JP2002089172A - Shield excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shield excavator which facilitates driving of an enlarged- width pit and taking-up of excavated soil, to thereby shorten a construction period required for construction of a width-enlarged tunnel and reduce construction costs for the same. SOLUTION: The shield excavator 1A is provided with a cutter 2 rotatably supported at a front portion of a shield main body 3, for driving a standard pit of a predetermined cross-sectional area. The shield excavator 1A is comprised of a width-enlarging cutter 4 which is protrudable from an external portion of the shield main body 3 in a direction that widens the width of the standard pit. The width-enlarging cutter 4 carries out driving of the enlarged- width pit, and taking-up of excavated soil of the enlarged-width pit into the shield main body 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield excavator capable of penetrating both a standard pit and a widening pit.

[0002]

2. Description of the Related Art Shield tunnels constructed by a shield method are becoming increasingly important especially in tunnels for roads and railroads in urban areas, and long-distance digging and deepening are required. Such shield tunnels often require partially widened tunnels along the way. For example, in the case of a railway tunnel such as a subway, a station must be provided every 500 m to 1000 m, and in the case of a road tunnel, an emergency parking zone must be provided approximately every 500 m. Conventionally, widening sections are built in tunnels by open-cutting, excavation and lining of widening tunnels by partially removing segments after constructing a standard tunnel shield tunnel with a predetermined cross section, or using a method specifically for widening tunnels The construction method using a shield excavator was carried out.

[0003]

In the open-cutting method,
The impact on the surrounding environment is large, such as occupying land for a long period of time, and the construction becomes very large. Also,
In the method of excavating and lining a widening pit by partially removing a segment after constructing a shield tunnel, removing the lining segment once is wasteful and requires ground improvement against soil pressure. Further, a construction method using a shield excavator dedicated to a widening pit requires operations such as disassembly, transportation and assembly of the shield excavator. As described above, the conventional method requires a great deal of labor and construction cost, and also results in prolonging the construction period. For these reasons, recently, a rotating cutter has been provided with an overcutter that can appear and disappear from the outside of the rotating cutter,
Attempts have been made to build and cover the standard and widening tunnels simultaneously. However, in this method, excavated earth and sand excavated by an overcutter in a widening pit is taken into a shield excavator through a hole formed in the cutter. Therefore, it is inconvenient to take in excavated earth and sand, and the excavation speed of the widening pit is extremely lower than that of the standard pit, and the construction period is not shortened much. In addition, the cutter, which is a rotating body, must be provided with both an over cutter and a hole, which greatly restricts the dimensions and complicates the structure, making maintenance difficult. The situation has not been planned.

The present invention has been made in view of the above circumstances, and makes it easy to excavate a widening pit and take in excavated earth and sand.
An object of the present invention is to provide a shield excavator capable of shortening the construction period and reducing the construction cost in building a widening tunnel.

[0005]

According to a first aspect of the present invention, there is provided a shield excavator having a cutter supported in front of a shield main body and excavating a standard pit having a predetermined cross-sectional area. A widening cutter is provided which is capable of protruding and retracting in the widening direction for widening the standard pit, and digs into the widening pit and takes in the excavated earth and sand of the widening pit into the shield main body.

As described above, since the widening cutter is provided on the shield main body, dimensional restrictions are relaxed, and the widening cutter can be appropriately protruded and retracted with a simple structure, and the excavated earth and sand can be taken in the widening pit. It can be done easily.

According to a second aspect of the present invention, there is provided the shield excavator according to the first aspect, wherein the widening cutter has an opening for taking in excavated earth and sand of the widening pit, and is rotatable with respect to the shield body. An outer shell portion that is pivotally supported by the outer shell portion and a cutter portion that rotates together with the outer shell portion and excavates the front of the opening portion.The outer shell portion and the cutter portion are used when excavating only the standard pit. Is housed in the shield main body, and when excavating the widening pit, is rotated so as to protrude from the shield main body in the widening direction, and the opening is directed to the excavation direction.

