JPH0893381A - Variable cross section shield excavator - Google Patents

Abstract

(57) [Summary] [Purpose] To make it possible to gradually increase and decrease the excavation diameter while excavating with a shield excavator. [Structure] An overcutter 16 capable of projecting from the outer peripheral surface of a cutter head 11 by a predetermined diameter expansion amount widens the ground around the excavator, and at the same time, the bulkhead 20 inside the excavator 1
Then, the plurality of cross-section varying means 30 and 40 supported by the inner cylinder C1 whose front end is supported in a cantilever manner are actuated to partially remove a part of the plurality of outer shell plates 22A constituting the shell from inside the excavator 1. From the other side, and the gap between the outer shell plates 22A generated by the pushing and expanding operation and the gap formed at the peripheral portion of the bulkhead 20 are closed by the diameter expansion plate and the diameter expansion flange to increase the tunnel diameter. To do. In addition, the plurality of cross-section varying means 30 and 40 are operated to narrow the gap between the outer shell plates 22A to reduce the diameter of the tunnel and to excavate a tunnel having a continuously changing tunnel diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable cross-section shield excavator, and more particularly to a variable cross-section that allows tunnels having different cross-sectional areas to be continuously constructed by excavating the ground while gradually increasing or decreasing the diameter of the excavated cross-section. Shield excavator.

[0002]

2. Description of the Related Art In recent years, in urban areas, underground tunnels have been widely excavated from the viewpoint of effective utilization of land for drainage of sewage and for laying power supply lines, communication lines and the like. In the sewerage system, it is preferable to change the diameter of the sewer trunk line from the viewpoint of economic efficiency and drainage efficiency based on a drainage plan. Therefore, when changing the direction, gradient, and pipe diameter of the pipes to be laid, an intermediate shaft 500 is constructed at a predetermined location as shown in FIG. 33, and pipes 501, 502, The direction, tube diameter, etc. are changed.
By the way, in such a sewer trunk line, since the cross section of the pipe is circular, it is common to perform continuous tunnel excavation by an excavator such as a shield excavator. However, since the diameter of an ordinary shield excavator is determined in advance, if you want to change the tunnel diameter on the way, replace the shield excavator at the position of the intermediate shaft,
We are also using a shield excavator equipped with an overcutter that can perform widening excavation in a partial range.

FIG. 34 is a partial cross-sectional view showing an example of a shield excavator 510 equipped with a conventional overcutter (see Japanese Patent Laid-Open No. 4-31595). The figure shows a state in which the intermediate shaft 500 has already been reached and a part of the earth retaining wall 520 in the traveling direction of the shield excavator 510 has been removed. At this time, an overcutter 512 extends outward from a part of the outer peripheral edge of the cutter face 511 of the shield excavator 510, and behind it is a blade opening portion 513 having an outer size matching the excavation diameter of the widening tunnel and the propulsion. Jack 51
A widening excavator 515 composed of 4 is mounted along the outer periphery of the shield excavator 510. From this state, the cutter face 511 of the shield excavator 510 is rotated to excavate the ground at the outer peripheral position of the normal tunnel cross section to a predetermined width. Thus, it is possible to excavate a concentric widened tunnel from a tunnel having a normal excavation diameter with the intermediate shaft 500 sandwiched therebetween.

On the other hand, in underground caverns for power lines and common ditches, the occupancy cross section of the accommodations such as electric wires continuously changes according to the extension of the laying. I want to make detailed settings. In such a case, a box culvert by an excavation tunnel is generally used as a tunnel structure type adopted.

[0005]

By the way, in the shield excavator provided with the above-mentioned over cutter, an intermediate shaft must be constructed in order to mount the widening excavator on the outer periphery of the shield excavator. However, it is difficult to secure a construction site for constructing an intermediate shaft in urban areas, and a large amount of cost is required for excavating and constructing the shaft, which results in a large increase in construction cost as a whole.

Further, for excavation of the widening tunnel, a widening excavator for securing the widening diameter as described above must be separately manufactured and carried into the intermediate shaft. As described above, in the above-described shield excavator, it is necessary to arrange the excavation equipment in an overlapping manner, which leads to an increase in equipment cost.

On the other hand, the box culvert can set a plurality of design sections along the extension direction, but since it is an excavation work, there are many restrictions in the linear plan, and the passage of the road on the road surface lining is restricted. There is a problem that the construction cost is enormous as well as being limited. Therefore, an object of the present invention is to solve the problems of the above-described conventional technology and provide a variable cross-section shield excavator that can continuously increase or decrease the excavation cross section as the shield excavator advances. It is in.

[0008]

In order to achieve the above object, the invention according to claim 1 widens the ground around the excavator with an overcutter capable of projecting from the outer peripheral surface of the cutter head by a predetermined diameter expansion amount. In addition, a plurality of cross-section varying means supported by an inner cylinder having a front end fixed to a bulkhead inside the excavator is operated to partially remove a part of the plurality of outer shell plates constituting the shell portion from the excavator. The inner diameter of the tunnel is expanded by closing the gap between the outer shell plates generated by the pushing and expanding operation and the gap formed in the peripheral portion of the bulkhead while expanding the diameter of the tunnel. The section varying means is operated to reduce the diameter of the tunnel by narrowing the gap between the outer shell plates generated by the spreading operation, and to excavate the tunnel having a continuously changing tunnel diameter. It is an butterfly. That is, specifically, in order to actuate the plurality of cross-section varying means and to spread a part of the plurality of outer shell plates forming the shell from the inside of the excavator, it is divided into a plurality of parts in advance. A part of the outer shell plate was equipped with a plurality of cross-section varying means such as jacks, and it was operated while being supported by an inner cylinder installed inside the excavator, and occurred when the outer shell plate was expanded. The gap is closed by a diameter-expanding plate integrally formed with the outer shell plate and a backing plate provided so as to contact an inner surface position of the outer shell plate,
While enlarging the gap formed at the peripheral edge of the bulkhead with the diameter expansion flange formed on the inner peripheral surface of the outer shell plate or the backing plate and the bulkhead, the tunnel diameter is expanded and predetermined excavation is performed. In the step, the diameter-expanded tunnel can be reduced to a predetermined tunnel diameter.

According to a second aspect of the present invention, there is provided a cutter head provided with an overcutter capable of projecting from the outer peripheral surface by a predetermined diameter expansion amount, and a plurality of outer shell plates divided in the tunnel longitudinal direction. A diametrical expansion plate that is a part of the outer shell is formed on one of the longitudinal edges of the shell plate, and a slit capable of accommodating the diametrical expansion plate is formed on the other edge of the outer shell plate. A shell portion in which a diameter-expanding flange is formed on an inner peripheral surface of the shell, and a peripheral edge portion is provided in the shell-shell portion so as to be slidable while maintaining water-tightness with the diameter-expanding flange,
A bulkhead for closing the front surface of the shell in a watertight manner and a front end thereof fixed to the bulkhead, extending substantially in the shape of a concentric circle with the shell portion, and extending in the shell portion, and at a rear position. An inner cylinder having a gripper that holds the concentric position with respect to the shell, a first cross-section varying means having one end connected to a part of the outer shell plate and the other end supported by the inner cylinder; and at least the inner shell. A second cross-section varying means capable of pressing the outer shell plate from the inside with one end supported by the cylinder and the other end of the outer shell plate from the reduced diameter state accommodated in the slit; The ground is widened by a cutter, and the first cross-section varying means and the second cross-section varying means are actuated to push the outer shell plate outward to expose it from the outer shell plate and the slit. With the expanded plate The outer diameter of the excavator is expanded, and the diameter of the tunnel is expanded by closing the front surface of the outer cylinder with the bulkhead and the diameter expansion flange that is in sliding contact with the peripheral portion of the bulkhead. On the other hand, the first cross-section varying means and the second cross-section varying means are actuated in a predetermined excavation stage so that the enlarged diameter of the tunnel can be reduced to a predetermined diameter of the tunnel. It is a feature.

According to a third aspect of the invention, a cutter head provided with an overcutter capable of projecting from the outer peripheral surface by a predetermined diameter expansion amount, a plurality of outer shell plates divided along the tunnel longitudinal direction, and an outer shell adjacent to the outer shell plate. A shell plate portion, which is composed of a backing plate arranged in contact with the inner peripheral surfaces of adjacent edge positions of the shell plate, and a peripheral portion of which is formed with an enlarged flange on the inner peripheral surface of the front end of the backing plate. A bulkhead that is provided in the shell portion so as to be slidably contactable with the enlarged diameter flange while maintaining watertightness, and a front end of the bulkhead that closes the front surface of the shellet portion while maintaining watertightness. An inner cylinder extending substantially concentrically with the shell and extending into the shell,
From the cross-section varying means having one end supported by the inner cylinder and the other end capable of pressing the backing plate, and the cross-section varying means having one end supported by the inner cylinder and the other end capable of pressing the outer shell plate. A first cross-section varying means, and a second cross-section varying means, one end of which is supported by a support body connectable to the rear end of the inner cylinder, and the other end of which can press the outer shell plate from the inside. From the reduced diameter state in which the backing plate is in contact with the inner peripheral surface at the edge position of the outer shell plate adjacent to each other, the ground is widened by the over cutter, and the first cross-section varying means and the second cross-section varying means. The cross-section varying means is actuated to bring the backing plate and the outer shell plate into close contact with each other and push them outward to expand the outer backing plate and the backing plate exposed between the outer shell plates adjacent to each other. When configuring the outer shell of a diameter excavator At the same time, while the bulkhead and the diameter-expanding flange that slidably contacts the peripheral portion of the bulkhead close the front surface of the outer case to increase the diameter of the tunnel, the diameter of the tunnel is increased at a predetermined excavation stage. It is characterized in that the first section varying means and the second section varying means are actuated so that the enlarged tunnel diameter can be reduced to a predetermined tunnel diameter.

