutter disk 15 for excavating the outer peripheral portion.

In FIG. 2, reference numeral 16 denotes a cutter spoke, which is radially arranged on the front surface of the cutter disk 15 of the large-diameter shield machine 1 and has a large number of cutter bits 16a. Reference numeral 17 denotes a cutter face plate mounted between cutter spokes 16 on the front surface of the cutter disk 15. A slit 18 communicating with the cutter chamber 4 is formed between the cutter spoke 16 and the cutter face plate 17. The slit 18 is for taking earth and sand cut by the cutter bit 16 a into the cutter chamber 4. The taken-in earth and sand is discharged backward by the exhaust pipe 9.

Due to the slit 18, the portion of the front end face of the large-diameter shield machine 1 outside the skin plate 2a of the small-diameter shield machine 2 is open to the outside even after the front ends of the shield machines 1 and 2 are pressed against each other. It will be.

Therefore, in this large-diameter shield machine 1, FIGS.
As shown in FIG. 5, closing members 19 and 20 are provided in the machine for closing the respective areas of the slits 18 outside the annular joining member 3. The slit 18
Since the size of the range of the outer portion of the annular joining member 3 differs depending on their angular position, the range may include closing members 19 and 20 having a size corresponding to the size. All may be unified to the size corresponding to the largest slit 18.

The closing member 19 shown in FIG. 3 comprises a partially cylindrical closing plate 21, a motor 22 for rotating the closing plate 21 about the central axis of the partial cylinder, a speed reducer 23 and a gear mechanism 24. (See FIG. 3A). Then, by rotating the closing plate 21, the slit 18 is rotated.
It gets inside and closes it (see FIG. 3 (b)). The vicinity of the left and right ends of the upper and lower ends of the closing plate 20 is close to the slit 18 when entering the slit 18.
In some cases, the taper is cut so as not to interfere with the upper and lower edges. In addition, FIG.
By mounting a guide 15a whose inner edge is formed in a partially cylindrical shape as shown in (c), the guide 1 can be inserted without inserting the closing plate 21 into the slit 18 in particular.
The slit 18 can be closed to the extent that the slit 18 is brought into contact with the inner edge of 5a.

Further, as shown in FIG.
Hydraulic cylinder 2 instead of a motor, etc.
5 and the arm mechanism 26 can also be used.

The closing member 20 shown in FIG.
7 is pushed forward by a jack 28 and the slit 1
8 has a simple configuration. FIG. 5A shows the non-operating state, and FIG. 5B shows the operating state.

FIG. 6 shows a joining procedure of the large-diameter shield machine 1 and the small-diameter shield machine 2 configured as described above, and a subsequent communication procedure of the different-diameter tunnel.

First, as shown in FIG. 6A, the two shield machines 1 and 2 are brought into close proximity to each other at the joining point and stopped.

Next, as shown in FIG. 6B, the side over cutter 14 of the small-diameter shield machine 2 is housed in the cutter disk 12 and the drive jack 11 (see FIG. 1).
As a result, the internal structure of the small-diameter shield machine 2 is retracted rearward of its own axis with respect to the skin plate 2a. Thereafter, the small-diameter shield machine 2 or the large-diameter shield machine 1 is advanced (both shield machines 1 and 2 may be moved),
The front edge of the skin plate 2a of the small-diameter shield machine 2 is pressed against the joining member 3 of the large-diameter shield machine 1 (see also FIG. 1). (See FIG. 2).

Next, as shown in FIG. 6 (c), the muddy water (in the case of a muddy water shield) containing the cut soil in the cutter chambers 4 and 5 of both shield machines or the cut soil is directly used (in the case of the earth pressure shield). ) Substitute with poorly mixed mortar M and solidify. In this case, since the slit 18 is closed, the mortar does not flow out, and the mortar can be reliably replaced and solidified.

As described above, since the portion of the large-diameter shield machine 1 that is in front of the small-diameter shield machine 2 is closed by the solidified mortar, the internal structure of both shield machines 1 and 2 can be easily dismantled and removed. it can. Then, a joint water stop plate P is provided to cover a staggered portion between the two shield machines, and FIG.
Communication of the different diameter tunnels T1 and T2 as shown in FIG. The reason why the poor mixture is used as described above is that the ease of disassembly is taken into consideration. Therefore, it is not particularly limited to poor blending, nor is it limited to mortar.

FIG. 6D is a view in which the internal member and the mortar of the shield machine have been removed. After the removal, the tunnel is penetrated by internal lining with a segment or concrete.