As described above, since the widening cutter is rotated to open and close in a so-called fan shape, the widening cutter can be accurately made to protrude and retract with a simpler configuration. Further, even in a state where the excavation of the shield excavator is stopped, the widening cutter can be opened while excavating and discharging, so that the cutter can be protruded in the widening direction.

According to a third aspect of the present invention, there is provided the shield excavator according to the first or second aspect, wherein the shield excavation is performed when the widened pit is dug behind the widened cutter of the shield body. At least a part of the main body protrudes toward the widening pit, and is provided with a widening member for retaining the widening pit. The invention according to claim 4 is the shield excavator according to claim 3, wherein the widening member is formed between the widening member and the widening cutter when excavating the widening pit. And a gap retaining member for retaining the set gap.

As described above, since the widening member is made to protrude to the rear side of the widening cutter, soil can be retained immediately after excavation of the widening pit. In addition, even when a gap is formed between the widening cutter and the widening member, since the soil of the widening pit at this portion can be retained by the gap soiling member, the widening tunnel between the widening cutter and the widening member can be formed. , Soil retention is performed continuously without gaps.

According to a fifth aspect of the present invention, there is provided the shield excavator according to the first aspect, wherein the widening cutter includes a cutter section for excavating the widening pit, and a housing for accommodating the cutter section and the widening pit. And an outer shell having an opening for taking in excavated earth and sand, wherein the outer shell and the cutter are housed in the shield body when excavating only the standard pit, and excavate the widening pit. In this case, it is characterized in that it protrudes straight from the shield body in the widening direction.

As described above, since the widening cutter is linearly projected in the widening direction, the widening cutter can be accurately protruded and retracted with a simpler configuration. In addition, even when excavation of the shield excavator is stopped, the widening cutter can be protruded in the widening direction while excavating and discharging the soil.

According to a sixth aspect of the present invention, there is provided the shield excavator according to any one of the first to fifth aspects, wherein the widening cutter includes a cutter shaft which is rotated around an axis. The shaft is supported by the shield main body so as to be rotatable in a cross section of the widening pit and extend and contract in the radial direction in the cross section.

With this configuration, the cross section of the widening pit, that is, the digging range of the widening pit can be excavated with one cutter shaft, and the energy such as electric power consumed for rotating the cutter shaft can be reduced. it can.

According to a seventh aspect of the present invention, there is provided the shield excavator according to any one of the first to fifth aspects, wherein the widening cutter includes a plurality of cutter shafts rotated around an axis. Are densely arranged so as to cover the cross section of the widening pit.

By doing so, it is possible to excavate almost the entire area of the widening pit by rotating only the cutter shaft, and it is not necessary to make the cutter shaft perform complicated movements such as swinging. It can be simple. In addition, since the actuators for driving these cutter shafts can be arranged intensively at a specific place, the structure can be simplified and the structure can be simplified.

The invention according to claim 8 is the shield excavator according to any one of claims 1 to 5, wherein the widening cutter has a cutter shaft that is rotated around an axis, and the cutter shaft rotates. Cutter moving means for pivotally supporting and moving vertically and horizontally within the cross section of the widening pit.

In this case, the number of members can be reduced and the weight of the shield excavator can be reduced. In addition, since the configuration is simplified by reducing the number of members, the flow of excavated earth and sand from the widening cutter to the shield main body can be improved, and the excavated earth and sand can be more easily taken in.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a shield excavator according to the present invention will be described below with reference to the drawings.

[First Embodiment] A first embodiment of a shield excavator according to the present invention will be described with reference to FIGS. This shield excavator 1A includes a cutter 2 and a shield body 3 as shown in FIGS.
, A widening cutter 4 and a widening member 5.