As a preferred aspect of the invention, in the invention of claim 2, the first cross-section varying means is disposed and supported by at least a flange formed on an inner peripheral surface of the shell. It is preferably composed of a circumferential jack and a radial jack supported by the inner cylinder and expanding the outer shell plate.

In the invention of claim 2, the second cross-section varying means is a radial jack arranged and supported on a pedestal slidable in the tunnel axis direction along the outer peripheral surface of the inner cylinder. Is preferred.

In a third aspect of the present invention, the first cross-section varying means has a radial jack whose one end is supported by the inner cylinder and the other end is connected to the backing plate, and one end of which is connected to the inner cylinder. Preferably, it comprises a radial jack supported and the other end connected to said shell plate.

In a third aspect of the present invention, the second cross-section varying means is disposed and supported on a ring-shaped carriage that can run in the tunnel axis direction along a pipe rail that can be connected to the rear end of the inner cylinder. It is preferably a radial jack.

In the invention of claim 2, the shell portion is
It is preferable that a tail seal is provided at a rear open end of each of the divided outer shell plates, and another tail seal that overlaps with the tail seal when the diameter is expanded is provided at a predetermined position of the diameter expansion plate.

In the invention of claim 3, the shell portion is
A tail seal is preferably provided at each of the rear open ends of the divided outer shell plate and the backing plate.

In the second aspect of the present invention, it is preferable that the inner cylinder has a double cylindrical structure having a nesting structure that slides and expands and contracts at the overlapping portion.

In any one of the first to third aspects of the invention, the shell portion and the inner cylinder are separated into a front body portion and a rear body portion by a center folding mechanism provided at a predetermined intermediate position, It is preferable to be able to bend and advance at a predetermined angle at the separation position.

It is preferable that a muddy water chamber is provided at a separation position where the front body portion and the rear body portion are separated by the center folding mechanism.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a variable cross-section shield excavator according to the first invention (hereinafter, simply referred to as a shield excavator).
Embodiments will be described with reference to the accompanying drawings. Figure 1
[Fig. 3] is a perspective view schematically showing the cross-section of each part in order to show the internal structure of the shield excavator of the present invention. As shown in FIG. 1, the shield excavator of the present invention is roughly equipped with a cutter head having an overcutter, a bulkhead supporting the cutter head, and a hull having a diameter-expanding plate which becomes a part of the hull at the time of diameter expansion. An inner cylinder having a gripper at a rear end installed at an inner peripheral position of the shell, a plurality of diameter-increasing jacks as first cross-section varying means for realizing diameter reduction and diameter expansion of the shell supported by the inner cylinder, It is composed of a plurality of tail diameter-increasing jacks as second cross-section varying means for diameter-increasing the rear end of the shell.

According to the embodiment of the present invention, the forward excavation by the overcutter is performed, and subsequently, the diameter of the shell can be uniformly expanded by the first cross-section varying means. The inner cylinder supporting the first cross-section varying means can evenly bear the reaction force, and the inner cylinder is held at a predetermined position to smoothly expand and reduce the diameter of the first cross-section varying means. Further, it is possible to realize even expansion and contraction of the rear open end of the shell by the second cross-section varying means, and further slide the second cross-section varying means along the inner cylinder. This makes it possible to improve the efficiency of segment assembly.

As shown in FIG. 3, the cutter head 10 is provided with four spokes 12 so as to partition the face plate 11 into a substantially cross shape. In the present embodiment, this cutter head 10 portion is rotatably supported by a center shaft 61 that penetrates the rear bulkhead 20. A plurality of cutter bits 13 are arranged on both sides of each spoke 12 at predetermined intervals. The cutter bit 13 is made of a cutting tip made of cemented carbide, and is firmly fixed to the spoke 12 by a known fixing method such as a shank.

Further, slits 14 having a predetermined width are formed along both sides of the spokes 12 in order to take in the earth and sand of the face scraped by the cutter bit 13 into the cutter chamber 21. Further, a center cutter 15 such as an arrow tip is formed at the center position of the cutter face. The center cutter 15 can support the tip portion of the shield excavator 1 on the natural side of the face when the shield excavator 1 performs the diameter expanding operation and the diameter reducing operation.
The center cutter 15 has a known structure and shape.

Further, inside the cutter head 10, 4
A table overcutter 16 is housed. In the present embodiment, each of the over cutters 16 has a substantially box shape that is housed in the cutter head 10 portion when not operating,
Each is supported by two hydraulic jacks 18. By extending the rod of the hydraulic cylinder jack 18, the overcutter 16 can be made to project from the outer peripheral surface of the cutter head 10 in the radial direction of the shield excavator 1 by a predetermined amount (see FIG. 3B and FIG. 4). ). At this time, a predetermined number of cutter bits 17 are arranged on the outer peripheral surface and the front surface of the overcutter 16. As a result, it is possible to excavate a concentric portion of a predetermined width with respect to the natural ground by the cutter bit 17 with the over cutter 16 protruding. FIG. 3A is a diagram showing a normal tunnel diameter excavation state in which the overcutter 16 is not projected. FIG. 3B is a diagram showing a state in which the rod 18 a of the hydraulic jack 18 of the overcutter 16 is extended to excavate the enlarged diameter section. In the present embodiment, the amount of one rod extension of the hydraulic jack 18 is set to 50 mm. This extension amount can be set as appropriate in consideration of the structure of the tail seal and the like.

The shell 22 is, as shown in FIG.
It is divided into a plurality of strip-shaped outer shell plates 22A that are equally divided in the tunnel axis direction. Hereinafter, in the present specification, a steel cylinder that is called a skin plate or the like that forms the outer shell of the excavator is referred to as a shell 22. Further, each outer shell plate 22
A diameter-expanding plate 23 is integrally formed on one of the end portions of A in the longitudinal direction of the tunnel. In addition, a slit 24 capable of accommodating the expanded diameter plate 23 is formed at the other edge portion. When the diameter is reduced, the diameter expansion plate 23 is accommodated in this slit. On the other hand, a gap generated between the outer shell plates 22A adjacent to each other when the shield excavator 1 is expanded in diameter can be closed by the expanded diameter plate 23 (see FIG. 5B, details of the expanding operation will be described later). ).

The bulkhead 20 is, as shown in FIGS. 1 and 2, a shell 22 which constitutes an outer shell of the shield excavator 1.
Is provided at a rear position of the cutter head 10 near the front end of the. And, it functions as a partition wall of the cutter chamber 21 that stores the drilling mud. In addition, the bulkhead 20
Supports the center shaft 61 rotatably at the central position, as shown in FIGS.

As shown in FIG. 6, in order for the bulkhead 20 to function as a partition wall with the cutter chamber 21, a T-shaped expansion is provided on the inner peripheral surfaces of the outer shell plate 22A and the diameter expansion plate 23. The radial flanges 25 and 26 are integrally formed.

When the diameter expansion flanges 25 and 26 are contracted (normal tunnel diameter), as shown in FIG. 6, the bulkhead 20 of the bulkhead 20 is sandwiched between the two flanges 25. It is housed in a recess 28 formed in the outer peripheral portion. Then, when the diameter is expanded, the flange 26 is slid and pulled out from the recess 28, the flange 26 is exposed from the overlapping portion in the flange 25, and forms a part of the bulkhead 20. At this time, in order to maintain the watertightness as a partition wall,
A plurality of sealing materials 27 are provided on the sliding surfaces of the recess 24, the outer shell plate 22 </ b> A, and the expanded diameter plate 23. Since the sealing material 27 is used for the sliding portion, it is preferable that the sealing material 27 is made of a material having high wear resistance.

