JPH0658077A - Shield pit widening method and device - Google Patents

Abstract

PURPOSE:To enhance the easiness in execution of works by arranging so that a skin plate, etc., for pit widening can be mounted freely in a pit. CONSTITUTION:A pit widening skin plate 13 is mounted on a normal skin plate 2 in a pit at the widening start part, and a widening tail plate 14 is coupled. A press ring 15 is installed on a shield jack 9, and excavation is made with an over0cutter 8, and widening segment B2 is assembled. Near the termination of the widening, the ring 15 is secured to the segment B2 side, and excavation is made forward, and a water stop segment B3 is connected with the ring 15 and assembled, and also a reactive force receptacle 16 is assembled. After the length of a normal tail plate is advanced, the reactive force receptacle 16 is removed, and the tail plate is carried into the segment B3 and coupled with the plate 2. The fastened plates 2, 13 are released, and the reactive force is taken in the normal dia. segment connected with the ring 15, and excavation is forwarded while the plates 13, 14 are left underground. Thereby excavation can be executed without requiring improvement of the ground, and the works can be completed easily and quickly using a simple device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield digging method and apparatus for constructing a widened portion having a concentric enlarged cross-sectional diameter with respect to a normal diameter shield pit.

[0002]

2. Description of the Related Art As a city tunnel, a shield tunnel has been constructed by the shield construction method for installing cables for electric power and communication lines as well as for subways, water and sewage.
In particular, in the case of a shield mine for installing cables for power and communication lines, the cable must be connected at every predetermined distance, so there is a widened section as a maintenance space with an enlarged tunnel cross section compared to the normal diameter shield pit. It is provided.

Conventionally, there is the following as a widening work in a shield pit constructed by the shield construction method.

(A) When excavating a normal-diameter shield pit using a conventional shield machine, a special-shaped cut segment is assembled to the normal-diameter segment at the widening location to provide various reinforcements and well-hole packings. Installation, set a special excavator for widening in the cut segment, insert the widening cutter into the cut segment, press the box frame with a jack, add the box frame to the predetermined widening amount and widen sideways, then , Pull out the widening cutter to complete the widening work.

(B) A conventional-diameter shield digging machine is used to excavate a normal-diameter shield mine beyond the widening point, and the ground at the widening starting end is improved by injecting a chemical solution or freezing, and then the existing widening starting end is installed. Remove the segment and assemble a shield machine for expanding the wide area here, and install a reaction force receiver for propulsion of the shield jack. Dig the widened part of. To dig this widened part,
The removal (removal) of the existing segment and the work of assembling the widening diameter segment are repeated, the construction of the widening portion is completed, the shield machine for widening portion excavation is disassembled, and the widening work is completed.

(C) The bearing portion of the cutter disk is made small so that the bearing portion has a double structure, the inner bearing portion is surrounded by a member corresponding to a skin plate, and another outer shield excavator is provided outside the inner shield excavator. Using a shield machine with a special structure such as that provided with, the outer shield machine excavates the wide-diameter shield pit first, the construction of the wide-width part is completed, the cutter device is reduced, and it is located behind the bearing part. A propulsion means such as a shield jack will be attached afterward to construct a normal diameter shield pit with a concentric reduced cross-sectional diameter in a hollowed-out shape with respect to the wide diameter shield pit. (As this prior art, for example, there is Japanese Patent Publication No. 2-44996).

[0007]