The cutter 2 has a substantially disk shape and is rotatably provided at the front end of the shield body 3. The cutter 2 is for excavating a standard hole, and is capable of excavating a standard hole by rotating a large number of cutter bits (not shown) provided at the tip. Although not shown, a hole for taking excavated earth and sand from a standard pit into the shield body 3 is provided on the front surface of the cutter 2. In the following, the “standard pit” refers to a pit excavated only by the cutter 2 and having substantially the same cross-sectional area as the outer diameter of the cutter 2. The shield body 3 has a substantially cylindrical shape as a whole, and supports the cutter 2 rotatably, and also retains a standard pit. A pressing jack (not shown) is provided in the vicinity of the rear end side of the shield main body 3, which presses a segment (not shown) which is sequentially wrapped behind the shield main body 3, and the reaction force of the pressing excavator 1 </ b> A Is to be excavated.

On both sides of the shield body 3, there are provided widening cutters 4 for digging in widening tunnels. The widening cutter 4 protrudes from the outside of the shield body 3 in a widening direction for widening the standard pit, that is, in a direction substantially orthogonal to the excavation direction, and excavates the widening pit. To take in the outer shell part 41,
And a cutter shaft (cutter portion) 42.
In the following, the term “widening pit” refers to a pit that cannot be dug with the cutter 2, that is, a pit dug using the widening cutter 4. The outer shell 41 is rotatably supported by the shield body 3 at the shaft 31. An opening 41a is formed in the outer shell 41 so that the excavated earth and sand of the widening pit can be taken in. Cutter shaft 42
Is rotatably supported by a fulcrum 31a near an intermediate portion of the shaft portion 31, and excavates earth and sand by a cutter bit 42a provided on an outer peripheral surface by rotating around an axis thereof. The cutter shaft 42 rotates together with the outer shell 41 to excavate earth and sand in front of the opening 41a. The cutter shaft 42 is rotatable in the vertical direction of the fulcrum 31a and expandable and contractible in the radial direction.
It is movable over almost the entire area of the pit, so that the entire widening pit can be excavated.

The outer shell 41 and the cutter shaft 42 are housed in the shield body 3 and are closed when only the standard shaft is dug. Then, when digging in the widening pit, the pit is rotated and opened so as to protrude from the shield body 3 in the widening direction, and the opening 41a is directed in the digging direction. That is, the widening cutter 4 is opened and closed in a fan shape, so that the widening cutter 4 can protrude and retract from the outside of the shield body 3 in the widening direction.

On the rear side of the widening cutter 4 of the shield body 3, there is provided a widening member 5 having a substantially rectangular outer shape. The widening member 5 forms a part of the shield main body 3 and is stored in the shield main body 3 when excavating only the standard pit. At this time, the outer portion of the shield main body 3 and the outer portion of the widening member 5 are substantially flush. And when excavating the widening pit, this widening member 5
Are made to protrude in the widening direction, so that the upper and lower sides and side portions of the widening pit are retained. On the front side of the widening member 5, a slide roof (clearance retaining member) 5a is provided so as to be slidable in the front-rear direction. This slide roof 5
a is stored in the widening member 5 when the widening member 5 is stored in the shield body 3. Then, when the widening member 5 projects toward the widening pit, the widening member 6 is slid so as to protrude from the front end side thereof, and performs soiling of a gap formed between the widening member 5 and the widening cutter 4. Things.

A procedure for excavating a standard pit and a widening pit using the shield excavator 1A will be described. First, Figure 1
As shown in (a) and (b), in a state where the widening cutter 4 and the widening member 5 are stored in the shield body 3,
Drill only the standard pit using. At this time, a segment for lining the standard pit is sequentially laid behind the shield body 3 to build a standard tunnel.