Next, various shield equipments arranged at the rear position of the bulkhead 20 will be briefly described. The inner cylinders C1 and C2 are housed inside the shell 22 of the shield excavator as shown in FIGS. 1 and 2. The inner cylinders C1 and C2 are steel cylindrical bodies having a predetermined diameter. The inner cylinder C1 has a tip fixed to the bulkhead 20, and a rear end further extending from the rear end of the shield excavator and extending to the segment assembly position. An inner cylinder C2 is slidably fitted onto the rear end position of the inner cylinder C1 as a double cylindrical structure having a nested structure. The overlapping amount of both is set to be equal to or larger than one segment ring. A slide jack 80 is provided at the boundary of the overlapping portion between the inner cylinder C1 and the inner cylinder C2. The tip 80a of the slide jack 80 is fixed to the rear end position of the inner cylinder C1, and the jack body and the rear end 80b are fixed to the inner cylinder C2 side.

The shield equipment in the inner cylinder C1 will be described. The rear end of the center shaft 61 projects at the tip position inside the inner cylinder C1. This center shaft 61
The rotary driving force from a plurality of cutter turning motors 63 is transmitted to the motor through a driving force transmitting portion 62 including a predetermined gear train. Cutter turning motor 63
Is a fixing means (not shown) at a predetermined position on the inner circumference of the inner cylinder C1.
It is fixedly held by.

Further, the excavation mechanism of the shield excavator 1 in the present embodiment is a mud pressure type. For this reason, the mud pipe 64 and the cutter chamber 2 for supplying muddy water to the face
A mud discharge pipe 65 for collecting the drilling mud in 1 is incorporated in the inner cylinder C1. The pipe rear ends 64a and 65a of the mud sending pipe 64 and the mud discharging pipe 65 are extended to a muddy water treatment unit (not shown) behind the shield excavator. Further, a segment carrying-in opening 66 is formed in a part of the inner cylinder C1 corresponding to the tail portion of the shield excavator 1. This opening 6
A segment loading device 67 is provided for loading the segments 70 up to 6. The segment carry-in device 67 includes a carry-in rail 68 and a transport hoist 69 that holds the segment 70 and travels on the carry-in rail 68. With this transport hoist 69, the opening 66 of the inner cylinder C1
The segments 70 that have been carried in are reloaded into the erector device 71, and are sequentially assembled as a tubular tunnel lining 72. The equipment such as the perfect circle holding device may have a known structure.

On the other hand, the inner peripheral surface of the shell 22 is provided with a shield jack 73 for propelling the shield excavator 1 along the circumferential direction. This shield jack 73
The front end 73a is fixed to the inner peripheral surface of the shell 22,
A pressing plate 75 is attached to the tip of the rod 74, and the rod 74 can be extended to press the end surface of the assembled segment 70 with the pressing plate 75 at the tip to propel the entire shield excavator in the cutting face direction.

Next, the structure of each cross-section varying means and the diameter expansion and contraction operations will be described with reference to the drawings. The first and second expanded diameter jacks 30 as the first cross-section varying means are both composed of a group of jacks that perform the same operation. As shown in FIG. 2, each of the diameter expansion jacks 30 expands (reduces) the outer shell plate 22A of the shield excavator 1 which is long in the tunnel axis direction by an even amount of expansion (reduction). ,
The inner cylinder C1 is supported at predetermined intervals in the tunnel axis direction. Hereinafter, the first cross-section varying means will be described by taking the second expanded diameter jack 30 arranged along the VII-VII cross-section line as an example.

The second expanded diameter jack 30 is shown in FIGS.
As shown in (a), the eight radial jacks 32 arranged radially and the eight circumferential directions attached to the mounting flanges 33 formed at the inner circumferential position of each outer shell plate 22A. It is composed of a jack 34. Of these, the radial jacks 32 are equiangularly spaced and the lower end is the inner cylinder C1.
While being fixed to the outer peripheral surface of the rod, the tip of the rod is pin-joined to the mounting flange 33 at a substantially central position. On the other hand, the circumferential jack 34 has its both ends pin-joined to the mounting flanges 33 of the outer shell plate 22A adjacent to each other, and the rod can be extended in synchronization with the rod extension of the radial jack. As a result, both diameter expansion jacks 3
As shown in FIG. 7B, by the operations of 2 and 34,
The diameter expanding operation of the shell 22 portion can be smoothly performed. At this time, the rod extension amount of the radial jack 32 and the rod extension amount of the circumferential jack 34 are controlled by a jack control unit (not shown), and the operation amount according to the set diameter expansion amount and diameter reduction amount. Is given.

Next, regarding the tail diameter-increasing jack 40 as the second cross-section varying means, as shown in FIGS.
This will be described with reference to (c). Tail diameter jack 40
In the present embodiment, is composed of a radial jack 42 disposed on a slide base 41 slidably fitted on the inner cylinder C1. A pressing plate 43 that can press the outer shell plate 22A from the inside is fixed to the rod tip of the radial jack 42. The slide base 41 is
A slider (not shown) slidable along a slide groove 44 formed at a predetermined position of the inner cylinder C1 is provided. Therefore, it is possible to slide at a predetermined timing between the pressing position of the outer shell plate 22A and the inner position of the ring-shaped assembled segment 70. When expanding,
In the tail portion of the shell 22, the outer shell plate 22A can be uniformly expanded in diameter, and when the segment 70 is assembled, the slide pedestal 41 can be retracted to secure an assembly space for the segment 70.

The tip of the rod of the tail diameter expanding jack 40 is not fixed to the inner peripheral surface of the outer shell plate 22A. For this reason, unlike the first and second expanded diameter jacks 30, the expanded state of the shell 22 cannot be maintained by maintaining the rod extended state. Therefore, at the position of the tail diameter expansion jack 40, as shown in FIG.
The spacer 45 is sandwiched between the outer shell plate 22A and the outer shell plate 22A.
The expanded state of is maintained. In FIG. 2B, the frame-shaped spacers 45 are mounted, but it goes without saying that various shapes can be applied as long as they are members that can be padded with the predetermined size. Thus, the rod of the radial jack 42 can be retracted as shown in FIG. 9 while maintaining the expanded state. Then, at the time of segment assembly, the slide base 41 may be retracted to the segment assembly completion position behind the face with the rod retracted.

By the operations of the first and second cross-section varying means described above, the outer shell plates 22A are spread one by one so that they are surely spaced apart from each other, and as a result, the diameter of the tunnel can be increased. . At this time, the acting reaction force of each circumferential jack is supported by the inner cylinder C1, but the center position of the inner cylinder C1 and the tunnel central axis position should be aligned so that the extension amounts of the circumferential jack are equal. It is also important. Therefore,
In the first invention, the segment gripper 46 is provided at the rear end position of the inner cylinder C2. The segment gripper 46 is a hydraulic jack that can press the inner surface of the segment with the tip of the rod when the rod extends. Further, as shown in FIGS. 1 and 2, it has a flat cylindrical shape having a large pressing portion area with respect to the rod stroke. In the present embodiment, three segment grippers 46 are fixed to the inner cylinder C2 at equal angular intervals in the circumferential direction of the inner cylinder C2. Therefore, the inner cylinder C2 can hold the concentric position with respect to the segment by uniformly extending the segment gripper 46 to the segment side. Then, the rods of the first and second diameter-expanding jacks 30 and the tail diameter-expanding jack 40 are extended (the shell 22
When the shield jack 73 is propelled in the expanded state of
By freeing the rod of the slide jack 80, only the inner cylinder C1 advances together with the shell 22 of the shield excavator 1. At this time, the axis of the inner cylinder C2 coincides with the tunnel axis. Therefore, the inner cylinder C1, that is, the shield excavator 1 can be propelled while the shield machine center is aligned with the tunnel axis. When the propulsion of the shield excavator 1 per ring is completed, the rod of the segment gripper 46 is retracted to retract the rod 81 of the slide jack 80 to prepare for the next propulsion. It should be noted that the center cutter 15 provided almost at the center of the cutter face
This ensures the stability of the front end of the shield excavator.

Next, the structure of the tail seal 50 attached to the rear end portion of the outer shell plate 22A when expanding the diameter will be described with reference to FIG. In a typical tail seal of a shield excavator, a wire brush type tail seal of the type shown in FIG. 4A is often attached over the entire circumference of the rear end of the shell. In this wire brush type tail seal, a brush formed by bundling a large number of wires is sandwiched by a protective plate and attached to the rear end of the shell in a circumferential shape. In addition, the tail seals may be arranged in a plurality of stages in order to realize a reliable waterproofing at the tail portion.
By the way, in the case where the outer peripheral length of the shell 22 is increased due to the diameter expanding operation as in the present invention, the fixed type tail seal cannot handle it. Therefore, in the present invention, an annular air seal 51, which is located between the outer circumference of the segment 70 and the inner circumference of the shell 22, which has a step due to the diameter expansion operation, and which has a ring-like overall shape and surrounds the segment is attached. ing. The air seal 51 expands by supplying air from the air supply hose 52 connected as shown in FIG. 10, and closes the inner peripheral surface of the shell 22 and the assembled segment 70, It can function as a seal member that can resist groundwater pressure and backfill injection pressure.