The small-diameter shield machine 2 in the present embodiment
Then, the drive jack 11 for retreating the internal structure
However, instead of this, the propulsion jack 10 may have a function of retracting the internal structure. That is, although not shown, the main body of the propulsion jack is fixed to a fixed base formed in the internal structure, and can be connected to the rear end of the spreader (piston rod) of the propulsion jack to the front end of the assembled segment. Have a mechanism. Then, the small diameter shield machine is made to reach the joining point by extending the spreader of the propulsion jack by a predetermined length. Then, the connection between the internal structure and the skin plate is released, and the rear end of the spreader spreader is connected to the front end of the assembled segment. When the spreader is contracted by the predetermined length, the internal structure is retracted together with the propulsion jack body.

FIG. 7 shows another embodiment of the excavator.

Large-diameter shield machine 31 in this excavator
Is different from the large-diameter shield machine 1 of FIG. The small-diameter shield machine 33 projects the front end edge of the joining member 32 of the large-diameter shield machine 31 by projecting forward a cylindrical slide ring 34 disposed around the front end of the shield machine main body 33a. This is different from the small-diameter shield machine 2 of FIG. 1 in which the inner structure is moved. The slide ring 34 also corresponds to one of the skin plates that can be relatively moved with respect to the internal structure described in the claims.

First, the joining member 32 of the large-diameter shield machine 31
Is formed as an annular groove on the front surface of the cutter disk 35. This annular groove 32 is provided with a small-diameter shield machine 33.
Of the slide ring 34, and has a width larger than the thickness dimension of the slide ring 34.

Slide ring 34 of small diameter shield machine 33
Is axially movable by a slide jack 36 disposed in the shield machine main body 33a, and has a seal member (tube seal) 37 on the inner peripheral side near the front end. When the two shield machines 31 and 33 are joined, the slide ring 34 fits into the annular groove 32, and the tube seal 37 of the slide ring 34 acts on the inner peripheral surface on the small diameter side of the annular groove 32 to form a circle. It is sealed in a shape. In this case, it is not necessary to press the front edge of the slide ring 34 against the bottom of the annular groove 32. With this configuration, the small-diameter shield machine 33 does not need to include the drive jack 11 of the small-diameter shield machine 2 in FIG. On the other hand, seal members 38a and 38b are disposed on the inner peripheral side near the front end of the slide ring 34 and on the outer peripheral side near the front end of the shield machine body 33a, respectively.

The other constructions of the shield machines 31 and 33 are the same as those of the excavator of FIG.

In the present invention, for example, FIG.
And the small diameter shield machine 33 shown in FIG. In that case, small diameter shield machine 33
The tube seal 37 is not particularly required. Further, the small-diameter shield machine 2 of FIG. 1 and the large-diameter shield machine 3 of FIG.
The combination with 1 is also included in the present invention.

[0046]

According to the present invention, it is possible to join excavators of different diameters without requiring a large-scale auxiliary construction method, and to easily achieve a tunnel with a different diameter by efficiently stopping water at the joint. Can be communicated with. As a result, the construction period of the tunnel construction can be shortened and the construction cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view showing a joining state of an excavator according to one embodiment of the present invention.

FIG. 2 is a front view of the large-diameter shield machine of the excavator of FIG.

3 (a) is a perspective view showing an embodiment of a closing member in the large-diameter shield machine of FIG. 1, and FIGS. 3 (b) and 3 (c) show A of FIG. 3 (a). FIG. 4 is a cross-sectional view taken along a line A.

FIG. 4 is a sectional view showing another embodiment of the closing member in the large diameter shield machine of FIG.

5 is a sectional view showing still another embodiment of the closing member in the large-diameter shield machine shown in FIG. 1; FIG. 5 (a) shows the non-operating state, and FIG. 5 (b) shows the non-operating state. Show.

FIG. 6 is an explanatory view showing one embodiment of a tunnel communication method performed by using the excavator of FIG. 1;

FIG. 7 is a side cross-sectional view showing a joining state of an excavator according to another embodiment of the present invention.

FIG. 8 is a sectional view showing an example of a conventional excavator joining method.