When the excavation of the widening pit is started, the excavation of the shield excavator 1A is temporarily stopped. In this state, FIG.
As shown in (a) and (b), the widening cutter 4 is opened while the cutter shaft 42 is rotated to excavate earth and sand in front of the opening 41a, and the opening 41a of the outer shell 41 is directed in the excavation direction. . With the widening cutter 4 thus opened, the standard pit and the widening pit are dug. The excavated earth and sand from the widening pit is taken into the shield main body 3 from the opening 41a through the outer shell 41, and is conveyed to the rear along with the excavated earth and sand from the standard pit by a conveyance means such as a screw conveyor (not shown). It is excavated.

In this state, if the digging is performed for several meters, that is, a distance that allows the widening member 5 to protrude, FIG.
As shown in (a) and (b), the widening member 5 is projected in the widening direction, and the widening pit is retained. At this time, the widening cutter 4 protrudes in the widening direction by opening in a fan shape, and the widening member 5 moves and protrudes substantially parallel to the widening direction, so that a gap S is formed between the two.

Then, as shown in FIGS. 4A and 4B, the slide roof 5a is slid in the digging direction,
The soil is retained by covering the gap S. By doing so, the space from the widening cutter 4 to the widening member 5 is retained without any gap, and in this state, the standard pit and the widening pit are excavated. At this time, behind the shield main body 3 and the widening member 5, segments for lining both the standard pit and the widening pit are sequentially lined, and a widening tunnel is built.

When the excavation of the widening pit is completed, the above procedure is reversed. That is, the slide roof 5a is stored in the widening member 5, the widening member 5 is stored in the shield main body 3, and then the widening cutter 4 is closed and stored in the shield main body 3.

The shield excavator 1A according to the present embodiment is provided with a widening cutter 4 that can protrude and retract in the widening direction to widen the standard pit from the outside of the shield main body 3, excavate the widening pit, and excavate the soil of the widening pit. Into the shield body 3. As described above, since the widening cutter 4 is provided on the shield main body 3, dimensional restrictions are relaxed, and the widening cutter can be appropriately protruded and retracted with a simple configuration, and the excavated earth and sand can be easily taken in the widening pit. Can be done. Therefore, the excavation speed of the widening pit can be improved, and the construction period can be shortened.
Maintenance can be facilitated and construction costs can be reduced.

The widening cutter 4 includes an outer shell 41 and a cutter shaft 42. The outer shell 41 and the cutter shaft 42 are housed in the shield body 3 when only the standard pit is dug. When excavating in the widening pit, it is rotated so as to protrude from the shield main body 3 in the widening direction so that the opening 41a faces in the excavation direction. As described above, since the widening cutter 4 is rotated to open and close in a so-called fan shape, the widening cutter 4 can be properly protruded and retracted with a simpler configuration, and the reliability and durability of the widening cutter 4 can be improved. The width of the widening pit can be easily changed. Further, even when the excavation of the shield excavator 1A is stopped, the widening cutter 4 can be opened and extruded in the widening direction while excavating and discharging, so that the influence on the surrounding ground is reduced, and It can be hardly affected by the hardness of the ground.

Further, since the cutter shaft 42 is rotatably supported in the cross section of the widening pit and is capable of radially extending and contracting in the cross section, the excavation range of the widening pit can be controlled by one cutter shaft 42. Can be excavated, energy such as electric power consumed for rotating the cutter shaft 42 can be reduced, and excavation of a widening pit can be performed more economically.

Further, on the rear side of the widening cutter 4 of the shield main body 3, there is provided a widening member 5 for projecting a part of the shield body 3 toward the widening pit and retaining the earth in the widening pit when excavating the widening pit. As a result, the soil can be retained immediately after the widening pit is excavated, and the subsidence of the widening pit can be prevented, so that the tunnel can be smoothly constructed. Further, the widening member 5 is provided with a slide roof 5a for retaining the gap S formed between the widening member 5 and the widening cutter 4 when the widening pit is dug. Can be continuously carried out without gaps in the widening pit from to the widening member 5. Therefore, it is possible to prevent the earth and sand from entering the gap S and causing land subsidence or causing resistance to the excavation of the shield excavator 1A.