Furthermore, a wire brush type tail seal 53 equivalent to the conventional shape is attached to the inner peripheral surface of each outer shell plate 22A. Then, in order to deal with the case of expanding the diameter, a cutout 24 is formed in a part of the shell 22 as shown in FIG.
The enlarged diameter plate 23 exposed from the cutout portion 24 is provided with the enlarged diameter tail seal 55. Thus, the expanded tail seal 55 can cover the portion where the tail seal 53 is separated and a gap is generated during expansion. In addition, it goes without saying that a plurality of tail seals 50 may be provided on the inner surface of the shell 22 or a grease supply device of a known technique may be additionally provided in order to enhance the waterproofness.

Incidentally, with the diameter expansion operation of the shield excavator,
Although it is necessary to change the dimensions of the segment 70 to be assembled, in this embodiment, a special segment that can absorb the difference in tunnel diameter after assembly is used. The special segment is made of steel, and the bolt hole position and the like are set so that the joint flanges 74 of the adjacent segments in the tunnel longitudinal direction can be reliably joined by the tightening bolt 75. Further, in order to close the gap between the ground and the natural ground caused by the diameter expansion, in the present embodiment, the segment with the injection bag having the injection bag 73 on the back surface of the segment is used. This makes it possible to reduce the influence of backfill injection on the rear surface of the segment on the tail seal.

With respect to the diameter expansion operation associated with the excavation and the diameter reduction operation associated with the excavation of the shield excavator 1 having the above-described configuration, the flowcharts of FIGS. 11 to 14, FIG. 15 and FIG.
The operation state diagram will be described with reference to FIG. First, the diameter expansion start section is entered with the tip of the shield excavator 1 at the position where the segment 70 is assembled in the normal diameter tunnel as the diameter expansion start point. First, the over cutter 16 housed in the cutter head 10 is expanded from the initial state shown in FIG.
= 50 mm is projected, and the shield head is excavated by the cutter head 10 and the over cutter 16 to advance by the length of one shield excavator. ((Steps 100, 110), FIG.
(B)). The tunnel diameter is 2 x d due to this excavation work.
Increase by.

Next, the overcutter 16 is projected again by the amount of diameter expansion d = 50 mm, and the diameter of the shell 22 is expanded (steps 120 and 130). This shell 2
The diameter-expanding operation of 2 is performed by the first and second first cross-section varying means described above.
This is realized by the rod expanding operation of the second diameter-increasing jack 30 and the tail diameter-increasing jack 40 that is the second cross-section varying means.
The expanded diameter of the shell 22 at this time is d1 = 25 mm,
After assembling the special segment, one ring is further excavated, and at this stage, the diameter of the shell 22 is expanded for the second time ((steps 120 to 140), see FIG. 15C). In this way, by performing the diameter expanding operation of the shell 22 portion in two steps, it is possible to reduce the load on the tail seal portion at the rear end of the shell 22. Then, the tunnel diameter (D
While assembling the ordinary segment of 0 + 2d), the excavation for one length of the shield excavator is performed (steps 150 and 160).
After that, the excavation / diameter expansion operation of steps 120 to 170 is performed, and the excavation / diameter expansion operation is repeatedly performed until a predetermined diameter expansion dimension is achieved. FIG. 15D shows that the over-cutter 16 is extended to perform double (2 × 2d) diameter expansion.
FIG. 7 is a work state diagram showing a state in which the diameter expanding operation is completed.

In such a digging and expanding operation, the digging distance L required to expand the tunnel diameter (DE) to a predetermined diameter can be obtained as follows. When the shield excavator length S = 5000 mm and the amount of diameter expansion ΔD = (DE−D0) = 1000 mm, the number of diameter expansion operations N = ΔD / (2d) = 1000 / (2 ×
50) = 10 excavation distance L = S × N = 5000 × 10/1000
= 50m

Now, with reference to FIG. 13, a rod expanding operation of the diameter expanding jacks 30 and 40 in the diameter expanding operation of the shell 22 will be described. First, the shield excavator is advanced by one machine length with the overcutter 16 protruding.
The ground excavation at the portion of the overcutter 16 forms a clearance having a width d between the shell 22 of the shield excavator 1 and the surrounding ground (see FIG. 15B). Next, the rod of the shield jack that has advanced the shield excavator 1 is retracted (step 121), and at the same time, the slide pedestal 41 is advanced to move the tail expansion jack 40 located in the retracted position to the rear end position of the shell 22. It is moved (step 122). In this state, the rods of the radial jack 32, the circumferential jack 34 and the tail diameter jack 40 of the first and second diameter-expanding jacks 30 are simultaneously extended (step 123). The timing of rod extension and the amount of extension of each jack can be controlled by a jack control device (not shown). In this embodiment, the extension amount of each rod once is set to 25 mm.
Therefore, the expansion amount (diameter increment) of the tunnel diameter (shell 22) is 50 mm.

Further, as the diameter of the shell 22 increases, the air seal (see FIG. 10) follows the diameter expanding operation in order to maintain the watertightness of the tail seal 50 portion which is the open end of the cylindrical shell 22. Inflate and deploy as if to do (step 124). This makes it possible to deal with groundwater pressure and backfill pressure when the diameter is expanded. Further, the spacer 45 is attached to the portion of the diameter expansion plate 23 exposed between the outer shell plates 22A to maintain the diameter expansion state of the rear end of the shell 22 (step 125). Further, from this state, the rod of the tail diameter expansion jack 40 is retracted, and the slide base 41 is retracted to the rear position of the tunnel along the inner cylinder C1 so as to avoid interference with the segment assembly position (step 126). In the expanding operation of the shell 22, the inner cylinder C1 is held by the segment gripper so that the center position of the cross section of the inner cylinder C1 coincides with the center of the tunnel cross section because each radial jack takes a reaction force. Further, the backing of the shell 22 due to the cutting face pressure can be handled by the inner cylinder C1 and the segment gripper 46.

Next, the operation of digging while reducing the diameter from the enlarged tunnel diameter (DE) to the normal tunnel diameter (D0) will be described with reference to FIGS. 12 and 16. First, at the diameter reduction start point, the rod of the extension jack of the overcutter 16 extended by a predetermined diameter expansion amount is retracted so that the cutter diameter reduction amount is d = 25 mm, and at the same time, the shell 22
Is reduced by d2 = 25 mm (steps 200 and 21)
0). In this state, the shield excavator is excavated by one ring, and a special segment matching the reduced diameter dimension is assembled according to the excavation (step 230). The diameter reduction operation can be completed by excavating while repeating the diameter reduction operation of steps 200 to 230.

In such a digging / reducing operation, the digging distance L required to reduce the diameter to the enlarged tunnel diameter (D0) can be obtained as follows. When the shield segment width B = 1 m and the amount of diameter reduction ΔD = (DE−D0) = 1000 mm, the number of diameter reduction operations N = ΔD / (2d) = 1000 / (2 ×
25) = 20 excavation distance L = B × N = 1 × 20 = 20 m

Here, with reference to FIGS. 14 and 16 (see FIG. 2 for the reference numerals of the structural parts), the retracting operation of the diameter-expanding jacks 30 and 40 in the diameter-reducing operation of the shell 22 will be described.
First, the rod of the shield jack (not shown) in the state in which the shield excavator 1 has advanced by one ring is pulled in (step 211, see FIG. 16A). The diameter reducing operation is started from this state. The tail expansion jack 40, which was retracted at the time of segment assembly, was attached to the slide pedestal 41 and the inner cylinder C1.
By moving it along the slide rail of No. 2, it is set at a predetermined position at the rear end of the shell 22 (step 212).

Next, the rod of the tail diameter-expanding jack 40 is extended to press the outer shell plate 22A from the inner side to such an extent that the spacer 45 mounted at the exposed position of the diameter expansion plate 23 between the outer shell plates 22A is loosened. The spacer 45 is removed and replaced with a spacer 45 having a narrower width (steps 213 and 214). After that, the rods of the first and second diameter-expanding jacks and the tail-expanding jack 40 are simultaneously retracted, and the air seal 51 is evacuated and contracted so that the diameter-increasing plates 23 between the outer shell plates 22A are adjacent to each other. The entire shell 22 is reduced in diameter so as to be housed in the recess of the plate 22A (steps 215, 2).
16). When the diameter reducing operation is completed, the slide base 41 supporting the tail diameter increasing jack 40 is retracted to the rear of the tunnel (step 217).

Next, the configuration of the shield excavator according to the second embodiment of the present invention will be described with reference to FIGS. 17 to 27. FIG. 17 is a schematic perspective view showing the internal structure by cutting out a part of the shell of the shield excavator of the second invention. In this figure, the schematic configuration of the shield excavator will be described. Then, the operating state and the positional relationship of the respective parts at the time of diameter reduction of the shell of the shield excavator (normal tunnel diameter) and at the time of diameter expansion will be described with reference to the cross-sectional views of FIGS. 18 to 21. In the embodiment of the present invention, the center folding mechanism is provided at an intermediate position of the shell of the shield excavator. According to this center folding mechanism, the shell of the shield excavator can be bent at this intermediate position.
The center folding mechanism will also be described.