In the conventional widening work described above, in the case of (a), the existing segment is removed (removed).
The mechanical structure is simple because it does not require. But,
Since the widening work is done for each segment ring and it is necessary to install a machine for the widening work for each ring one by one, it takes time, and the widening excavation in the shield shaft axis direction cannot be performed continuously. Is bad. Further, it is relatively difficult to stop the water between the box frame and the existing segment, and the existing segment is likely to be deformed when the widened portion is excavated. In the case of (b), the work efficiency is comparatively good because the widening excavation in the shield shaft axial direction is continuously performed, and the excavation style of the shield excavator for the widening portion excavation is a manual excavation type according to the target soil quality, It can be selected as a mechanical type and has flexibility in construction equipment, etc. Moreover, since the cross-sectional shape of the widened diameter segment is circular, it is stable in strength against water pressure and earth pressure.
However, by the time the widening work is started, the ground at the widening start end is improved, the existing segment is removed, the widening work for machine installation, the assembly of the shield excavator for the widening part excavation, the reaction force reception for the shield jack propulsion. Need to be installed. In addition, after the widening work is started, it is necessary to remove the existing segment in front of the machine as the work progresses. There is also a problem in terms of efficiency. In addition, it is economically disadvantageous because it is necessary to improve the ground, and it may not be possible to perform the construction in a place where it is difficult to improve the ground by injecting a chemical solution or freezing. In the case of (c), a special shield excavator that has a double structure inside and outside is used to first perform widening work, and then a normal diameter shield pit with a smaller pit diameter is constructed. It cannot be applied to such cases, and the structure of the shield machine is complicated and expensive.

The present invention has been made in view of the above-mentioned points, and the widening work is started from the vertical shaft portion provided from the ground, and at the widening end portion, it is possible to easily return to the excavation of the normal diameter shield pit by in-machine work. It is an object of the present invention to provide a shield digging method and a device therefor capable of performing.

[0009]

In order to achieve the above-mentioned object, the gist of the first invention of the present invention is to construct a shield pit using a shield machine and to construct a vertical shaft at the widening start end. By installing a widening skin plate on the outer periphery of the normal skin plate in the vertical shaft work, the widening part is dug using both the regular cutter and the over cutter of the cutter device, and the widening diameter segment is assembled to the widening diameter segment. The propulsion reaction force of the shield jack is obtained via the press ring, and the work of advancing the widened part and the assembly of the widened part segment is continued.The press ring is fixed to the end of the widened diameter segment before the end of the widening part, and the segment 1 ring is advanced. Then
The guide segment whose outer diameter corresponds to the widened diameter segment is connected to the press ring to be assembled, and the reaction force receiving ring is connected to the press ring in the guide segment to form a shield jack on the reaction force receiving ring. After the propulsion reaction force was taken, the excavation of the widening part of the length corresponding to the length of the normal tail plate and the work of assembling the guide segment and the reaction force receiving ring were continued, and then connected to the widening skin plate by the work inside the shield body. Fix the widening tail plate to the guide segment, remove the reaction force receiving ring and the ring body inside the press ring, bring the regular tail plate into the guide segment, connect it to the regular skin plate, and connect it to the regular skin plate. Unravel the attachment relationship with the widening skin plate, assemble the press ring inner ring body,
The normal diameter segment is assembled in place of the reaction force receiving ring removed earlier, and the propulsion reaction force of the shield jack is taken on the normal diameter segment to use the normal cutter of the cutter device to dig the normal diameter shield pit and the normal diameter segment assembly. The shield pit widening method is characterized by continuing the work, and the gist of the second invention of the present invention is to provide a shield body composed of a regular skin plate and a regular tail plate, a regular cutter and an overcutter. In a shield machine equipped with a cutter device having an erector for assembling segments, a widening skin plate detachably attached to the common skin plate, and a widening tail plate connected to the widening skin plate, The outer ring body and the inner ring body are combined so that the outer diameter corresponds to the widening diameter segment. The inner diameter corresponds to the normal diameter segment, and the press ring that can be connected to the widened diameter segment and the normal diameter segment to transmit the propulsive reaction force of the shield jack, and the outer diameter corresponds to the widened diameter segment and is connected to the press ring. And a guide ring and a reaction force receiving ring that is connected to the press ring and transmits the propulsion reaction force of the shield jack. A shield excavating device is also provided, and the gist of a third invention of the present invention. In the construction method of constructing a shield pit using a shield machine, a vertical shaft is provided at the widening start end, and a cylindrical outer frame for widening is attached to the outer circumference of the shield body in the vertical shaft, A connecting segment that can connect the wide diameter segment and the normal diameter segment is connected to the rear of the frame at the rear of the shield, and the original push jack is set on the fixed body in the vertical shaft. A propulsive reaction force is applied to the fixed body to integrally advance the shield body, the widening outer frame body, and the normal diameter segment connecting segment in the shield body, and the widening diameter segment is used in combination with a regular cutter and an over cutter of the cutter device. After excavating one ring, connect the connecting segment by forming an expanded diameter segment, and then apply a propulsive reaction force to the fixed body to push the shield body through the connecting segment and the expanded diameter segment using the push tube method. Continue the work of assembling the widening segment by advancing the widening and advancing the widening segment, and constructing the widening segment of the planned length, and connecting the segment at the end of the widening segment and the normal diameter segment in the shield body. Using the shield jack installed inside the shield body by taking the propulsion reaction force, the shield body is moved forward from the outer frame, and the cutter device is used regularly. Use the cutter to excavate the normal diameter shield pit and connect the connection to the normal diameter segment by connecting the normal diameter segment with the normal diameter segment by the erector equipped in the shield body, and then advance the shield main body by applying the propulsion reaction force to the normal diameter segment.
There is a shield mine widening method characterized by continuing excavation of a normal diameter shield pit and normal diameter segment assembly work,
Further, the gist of a fourth invention of the present invention is that in a shield machine having a shield body including a skin plate and a tail plate, a cutter device having a regular cutter and an overcutter, and an erector for assembling the segment, A cylindrical widening outer frame that is detachably attached to the outer periphery of the shield body, a connecting segment that is connected to the rear part of the outer frame and is capable of connecting a widening diameter segment and a normal diameter segment, and the connecting segment And the shield jack are connected to the normal diameter segment, the connecting segment and the subsequent widening diameter segment are set in the vertical shaft fixed body, and the shield body is advanced by a pushing tube method by applying a propulsive reaction force to the fixed body. It is a shield excavation device characterized in that it is provided with an original pushing jack.