[Explanation of symbols]

 1, 31 large-diameter shield machine 2, 33 small-diameter shield machine 3, 32 joining member 4, 5 cutter chamber 10 propulsion jack 11 drive jack 18.・ Slits 19, 20 ・ ・ ・ Closing member 34 ・ ・ ・ Slide ring 36 ・ ・ ・ Slide jack

Claims (8)

(57) [Claims] An underground shield-type excavator comprising a large-diameter shield machine and a small-diameter shield machine whose front end can be joined to the large-diameter shield machine, wherein the large-diameter shield machine has a cutter disk. On the front surface, a circular ring-shaped joining member having a diameter substantially equal to the skin plate of the small-diameter shield machine and a width equal to or greater than the thickness of the skin plate is provided, and a slit formed between cutter spokes on the front surface of the cutter disk is further provided. The small-diameter shield machine has a closing means for closing from the inside, and in the small-diameter shield machine, the skin plate and the structure inside the skin plate are configured to be relatively movable in the axial direction. The configuration is such that the front edge of the skin plate of the small-diameter shield machine after the structure is retracted can be joined to the joining member of the large-diameter shield machine. This is an underground junction type different diameter shield excavator. 2. A large-diameter shield machine which can be joined to a small-diameter shield machine at a front end thereof, wherein a front surface of the cutter disk has a diameter substantially equal to the skin plate of the small-diameter shield machine and a width not less than the thickness of the skin plate. And a closing means for closing a slit formed between the cutter spokes on the front surface of the cutter disk from the inside, the closing means comprising a driving device and the driving device A large-diameter shield excavator in an underground junction type different-diameter shield excavator comprising a closing plate that can be extruded so as to close a slit. 3. A large-diameter shield machine which can be joined to a small-diameter shield machine at a front end thereof, wherein a front surface of the cutter disc has a diameter substantially equal to the skin plate of the small-diameter shield machine and a width not less than the thickness of the skin plate. And a closing member for closing a slit formed between the cutter spokes on the front surface of the cutter disk from the inside, the closing device comprising: a rotation driving device; and the rotation driving device. And an undershaft that can be rotated by the rotary drive so as to substantially fit into the slit and close the slit, the output shaft comprising a partially cylindrical closing plate fixed to the concave side thereof. Large diameter shield machine in different diameter shield machine. 4. The small diameter shield machine according to claim 1, further comprising a skin plate configured to be able to move axially forward with respect to the internal structure by a driving device mounted on the internal structure. Underground junction type shield machine described. 5. The ground according to claim 1, wherein said small-diameter shield machine is configured such that an internal structure can be moved in an axial direction with respect to the skin plate by a driving device mounted on the skin plate. Medium junction type shield machine. 6. The small-diameter shield machine, wherein a main body of the propulsion jack is connected to a fixed portion formed on an internal structure, and a rear end of the spreader of the propulsion jack is detachable from an assembled segment. The fixed part is configured to be detachable from the skin plate,
Thereby, the fixed part and the skin plate were connected, and the excavator was dug in a state where the rear end and the segment were separated, the connection between the fixed part and the skin plate was released, and the rear end of the spreader and the segment were connected. The underground shield type excavator according to claim 1, wherein the inner structure can be moved in the axial direction with respect to the skin plate in the state. 7. A method for joining the front ends of a large-diameter shield machine and a small-diameter shield machine that have come close to each other in the ground, comprising: And a step of retracting the internal structure including the cutter disk relative to the skin plate and storing the internal structure in the skin plate, and (2) bringing both shield machines closer to each other to make the skin plate of the small-diameter shield machine closer. (3) joining the front edge of the to the annular joining member provided on the front surface of the cutter disk of the large-diameter shield machine, and (3) the slit exposed to the outside from the small-diameter shield machine on the front surface of the cutter disk of the large-diameter shield machine Closing the machine with a closing member provided inside the cutter disk of the large-diameter shield machine. Underground joining method. 8. A method of connecting tunnels by joining front ends of a large-diameter shield machine and a small-diameter shield machine in the ground, comprising: (1) forming a side-over cutter on the outer periphery of a cutter disk of the small-diameter shield machine; Housed in a disc, retracting the internal structure including the cutter disc relative to the skin plate and housing it in the skin plate, and (2) bringing both shield machines closer to each other to reduce the size of the small-diameter shield machine. Joining the front edge of the skin plate to the annular joining member provided on the front of the cutter disk of the large-diameter shield machine, and (3) exposing the front edge of the cutter disc of the large-diameter shield machine to the outside from the small-diameter shield machine. Closing the cut slit with a closing member provided inside the cutter disk of the large-diameter shield machine, and (4) A step of injecting and solidifying the solidifying filler into the cutter chamber while discharging earth and sand and the like in the cutter chamber of the cutter machine, and (5) excavating and removing the solidified filler and using both shield machines. Cutting and removing the internal structure at the junction of the tunnel.