As shown in FIG. 17, the shield excavator of the present invention is roughly equipped with a cutter head having an overcutter, a bulkhead supporting the cutter head, a double-structured shell, and an inner circumferential position of the shell. Inner cylinder installed, a plurality of diameter-expanding jacks as first cross-section changing means for realizing diameter reduction and diameter expansion of the shell supported by the inner cylinder, second cross-section variable for expanding the rear end of the shell It is composed of a plurality of tail expansion jacks as a means.

The cutter head 110 is located at the tip of the shield excavator 1. This cutter head 110 has
Six spokes 112 extending radially from the position of the center cutter 115 are provided. Note that FIG. 17 shows a state in which one spoke is removed for the sake of explanation. A plurality of cutter bits 113 are arranged on both sides of the front surface of each spoke 112 at predetermined intervals. The cutter bit 113 is a cutting tip made of cemented carbide, and is firmly fixed to a predetermined position of the spoke 112 by a known fixing method.

At the tip of each spoke 112, there is provided a rod which can be expanded and contracted in the radial direction by the extension of the built-in hydraulic cylinder jack. At the end of this rod,
The overcutter 116 is fixed. The overcutter 116 has a substantially rectangular parallelepiped shape and is normally housed in the recess of the cutter head 110. When the diameter is increased, the rod of the built-in hydraulic cylinder jack can be extended so that the shield excavator 1 can be projected from the outer peripheral surface of the cutter head 110 in the radial direction by a predetermined amount (see FIG. 19). The function of the overcutter 116 is the same as that of the first invention, and by rotating the cutter head 110 with the overcutter 116 protruding, the ground around the excavator can be excavated in concentric circles with a predetermined width.

As shown in FIG. 17, the cutter head 1
The reference numeral 10 is rotatably supported by the center shaft 161. The rotational force of a cutter turning motor 163 attached to the bulkhead 120, which will be described later, is applied to the center shaft 161 via a reduction gear train (not shown).
And the cutter head 110 is rotated. It goes without saying that a drive mechanism for rotating the cutter head 110 may be provided by a known intermediate support method.

The bulkhead 120 is the cutterhead 1.
Located on the back of 10. A cutter chamber 121 is formed in a space defined by the cutter head 110 and the bulkhead 120. That is, the bulkhead 1
20 is a partition that partitions the cutter chamber 121 and the propulsion mechanism portion of the shield excavator 1. The earth and sand of the cutting face taken into the cutter chamber 121 is carried out to the rear of the shield excavator 1 by the mud discharge pipe 165 along with the circulation of the muddy water from the mud pipe 164 connected to the upper part of the bulkhead 120. Has become. Bulkhead 12
As shown in FIGS. 25 (a) and 25 (b), the peripheral edge portion of 0 slides between the diameter-enlarging flanges 125a and 125b that are fixed to the inner surface of the tip of the shell, which will be described later, at a predetermined distance. It is designed to be inserted as much as possible. Further, the seal packing 128 is mounted between the diameter-expanding flange 125 and the bulkhead 120 to maintain watertightness. This allows
The muddy water circulating in the cutter chamber 121 does not leak out of the cutter chamber 121. Expanded flange 1
The overlapping portion of 25 and the peripheral portion of the bulkhead 120 is set to a size such that an overlapping portion can be formed between the two even when the maximum diameter is increased. In addition, it is preferable that grease or the like is press-fitted as a filling material into a space position between the diameter-enlarging flanges 125a and 125b generated during the diameter-enlarging so as to resist the working earth pressure.

In the embodiment of the present invention, the shell 122 is divided into a plurality of arcuate plates having a double structure on the inner and outer circumferences, as shown in FIGS. 17, 20 and 21. These arc-shaped plates are composed of an outer shell plate 123 arranged at an outer peripheral position and a backing plate 124 arranged at an inner peripheral position of a side portion where the outer shell plates 123 are circumferentially adjacent to each other. There is. Of these, the outer shell plate 123 is composed of twelve plates obtained by dividing the outer shell 122 into 12 in the circumferential direction in the present embodiment. The backing plate 124 is located inside the adjacent side portion of the outer shell plate 123, and is always held in contact with the inner surface of the outer shell plate 123. Therefore, even when all the outer shell plates 123 slide radially outwardly when the diameter is expanded, and even when a gap is created between adjacent outer shell plates 123, one of the surfaces of the backing plate 124 is The part is exposed on the outer peripheral surface of the shell 122 and constitutes a part of the outer shell integrally with the outer shell plate 123. The width of the backing plate 124 in the circumferential direction is narrower than the width of the outer shell plate 123, and as shown in FIGS. 20 (b) and 21 (b),
The width is set to be wider than the gap width generated in the shell 122 when the diameter is expanded. Further, the outer shell plate 123 and the backing plate 124 are divided into a front body portion A and a rear body portion B at the position of the center folding mechanism 200 in the longitudinal direction of the body shell 122. (Hereinafter, outer shell plate 123, backing plate 12
4. In the inner cylinder 100, in order to distinguish between the front torso part A and the back torso part B, for example, the reference numeral 123A or the like is used. 18) As shown in FIGS. 18 and 19, the rear end of the rear trunk portion B extends to the segment 170 assembly completion position behind the installation position of the erector 171. At the rear end of this rear body part B,
As in the first invention, a known tail seal 150 is attached. The tail seals 150 are independently attached to the rear end of the outer shell plate 123 and the rear end of the backing plate 124. Therefore, even when the end surface of the outer shell plate 123 separates when the diameter is expanded, the tail portion can be closed by the tail seal 150 attached to the backing plate 124.

One end of the inner cylinder 100 is the bulkhead 1
It is made of a steel cylinder that is concentrically attached to the shell 122 on the rear face side of the facet 20. A segment elector 171 is installed at the rear end position so that the radial roller of the segment elector 171 can travel using the inner peripheral surface of the inner cylinder 100 as a guide. A middle folding mechanism 200 is provided at this intermediate position, and the middle folding mechanism 200 divides the front body portion 100A and the rear body portion 100B.
The front end portion of the front body portion 100A is fixed to the back face of the face of the bulkhead 120, and the rear end portion is fixed to the front partition wall 101 of the muddy water chamber 204 constituting the center folding mechanism 200. Further, the rear body part 100B extends from the rear partition 102 position of the muddy water chamber 204 to the erector 171 installation position, and the rear end part is an open end.

The diameter-expanding jack 13 as the first cross-section varying means.
In the embodiment, 0 is a hydraulic cylinder jack arranged in the tunnel radial direction and supported by the inner cylinder 100. The structure of the hydraulic cylinder jack is a double-acting cylinder type, and the extension stroke can be displacement-controlled by a command from a hydraulic control unit (not shown). An example of the arrangement of the diameter expansion jack 130 is shown in FIG.
As shown in FIG. 8, FIG. 20 and FIG. 21, three rows are formed on the front body 100A and three rows are formed on the rear body 100B along the tunnel axis direction.
Rows are supported and 10 to 1 along the circumference of the tunnel
Two units are arranged at equal intervals. Expanding jack 130
Is the fixed side 1 of the cylinder cover, as shown in FIG.
30a is firmly supported by the penetrating portion of the inner cylinder 100.
Further, the cylinder tip portion 130b as an operating portion is fixed to the inner surface of the outer shell plate 123 and the inner surface of the backing plate 124 for each arrangement row. Note that FIG.
Then, for simplification of the drawing, the illustration of the enlarged diameter jack 130 is partially omitted.

Expanding jack 1 arranged in this way
In No. 30, all the cylinder rods in the circumferential direction in each row can be extended by the same stroke amount in response to the instruction of the extension operation. For this reason, in order to perform the diameter expansion of the shell 122 of the shield excavator 1, the diameter expansion jack (left half view) of the front body A first row and the rear body B first shown in FIG.
Extend the cylinder rods of all the diameter expansion jacks 130 like the diameter expansion jacks (right half figure). At this time, the diameter expansion jack 130 that presses the outer shell plate 123
On the other hand, it is preferable that the diameter-enlarging jack 130 that presses the backing plate 124 be slightly advanced and extended. Thereby, the outer surface of the backing plate 124 can be always brought into close contact with the inner surface of the outer shell plate 123 during extension. As a result, the outer shell plate 123 and the backing plate 124 can be expanded in diameter while surely slidingly contacting each other. At the same time, since the cylinder rod extension amounts of the respective diameter expansion jacks 130 arranged along the tunnel axis direction are also controlled at the same time, a uniform diameter expansion speed and diameter expansion amount are secured in the tunnel axis direction. be able to.