[0010]

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

FIG. 1 is a schematic view of a shield shaft constructed according to the present invention.

According to the apparatus of the present invention, the widened portion A2 having the concentric enlarged cross-sectional diameter is continuously dug in the normal-diameter shield pit A1 in the direction of arrow a. These normal diameter shield pits A1
And the excavated wall surface of the widened portion A2 is constructed by the normal diameter segment B1 and the widened portion segment B2 of the divided structure. In the figure, A3 is a vertical shaft provided from the ground with respect to the widening start end.

FIG. 2 is a block diagram showing a main part of a shield machine to which the first invention of the present invention is applied.

The shield main body 1 of the shield machine shown in the drawing is capable of being bent in the middle, and is composed of a cylindrical regular skin plate 2 and a cylindrical regular tail plate 3 connected to the rear portion of the regular regular skin plate 2. Two or three rows of tail seals 4 are equipped on the inner circumference of the end. The cutter device 5 provided in the shield body 1 is provided with a cutter disk 6 in the front part of the shield body 1 and is connected to a cutter motor 7 provided in the shield body 1.
Has a regular cutter (not shown) for excavating the front face and an overcutter 8 protruding and retracting from the outer circumference of the cutter disk. A plurality of shield jacks 9 arranged along the inner surface of the shield body 1 are adapted to apply a propulsive reaction force to the normal diameter segment B1. The tip of a screw conveyor 11 is inserted into the chamber 10 defined at the rear of the cutter disk to discharge the excavated earth and sand taken into the chamber while maintaining a constant earth pressure. Erector 1 installed inside the shield body
2 is to complete segments one by one by assembling divided segments according to the excavation process.
The erector grip also has a margin in the radial direction and can be assembled with both the wide diameter segment B2 (see FIG. 1) in addition to the normal diameter segment B1.

In the above structure, the normal diameter shield pit A1
(Refer to FIG. 1) rotates the cutter disk 6 by the cutter motor 7, and advances the cutter disk 6 together with the shield body 1 by the shield jack 9 to excavate a face by a regular cutter, and excavates the excavated sand in the chamber 10. Take it into the screw conveyor 11
Is discharged to the outside of the chamber, and the normal diameter segment A1 having a divided structure is assembled by the erector 12 in each excavation process to complete each ring and sequentially connect them in a butt shape to work the excavation wall surface.

