JPH0455597A - Shield excavator for free cross section - Google Patents

Abstract

PURPOSE:To obtain different cross sections of excavation by a method in which cutter heads are set eccentrically to the turning center of each turning driver, and a cutting device is provided to the periphery of each cutter in such a way as to lap its tip locuses mutually. CONSTITUTION:Cutter heads 10A and 10B are eccentrically attached to drums 16A and 16B rotatably attached to a shield machine 12, where the drums 10A and 10B are set eccentrically at a fixed distance from the turning centers OA and OB Front excavation is made by rotation of the heads 10A and 10B of the drums l6A and 16B. An actuator 40 such as oil-pressure jack which goes or comes out of the periphery of the heads 10A and 10B is provided to a cutting device 18, and a cutter bit 42 is provided to the front side and tip side of a cutting device 38 appearing or disappearing. Unexcavated portion is excavated by the device 18. Different cross sections of excavated portions can thus be optionally set up.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a flexible cross-section shield excavator whose shield excavation cross section can be set to any shape, and relates to a flexible cross-section shield excavator having a structure that can be used as a mountain tunnel excavator or a special cross-section excavator.

[Conventional technology]

A conventional general shield excavator has a cylindrical shield main body, and a force/interval/end is attached to the front end face of the shield, and by rotating the cutter head, the force/interval/end provided on the surface of the cutter head is released. It is designed to excavate the ground. Then, the excavated earth and sand are taken into the shield chamber and carried out by a screw conveyor. With such a shield excavator, the excavation cross section must be a circular cross section determined by the rotation of the cutter and the cutting edge, and it is not possible to excavate an arbitrary cross section. For this reason, in the case of multi-lane tunnels or double-track tunnels, it is recommended to perform circular shield excavation with a large cross section, or to use multiple shield excavators as shown in Figures 8 and 9. A method has been proposed in which a tunnel cross section with a cocoon shape is excavated. The one shown in Fig. 8 is a mud pressure type irregular cross-section shield excavator, which is equipped with a plurality of spoke-type cutter heads 1 and
The ivy heads are meshed like gears and controlled to rotate synchronously, so that the cutting face is excavated in the same plane, similar to the conventional circular cross-section. This is known as the DOT (multiple mud pressure) shield method. - On the other hand, the one shown in Fig. 9 is a muddy water type irregular cross-section shield excavator, in which the cutter heads 2 are stacked front and back with a phase difference, and the respective forces, vines, and directions of rotation are freely controlled. By changing to , the attitude of the shield excavator is controlled and the cocoon-shaped cross section is excavated all at once. This is known as the MF (multi-face) shield method.

[Problem to be solved by the invention]

However, even in the conventional method of excavating special cross sections mentioned above, basically circular excavation cross sections are connected together.
There was a problem in that it was not possible to actually perform shield excavation with an arbitrary cross-sectional shape. In particular, since the excavation cross section is cocoon-shaped with overlapping circular cross sections, there is a recess 3 in the overlapped part (the 71 cutting part in Figures 8 and 9) that cannot be excavated, and this makes the direction of propulsion difficult. There was a problem in that it was difficult to move in a direction along a horizontal curve. For curved excavation, this type of excavator is equipped with a copy cutter as an over-drilling device on the outer periphery of the cutter, but this actually has a short stroke and is not suitable for ordinary single circular section excavation. Although the above-mentioned shield excavator is effective, the cutter cannot reach the outer edge of the recess 3 in the above-mentioned irregular cross-section shield excavator, so no practical effect can be expected. In addition, in the above-mentioned Tonosho type shield excavator (Fig. 8), it is necessary to have a large installation space for the earth removal screw conveyor, so the installation space for the motor and gears of the cutter head drive section is limited, and the drive section There is a problem in that the reduction ratio cannot be set large and the equipment torque is limited. Furthermore, in order to avoid interference between the cutter drive unit and the screw conveyor, it is necessary to increase the length of the shield machine, and as the machine length increases, steering performance deteriorates, making attitude control and construction of sharp curves difficult. There was a problem of increased costs. Furthermore, in the muddy water type shield excavator (Figure 9), it is necessary to have a large installation space for the mud feed vibrator, mud removal pipe, and agitator device, so the drive unit is installed in the same way as the earth pressure type shield excavator. Due to space limitations, there were problems such as reduced steering performance, difficulty in constructing sharp curves, and disadvantages in terms of cost. In particular, in this type of shield excavator, the number of motors that can be installed is limited due to interference between drive units between the plurality of cutter heads. The present invention focuses on the above-mentioned conventional problems, allows the excavation cross section to be arbitrarily set, allows for curved excavation construction freely, does not involve an increase in the length of the shield machine, and secures sufficient equipment installation space. The purpose of the present invention is to provide a flexible cross-section shield excavator with a structure that allows for