The shield jack 173 is shown in FIGS.
As shown in FIG. 8, it is fixed along the inner surface of each outer shell plate 123. Shield jack 173 in this state
The front end of the outer shell plate is the diameter-increasing jack 1 in the first row
FIG. 21 (a) is connected to the operation part at the rear end, which is connected to 30B.
As shown in the right half diagram of (b), a spreader 175 for pressing the end surface of the assembled segment is attached. By the way, among the large number of diameter expansion jacks 130 supported by the inner cylinder 100, the diameter expansion jacks 130 fixed to the rear trunk portion 123B first row of the outer shell plate 123.
In the cylinder body of B, the outer shell plate rear body portion 123
One end of a shield jack 173 attached to the inner surface of B is connected. As a result, the shield jack 1
The thrust of the shield excavator 1 transmitted from 73 is transmitted to the inner cylinder 100 via the diameter expansion jack 130. In order to reliably transmit the thrust, the diameter-expanding jack 130B on the rear trunk first row is set to have a larger cylinder diameter than the other diameter-expanding jacks 130.

As shown in FIG. 23, the tail diameter expansion jack 140 as the second section varying means is attached to the outer peripheral position of the ring-shaped carriage 141 so that the cylinder axis is arranged radially from the tunnel central axis. It is a hydraulic cylinder jack. As shown in FIG. 23, the ring-shaped carriage 141 has wheels 146 on the inner peripheral portion of the carriage, and is fitted to the pipe rail 142 via the wheels 146.
As a result, the ring-shaped carriage 141 can travel in the tunnel axis direction along the outer circumference of the pipe rail 142 (see FIGS. 22A and 22B). An inner cylinder support frame 143 is fixed to the front end of the pipe rail 142. The inner cylinder support frame 143 has an outer diameter equal to the diameter of the inner cylinder 100, and can be connected to the rear end portion of the inner cylinder 100 with the erector 171 removed. Accordingly, the front end of the pipe rail 142 can be supported by the inner cylinder 100 such that the tunnel center axis and the pipe rail center axis are aligned with each other. When expanding the diameter, the inner cylinder support frame 143 at the front end of the pipe rail 142 is moved to the inner cylinder 10
It is fixed to 0, and a pipe rail supporting member 144 made of a tie rod is installed between a predetermined position of the pipe rail 142 and the fixing end of the segment. Then, the ring-shaped carriage 141
Is moved to the front end of the pipe rail 142. Further, the tail diameter expansion jack 14 mounted on the ring-shaped carriage 141
The cylinder rod of 0 is extended to expand the tail portion of the shell 122 by a predetermined amount. When the diameter is reduced, the cylinder rod of the tail diameter expansion jack 140 is elongated to slightly increase the diameter of the tail portion, and the spacer member 145 described later is exchanged for a predetermined size. In addition, after that, FIG.
As shown in FIG. 3A, the ring-shaped carriage 141 is retracted to the segment assembly completion position. Then, the segment 170 is pressed by the tip of the cylinder rod of the tail diameter expansion jack 140 of the ring-shaped carriage 141 to press the pipe rail 1
42 can be fixed in place. In addition,
The pipe rail 142 of the present invention functionally corresponds to the inner cylinder C2 of the first invention, and the ring-shaped carriage 141 corresponds to the slide pedestal 41.

By the way, in order to maintain the expanded state of the shell shell 122, if the hydraulic pressure acting on all the expanded diameter jacks is held in the load state, the load on the equipment becomes large. Therefore, in the diameter-expanding jack 130 as the first cross-section varying means, it is preferable to attach the rod length holder 131 formed of a half ring to the extended cylinder rod portion. Further, it is preferable to use a spacer member 145 as a shape-maintaining jig in order to maintain a perfect circular shape when the diameter of the tail portion is expanded. The structure of the spacer member 145 will be described later with reference to FIG.

Now, the center folding mechanism 200 that divides the shell 122 and the inner cylinder 100 into a front body portion A and a rear body portion B will be described with reference to FIG. As shown in FIG. 24A, the rear end of the front body portion 100A of the inner cylinder 100 and the rear body portion 1
00B has a front partition 101 and a rear partition 10 at the front end.
2 is stuck. In addition, outer shell plates 123A, 1
23B and the backing plates 124A, 124B from the ends thereof, respectively, toward the inner cylinder 100, and the enlarged diameter flange 12
5, 126 are fixed. These expanded flanges 12
A slit 127 capable of accommodating the front partition 101 and the rear partition 102 is provided between 5 and 126. A seal member 128 is mounted at a predetermined position on the sliding contact surface between the diameter-expanding flanges 125 and 126 and the slit 127 to prevent leakage of muddy water filled in the muddy water chamber 204 described later.

A bellows 201 made of synthetic rubber is mounted between the front body portion 123A and the rear body portion 123B of the outer shell plate. This synthetic rubber bellows 201 is a ring-shaped body having a substantially L-shaped cross section, and is a shell 1 constituting an outer shell.
It is attached so as to cover the entire circumference of 22. That is, the front body portion A and the rear body portion B are flexibly connected. Also,
A spherical seat portion 202 is provided in the inner cylinder 100 portion.
The spherical seat portion 202 is a ring-shaped body whose outer peripheral surface is finished to be a convex surface having a predetermined curvature. The rear end of the spherical seat portion 202 is fixed to the inner cylinder rear body portion 100B toward the tunnel face, and the front end thereof is the inner cylinder front body portion. 1
It is extended so as to dig into the inner peripheral position of 00A.
At this time, a synthetic rubber seal member 203 is attached to the rear end of the front body portion 100A, and when the front body portion 100A is bent with respect to the tunnel axis by the operation of the center folding jack 210 described later, The rear end portion of the portion 100A can slide along the spherical seat portion 202. In this way, the portion surrounded by the front and rear partitions 101, 102, the synthetic rubber bellows 201, and the spherical seat portion 202 constitutes the muddy water chamber 204. The mud water for supplying earth pressure is supplied from the mud pipe 205 into the mud chamber 204.

A stiffening frame 206 is fixed to the inner circumferential position of the spherical seat portion 202 over the entire circumference. The stiffening frame 206 has a flange 207 that supports the spherical seat portion 202 at a predetermined interval, and a fixing portion 208 that rotatably supports the rod end of the center folding jack 210. The front end of the center folding jack 210 is fixed to a predetermined position of the inner cylinder front body portion 100A. As an example, ten of the middle-folded jacks 210 are arranged along the circumferential direction. These ten jacks 210 are independently or synchronized, and the cylinder rod extension amount is controlled by a control unit (not shown). You can control. Accordingly, by setting a predetermined extension amount and extension timing for each jack, the front trunk portion A of the shield excavator 1 can be bent in a predetermined direction from the tunnel axis at an arbitrary angle. Thereby, in the shield excavator 1 of the present invention, it is possible to easily construct a tunnel whose linear shape is a curve having a predetermined curvature. Middle broken jack 2
Since 10 is supported astride the inner barrel rear trunk 100B and the front barrel 100A, the thrust force of the shield excavator 1 transmitted from the shield jack 173 to the inner barrel rear trunk 100B is the center-folded jack. The inner barrel front body portion 10 via 210
It is transmitted to 0A. As shown in FIG. 24 (b), this center folding mechanism effectively functions even when the diameter is expanded, and the volume of the muddy water chamber 204 also increases in accordance with the diameter expansion. Can resist external pressure.

Next, the detailed structure of the shield excavator 1 of the present invention will be briefly described with reference to FIGS. 25 to 27.
FIG. 25A is a front view showing the configuration of the protection plate 129 at the front position of the bulkhead 120. At the front position of the bulkhead 120, the backing plate 124 is not provided at the inner surface position of the outer shell plate 123. Therefore, the protective plate 129 is provided so that the collapsed earth and sand do not enter from the gap between the outer shell plates 123 when the diameter is expanded. This protective plate 129 is the outer shell plate 12
3 (a) is extended from the front surface position of the diameter-expanding flange 125 fixed to the inner surface to the tip position of the outer shell plate 123.
As shown in FIG. 5, the inner surface of the outer shell plate 123 is welded. The outer surface of the protective plate 129 and the inner surface of the outer shell plate 123 are in sliding contact with each other when the diameter is expanded or reduced. A seal packing 128 is attached to this sliding contact surface. Further, it is also preferable to provide a scraper at the end of the outer shell plate so that earth and sand do not enter between the sliding contact surfaces when the diameter is reduced. As the structure of the scraper, various types such as well-known plate type and wire type can be applied,
As the material to be used, steel, synthetic resin, synthetic rubber, and various composite materials can be used.

26 shows the sealing members 230 and 24.
It is a partial view showing the attachment state of 0. Seal member 2
30 and 240 are provided on the sliding contact surface between the outer shell plate 123 and the backing plate 124. Sealing member 230
Is a set screw 231 and a pressing plate 232 on the side surface adjacent to the outer shell plate 123 along the tunnel axis direction.
It is fixed through. The seal member 230 has a plate shape and is fixed to the outer shell plate 123 such that the tip end presses the outer peripheral surface of the backing plate 124. The seal member 240 attached to the backing plate 124 is
As shown in FIG. 26A, the backing plate 124 is attached to the notch 241 formed in the peripheral portion of the outer peripheral surface thereof. The notch 241 is covered with the cover plate 242 so that the seal member 240 is not exposed to the outside. The cross-sectional shape of the seal member 240 is a substantially L-shape, and the L-shape is slightly bent to be pressed against the inner peripheral surface of the outer shell plate 123 and housed in the notch 241 (FIG. 26C). reference). As the material of the seal member, NBR (acrylonitrile butadiene rubber) having high oil resistance is used, but various synthetic rubber materials such as neoprene rubber and polysulfide rubber can be used if the specifications are met.