[Second Embodiment] A second embodiment of the shield excavator according to the present invention will be described with reference to FIGS. The shield excavator 1B is different from the shield excavator 1A in the first embodiment in that the cutter 2 includes a copy cutter 2a as an over cutter, and includes a widening cutter 8 instead of the widening cutter 4. Is different. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 6, the cutter 2 has a built-in copy cutter 2a which can be protruded and retracted from the outside in the widening direction. The copy cutter 2a has a rod shape, and is immersed in the cutter 2 when excavating only the standard pit. When excavating the widening pit, it protrudes from the cutter 2, rotates around the axis in the protruding direction, and loosens the ground at the portion where the widening pit is excavated by a cutter bit (not shown) provided on the outer peripheral surface thereof. I can do it.

As shown in FIG. 5, on both sides of the shield main body 3, widening cutters 8 for excavating widening pits are provided. The widening cutter 8 slides in the widening direction from the outer side of the shield body 3 to linearly protrude there, excavates the widening pit, and takes in the excavated earth and sand of the widening pit into the shield main body 3. 81, and a number of cutter shafts 82 protruding and retracting integrally with the outer shell portion 81.
The widening cutter 8 is configured to protrude in the widening direction independently of the widening member 5 provided on the rear side thereof for retaining the widening pit.

The outer shell portion 81 forms a part of the shield main body 3 and takes in the excavated earth and sand by the cutter shaft 82 and introduces it into the shield main body 3.
1a is formed. The outer shell portion 81 is housed in the shield body 3 when excavating only the standard pit. Further, the outer portion is always open, and when the widening cutter 8 is linearly protruded in the widening direction in order to excavate the widening pit, soil in the protruding direction is excavated at the tip end of the cutter shaft 82. And can be captured.

The cutter shaft 82 is rotatably supported in the vicinity of the opening 81a on the tip side in the excavation direction of the outer shell 81 so as to be rotatable around each axis. The cutter shafts 82 are provided so that their respective axes are substantially parallel to the widening direction, and are densely arranged so as to cover almost the entire area of the opening 81a. In other words, the pits are densely arranged so as to cover the cross section of the pit, and by rotating these cutter shafts 82, the pit can be dug. Each cutter shaft 8
A number of cutter bits 82a are provided on the outer peripheral surface of the cutter 2 and rotate to excavate earth and sand in the widening pit. These cutter shafts 82 are interconnected via a gear or a chain (not shown), and are controlled to rotate collectively by an actuator (not shown). An independent actuator may be connected to each of the cutter shafts 82 so that the rotation can be controlled independently.

A procedure for excavating a standard pit and a widening pit using the shield excavator 1B will be described. First, only the standard pit is dug using the cutter 2 with the widening cutter 8 stored in the shield body 3. At this time, the shield body 3
Behind the pit, a segment for lining the standard pit will be gradually laid, and a standard tunnel will be built.

When starting the excavation of the widening pit, as shown in FIG. 6, the copy cutter 2a is gradually protruded from the cutter 2, and while excavating the standard pit, the widening pits on both the left and right sides of the standard pit are excavated. Loosen the part where you want to. In this way, the widening cutter 8 can gradually protrude in the direction in which the ground is loosened. The cutter shaft 82 is rotated while gradually protruding the outer shell portion 81 to excavate the standard pit and the widening pit. Excavated earth and sand from the widening pit is taken into the shield main body 3 from the opening 81a through the outer shell part 81, and is conveyed to the rear along with the excavated earth and sand from the standard pit by a conveyance means such as a screw conveyor (not shown). It is excavated. In addition, the widening member 5 is also protruded so as to match the protrusion of the widening cutter 8, and earth retaining of the widening pit is performed.

When the widening cutter 8 is widened to the maximum position, the standard pit and the widening pit are excavated in this state. The widening pit dug by the widening cutter 8 is immediately retained by the widening member 5. At this time, a segment for a standard pit or a segment for a widening pit is sequentially lined behind the shield body 3 or the widening member 5 to construct a widening tunnel.

