JP2001317291A - Tunnel excavation method and shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously excavate a tunnel with an eyebrow type section at a normal part and a tunnel with a flat eyebrow type section at an expansion part where width has been expanded. SOLUTION: When normal and expansion parts are to be excavated continuously by a shield machine having two cutter heads 11 where a top part is inflated to the positions of three vertexes of a Rulon's triangle in terms of front view, a cutter rotation shaft 9 for rotating and driving the cutter head 11 when excavating the expansion part is arranged while it is eccentric by a specific amount from an eccentricity shield axis center Oe and at the same time is revolved around the eccentricity shield axis center Oe, and the ratio between the rotation speed and revolution speed of the cutter rotation shaft 9 is set to 1: 3 for rotating in the same direction, thus excavating a tunnel Te with a flat eyebrow type section where two elliptics overlap partially by the cutter header 11, rotating and driving the cutter rotation shaft 9 and at the same time stopping the revolution drive for excavating a tunnel Tc with the eyebrow type section where two circles overlap partially at the time of the excavation of the normal part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield excavator having a double cutter head for excavating a tunnel in a scalable manner by a shield method.

[0002]

2. Description of the Related Art For example, in a tunnel for setting a road or a railway, an extension part for forming a retreat part or a station part is usually provided during excavation of a excavation part.

[0003] The excavation of such an extension is described in US Pat. After excavating and lining a circular tunnel, the ground of the extension is frozen and the side walls are crushed, excavated and lining. . Use a copy cutter to increase the diameter of the shield machine. . There has been proposed a method in which a plurality of sub-cutter heads are detachably provided around a main cutter head, and tunnels having different diameters are excavated by mounting or removing the sub-cutter heads on the way.

[0004]

However, in the above-mentioned conventional method, the excavation distance of the extension part becomes long,
When there are a plurality of locations, there is a problem that excavation of the extension requires a large cost and time. In addition, the diameter increase amount cannot be increased due to the structure. In addition, if it expands up, down, left and right around the tunnel, it will be necessary to excavate an extra part, which is disadvantageous in terms of segment and cost. In this case, there is a problem that the structure of the shield machine becomes complicated, and it takes a long time to attach and detach the sub cutter head in the tunnel, thereby increasing the cost.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a shield machine capable of continuously excavating a tunnel at a normal portion and a tunnel at an extended portion during excavation at a low cost.

[0006]

According to a first aspect of the present invention, there is provided a tunnel excavating method according to the first aspect of the present invention, wherein a top of the shield body bulges at three vertexes of a ruler triangle in a front view in a front view. A tunnel excavation method for continuously excavating a normal portion and an extension portion of a tunnel by a shield machine having two cutter heads, wherein the excavation of the normal portion includes
Each of the two cutter heads is driven to rotate about the cutter rotation axis to excavate a tunnel having a cocoon-shaped cross section or a tunnel having an elliptical cross section in which a part of two circular cross sections is overlapped. The cutter head is driven to rotate around the cutter rotation axis and revolves around the eccentric shield axis, which is eccentric by a predetermined amount from the cutter rotation axis, and rotates in the same direction at a rotation speed ratio of the rotation drive and the rotation drive of 3: 1. With the cutter head, a tunnel having an elliptical cross section is excavated by the cutter head, and a tunnel having a deformed cocoon cross section in which a part of the ellipse and a circle overlap or a tunnel having a flat cocoon cross section in which two ellipses partially overlap is excavated. Things.

[0007] According to the above excavation method, by simply revolving one or two cutter heads by the extension part by one shield excavator, an irregularly shaped eyebrow shape having an elliptical cross section expanded in the major axis direction. A tunnel having a cross-section or a flat cocoon-shaped cross section can be excavated. A tunnel having a cocoon-shaped cross section in which a part of a circular portion of a normal portion is overlapped can be excavated simply by stopping the revolution drive and driving the cutter head to rotate. Therefore, it is possible to easily and continuously form a wide-width tunnel and a normal-width tunnel, and it is possible to obtain an arbitrarily wide width by setting the amount of eccentricity.

The tunnel excavation method according to claim 2 is
In the above method, the two eccentric shield axes are respectively arranged on the same plane including the rotation axis at the time of normal part excavation, and the major axis of the ellipse coincides with the plane by setting the cutter head at a predetermined angular position. Then, at the time of excavation of the normal part, the three apexes of the two cutter heads are respectively retracted to match the minor diameter of the ellipse of the flat cocoon-shaped tunnel with the circular diameter of the cocoon-shaped tunnel.

According to the above construction, the circular rotary tunnel is excavated by driving the cutter rotation axis on the major axis of the elliptical cross-sectional tunnel in the flat cocoon shape, and the minor diameter of the flat cocoon-shaped tunnel and the circular shape of the cocoon-shaped tunnel are rounded. Since the diameter of the lining is made to be the same, the step of the tunnel in the minor axis direction can be eliminated, and the wall surface of the lining can be continued, and the construction can be facilitated.

[0010] The shield machine according to claim 3 further comprises:
At the front of the shield body, two revolving supports are arranged rotatably around an axis parallel to the shield axis, and these revolving supports are parallel to the shield axis and a predetermined distance from the eccentric shield axis. The two eccentric cutter rotation shafts are rotatably arranged, and the cutter heads provided at the front of the cutter rotation shafts have a shape in which the top bulges at the vertex position of a ruler triangle in front view. A shield machine capable of continuously excavating a normal portion and an extended portion of a tunnel, wherein at the time of excavating a normal portion, the revolving supports are respectively fixed at predetermined positions, and the cutter rotation shafts are respectively rotationally driven to rotate. The cutter head is configured to excavate a tunnel having a cocoon-shaped cross section in which a part of two circular cross sections is overlapped, and at the time of excavation of the extension portion, at least one of the revolution support and the cutter rotation axis have a rotation speed ratio in the same direction. A tunnel head with an elliptical cross section is excavated by its cutter head by rotating and driving so as to be in a one-to-one relationship, and a tunnel with an irregularly shaped eyebrow cross section in which a part of the ellipse overlaps a circle or a flat in which a part of two ellipses overlaps. It is designed to excavate a tunnel with a cocoon-shaped cross section.

[0011] According to the shield machine described above, in the extension portion,
By rotating one or both revolving supports and the cutter rotation axis in the same direction at a speed ratio of 3: 1, a tunnel with an elliptical cross-section is excavated, and a tunnel with an irregular or oblong cross section is excavated. Then, by stopping the rotation of the revolving support and rotating only the cutter rotation shaft, it is possible to excavate a tunnel having a cocoon-shaped section of a normal portion. Thereby, the extension part and the normal part can be continuously excavated by one shield excavator. In addition, the position of the circular tunnel in the eyebrow section can be arbitrarily set on the eccentric arc by the stop position of the cutter rotation shaft, and a sufficient expansion width can be obtained by setting the amount of eccentricity.

According to a fourth aspect of the present invention, in the above construction, the two eccentric shield axes are respectively arranged on the same plane including the rotation axis at the time of excavating the normal part, and the cutter head is set at a predetermined angle. Set the position of the ellipse to match the major axis of the ellipse on the plane, provide a top retreat device capable of retreating the top of the cutter head, at the time of excavation of a normal part, retreat the top of the cutter head by the top retreat device, The configuration is such that the diameter of the cutter head is the same as the minor diameter of the ellipse of the tunnel with the oblique cross section and the tunnel with the cross section is excavated.

[0013] According to the above construction, the circular section tunnel is excavated by driving the cutter rotation axis on the major axis of the ellipse of the irregular or flat cocoon-shaped section tunnel. The construction body wall can be continuous, and the construction can be facilitated.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shield machine according to the present invention will be described with reference to FIGS.

As shown in FIG. 7, this double shield excavator has a normal portion Ec composed of a cannulated cross-section tunnel Tc in which two circular cross-section sides are overlapped, and two side portions having a horizontally long elliptical cross-section. It is configured to be able to continuously excavate the extended portion Ee composed of the tunnel Te having a superimposed horizontal oblong cross section. For example, two pairs of rails R provided in the tunnels Tc and Te are provided.
A station ST or the like can be formed in the center of R1, R2.