The construction method of the above-described normal diameter shield pit A1 and the basic construction of the shield machine are well known.

Next, FIG. 3 shows a method of constructing the widened portion A2 (see FIG. 1) continuously with the above-mentioned normal diameter shield pit A1.
-It demonstrates, referring FIG.

FIG. 3 As a work in a shaft A3 (see FIG. 1) provided from the ground for the widening construction start portion, a widened diameter skin having an outer diameter corresponding to the widened portion diameter with respect to the common skin plate 2 of the shield machine The plate 13 is attached as an outer frame. The attachment of the widened diameter skin plate 13 is performed from the inside of the shield body 1 (inside the machine) by a fastening means such as a bolt.

The regular tail plate 3 (see FIG. 2) is removed from the regular skin plate 2, and the widened diameter skin plate 13 is removed.
The widened diameter tail plate 14 is connected to. However, the normal skin plate 2 and the widened diameter skin plate 13 can be pulled out toward the front of the widened diameter skin plate 13 in a state where the attachment relationship between them is released. The widened diameter tail plate 14 has the same structure as the regular tail plate 3, and can be detached from the widened diameter skin plate 13 from within the shield body 1.

A press ring 15 capable of taking a propulsive reaction force is attached to the widened diameter segment B2 on the spreader 9a of the shield jack 9. The press ring 15 has a donut shape in a box cross section and can be divided into an outer ring body 15a and an inner ring body 15b, and an engaging step 15c is formed at a joint portion of both ring bodies.

After the above-mentioned setup, excavation of the widened portion A2 is started. At the time of excess digging at this time, that is, digging in the outer peripheral portion of the cutter disk, the overcutter 8 is projected from the cutter disk 6 to overcut, and the erector 12 widens the diameter segment B2 in accordance with the excavation work.
Assemble.

FIG. 4 Before the excavation of the widened portion A2 of a predetermined length is completed, that is, near the end of the widened portion, the excavation work is temporarily stopped to fix the press ring 15 to the end of the widened diameter segment B2, and then continue the press ring. The propulsive reaction force of the shield jack 9 is applied to the widening diameter segment B2 via 15 to dig one ring.

FIG. 5: A water-blocking segment B3 having the same outer diameter as the widened diameter segment B2 and having an inner diameter larger than the outer diameter of the regular tail plate 3 is connected to the press ring 15 to be assembled, and the press ring 15 is connected to the shield jack. After removing the spreader 9a of 9 and shrinking the shield jack 9, it was made inside the water stop segment (guide segment) B3 of the groundwater pipe to the press ring 15 in a size corresponding to the normal diameter segment B1. Assemble the reaction force receiving ring 16 for propelling the shield jack 9. The reaction force receiving ring 16 used here has a structure in which holes are appropriately opened for work on the water blocking segment (guide segment) B3 assembled on the outer side thereof.

FIG. 6 Regular tail plate 3 (see FIG. 2)
Digging the length (for 3 rings) that contains. Here, two rings are dug forward to assemble the water blocking segment (guide segment) B3 and the reaction force receiving ring 16, and one ring is the last (third) stop with the shield jack 6 extended. Assemble the water segment (guide segment) B3.

FIG. 7 After fixing the widened diameter tail plate 14 to the water-blocking segment (guide segment) B3 so that the shield machine will not retreat due to the pressure of the ground, etc., the reaction force receiving ring 16 is completely removed, The tail plate 3 is moved within the normal diameter shield pit A1 and brought into the water blocking segment (guide segment) B3 from the rear of the widened portion. When bringing the regular tail plate 3 into the water blocking segment (guide segment) B3, the press ring 15 sandwiched between the widened diameter segment B2 and the water blocking segment (guide segment) B3 interferes. Therefore, the press ring 15 removes its inner ring body 15b and allows the regular tail plate 3 to pass therethrough.

By setting the inner diameter of the widened diameter segment B2 to be larger than the outer diameter of the regular tail plate 3, the regular tail plate 3 can be carried in from the vertical shaft without circumferential division.