FIG. 27 shows a spacer member 14 which is a shape-maintaining jig used to maintain the perfect circular shape of the tail portion when the diameter is enlarged.
5 is a partial cross-sectional view showing an example of No. 5 of FIG. As shown in the figure, a spacer member 145 is fitted in the inner peripheral surface position of the outer shell plate 123 between adjacent backing plates 124. This spacer member 145 is
An arc member that is curved so as to have the same curvature as the inner peripheral surface of the outer shell plate 123, and by mounting the spacer member 145 along the inner peripheral surface of the outer shell plate 123 when the diameter of the shell 122 is expanded. It is possible to maintain the perfect circular shape of the open end at the rear end of the outer shell plate 123. The spacer member 145 has the same function as the spacer 45 (see FIG. 8) of the shield excavator 1 of the first invention.

Next, an embodiment in which the diameter expanding mechanism according to the present invention is applied to the shield excavator 1 having a relatively small diameter will be described.
This will be described with reference to FIGS. 28 to 32. As shown in FIG. 28, the shield excavator according to the present embodiment is roughly installed at a cutter head having an overcutter, a bulkhead supporting the cutter head, a double-structured shell, and an inner circumferential position of the shell. The inner cylinder, the diameter of the shell that is supported by the inner cylinder,
It is composed of a plurality of diameter expansion jacks as first cross-section varying means for achieving diameter expansion and a plurality of tail diameter expansion jacks as second cross-section variation means for expanding the rear end of the shell. In addition, about a code | symbol, the same code | symbol is attached | subjected and demonstrated about the same structure as the structure shown in the shield excavator 1 shown in FIG.

In the present embodiment, the cutter head 110 is provided with three spokes 112 as shown in FIG. 30 (a), and the tip of each spoke 112 is an over-cutter that can expand and contract in the radial direction. 116 is attached. A copy cutter is also installed at a predetermined position on the peripheral edge of the cutter head 110. At the time of expanding the diameter, as shown in FIG.
The 16 parts are extended to the natural ground side, and are dug forward. Expanding diameter jack 130 as first cross-section varying means
As shown in FIG. 29, the first row of large-diameter expanding jacks 130 for transmitting the thrust of the shield jack 173 to the inner cylinder 100, and the two rows of the large-diameter expanding jacks 130 contributing to spread the shell 122 in the radial direction. It is composed of a diameter expansion jack 130. In the present embodiment, the first row large diameter expansion jack 13
0 is supported by the inner cylinder 100 as shown in FIG. 31, and the rod operating portion pushes the outer shell plate 123 outward. Further, FIG. 32 shows the enlarged diameter jack 130 that pushes the backing plate 124 outward. Further, as shown in the right half of the figure, the spreader of the shield jack 173 can press the segment along the inner peripheral portion of the outer shell plate 123.
The tail diameter expansion jack 140 is not shown.

In the above description. The maximum diameter expansion amount as a tunnel diameter in the shield excavator 1 shown in FIG. 18 can be set to about 300 mm at maximum, and in the shield excavator 1 shown in FIG. 29, the diameter expansion amount is specified to be 75 mm. The operation flow of diameter expansion operation and diameter reduction operation accompanying excavation is
The diameter expansion operation and the diameter reduction operation of the shield excavator 1 of the first invention can be performed in the same manner. At this time, in the second invention,
With the inner cylinder support frame 143 and the pipe rail support 144, the central axis of the pipe rail 142 can be held in alignment with the central axis of the tunnel. In this respect, in the first aspect of the invention, the inner cylinder C2 is different in that the front end is fitted onto the inner cylinder C1 and the rear end is supported by the segment gripper 46.
The expansion and contraction operations of the cylinder rod of each of the diameter expansion jacks 130 and the propulsion operation of the shield excavator 1 described above can be performed by remote operation from the operation command room located behind the shield excavator 1. Further, it is needless to say that the operation timing and the operation amount of each diametrical expansion jack 130 can be realized by a known control means, and only the diametrical expansion jack at a partial position can be operated independently. .

As described above, the rod expanding operation of each of the diameter-expanding jacks pushes the shell plate outward to continuously expand the tunnel diameter to the set tunnel diameter while excavating the predetermined distance. While the diameter of the shield excavator is narrowed, the diameter of the shell shell plate that has been expanded by the rod retracting operation of each diameter expansion jack is reduced by a predetermined distance, and the diameter is continuously reduced to the set tunnel diameter. Therefore, it is possible to efficiently and easily construct a tunnel having a variable cross-section, and it is possible to realize economical tunnel excavation without using auxiliary structures such as intermediate shafts and redundant excavation equipment.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view illustrating an embodiment of a variable cross-section shield excavator according to the first invention by showing a predetermined cross section.

FIG. 2 is a vertical cross-sectional view of the variable cross-section shield excavator shown in FIG.

FIG. 3 is a III-II of the variable cross section shield excavator shown in FIG.
The front view which showed the end surface of the cutter head by I end surface line.

FIG. 4 is a partial side view showing a schematic structure of an overcutter portion shown in FIG.

5 is a front view showing the end surface of the bulkhead along the VV end surface line of the variable cross-section shield excavator shown in FIG. 2;

6 is a partial cross-sectional view showing the cross-sectional shape of the sliding portion between the bulkhead shown in FIG. 5 and the flange portion from the shell.

FIG. 7: VII-VI of the variable cross section shield excavator shown in FIG.
FIG. 6 is a transverse cross-sectional view showing an arrangement and an operating state of the first cross-section varying means along the I-section line.

8 is a transverse cross-sectional view showing the arrangement and operating state of the second cross-section varying means taken along the line VIII-VIII of the shield excavator shown in FIG.

FIG. 9 is a transverse cross-sectional view showing a second cross-section varying means fixing structure and an operating state by the VIII-VIII cross-section line of the shield excavator shown in FIG.

FIG. 10 is a partially enlarged sectional view showing the details of the structure of the tail seal at the rear end position of the shell.

FIG. 11 is a flow chart showing a series of operation sequence of a diameter expanding and advancing operation of the shield excavator.

FIG. 12 is a flow chart showing a series of operation sequences of a diameter reduction advancing operation of the shield excavator.

FIG. 13 is a flowchart showing a jack operation sequence when expanding the diameters of the first cross-section varying means and the second cross-section varying means.

FIG. 14 is a flowchart showing a jacking operation sequence of the first cross-section varying means and the second cross-section varying means when the diameter is reduced.

FIG. 15 is an operation state diagram showing an operation state of the shield excavator at the time of advancing the diameter.

FIG. 16 is an operation state diagram showing an operation state of the shield excavator during the diameter reduction digging.

FIG. 17 is a partial cross-sectional perspective view illustrating an embodiment of a variable cross-section shield excavator according to the second invention by showing a predetermined cross section.

18 is a vertical cross-sectional view of the variable cross-section shield excavator shown in FIG. 17 when the diameter is reduced.

FIG. 19 is a vertical cross-sectional view of the variable cross-section shield excavator shown in FIG. 17 when the diameter is expanded.

20 is a cross-sectional view taken along line XXa-XXa and XXb-XXb in FIGS. 17 and 18.

21 is a cross-sectional view taken along the line XXIa-XXIa, XXIb-XXIb in FIG. 17 and FIG.

FIG. 22 is a partial vertical cross-sectional view showing one form of a second cross-section varying means of the second invention.

23 is a cross-sectional view taken along the line XXIIIa-XXIIIa, XXIIIb-XXIIIb in FIG.

FIG. 24 is a partial cross-sectional view showing an embodiment of a center folding mechanism.

FIG. 25 is a partial cross-sectional view showing an embodiment of the tip portion of the shell.

FIG. 26 is a partial cross-sectional view showing an embodiment of the seal member between the outer shell plate and the backing plate.

FIG. 27 is a partial cross-sectional view showing an embodiment of a spacer member interposed between the outer shell plate and the backing plate.

FIG. 28 is a partial vertical cross-sectional view (when the diameter is reduced) showing another embodiment of the variable cross-section shield excavator according to the second invention.

29 is a longitudinal sectional view of the variable cross-section shield excavator shown in FIG. 28 when the diameter is expanded.

30 is a sectional view taken along a section line XXXa-XXXa, XXXb-XXXb in FIGS. 28 and 29.

FIG. 31 is a schematic diagram of XXXIa-XXXIa and XXXIb-XXXIb of FIGS. 28 and 29;
Sectional drawing by a section line.