Here, a description will be given of a cross-sectional shape of a tunnel excavated by the shield machine. FIG. 8A shows a cocoon-shaped cross section in which a part of two circular tunnels overlaps, and this is a tunnel of the normal part Ec. FIG. 8 (b) shows an oval cross-section in which the tops of the cocoon-shaped arcs are connected by a plane. When the cocoon-shaped cross-section is changed to an oval cross-section, the fixed cutter disposed on the shield body 1 is used. 10 and the like can easily be formed by excavating. Therefore, in the description of this specification, it is assumed that an oval cross section is included in the eyebrow cross section, and different display lines are used in the drawings to mix. In the case shown in FIG. 8 (c), a shape in which a part of a circle and a part of an ellipse are overlapped is referred to as a deformed eyebrow shape. Further, the one shown in FIG. 8 (d) has a shape in which a part of two oblong cross sections in the major axis direction overlaps with each other, and is called a flat cocoon shape. Here, the expanded portion Ee has this cross section. It also includes an oblong shape in which the tops are connected by a plane.

In FIG. 1 to FIG. 3, reference numeral 1 denotes a shield main body which can be expanded and contracted in the width direction, and a pressure partition wall 3 which forms a pressure chamber 2A for holding a face collapse earth pressure is provided at a front portion. Revolution support members 5 and 5 are rotatably supported around eccentric shield axis Oe through bearings in through holes 4 and 4 formed on both sides of the center of pressure partition wall 3, respectively. The center Oe is arranged on the major axis La.
The revolving support 5 is formed with aligning holes 6 and 6, respectively. In the aligning holes 6 and 6, the aligning bodies 7 and 7 are rotated via a bearing in parallel with the eccentric shield axis Oe. Axis Os
Each is rotatably supported around. In both aligning bodies 7, shaft support holes 8 are respectively formed on eccentric circular arcs Ce whose eccentric distance e is a radius from the eccentric shield axis Oe, and the cutter rotation shafts 9 are respectively eccentric in the shaft support holes 8. It is rotatably supported around a rotation axis Os parallel to the shield axis Oe. Here, the cutter driving mechanism such as the cutter rotation shaft 9 and the cutter head 11 and the aligning body 7 attached to the front end of the cutter rotation shaft 9 disposed on the right and left sides of the shield body 1 have a symmetrical structure as shown in the drawing, or Since they have the same structure, only one will be described, and the other will be assigned the same reference numerals and description thereof will be omitted.

At the front end of the cutter rotation shaft 9, a cutter head 11 having a triangular shape as viewed from the front is attached. As shown in FIG. 4, this Luro triangle is formed around any vertices C1 to C3 of an equilateral triangle.
The shape is surrounded by three subarcs S passing through two vertices with one side as a radius. And this cutter head 11
As shown in FIGS. 1 and 2, for example, a spoke arc 12 extending radially every 60 ° from the cutter rotation axis, and a subarc connecting the tops 11 a to 11 c adjacent to the tip tops 11 a to 11 c of the spokes 12. It has a frame portion 13 and a sediment inlet 14 formed between the spoke portion 12 and the subarc frame portion 13. A large number of cutter bits 15 are attached to the spoke portion 12 and the subarc frame portion 13, respectively. . Each of the tops 11a to 11c is cut out by an arc surface having a radius Rb centered on the rotation axis Os of the cutter rotation shaft 9, and each of the cut tops 11a to 11c is cut out.
The top cutter 17 that can move back and forth to the vertices C1 to C3 at c.
And a top retracting device 19 comprising a cutter retracting device 18 which is provided in the spoke portion 12 and drives the top cutter 17 to move back and forth from the vertices C1 to C3 to the retracted position.

A cutter driving device 21 and an aligning device 22 are provided on the pressure chamber 3 on the side of the atmosphere chamber 2 B. The cutter driving device 21 causes the cutter head 11 to rotate the eccentric arc through the revolution support 5. It comprises a revolving drive unit 23 that revolves on Ce, and a revolving drive unit 24 that drives the cutter rotation shaft 9 to rotate around the rotation axis Os.

That is, the revolving drive unit 23 is driven by a revolving ring gear 31 provided on the back surface of the revolving support 5 and a revolving drive unit 32 meshed with the revolving ring gear 31 and disposed on the pressure partition 3. And a revolving pinion 33 to be used. The rotation drive unit 24 includes a gear box 36 disposed on the shield body 1 via a reaction force support mechanism 35, a rotation gear 34 fixed to the cutter rotation shaft 9 in the gear box 36, and the gear box 36. A rotation driving device 37 provided on the motor 36 and a rotation pinion 38 that is rotationally driven by the rotation driving device 37 and meshes with the rotation gear 34.

The reaction force support mechanism 35 is constituted by a cross slider mechanism for following the cutter rotation shaft 9 which is revolved (and displaced). That is, as shown in FIG. 6, the reaction force support mechanism 35 has an opening 41a.
A pair of first slider rods 4 on a line orthogonal to the rotation axis Os on the intermediate support 41 on which the cutter rotation axis 9 is loosely fitted.
2 project in the symmetrical direction, and these first slider rods 4
2 are supported by first slide support members 43 provided on the shield body 1 slidably in the length direction. A pair of second slider rods 44 orthogonal to the rotation axis Os and the axis of the first slider rod 42 project from the gear box 34 in a symmetrical direction.
A second slide support member 45 that supports the second slider rod 44 slidably in the length direction is provided on the intermediate support 41. This cross slider mechanism allows the cutter rotation shaft 9 and the gear box 36 that revolve and move (and aligns) to move, while reducing the rotational reaction force applied to the gear box 36 when the rotation pinion 38 is driven to rotate. 1 can be supported. When the extension Ee is excavated, the cutter driving device 21 rotates the revolving speed of the cutter head 11 revolved on the eccentric arc Ce by the revolving driving unit 23 and the cutter driving shaft 24 via the cutter rotating shaft 9. Rotation speed (number of rotations) at which the cutter head 11 is rotated (rotated) by 3 in the same direction.
By setting the ratio to one, a tunnel having an elliptical cross section shown in FIG. 2 can be excavated. Also, by increasing the amount of eccentricity e, it is possible to excavate a tunnel having an elliptical cross section having a large minor axis: major axis ratio, and to obtain a flat eyebrow-shaped tunnel T
The extension width of e can be increased.

The cross section of the tunnel Te excavated by the one cutter head 11 is, as shown in FIGS.
R = 3r ² / [8 × (r / 2−2 × e)] where R is the distance r to 3 and the length of the side connecting the tops C1 to C3.
+ R / 4-e ... Therefore, assuming that the major axis of the ellipse is a and the minor axis is b, a = 2 × (r + e)... B = 2 × (r−e).

In this embodiment, the excavation is performed so that the diameter of the circular portion of the tunnel Tc of the eyebrow-shaped section of the normal portion Ec is equal to the minor axis of the elliptical portion of the tunnel Te of the flat-shaped cocoon-shaped cross section of the expanded portion Ee. Therefore, the radius Rb × 2 = b of the notches 11 a to 11 c of the cutter head 11 is set.

The centering device 22 adjusts the relative position between the circular portion of the tunnel Tc having a cocoon-shaped cross section and the elliptical portion of the tunnel Te having a flat cocoon-shaped cross section at the same position. It can be set arbitrarily and can be displaced depending on the position of the revolution support 5.
Here, the eyebrow section tunnel Tc is used as the tunnel design.
In order to extend both sides of the tunnel, the inside of the circular portion of the cocoon-shaped tunnel Tc and the flat cocoon-shaped tunnel T
Are set so that the long-diameter ends of the elliptical portions are in contact with each other at the contact point (C2).

That is, as shown in FIGS. 4 and 5, when one of the cutter heads 11 excavates the normal portion Ec,
The circular shield axis Oc is located on the major axis La of the flat cocoon-shaped section tunnel Te, and is used for transition from the flat cocoon-shaped section tunnel Te to the cocoon-shaped section tunnel Tc or from the cocoon-shaped section tunnel Tc to the flat-shaped cocoon section tunnel Te. In order to minimize the moving distance of the cutter rotation axis 9 (rotation axis Os), the intersection point of the contact point where the eccentric arc line Ce and the major axis La intersect at the shift to the rotation stop position Cep of the revolution support 5. Is set to Then, the rotation center Od of the aligning body 7 may be arranged on a bisector connecting the revolution stop position Cep and the circular shield axis Oc. Here, the rotation center Od is arranged on the major axis La. . Therefore, the cutter rotation axis 9 (rotation axis Os) is moved between the revolution stop position Cep and the circular shield axis Oc by rotating the alignment body 7 by 180 ° using the alignment apparatus 22. Can be.

As shown in FIG. 9, the aligner 7 is rotated about the rotation center Od in the direction of the arrow, and at the same time, the revolving support 5 is rotated about the elliptical shield axis Oe. 9 can be moved along the major axis La. At this time, while the cutter head 11 is driven to rotate, the top cutter 17 is projected by the cutter retracting device 18 on the long diameter side of the rotation trajectory, as shown in FIG. Or the tunnel transition portions Te1, Te2, Te3 which transition from the flat-shaped cocoon-shaped section tunnel Te to the cocoon-shaped section tunnel Tc can be excavated sequentially.

As shown in FIG. 3, the centering device 22 includes:
A ring-shaped aligning worm gear 46 provided on the back surface of the aligning body 7, and an aligning drive device 47 provided on the revolution support 5;
And an aligning worm 48 which meshes with the aligning worm gear 46 and is rotationally driven by an aligning drive device 47.

In FIG. 3, reference numeral 61 denotes a mud pipe for supplying muddy water or slurry for improving the properties of the soil to the pressure chamber 2A, 62 a mud drain pipe for discharging the excavated sediment, and 63 agitating the sand in the pressure chamber 2A. Agitator. Although not shown, the shield body 1 is divided into a plurality of sections and a tunnel T having a circular cross section.
It is configured to be able to expand and contract between a cocoon-shaped cross section that matches c and an elliptical cross section that matches a tunnel Te with a flat cocoon-shaped cross section. A segment assembling apparatus for assembling a segment having a circular cross section or an elliptical cross section is provided at a rear portion of the shield main body 1. Further, a well-known propulsion jack is provided for advancing the shield main body 1 with the assembled segment as a reaction force receiver.

Next, an excavation method using the above-described double shield excavator will be described. In the excavation work of the normal part Ec, the top cutter 17 is retracted by the top retreating device 19, and both revolving supports 5 are stopped (fixed) at predetermined positions.
Each of the circular shield axes O
The left and right cutter heads 11 at the position c are driven to rotate to excavate a tunnel Tc having a brow-shaped cross section with a radius Rb (= short diameter b), and stop just before the extension Ee.

Next, the shield main body 1 is expanded while performing widening excavation of the cutter. The procedure is as follows. For example, the aligning body 7 is rotated by 180 ° by the aligning device 22, and the cutter rotation shaft 9 is moved from the circular shield axis Oc position to the revolution stop position C.
Turn to ep. Next, the top cutter 17 is projected to the vertices C1 to C3 of the rule of the ruler, respectively,
The cutter head 11 is rotated by the rotation drive unit 24 of the cutter driving device 21 through the cutter rotation shaft 9, and the cutter head 11 is rotated by the orbital drive unit 23 through the revolution support 5 along the eccentric arc Ce. I do. By making the revolving speed and the rotation speed of the cutter head 11 3: 1 in the same direction, it is possible to continuously form the flattened oval-shaped tunnel Te with the left and right sides expanded, respectively. .

In the above-mentioned method, the tunnel head Tc having the circular cross section is directly shifted to the tunnel Te having the elliptical cross section, and the tunnel head Te having the elliptical cross section is directly shifted to the tunnel Tc having the circular cross section. By rotating and driving the cutter head 11 while moving the cutter head 11 along the same direction and projecting the top cutter 11 only on the extension side, it is possible to excavate the tunnel of the elliptical transition parts Te1 and Te2 shown in FIG. That is, when shifting from the tunnel Tc having a cocoon-shaped cross section to the tunnel Te having a flat cocoon-shaped section, the aligning body 7 is rotated around the rotation center Od to Oc1 as shown by an arrow A, and at the same time, the revolution support 5 is made elliptical. By rotating around the shield axis Oe, the cutter rotation axis 9 is moved along the major axis La to the circular shield axis Oc2. At this time, while the cutter head 11 is driven to rotate, the top cutter 17 is projected by the cutter retracting device 18 on the extension side of the rotation trajectory to excavate the surplus portion Ee1, thereby excavating the tunnel transition portion Te1. Similarly, the cutter rotation axis 9 is moved along the major axis La to the circular shield axes Oc3 and Oc4.
To Cep, and the top cutter 17 is protruded, thereby excavating the extra excavations Ee2 to Ec4. When the cutter rotation shaft 9 is moved to Cep, the top cutter 17 is protruded to the vertices C1 to C3 of the ruler triangle, respectively, and the revolution speed and the rotation speed of the cutter head 11 are set to 3: 1 in the same direction, and The cutter head 11 excavates an elliptical portion having a long diameter a and a short diameter b, one side of which is in contact with the circular portion of the tunnel Tc having a cocoon-shaped cross section and the other side of which is expanded, to form a horizontally long cocoon-shaped cross-section tunnel Te.

In the case of shifting from the tunnel Te with a flat-shaped cocoon section to the tunnel Tc with a cocoon-shaped section, the procedure can be reversed. According to the above embodiment,
At the time of excavation of the extension part Ee, the revolving support unit 5 of the left and right cutter driving devices 21 rotates the revolving support 5 to revolve the left and right cutter heads 11 at eccentric positions, and the rotation driving unit 24 causes the cutter rotation shaft 9 to rotate. By rotating the cutter head 11 through each of the tunnels, a tunnel Te having a flat-eyebrow-shaped section is excavated. Further, when the normal portion Ec is excavated, the left and right cutter heads 11 are respectively driven to rotate by the rotation driving unit 24 via the cutter rotation shaft 9 in a state where the left and right revolving supports 5 are fixed, and a part of the circle is overlapped. It is possible to excavate a tunnel Tc having a cocoon-shaped cross section. Therefore, the extension excavation part Ee
And the normal excavation portion Ec can be formed continuously, and a sufficient expansion width can be obtained by setting the amount of eccentricity e.

When excavating the extension Ee, the top cutter 1
7 is protruded to make the cutter head 11 have a triangular shape with a ruler in front view, and the top cutter 17 is retracted during the excavation of the normal portion Ec to use the cutter head 11 having a reduced diameter. The minor axis of Te and the minor axis of the tunnel Tc of the eyebrow section are set to be the same, and the cutter rotation axis 9 at the time of excavation of the normal part Ec is changed to the major axis La of the elliptical section tunnel.
Since it is arranged at the position of the circular shield axis Oc above, the tunnel Te having a flat cocoon-shaped cross section and the tunnel Tc having a cocoon-shaped cross section can be continued without any vertical step. When the center of rotation of the aligning body 7 is set at a position eccentric from the major axis La, the rotation of the aligning body 7 can be set to 180 ° or less.

FIGS. 9 and 10 show another embodiment of the centering device 22. FIG. In the above embodiment, the cutter rotating shaft 9 is configured to be displaced between the revolution stop position Cep and the circular shield axis Oc by rotating the aligning body 7 by the aligning device 22. In 53, the cutter rotation shaft 9 is configured to move linearly.

That is, a slide space 51 including the revolution stop position Cep of the cutter rotation shaft 9 and the circular shield axis Oc is formed in the revolution support 5 at the revolution stop position Cep, and the cutter rotation shaft 9 is formed in the slide space 51. A rotatably supported bearing block 52 is slidably disposed via a guide device, and the bearing block 52 is rotated around a revolution stop position Cep.
Aligning device 5 for moving between the shaft center Oc and the circular shield axis Oc
3 and a slide cover 54 that covers a portion of the slide space 51 where the bearing block 52 is not provided. The centering device 53 may be a hydraulic cylinder device or the like as long as it is a linear drive mechanism, but here is constituted by a feed screw mechanism. That is, screw shafts 53a are respectively arranged on both sides of the slide space 51 on the back surface of the revolving support 5, and a winding interlocking mechanism 53b that interlocks the left and right screw shafts 53a and a control that rotationally drives one of the screw shafts 53a. A heart drive 53c is provided. And the bearing block 5
Female screw member 5 fitted on the screw shaft 53a
3d is provided. Therefore, the screw shaft 53a is rotationally driven by the alignment driving device 53c, the bearing block 52 is slid via the female screw member 53d, and the cutter rotation shaft 9 is moved between the revolution stop position Cep and the circular shield shaft Oc. Can be.

In the above-described embodiment, the cutter head 11 is formed in a triangular shape with a ruler when viewed from the front, but it may be a spoke-shaped cutter head in which three spokes extend to the top of the triangular rule. Also, a cutting tool can be appropriately provided with a cutting tool within the range of the ruler triangle.

Further, although the major axis La of the tunnel Te having a flat cocoon cross section is set to the horizontal direction, the major axis La may be inclined according to the cross section or may be set to the vertical direction depending on the specification of the tunnel. it can.

Further, the left and right cutter heads 11 were revolvingly driven during the excavation work of the expansion portion. However, one cutter head 11 was revolvingly driven and revolvingly driven, and the other cutter head 11 was revolvingly driven only by elliptical and circular shapes. Can be excavated to form a partially magnified cocoon shaped tunnel to form an extension with only one side extended.

[0039]

As described above, according to the tunnel excavation method of the first aspect, one shield excavator can
By simply revolving one or two cutter heads in the extension part, a tunnel with an elliptical cross-section or an oblong cross-section that is extended in the major axis direction can be excavated. Just drive the cutter head to rotate,
It can excavate a tunnel with a cocoon-shaped cross section in which a part of the normal part overlaps. Therefore, it is possible to easily and continuously form a wide-width tunnel and a normal-width tunnel, and it is possible to obtain an arbitrarily wide width by setting the amount of eccentricity.

Further, according to the tunnel excavation method of the second aspect, the circular section tunnel is excavated by driving the cutter rotation axis on the major axis of the elliptical section tunnel of the flat eyebrow shape.
Since the minor axis of the flat-shaped cocoon-shaped cross-section tunnel and the diameter of the circular portion of the cocoon-shaped cross-section tunnel are matched, the step of the tunnel in the minor axis direction can be eliminated and the lining wall can be continued,
Construction can be facilitated.

In the shield machine according to the third aspect of the present invention, one or both of the orbital revolving supports and the cutter rotating shaft are rotated in the same direction at the expansion portion at a speed ratio of 3: 1 to form an elliptical shape. By excavating a tunnel with a cross section, excavating a tunnel with a deformed cocoon-shaped or flat cocoon-shaped section, stopping the rotation of the revolving support and rotating only the cutter rotation axis, the tunnel with a cocoon-shaped section of the normal part is formed. Can excavate. Thereby, the extension part and the normal part can be continuously excavated by one shield excavator. In addition, the position of the circular tunnel in the eyebrow section can be arbitrarily set on the eccentric arc by the stop position of the cutter rotation shaft, and a sufficient expansion width can be obtained by setting the amount of eccentricity.

According to the shield excavator of the fourth aspect, the circular section tunnel is excavated by driving the cutter rotation axis on the elliptical major axis of the tunnel having the irregular or flat-shaped cocoon section. By eliminating the step, the wall surface of the lining can be continuous, and the construction can be facilitated.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a shield machine according to the present invention and showing an excavation work of a normal part.

FIG. 2 is a front view showing excavation work of an extension of the shield machine.

FIG. 3 is a side sectional view of the shield machine.

FIG. 4 is an overall front view illustrating driving of a cutter head of the shield machine.

FIG. 5 is an enlarged view of a main part shown in FIG. 4;

FIG. 6 is a rear view showing a gear box reaction force support mechanism of the shield machine.

7A to 7D show a tunnel excavated by the shield machine, FIG. 7A is a plan sectional view of the tunnel, FIG. 7B is a sectional view taken along line II, and FIG. II cross section,
(D) is a III-III sectional view.

8 (a) to 8 (d) show cross-sectional shapes of a tunnel excavated by the shield machine, (a) is a tunnel having a cocoon-shaped cross section, (b) is a tunnel having an oval cross section, and (c). FIG. 3 is a cross-sectional view showing a tunnel having a deformed cocoon shape, and FIG.

FIG. 9 is a main part front view for explaining an excavation operation of a tunnel transition part by the shield machine.

FIG. 10 is a front view illustrating an excavation state of a tunnel transition portion by the shield machine.

FIG. 11 is a fragmentary front view of a modified example of the cutter driving device of the shield machine, illustrating an excavation operation of a tunnel transition portion.

FIG. 12 is a rear view showing another embodiment of the centering device of the shield machine.

13 is a sectional view taken along the line II shown in FIG. 12;

[Explanation of symbols]

 Tc Eyebrow cross section tunnel Te Flat eyebrow cross section tunnel Ec Normal part Ee Expansion part Oe Eccentric shield axis Oc Circular shield axis Ce Ce Eccentric arc La Long axis 1 Shield body 3 Pressure bulkhead 5 Revolution support 7 Alignment body 9 Cutter rotation Shaft 11 Cutter head 17 Top cutter 18 Cutter retracting device 19 Top retracting device 21 Cutter driving device 22 Alignment device 23 Revolution driving unit 24 Rotation driving unit 32 Revolution driving device 35 Reaction force support mechanism 37 Rotation driving device 47 Alignment Drive

Claims (4)

[Claims] 1. A normal section and an extension section of a tunnel are provided at a front portion of a shield body by a shield excavator having two cutter heads whose tops bulge at three apexes of a ruler triangle in front view. A tunnel excavation method for continuously excavating a tunnel, wherein, when excavating a normal portion, two cutter heads are each driven to rotate about a cutter rotation axis, and two circular cross-sections partially overlap each other. Or excavate a tunnel with an oval cross section, and at the time of excavation of the extension, rotate and drive at least one of the cutter heads around the cutter rotation axis and revolve around the eccentric shield axis eccentric by a predetermined amount from the cutter rotation axis, By rotating the rotation speed ratio of the revolution drive and the rotation drive in the same direction at a ratio of 3: 1, a tunnel having an elliptical cross section is excavated by the cutter head, and the ellipse and the circle are excavated. Tunneling method, wherein a portion to excavate tunnel flat cocoon-shaped cross section partially overlap profiled cocoon-shaped cross section or two oval overlap of. 2. The two eccentric shield axes are respectively arranged on the same plane including the rotation axis at the time of excavating a normal part, and the major diameter of the ellipse is set on the plane by setting the cutter head at a predetermined angular position. When excavating a normal part, the three apexes of the two cutter heads are retracted, respectively, so that the minor diameter of the ellipse of the flat cocoon-shaped tunnel matches the circular diameter of the cocoon-shaped tunnel. The tunnel excavation method according to claim 1, wherein: 3. A revolving support body is provided at a front portion of a shield body so as to be rotatable around an axis parallel to the shield axis.
On these revolving supports, two cutter rotation axes parallel to the shield axis and eccentric from the shield axis by a predetermined distance are rotatably disposed, respectively, and cutter heads provided respectively in front of the cutter rotation axes are provided. Is a shield excavator capable of continuously excavating a normal portion and an extended portion of a tunnel, the top portion of which is bulged at the vertex position of a triangle of a ruler in a front view. Are fixed at predetermined positions, respectively, and the cutter rotation shafts are respectively driven to rotate so as to excavate a tunnel having a cocoon-shaped cross section in which a part of two circular cross sections is overlapped by both cutter heads. At least one revolving support and the cutter rotation axis are driven to rotate in the same direction so that the rotation speed ratio becomes 3: 1, and a tunnel having an oval cross section is excavated by the cutter head. Shield machine, characterized by being configured so as to excavate round and round profiled cocoon-shaped cross section partially overlap tunnel or two tunnels flat cocoon-shaped cross section partially overlap the oval. 4. The two eccentric shield axes are arranged on the same plane including the rotation axis at the time of excavation of a normal part, and the major axis of the ellipse is set on the plane by setting the cutter head at a predetermined angular position. A top retreat device capable of retreating the top of the cutter head is provided.When excavating a normal portion, the top retreat device retreats the top of the cutter head to reduce the diameter of the cutter head to the elliptical length of the flat-browned cross section tunnel. 4. The shield machine according to claim 3, wherein the tunnel has the same diameter as that of the tunnel and is excavated.