[Means to solve the problem]

In order to achieve the above object, a flexible cross-section shield excavator according to the present invention is a shield excavator in which a plurality of cutter heads are attached to the front surface of a shield main body, in which the plurality of cutter heads are aligned with respect to the rotation center of each rotary drive part. Each cutter head is arranged eccentrically, and a cutting device is provided on the outer periphery of each cutter head so that the loci of the tip thereof can overlap with each other.

[Effect]

According to the above configuration, the plurality of cutter heads attached to the front surface of the shield body are arranged eccentrically with respect to the rotation center on the rotation driving part side, so that the cutter heads are rotated independently while approaching each other or moving away from each other. Ru. As a result, the front surface of the excavator has a so-called cocoon-shaped excavation cross section corresponding to the eccentric rotating surface of the cutter head. Furthermore, each cutter head has a cutting device installed on its outer periphery that can be moved in and out, and the trajectories of these tips can overlap each other, so it is possible to remove areas that could not be excavated by the eccentrically rotating cutter head. I hope the excavation is possible. In other words, when one of the adjacent cutter heads rotates eccentrically and is in the retracted position,
While rotating the other cutter head, bring it closest to the unexcavated area, and simultaneously project the cutting device. As a result, the tip of the cutting device can be successively projected along the outer edge of the unexcavated area to perform excavation without interfering with the retracted cutter head. For this reason, in the shield excavator, the excavation cross section can be arbitrarily set in the range between the outer edge trajectory caused by the eccentric rotation of the cutter head and the tip trajectory of the cutting device. In particular, it is possible to excavate concave areas surrounded by the circular trajectories of multiple cutter heads and their tangents, making it possible to excavate not only elliptical cross-sections but also elliptical or rectangular cross-sections, allowing curved excavation. This makes it possible to excavate areas that may pose obstacles during construction, making it possible to construct steep curves. In addition, in a shield excavator with such a configuration, the cutter head rotates eccentrically, so it is possible to secure installation space for screw conveyors, agitators, etc. without increasing the shield machine length, and the structure has a flexible cross section with excellent durability and economic efficiency. Can be a shield excavator.