FIG. 32 shows XXXIIa-XXXIIa, XXXIIb-XX in FIGS. 28 and 29.
Sectional drawing by the XIIb section line.

FIG. 33 is a schematic tunnel layout sectional view showing an example of a conventional tunnel construction example in which the tunnel diameter is changed by using an intermediate shaft.

FIG. 34 is a partial cross-sectional view showing an example of a shield excavator having a conventional diameter-expanding excavating means.

[Explanation of symbols]

 1 Shield excavator 10,110 Cutter head 16,116 Over cutter 20,120 Bulkhead 22,122 Shell (outer shell)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kotaro Masaki, 2 Sanbancho, Chiyoda-ku, Tokyo, Tobishima Construction Co., Ltd. (72) Toshio Izawa, 2 Sanbancho, Chiyoda-ku, Tokyo, Tobishima Construction Co., Ltd. (72) Inventor Takashi Mochizuki 2 Sanbancho, Chiyoda-ku, Tokyo Inside Tobishima Construction Co., Ltd. (72) Inventor Masatoshi Uehara 2 Sanbancho, Chiyoda-ku, Tokyo Toshima Construction Co., Ltd. (72) Inventor Takehiko Goto 2 Sanbancho, Chiyoda-ku, Tokyo Within Tobishima Construction Co., Ltd. (72) Inventor Yoshikazu Inada In Sanbocho, Chiyoda-ku, Tokyo Inside Tobishima Construction Co., Ltd. (72) Inventor Masahiro Fujiwara Chiyoda-ku, Tokyo Sanbancho No. 2 Tobishima Construction Co., Ltd. (72) Inventor Hiroshi Manaka No. 2 Sanbancho, Chiyoda-ku, Tokyo Tobishima Construction Co., Ltd. (72) Inventor Kiyoshi Sugie Tokyo 2nd Sanbancho, Shirota-ku, Tobishima Construction Co., Ltd. (72) Inventor Yasuaki Ishida 2nd Sanbancho, Chiyoda-ku, Tokyo Inside 72, Tobishima Construction Co., Ltd. Shinichi Yamada Sanbancho, Chiyoda-ku, Tokyo No. 2 In the Tobishima Construction Co., Ltd. (72) Inventor Shunji Hatori No. 2 Sanbancho, Chiyoda-ku, Tokyo No. 2 In the Tobishima Construction Co., Ltd. (72) Inventor Mitsuo Shimizu 1-3 1-3 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd.Kobe Head Office

Claims (12)

[Claims] 1. A ground excavator ground is widened by an overcutter capable of protruding by a predetermined diameter expansion amount from the outer peripheral surface of a cutter head, and is supported by an inner cylinder whose front end is fixed to a bulkhead inside the excavator. By operating the plurality of cross-section varying means, a part of the plurality of outer shell plates constituting the shell portion is spread from the inside of the excavator, and the gap between the outer shell plates generated by the spreading operation is generated. While expanding the tunnel while closing the gap formed in the peripheral portion of the bulkhead, the plurality of cross-section varying means are operated to reduce the gap between the outer shell plates generated by the pushing and expanding operation. A variable cross-section shield excavator, which is characterized in that the diameter of a tunnel is reduced in such a manner as to narrow it, and a tunnel having a continuously changing tunnel diameter is excavated. 2. A cutter head provided with an overcutter capable of projecting from the outer peripheral surface by a predetermined diameter expansion amount, and a plurality of outer shell plates divided along the tunnel longitudinal direction, the outer shell plate having a longitudinal direction. A diametrical expansion plate that is a part of the outer shell is formed at one of the edge ends of the outer shell plate, and a slit that can accommodate the diametrical expansion plate is formed at the other edge of the outer shell plate, and the inner peripheral surface near the front end is formed. A shell portion formed with a diameter-expanding flange and a peripheral portion thereof are provided inside the shell shell so as to be in sliding contact with the diameter-expansion flange while maintaining water-tightness, and the front surface of the shell is closed while maintaining water-tightness. A bulkhead and a gripper having a front end fixed to the bulkhead, extending substantially in the shape of a concentric circle with the shell and extending into the shell, and holding a concentric position with respect to the shell at the rear position. Inner cylinder, one end is the outer shell play A first cross-section varying means that is connected to a part of the inner cylinder and the other end of which is supported by the inner cylinder; and at least one end of which is supported by the inner cylinder and the other end of which can press the outer shell plate from the inside. A second cross-section varying means, wherein the over-cutter widens the ground from a reduced-diameter state in which the diameter-expanding plate is accommodated in the slit, and the first cross-section varying means and the second cross-section By actuating the variable means, the outer shell plate is expanded outward, and the outer shell of the excavator having a diameter increased by the outer shell plate and the diameter expansion plate exposed from inside the slit, The bulkhead and the diameter-increasing flange that is in sliding contact with the peripheral edge of the bulkhead close the front surface of the outer case to increase the diameter to a predetermined tunnel diameter, and at the same time, perform the first excavation step at a predetermined excavation stage. Cross section changing means Sectional variable shield excavator, wherein a second tunnel diameter as the enlarged diameter by operating the cross-section varying means, and to be reduced in diameter to a predetermined tunnel diameter. 3. A cutter head provided with an overcutter capable of projecting by a predetermined diameter expansion amount from an outer peripheral surface, a plurality of outer shell plates divided along a tunnel longitudinal direction, and adjacent outer shell plates adjacent to each other. A shell portion formed of a backing plate arranged in contact with the inner peripheral surface at the edge position, and a shell shell portion having a diameter-expanding flange formed on the inner peripheral surface of the front end of the backing plate; A bulkhead that is provided inside the shell so as to be slidable while maintaining watertightness, and that closes the front surface of the shell while maintaining watertightness, and a front end is fixed to the bulkhead, An inner cylinder extending substantially concentrically with the inside of the shell, one end supported by the inner cylinder, the other end capable of pressing the backing plate, and one end having the inner cylinder. Supported by the other end, and the other end can press the outer shell plate. A first cross-section varying means including an effective cross-section varying means, and one end supported by a support body connectable to a rear end of the inner cylinder,
A second cross-section varying means capable of pressing the outer shell plate from the inner side at the other end, wherein the backing plate is in a reduced diameter state in which the backing plate is in contact with the inner peripheral surface of the adjacent edge position of the outer shell plate. , While widening the ground with the overcutter and actuating the first cross-section varying means and the second cross-section varying means to push the backing plate and the outer shell plate in close contact with each other. The outer shell of the excavator, which is expanded and has a diameter increased by the outer shell plate and the backing plate exposed between the outer shell plates adjacent to each other, is configured and slidably contacts the bulkhead and the peripheral portion of the bulkhead. While expanding the diameter to a predetermined tunnel diameter so as to close the front surface of the outer shell with the expanded diameter flange that is present, the first cross-section varying means and the second cross-section varying means are operated in a predetermined excavation stage. Let me before A variable cross-section shield excavator characterized in that the diameter of the enlarged tunnel can be reduced to a predetermined tunnel diameter. 4. The first cross-section varying means includes a circumferential jack disposed and supported by at least a flange formed on an inner peripheral surface of the shell, and the outer shell plate supported by the inner cylinder. 3. The variable cross-section shield excavator according to claim 2, further comprising: 5. The second cross-section varying means is a radial jack arranged and supported on a pedestal slidable in the tunnel axis direction along the outer peripheral surface of the inner cylinder. Item 2. A variable cross-section shield excavator according to item 2. 6. A radial jack having one end supported by the inner cylinder and the other end connected to the backing plate, and one end of the first cross-section varying means supported by the inner cylinder and the other end. 4. The variable cross-section shield excavator according to claim 3, further comprising a radial jack connected to the outer shell plate. 7. The second cross-section varying means is a radial jack arranged and supported on a ring-shaped carriage that can travel in the tunnel axis direction along a pipe rail connectable to the rear end of the inner cylinder. The variable cross-section shield excavator according to claim 3, wherein 8. The body shell portion is provided with a tail seal at a rear open end of each of the divided outer shell plates, and another tail which overlaps with the tail seal at the time of expanding the diameter at a predetermined position of the diameter expanding plate. The variable cross-section shield excavator according to claim 2, wherein a seal is provided. 9. The variable cross-section shield excavator according to claim 3, wherein the shell shell portion is provided with tail seals at the rear open ends of the divided outer shell plate and backing plate, respectively. 10. The variable cross-section shield excavator according to claim 2, wherein the inner cylinder has a double-cylindrical structure having a nested structure capable of sliding and expanding and contracting at an overlapping portion. 11. The body shell and the inner cylinder are separated into a front body and a rear body by a center folding mechanism provided at a predetermined intermediate position, and can be bent and advanced at a predetermined angle at the separated position. It is any one of Claim 1 thru | or 3 characterized by the above-mentioned.
Section variable shield excavator according to the item. 12. The variable cross-section shield excavator according to claim 11, wherein a mud chamber is provided at a separation position where the front body portion and the rear body portion are separated by the center folding mechanism.