FIG. 8: The normal tail plate 3 is connected to the normal skin plate 2, and the attachment relationship between the normal skin plate 2 and the diameter expanding skin plate 13 is released to restore the original shield body 1. Further, after the inner ring body 15b of the press ring 15 is rejoined to the outer ring body 15a, the normal diameter segment B1 (three rings) is connected to the press ring 15 in place of the reaction force receiving ring 16 previously removed. Team up. Since the normal diameter segment B1 floats in the air in the widened portion, an appropriate holding member (not shown) holds the widened portion A2 so that its axial center is aligned.

FIG. 9 The wide-diameter tail plate 14 fixed to the water-stopping segment (guide segment) B3.
The widening diameter skin plate 13 and the widening diameter skin plate 13 are left in the ground in a connected state, and the water blocking segment (guide segment) B
When the propelling reaction force of the shield jack 9 is collected in the normal diameter segment B2 assembled in the 3 and the excavation is resumed, the common skin plate 2 and the common tail plate 3 slip out to the front of the wide diameter skin plate 13 and the widened portion A2 (see FIG. 1). ) Continuous normal diameter shield pit A1 (see FIG. 1) is rebuilt.

FIG. 10 is a schematic view showing a shield body of a shield machine to which the third invention of the present invention is applied, and FIG.
(A), (b) is the front view and side sectional view of the widening outer frame.

In the figure, reference numeral 17 denotes a shield body of a shield machine, which is formed by integrally connecting a tail plate 17b having a slightly smaller diameter to the rear portion of a cylindrical skin plate 17a. Since the cutter device 5 having the regular cutter and the over cutter provided in the shield body 17 and other in-flight equipment are the same as those of the above-described second invention, the same reference numerals are given and duplicate detailed description will be given. The description is omitted.

Reference numeral 19 denotes a cylindrical outer frame for widening which is detachably attached to the outer periphery of the shield body 17, and is shown in FIG.
As shown in (b), a hollow portion 19a is formed into which the shield body 17 fits, and a connecting segment (described later) is formed in the rear portion.
It has a connecting portion 19b and the outer diameter is adapted to the widened portion A2. Reference numeral 20 denotes a connecting segment that is connected to the rear portion of the outer frame body 19, and can connect the normal diameter segment B1 and the widened diameter segment B2 (see FIG. 1). Reference numeral 21 is a fixed body set in the vertical shaft A3 (see FIG. 1) corresponding to the connecting segment 20, and 22 is an original push jack set between the connecting segment 20 and the fixed body 21. This is for advancing the shield body 17 by taking a propulsion reaction force.

A construction method for constructing the normal diameter shield pit A1 (see FIG. 1) continuously with the widened portion A2 in the above structure will be described with reference to FIGS.

FIG. 12 A shaft A3 (see FIG. 1) is installed from the ground at the start of the widening work. As work inside the shaft A3,
The widening outer frame body 19 is attached to the outer periphery of the shield body 17. Here, the shield jack 9 and the connecting segment 20
The normal diameter segment B1 in between is set. Similarly, the connecting segment 20 is connected to the rear portion of the outer frame body 19 by the work in the vertical shaft A3. Vertical shaft A corresponding to this connecting segment 20
The fixed body 21 is set in 3. Further, the original push jack 22 is set between the connecting segment 20 and the fixed body 21.

FIG. 13 After the above-mentioned setup, the fixed body 21
Then, the propulsion reaction force is applied to extend the original push jack 22 to advance the shield body 17, the widening outer frame body 19 and the connecting segment 20 integrally to start the excavation of the widening portion A2. Excessive excavation at this time, that is, excavation of the cutting face on the outer peripheral portion of the cutter disk is overcut by the overcutter 8 of the cutter device 5. After excavating one ring of the widened diameter segment B2, the widened diameter segment B2 is assembled in the work in the vertical shaft A3 and connected to the connecting segment 20. Subsequently, the propulsion reaction force is applied to the fixed body 21, and the shield body 17 is moved forward by the push-tube method by the original push jack 22 to increase the widened diameter segment B2 connected to the excavation and connection segment 20 to work on the excavated wall surface. .

FIG. 14 When the excavation of the widened portion A2 of a planned length is completed and the normal diameter shield pit A1 continuous to the widened portion A2 is constructed, the shield jack 9 provided in the shield body 17 is used, A propulsive reaction force is applied to the connecting segment 20 to move the shield body 17 forward, and the face is excavated by the regular cutter of the cutter device 5. Here, the shield body 17 is pulled out forward from the outer frame body 19. And
The first one ring is dug and the normal diameter segment B1 having a divided structure is assembled by the erector 12 (see FIG. 2) provided in the shield body 17 and connected to the connecting segment 20. After that, the reaction reaction force is applied to the normal diameter segment B1 connected to the connecting segment 20 and the shield jack 9 is used to excavate the normal diameter segment B1 by the ordinary method. Complete and connect in sequence to work on the excavated wall.

FIG. 15 The original push jack 2 in the vertical shaft A3 after the planned normal diameter shield shaft A1 is constructed.
2 is removed, and if there is a widening diameter segment A2 in the vertical shaft A3, this is removed. The widening outer frame body 19 and the connecting segment 20 are left in the ground as they are.

[0037]

According to the present invention having the above description,
It has the following effects.

(1) In constructing the widened portion for the shield pit having the normal diameter, it is not necessary to improve the ground in the ground, so that the construction is reliable.

(2) Out-of-machine work for the shield machine for starting the widening work is carried out in the shaft, and all work for finishing the widening work and constructing the original normal diameter shield shaft is carried out in the machine and in the vertical shaft. Since the work is performed inside the work, it is possible to eliminate the work in which the worker dismantles the segment that is the tunnel wall during excavation, which reduces the labor load on the worker and shortens the work time.

(3) A general-purpose shield excavator can be implemented with a slight modification, and a cutter for excavating the widening part uses an overcutter that is freely retractable around the outer periphery of the cutter disk. Since the equipment is effectively used, for example, segments are assembled by using a common erector for the mine and the widened part, it is possible to improve the utilization efficiency of the shield machine.

(4) In the third aspect of the invention, since the propulsion reaction force is applied to the fixed body set in the shaft to use the push-push jack to excavate the widened portion by the push tube method, the widening at each excavation step is performed. The diameter segment can be assembled efficiently by dividing the key segment into unnecessary segments in the vertical shaft. Further, if the widening excavating device is installed on the outer frame instead of on the shield side, the widening portion can have any cross-sectional shape.

[Brief description of drawings]

FIG. 1 is a schematic view of a shield shaft constructed according to the present invention.

FIG. 2 is a schematic configuration diagram showing a main part of a shield machine to which the first invention of the present invention is applied.

FIG. 3 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 4 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 5 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 6 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 7 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 8 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 9 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 10 is a schematic diagram showing a shield body of a shield machine to which the third invention of the present invention is applied.

11A and 11B are a front view and a side sectional view of an outer frame body.

FIG. 12 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 13 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 14 is an explanatory diagram illustrating a construction procedure of a widened portion.

FIG. 15 is an explanatory diagram illustrating a construction procedure of a widened portion.

[Explanation of symbols]

 1 ... Shield body 2 ... Regular skin plate 3 ... Regular tail plate 4 ... Tail seal 5 ... Cutter device 6 ... Cutter disk 8 ... Over cutter 9 ... Shield jack 12 ... Elector 13 ... Wide diameter skin plate 14 ... Wide diameter tail plate 15 … Press ring 16… Reaction force receiving ring 17… Shield body 19… Outer frame 20… Connecting segment 21… Fixing body 22… Original jack A1… Normal diameter shield pit A2… Wide-width section A3… Vertical shaft B1… Normal diameter segment B2: Widening diameter segment B3: Water blocking segment (guide segment)

Claims (4)