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a flexible cross-section shield excavator according to the present invention will be described in detail below with reference to the drawings. 1 and 2 are a front view and a sectional view of a flexible cross-section shield excavator according to an embodiment in which the present invention is applied to a muddy water type shield excavator. As shown in these figures, the shield excavator according to the embodiment includes two cutter heads IOA, 1. The shield machine body 12 is provided with O and B at the front end. This shield machine main body 12 is formed in an oval cross-sectional shape, which circumscribes a pair of base circles CA, C, of the same diameter,
It is constituted by a skin plate formed along an outline formed by connecting both base circles CASCB with a common tangent. A ring gutter 14 that also serves as a bulkhead is formed on the front body side of the shield machine main body 12 having such an oval cross-sectional shape so as to partition the inside of the main body 12 into front and rear parts, and the ring gutter 14 also has an oval front shape. It is supposed to be done. In such a bulkhead ring gutter 14, the arc centers OA, O, (the base circle CA%C3
A through hole is formed with the center of the drum 16A, 16B rotatably mounted thereon as a bearing. The drums 16A and 16B, together with the ring garter 14, are rotating cylindrical bodies that also serve as bulkheads, and a ring gear 18A,
18B is integrally provided. both drums 1
A transmission section 22 consisting of a gear train is meshed with the ring gears 18A and 18B of the 6A116B, and the transmission section 22 which consists of a gear train is engaged with the rotational force from a drive motor 20 fixedly installed on the ring gutter 14.
B is now rotated. The cutter heads 10A and IOB, which directly face the face and perform excavation, are eccentrically attached to the drums 16A and 16B, which are rotatably attached to the shield machine body 12 as described above. For this reason, in the embodiment, the drum 1
6A and 16B are eccentric drums having eccentric bearing parts 24A and 24B, which are provided at a certain distance e from the center of rotation (corresponding to the arc center of the base circle CASCl) OA and Os. This eccentric bearing is part 24A1
The cutter heads IOA and 10B attached to the drum 1 are formed to have a smaller diameter than the base circle CASCB.
By rotating 6A and 16B, cutter head IOA, 10
The head center OH of B moves around the arc center 0A10B of the base circles CA, C. Further, the diameters of the cutter heads 10A and IOB are determined so that the circular locus of the outer edge of the cutter heads IOA and IOB becomes an inscribed circle to the base circle CA%CB during such eccentric rotation. Furthermore, the cutter heads IOA and IOB themselves are connected to the drum 1.
The eccentric bearings 6A and 16B are driven to rotate around the portions 24A and 24B. This structure will be explained for one cutter head IOA. Cutter head I
A shaft cylindrical portion 26A is formed protruding from the center rear side of the OA, and the eccentric bearing is mounted on the portion 24A via a cutter head support 28A. As shown in FIG. 2, the rear end of the shaft cylindrical portion 26A is connected to a cutter head support 28A, and is rotatable via a bearing of the cutter head support 28A. Then, the drive shaft of the drive motor 32A installed inside the eccentric drum 16A is passed through the inner ring gear 30A in the cutter head IOA, and the drive gear 33A attached thereto is meshed. I have to. Then, by operating the drive motor 32A, the cutter head IOA is driven to rotate around the eccentric bearing of the eccentric drum 16A around the portion 24A. Since such a configuration is the same in the other cutter head IOB, the same constituent members are given the same numbers and the symbol B, and the explanation thereof will be omitted. The cutter heads IOA and 10B attached to the eccentric drums 16A and 116B as described above each have a cutter bit 34 on the front surface thereof, and
, frontal excavation is performed by rotation of the IOB. Cutter head I
As described above, since the OA and IOB rotate on their own axis and eccentrically, the range surrounded by the base circle CASC1 becomes the excavation range. And cutter head IOA like this
, 10B are provided with a cutting device 38 that performs an excavating function separately from the cutter bit 34 on the front surface. In this embodiment, this cutting device 38 has the following features:
4 at 90 degree intervals on the outer circumferential surface of cutter head IOA, IOB.
The cutter heads IOA and IOB are installed in a built-in manner so as to be retractable along the radial direction of the cutter heads IOA and IOB. The number of cutting devices 38 is cutter head IOA
, 10B may be provided in accordance with the number of spokes, and as the number of spokes increases, the number of spokes may be provided in accordance with the increased number of spokes. The cutter head 10A has an actuator 40 such as a hydraulic jack or a screw jack for making the cutter head 10A come out and go out from the outer peripheral surface of the IOB, and a cutter bit 42 is provided on the front and tip side of the cutting device 38 that comes out and goes out. ing. Therefore, the cutting device 38 performs an excavating operation by the action of the cutter bit 42 by rotating the cutter heads 10A and 10B and moving them in and out at a predetermined angular position of the eccentric drum. The excavation range by this cutting device 38 is a range of concentric circles larger than the circular trajectory (base circle CA, C,) of the outer circumference of the cutter head 10A110B by the maximum protrusion amount of the cutting device 38. When viewed as a whole, it has a cocoon-shaped cross section that encloses the shield machine body 12, as shown in FIG. In addition, in the figure, 44 is a hydraulic pipe for the actuator 40 of the cutting device 38, 46 is a cutter head IOA,
This is hydraulic piping for the drive motors 32A and 32B of the IOB. Since these hydraulic pipes 44 and 46 are arranged in a rotating system, they are connected to a rotary joint 48 provided on the side of the shield machine main body 12 as a fixed system, and are connected to the rear of the bulkhead ring gutter 14 leading to a pressure oil supply source. The connection with the hydraulic piping 50 is attempted. Further, the interior of the shield machine body 12 between the bulkhead ring gutter 14 and the cutter heads IOA and IOB is a shield chamber 52 that serves as a space for taking in excavated earth and sand. For this purpose, the agitator devices 54a, 54b and the slurry feed vibrator 5 are utilized by making use of the wide space created by arranging the drive devices such as the cutter heads IOA, 10B and their drive motors 32A, 132B eccentrically by the amount of eccentricity e.
5. A mud removal vibrator 56 is attached. This is arranged so as not to interfere with the drive units of the cutter heads IOA and IOB and the eccentric drums 16A and 16B. The excavated soil taken into the shield chamber 52 is agitated by the agitator devices 54a and 54b, and is discharged rearward through the mud removal vibrator 56. In addition, in the earth pressure type shield excavator, the agitator device 54
a, 54b, the mud feeding vibrator 55, and the mud removing vibrator 56, a plurality of screw conveyors and the like are arranged at the lower part of the bulkhead ring gutter 14. A shield jack 58 is provided on the back side of the bulkhead ring gutter 14 in the shield machine body 12, and the shield jack 58 is extended while being supported by a reaction force from a segment 60 formed at the rear to propel the shield excavator. It is something that makes you feel good. In addition, the bulkhead ring gutter 14 and the eccentric drum 16A
, 16B support the earth pressure and mud water pressure generated within the shield chamber 52. Excavation operations using the shield excavator configured as described above are as follows. First, the two small-diameter cutter heads IOA and 10B are installed eccentrically by e with respect to the drive centers of the eccentric drums 16A and 16B, respectively. , 10B can excavate only within the range of the circumscribed circular locus (basic circles CA, C, . . . ) around which the excavators rotate with eccentric action. In such a state, the shield machine body 1
2 and the base circle CAXCB, the triangular portions above and below the center of the main body become unexcavated sites. Therefore, in the shield excavator of the embodiment, the unexcavated portion is excavated by the cutting device 38. Therefore, the cutting device 3 is connected to the hydraulic pipe 50, rotary joint 48, and hydraulic pipe 44.4B.
Pressure oil is supplied to the actuator 40 of No. 8, and the cutting device 38 is driven to protrude and retract in accordance with the rotation of the cutter heads IOA and IOB, and the amount of protrusion and retraction is controlled. In other words, the amount of protrusion and retraction is controlled so that the locus of the tip of the cutting device 38 follows the skin plate of the shield machine body 12. This detects the rotation angle of the eccentric drums 16A, 16B, detects the point in time when the internal contact points of the base circles CA, CI and the cutter heads IOA, IOB reach the protruding position of the cutting device 38, and based on this detection data, each cutting This can be easily realized by calculating the relative position of the device 38 to start protruding the cutting device 38, and at the same time calculating the protrusion speed in relation to the rotational speed and performing hydraulic control. The rotation angles of the eccentric drums 16A and 16B are detected from the rotation of the gears of the transmission section 22. Note that these processes may be controlled by an on-board computer. FIG. 3 is a schematic diagram showing a control state of the protrusion/retraction stroke of the cutter bit 42 of the cutting device 38 when excavating an ellipse E along the outline of the shield machine body 12. The eccentrically rotating cutter heads IOA and IOB are both set to rotate counterclockwise in the same direction at the same time, for example, in the 12 o'clock direction, so that they are in internal contact with the base circles CA and CA, respectively. There is. In the cutter head IOA on the right side of the diagram, assuming that the 12 o'clock direction is the O° position,
The cutting device 38 is made to protrude within the rotation range of the eccentric drum 16A from the O degree position to 45 degrees, and the amount of protrusion is controlled so that its tip trajectory follows the horizontal line of the ellipse E (arm positions 380.38p, 38q). ). 45
At the position 38q at 38.degree., the cutting device 38 reaches its maximum protrusion and reaches the intersection of the common tangent of the contact points of the base circles CA, C, and the skin plate of the shield machine body 12. In the range of 45° to 90°, the cutting device 3 faces the left cutter head IOB.
8 retraction drive (arm position 38q, 3
8r, 38s). During this retraction, stroke control is performed to draw a locus F on an arc so as to exceed the common tangent line. In the range of 90° to 180°, the stroke control may be reversed from that in the case of 0° to 90°. In addition, since the outer shape of the shield machine body 12 and the base circle CA are the same from the 180° position to the original base position, the cutting device 38 can be kept in a retracted state or with a constant minute protrusion amount. Just let them do the digging. Here, one left cutter head 10B protrudes its cutting device 38 when the right cutter head IOA is inscribed with the base circle CA in the range of 180 to 0 degrees, and the cutter head 10A and IOB This involves excavating the unexcavated areas. These cutting devices 38
When excavating with the cutter spatula), the double-force vine heads IOA, 10B) rotate synchronously with the same base point, so the cutter spatula)
When the cutting device 38 of one of the IOA and IOH excavates an unexcavated area, the other cutter head is in the retracted position and does not interfere with each other. FIG. 4 shows the stroke control of the cutting device 38 when excavating an elliptical cross-sectional shape G. In this case as well, the cutting device 38 is moved along the elliptical line G.
By controlling the stroke, it is possible to easily excavate a desired elliptical cross-sectional shape. FIG. 5 shows the process of excavating an elliptical cross section using the shield excavator according to the embodiment. In this explanation, an area I is divided into left and right parts of an upper and lower triangular part surrounded by a base circle CA1CB and an elliptical shape G,
II, ■, and ■ will be explained separately. First, at the initial excavation position shown in FIG.
Both IOBs are located at the upper 12 o'clock position of the base circles CA and C.・Cutter heads IOA and IOB are base circles CA and C. Excavate within each inscribed circle. Therefore, after giving free rotation to the cutter heads IOA and IOB from such a state, the eccentric drums 16A and 16B are
Rotate counterclockwise. After that, on the right cutter head 10A side that starts excavation, while the eccentric drum 16A is in the range of 00 to 90', the upper right area I is excavated by the protruding drive of the cutting device 38 built in the cutter head IOA. Ru. After that, when the eccentric drums 16A and 16B further rotate and reach the angular position of 45°, the inside of the base circles CA and C1l is excavated by the eccentric rotation amount of the cutter heads IOA and 10B, as shown in FIG. Ru. Furthermore, when it rotates to the 90' position, as shown in the same figure (3), the excavation area by the cutter head IOA and the IOB eye increases, and at the same time, the lower right area (2) by the built-in cutting device 38 of the right cutter head IOA is Excavation begins. Next, eccentric drum 1 is placed between 900 and 180'.
6A and 16B rotate further, and the excavation in area ■ progresses, as shown in the figure (4) and (5)), right cutter heads IOA and I.
Excavation of areas I and IV by the cutting device 38 on the OB side is completed. During this time, on the left cutter head IOB, the 0 of C8 in the basic circle
Excavation is completed only in the range of 180° to 180°. On the other hand, when the rotational position of the eccentric drum 16A begins to exceed 1800 degrees, the cutter head IOA begins to retreat to the right, and then the left eccentric drum 16B
The angular position approaches 180°, the cutter head 10B approaches the lower left region (■), and the cutting device 38 built in the cutter head 10B starts excavating the region ((6) in the same figure).
). Thereafter, the rotation of the eccentric drum 16B progresses, and the eccentric rotation of the left cutter heads IOA and 10B progresses to excavate. The cutting device 38 of the left cutter head IOB excavates areas (7), (8), and (9) in the order of area (Fig. Since the cutter head 10A110B goes around once, the whole area is excavated by the cutter bit 34 of the cutter head 10A110B itself. At this time, the eccentric drums 16A and 16B are also rotating once. Thereafter, by repeating the above steps, shield excavation with an elliptical cross-sectional shape can be performed continuously. According to such a shield excavator, the cutter head IO
A and IOB are formed to have a smaller diameter than the base circles CA and C of the shield machine body 12, and this cutter head IO
A. The IOB drive unit will also be downsized accordingly. Also,
Cutter head IOA. The axis of 10B is eccentric drum 16A116B
Since it is installed eccentrically on the shield machine body 1
A wide earth removal space is secured at the front lower part of 2, which provides the advantage of easy installation and maintenance. Furthermore, the manholes in the bulkhead can be made large and can be effectively used as access holes for maintenance. Furthermore, there is no need to increase the length of the shield plane in order to secure installation space for earth removal equipment, etc., and there is no reduction in steering performance. This not only makes it possible to propel the vehicle through sharp curves, but also improves the water resistance and durability of the tail seal portion. In the above embodiment, the diameter of the cutter heads IOA and IOB is reduced, so the excavation energy of the shield excavator can be saved, and together with the miniaturization of the driving parts of the cutter heads IOA and 10B, the structure is simple and high. It is possible to create a shield excavator with excellent hydraulic performance, durability, and economic efficiency. In addition, in the above embodiment, since the face and water pressure act on the lower space of the cutter head IOA, 10B and the eccentric drum 16A, 16B drive unit, in the case of a Tonosho type shield excavator, a screw conveyor device for soil removal, etc. The excavated soil in the shield chamber 52 is transferred to the cutter heads IOA, IOB and the eccentric bearings that drive the cutter heads IOA, IOB and the eccentric rotation of the parts 24A, 24B. This action increases the stirring effect, promotes plastic fluidization of the excavated soil, makes it possible to control earth pressure at the tip of the screw conveyor, and has the advantage of improving the safety of the face. Further, in the muddy water shield excavator as well, the muddy water agitation effect can be improved in conjunction with the stirring action of the agitator devices 54a and 54b disposed in the shield chamber 52. In this embodiment, the cutting device 38 protrudes and pushes up the earth and sand toward the crown (crown), so that the soil pressure at the crown is higher than at other locations, and the effect of preventing face collapse is obtained. Since the shield excavator of the embodiment can directly excavate with an oval or elliptical cross-sectional shape, the structure of the segment becomes a simple shape that follows a circular or oval shape, and the effect of reducing the segment cost can also be obtained. In the above embodiment, the cutting device 38 is attached to the cutter heads IOA and IOB, but this uses a structure with a telescopic element such as a copy cutter, and is designed to eccentrically rotate the cutter heads IOA and IOB. You can just do it. With such a configuration, the degree of freedom in the cross-sectional shape that can be excavated is reduced, but it is also possible to excavate a flexible cross-section while minimizing the factor of cost increase. Furthermore, although the cutter heads IOA and IOB are arranged on the same plane, they can also be arranged with their positions shifted back and forth. Further, the cutter heads IOA and IOB are not limited to two, but can have a multiple structure of two or more, and can of course be arranged horizontally or vertically. In the embodiment, the eccentric drum 16A
, 16B are configured to rotate at a fixed position on the bulkhead ring gutter 14, but the eccentric drum 1
6A and 16B themselves may be offset from the horizontal center line of the shield body and arranged eccentrically. Examples of this structure are shown in FIGS. 6 and 7. A pair of through holes are formed in a ring gutter 14 that partitions the inside of the shield machine main body 12 into front and rear parts at a position offset upward by a distance e' from the horizontal center line O of the main body 12. An eccentric drum 16A (16B) is attached to each through hole as in the previous embodiment, and the eccentric drum 16A itself is rotatably driven within this through hole. The eccentric drum 16A is further provided with a bearing portion 24A (24B) eccentrically arranged by e, to which the cutter head 10A (IOB) is attached. Since the other configurations are the same as those in the previous embodiment, the same constituent members are given the same numbers and the description thereof will be omitted. According to such a configuration, in addition to the eccentric arrangement of the eccentric drum 16A itself, the eccentric rotation of the cutter head 10A and the protruding and retracting movement of the cutting device 38 have the advantage that the range of excavation of irregular cross-sections, such as excavation of large horseshoe-shaped cross-sections, is expanded. be.

【Effect of the invention】

As explained above, according to the flexible cross-section shield excavator according to the present invention, a plurality of cutter heads are arranged eccentrically with respect to the rotation center of each rotary drive part, and the outer circumference of each cutter head has a tip end. Since the structure is equipped with a cutting device whose trajectories can overlap each other, it is possible to arbitrarily set irregular excavation cross-sections such as oval, elliptical, rectangular cross-sectional shapes, and even large and small cocoon-shaped shapes. This excellent effect can be obtained. Furthermore, it is possible to freely carry out curved excavation work, without increasing the length of the shield machine, and with the advantage of being able to provide a shield excavator with a structure that can secure sufficient equipment installation space.

[Brief explanation of drawings]

FIG. 1 is a front view of a shield excavator according to an embodiment, FIG. 2 is a side cross-sectional view of the same shield excavator, and FIG. 3 is a schematic diagram illustrating the operation of the cutting device during oblong excavation by the same device. FIG. 4 is a schematic diagram for explaining the same during elliptical excavation, FIG. 5 is an explanatory diagram showing the steps of the excavation cycle of the flexible section shield excavator, and FIG. 6 is a front view of the shield excavator according to another embodiment.
FIG. 7 is a side sectional view thereof, FIG. 8 is a front view of a conventional mud pressure system shield excavator for irregular cross section excavation, and FIG. 9 is a front view of a conventional mud water system shield excavator for irregular cross section excavation. 10A, IOB...Cutter head, 12...
... Shield excavator, 16A, 16B ... Eccentric drum, 24A, 24B ... Eccentric bearing part, 38 ... Cutting device, 40
...actuator, 42 ... cutter pit, 52 ... shield chamber. Figure Figure Figure Figure Figure

Claims (1)

[Claims] 1) In a shield excavator with a plurality of cutter heads attached to the front of the shield main body, the plurality of cutter heads are arranged eccentrically with respect to the rotation center of each rotation drive part, and the outer periphery of each cutter head is A flexible cross-section shield excavator characterized by being provided with a cutting device whose tip trajectories appear and retract so that they overlap each other.