At the end of excavation of the widening pit, the copy cutter 2a may be immersed in the cutter 2, and the widening cutter 8 and the widening member 5 may be stored in the shield body 3.

In the shield excavator 1B according to the present embodiment, a plurality of cutter shafts 82 rotated around the axis are provided on the widened cutter 8, and these cutter shafts 82 are densely arranged so as to cover almost the entire area of the opening 81a. Therefore, if only the cutter shaft 82 is rotated, almost the entire area of the widening pit can be dug. Therefore, it is not necessary to make the cutter shaft 82 move complicatedly such as swinging, so that the configuration of the widening cutter 8 can be simplified, the excavation speed can be improved, and the construction period can be shortened. . In addition, since the actuators for driving the cutter shafts 82 can be intensively arranged at a specific location, the structure can be simplified as a reasonable structure. for that reason,
The reliability and durability of the shield excavator 1B can be improved, the manufacturing cost and the operating cost can be suppressed, and the construction cost can be reduced.

The widening cutter 8 is composed of an outer shell 81 and a cutter shaft 82. The outer shell 81 and the cutter shaft 82 are stored in the shield body 3 when only a standard pit is dug. When excavating in the widening pit, it protrudes linearly from the shield body 3 in the widening direction. In order to protrude the widening cutter 8 linearly, the widening cutter 8 is used.
The moving mechanism can have a simpler configuration, and the widening cutter 8 can be accurately moved in and out, and the reliability and durability of the widening cutter 8 can be improved. Also, since the outer portion of the outer shell 81 is always open, the shield excavator 1
Even when the excavation of B is stopped, the widening cutter 8 can be made to protrude in the widening direction while excavating and discharging the soil.
The influence on the surrounding ground can be reduced, and the influence of the hardness of the surrounding ground can be reduced.

A large number of cutter shafts 8 are used as the cutter unit.
Instead of 2, a cutter shaft 85 and cutter moving means 86 as shown in FIG. 7 may be provided. The cutter shaft 85 is rotatable about its axis.
6. On the outer peripheral surface of the cutter shaft 85,
A large number of cutter bits 85a are provided, and when they rotate, excavate earth and sand in the widening pit. The cutter moving unit 86 includes a vertical moving unit 85a that moves the cutter shaft 85 in the vertical direction, and a left-right moving unit 86b that moves the cutter shaft 85 in the left-right direction. The vertical moving unit 86a and the horizontal moving unit 86b are driven by an actuator such as a hydraulic motor (not shown),
5 is moved vertically and horizontally within the cross section of the outer shell 81. That is, the cutter 85 is moved vertically and horizontally within the cross section of the widening pit so that the cutter 85 can excavate.

With such a configuration, there is an advantage that the shield excavator 1B can be reduced in weight by the number of the cutter shafts and the number of members is small, so that maintenance such as repair can be easily performed. Further, since the configuration is simplified by reducing the number of members, the flow of excavated sediment from the widening cutter 8 to the shield body 3 is improved, so that the excavated sediment can be taken in more easily, and the efficiency of sediment transport is improved. There is also an advantage that can be increased.

In each of the above-described embodiments, the first embodiment has a cutter shaft 42 which is rotatable and expandable, and the second embodiment has a plurality of densely arranged cutters. Although the cutter shaft 82 or the cutter shaft 85 and the cutter moving means 86 have been described as being respectively used,
These can be used interchangeably. That is, the cutter shaft 82, the cutter shaft 85, and the cutter moving unit 86 can be applied to the shield excavator 1A, or the cutter shaft 42 can be applied to the shield excavator 1B.