[Claims] 1. A method for constructing a shield pit using a shield machine, in which a vertical shaft is provided at a widening start end, and a widening skin plate is attached to the outer periphery of a normal skin plate in the vertical shaft work. And the overcutter are used together to excavate the widened portion, assemble the widened diameter segment, and the propulsive reaction force of the shield jack is obtained via the press ring to the widened diameter segment to continue the work for the widened portion to be dug and the widened portion segment. Then, the press ring is fixed to the end of the widening diameter segment before the widening end portion, the segment 1 ring is dug, and the guide segment whose outer diameter corresponds to the widening diameter segment is connected to the press ring to assemble the guide. The reaction force receiving ring is connected to the press ring in the work segment and the reaction force receiving ring receives the propulsion reaction force of the shield jack. After continuing the excavation of the widened part of a length corresponding to the length of the normal use tail plate and the assembly of the guide segment and the reaction force receiving ring, the widening tail plate connected to the widening skin plate by the work inside the shield body Fixed to the guide segment, remove the reaction force receiving ring and the inner ring of the press ring, bring the common tail plate into the guide segment, connect it to the common skin plate, and connect the common skin plate and widening skin plate. After removing the attachment relationship with the press ring, the ring body inside the press ring is assembled, the normal diameter segment is assembled in place of the reaction force receiving ring that was removed earlier, and the propulsive reaction force of the shield jack is taken on the normal diameter segment for regular use of the cutter device. It is characterized by continuing the excavation of the normal diameter shield pit and the normal diameter segment assembly work using the cutter. Shield anti widening method that. 2. A shield main body comprising a regular skin plate and a regular tail plate, a cutter device having a regular cutter and an over cutter, and a shield machine equipped with an erector for assembling segments, which is detachably attached to the regular skin plate. A widening skin plate, a widening tail plate connected to the widening skin plate, an outer ring body and an inner ring body, and the outer diameter corresponds to the widening diameter segment, and the inner diameter is the normal diameter. Corresponding to the segment, a press ring that can be connected to the expanded diameter segment and the normal diameter segment and transmits the propulsive reaction force of the shield jack, and a guide segment whose outer diameter corresponds to the expanded diameter segment and is connected to the press ring, A reaction force receiver that is connected to the press ring and transmits the propulsion reaction force of the shield jack. A shield excavation device characterized by having a ring. 3. A method for constructing a shield pit using a shield machine, wherein a vertical shaft is provided at the widening start end, and a cylindrical outer frame for widening is attached to the outer circumference of the shield body during the vertical shaft work, A connecting segment that can connect the wide diameter segment and the normal diameter segment to the rear part of the frame is connected to the rear of the shield, and the pusher jack is set on the vertical shaft fixed body, and the thrust reaction force is applied to the fixed body to shield the shield body, The outer frame for widening and the normal diameter segment inside the shield main body are connected together and the segment for connecting is used together to excavate one ring of the wide diameter segment by using both the regular cutter and the over cutter of the cutter device. Assembled to connect to the connecting segment, and then continuously apply a propulsive reaction force to the fixed body to push the shield body through the connecting segment and wide-width segment using the push tube method. Continue the work of assembling the widening segment by advancing the widening and advancing the widening segment, and constructing the widening segment of the planned length, and connecting the segment at the end of the widening segment and the normal diameter segment in the shield body. With the shield jack installed in the shield body by taking the propulsion reaction force, the shield body is advanced from the outer frame, and the regular cutter of the cutter device is used to excavate the normal diameter shield pit and the erector equipped in the shield body. It is characterized by constructing a normal diameter segment and connecting it to the connecting segment, then continuously applying a propulsive reaction force to the normal diameter segment to advance the shield body, and continuing the normal diameter shield pit excavation and the normal diameter segment assembly work. Shield pit widening method. 4. A shield excavator including a shield body including a skin plate and a tail plate, a cutter device having a regular cutter and an over cutter, and an erector that assembles a segment, and a cylinder detachably attached to the outer periphery of the shield body. -Shaped widening outer frame body, a connecting segment connected to the rear portion of the outer frame body and capable of connecting a widening diameter segment and a normal diameter segment, and a normal diameter segment connecting between the connecting segment and the shield jack, It is characterized in that it is provided with a source push jack which is set in the vertical shaft fixed body corresponding to the connecting segment and the widening diameter segment which follows, and which advances the shield body by a pushing tube system by taking a propulsive reaction force to the fixed body. A shield excavator.