[0048]

As described above, according to the shield excavator according to the present invention, it is possible to facilitate the excavation of the widening pit and to take in the excavated earth and sand, thereby shortening the construction period and the cost of the construction of the widening tunnel. And a shield excavator capable of performing the same.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment of a shield excavator according to the present invention, in which (a) is a partial cross-sectional view as viewed from a digging direction, and (b) is a partial cross-sectional view as viewed from above. .

FIG. 2 is a partial cross-sectional view of the shield excavator,
(A) is a partial sectional view as seen from the excavation direction, and (b) is a partial sectional view as seen from above.

FIG. 3 is a partial sectional view of the shield excavator,
(A) is a partial sectional view seen from above, and (b) is a partial sectional view seen from the side.

FIG. 4 is a partial sectional view of the shield excavator,
(A) is a partial sectional view seen from above, and (b) is a partial sectional view seen from the side.

FIG. 5 is a partial cross-sectional view showing a second embodiment of the shield excavator according to the present invention, as viewed from the direction of excavation.

6 is a partial sectional view of the shield excavator shown in FIG. 5 as viewed from above.

FIG. 7 is a partial cross-sectional view showing a modified example of the shield excavator shown in FIG. 5, as viewed from the excavation direction.

[Explanation of symbols]

 1A, 1B Shield excavator 2 cutter 2a copy cutter 3 shield body 4 widening cutter 41 outer shell 41a opening 42 cutter shaft (cutter) 5 widening member 5a slide roof (gap retaining member) 8 widening cutter 81 outer shell 81a Opening 82, 85 Cutter shaft (cutter) 86 Cutter moving means (cutter)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tohru Goto 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Osamu Urata 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Yasuhiko Shigeta 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation F-term (reference) 2D054 AA05 AC02 BA03 BA25 DA01 2D055 AA01 AA02 BA02 CA01

Claims (8)

[Claims] 1. A shield excavator having a cutter supported in front of a shield body and excavating a standard pit having a predetermined cross-sectional area, wherein the cutter is capable of protruding and retracting from an outer portion of the shield body in a widening direction for widening the standard pit. A shield excavator, comprising: a widening cutter that excavates a widening tunnel and takes excavated earth and sand from the widening tunnel into the shield body. 2. The widening cutter has an opening portion for taking in excavated earth and sand of the widening pit, and an outer shell portion rotatably supported by the shield body. A cutter section for excavating the front part, and these shell parts and cutter parts are stored in the shield main body when excavating only the standard pit, and when excavating the widening pit, The shield excavator according to claim 1, wherein the opening is turned in the excavation direction by being rotated so as to protrude from the shield main body in the widening direction. 3. A widening for rearwardly enlarging the widening pit, wherein at least a part of the shield body protrudes toward the widening pit when the widening pit is dug behind the widening cutter. The shield excavator according to claim 1 or 2, further comprising a member. 4. The widening member includes a gap retaining member that retains a gap formed between the widening member and the widening cutter when excavating the widening pit. The shield excavator according to claim 3. 5. The widening cutter comprises a cutter portion for excavating the widening pit, and an outer shell portion having an opening for accommodating the cutter portion and taking in excavated earth and sand of the widening pit. The part and the cutter part are housed in the shield main body when digging only the standard pit, and when digging the widening pit, linearly protrude from the shield main body in the widening direction. The shield excavator according to claim 1, wherein 6. The widening cutter includes a cutter shaft that is rotated about an axis, wherein the cutter shaft is rotatable within a cross section of the widening pit and radially expandable and contractable within the cross section. The shield excavator according to any one of claims 1 to 5, wherein the shield excavator is pivotally supported by the shield body. 7. The widening cutter includes a plurality of cutter shafts rotated around an axis, and the cutter shafts are densely arranged to cover a cross section of the widening pit. The shield excavator according to any one of the above. 8. The widening cutter includes a cutter shaft that is rotated around an axis, and a cutter moving unit that rotatably supports the cutter shaft and moves the cutter shaft vertically and horizontally within a cross section of the widening pit. The shield excavator according to any one of claims 1 to 5, characterized in that: