JP2021075842A - Construction method of tunnel curved part in shield tunneling method - Google Patents

Abstract

To provide a construction method of a tunnel curved part preventing rolling of a shield machine, when constructing the tunnel curved part using a tapered hexagonal segment.SOLUTION: In the construction method of a tunnel curved part in a shield tunneling method, long side joint parts J1 of hexagonal segments SG having long side joint parts J1 formed facing each other and tapered in plan view and V-shaped inclined joint parts J2 projectedly formed at both sides of the long side joint part J1, are assembled zigzag toward front and rear directions of an excavation pit, to thereby construct the tunnel curved part covering an inner peripheral face of the excavation pit. The cutting face sides of a lining body B formed of an annularly assembled tapered hexagonal segment SG are pressed with an equal pressing force, respectively, by all of the shield jacks 9b of a shield machine.SELECTED DRAWING: Figure 10

Description

The present invention relates to a method for constructing a curved portion of a tunnel in a shield method, and more particularly to a technique for constructing a curved portion of a tunnel by assembling hexagonal segments in an annular shape.

The shield excavator excavates the ground by rotating the cutter board pressed against the face while stabilizing the face, while constructing a tunnel by assembling segments in a ring shape on the inner circumference of the excavated pit. It is a device.

The main body of the shield excavator has a front body and a rear body. The front torso is flexibly connected to the front end of the rear torso. In the main body of the device, a plurality of center-folding jacks are arranged between the front body and the rear body, and a plurality of propulsion jacks are arranged on the rear body along the circumferential direction of the device. Generally, the attitude of the shield excavator is controlled by selecting the center-folding jack or the propulsion jack.

Then, when constructing a tunnel curved portion with a shield excavator, it is a segment assembly that is bent in a target direction by using a segment in which the front and rear joints located in front of and behind the excavation pit are tapered. Build a lining body.

As for the construction of the tunnel curved portion by the shield excavator, for example, the one described in Patent Document 1 is known.

JP-A-2005-330794

The segment includes a hexagonal segment having a long-sided joint formed to face each other and a V-shaped inclined joint formed to protrude on both sides of the long-sided joint. In the hexagonal segment, the long side joints are arranged facing the front and back of the excavation pit and assembled in a staggered manner to construct a tunnel covering the inner peripheral surface of the excavation pit. When a tunnel curved portion is constructed using this hexagonal segment, a hexagonal segment for the curved portion in which the opposing long side joints are tapered in a plan view is used.

Here, when a tapered hexagonal segment is used, a couple is generated in the circumferential direction because the propulsion jack and the end surface of the hexagonal segment (pressing surface by the propulsion jack) are not orthogonal to each other.

In the hexagonal segment, convex portions close to the face and trapezoidal concave portions recessed by half the width of the hexagonal segment from the convex portion are alternately formed along the circumferential direction (concave and convex formation). In the hexagonal segment forming the convex portion, the binding force in the circumferential direction becomes weak. In addition, the difference in stroke length between the plurality of propulsion jacks that press the end faces of the hexagonal segments formed in the uneven shape becomes large, and the balance deteriorates.

Therefore, when the end face of the tapered hexagonal segment assembled in a staggered manner is pressed to advance the shield excavator, rolling is more likely to occur as compared with the case where the normal rectangular segment is pressed.

The present invention has been made from the above-mentioned technical background, and provides a technique capable of preventing rolling of a shield excavator when constructing a curved portion of a tunnel using a tapered hexagonal segment. The purpose is to do.

In order to solve the above problems, the method of constructing the tunnel curved portion according to claim 1 of the present invention includes a front body portion provided with a cutter head and a rear end of the front body portion provided with a plurality of propulsion jacks in the circumferential direction. A center-folding jack provided on the portion and a plurality of jacks arranged in the circumferential direction between the front body portion and the rear body portion to flexibly connect the front body portion and the rear body portion. It is provided with a long-sided joint formed to face each other and tapered in a plan view, and a V-shaped inclined joint formed to protrude on both sides of the long-sided joint. It is a construction method of the tunnel curved part in the shield method in which the long side joint of the hexagonal segment is assembled in a staggered manner toward the front and back of the excavation pit to construct the curved part of the tunnel covering the inner peripheral surface of the pit. Then, the face side of the lining body composed of the hexagonal segments assembled in an annular shape is pressed by all the propulsion jacks with the same pressing force to take a reaction force, and the shield excavation is carried out by the center-folding jack. It is characterized by controlling the propulsion direction of the machine.

According to the present invention, when a lining body composed of tapered hexagonal segments is pressed by a propulsion jack, the couple generated in each hexagonal segment is offset. In this way, the couple when the end face of the tapered hexagonal segment assembled in a staggered pattern is pressed by the propulsion jack is canceled between the segments, so the curve of the tunnel using the tapered hexagonal segment is used. It is possible to prevent the shield excavator from rolling when constructing the part.

It is a block diagram which saw through the inside of the shield excavator used in the construction method of the tunnel curve part in the shield construction method which is one Embodiment of the invention from the side. It is a top view of the hexagonal segment used for the construction of the straight part of a tunnel. It is a front view of the hexagonal segment of FIG. It is a side view of the hexagonal segment of FIG. It is a figure which shows the ring-shaped lining body constructed by assembling the hexagonal segment of FIG. 2 from the side view. (A) is a plan view showing an example of a tapered hexagonal segment used for construction of a curved portion of a tunnel, and (b) is a cross-sectional view taken along line xx of (a). (A) is a plan view showing another example of the tapered hexagonal segment used for construction of the curved portion of the tunnel, and (b) is a cross-sectional view along the yy line of (a). It is a figure which shows the ring-shaped lining body constructed by assembling the tapered hexagonal segment from the side. It is explanatory drawing which shows the couple generated when the tapered hexagonal segment is pressed by a propulsion jack. It is explanatory drawing which shows a couple when pressed by a propulsion jack in the unfolded state of the ring-shaped lining body constructed by assembling the tapered hexagonal segment.

Hereinafter, embodiments as an example of the present invention will be described in detail with reference to the drawings. In addition, in the drawing for demonstrating the embodiment, the same constituent elements are in principle given the same reference numerals, and the repeated description thereof will be omitted.

FIG. 1 is a configuration diagram of the inside of a shield excavator used in a method of constructing a tunnel curved portion in a shield method according to an embodiment of the invention, as seen through from the side.

As shown in FIG. 1, the shield excavator 1 of the present embodiment generates mud with impermeable property and plastic fluidity by injecting an additive into the earth and sand excavated by the cutter head 2 and kneading it. Then, the mud pressure is generated by digging with the mud filled in the room between the cutter head 2 and the equipment body 3, and the excavation pit is constructed with the mud pressure counteracting the earth pressure of the face. It is a device to do.

The cutter head 2 is a member for excavating the face of the ground, and is installed on the front surface of the device main body 3 in a state of being rotatable along the circumferential direction of the cutter head 2. The cutter head 2 is equipped with various types of bits 4 for excavating a face.

The device main body 3 includes a front body portion 3a provided with the cutter head 2 described above, and a rear body portion 3b behind the front body portion 3a. The front body portion 3a and the rear body portion 3b are formed of, for example, a cylindrical steel plate, and are members that form the outer shape of the device body 3 and form a hollow space inside the device body 3.

On the front side of the front body portion 3a, a partition wall 7 is provided at a position retracted from the front surface to the inside of the device main body 3 to divide the hollow space in the device main body 3 into the face side and the inside of the machine. A chamber 6 is provided on the face side of the partition wall 7, that is, between the cutter head 2 and the partition wall 7, which is a space for taking in the earth and sand excavated by the cutter head 2. Further, inside the partition wall 7, an additive injection portion 5b, a cutter drive body 8, a center-folding jack 9a, a propulsion jack 9b, a screw conveyor 10, an erector 11, and the like are provided.

Here, the additive injection unit 5b is a device that injects the additive toward the outside of the device body 3 or the inside of the chamber 6. The cutter drive body 8 is a drive source for rotating the cutter head 2. The center-folding jack 9a is a device that flexibly connects the front body portion 3a and the rear body portion 3b and controls the propulsion direction of the shield excavator 1. The propulsion jack 9b is a device that generates a propulsive force for advancing the shield excavator 1 by taking a reaction force on a segment SG installed behind the device main body 3, and as shown in FIG. 1, the device main body 3 A plurality of shield excavators 1 are arranged side by side on the rear body portion 3b along the circumferential direction. The screw conveyor 10 is a device for discharging the earth and sand taken into the chamber 6 to the outside of the machine. The Elekta 11 is a device for gripping a segment and assembling it into an annular lining body.

By the way, in the present embodiment, the shield excavator 1 having the above configuration is used, and the hexagonal segments are assembled in a staggered manner to form an annular lining body, which is continuously connected to cover the inner peripheral surface of the excavation pit. A tunnel is built.

Here, the hexagonal segment used for the construction of the straight portion of the tunnel will be described with reference to FIGS. 2 to 4.

As shown in these drawings, the hexagonal segment SG is formed into a plane hexagonal shape curved in the circumferential direction of the tunnel, and two long-sided joints formed so as to face each other and parallel to each other in a plan view. It has a V-shaped inclined joint J2 formed so as to project on both sides of the portion J1 and the long side joint J1. Further, a gripping hole H1 into which an anchor (not shown) to be gripped by the Elekta 11 is inserted is formed in the central portion of the inner surface.

In this hexagonal segment SG, a sheath pipe T through which the hypotenuse joint bolt penetrates is embedded in parallel with one inclined surface of the inclined joint J2, and the hypotenuse joint bolt is embedded in one long side joint J1. A tightening hole H2 for tightening the sheath tube T is formed continuously with the sheath tube T. Further, in parallel with the other inclined surface of the inclined joint portion J2, an insert anchor F1 screwed with an inter-hypotenuse joint bolt penetrating the sheath pipe T of another hexagonal segment SG to be joined is embedded. Further, a suspension insert F2 used for suspending the hexagonal segment SG is embedded from the other long side joint J1 toward the inside.

Then, on the outer peripheral surface of the hexagonal segment SG, a concave ring-to-ring socket R1 and a convex inter-ring plug R2 are provided as a portion for unevenly fitting and aligning with another hexagonal segment SG. It is formed.

The hexagonal segment SG is made of reinforced concrete in the present embodiment, but may be made of steel.

Such a hexagonal segment SG is assembled in a staggered manner in the circumferential direction of the excavation pit to construct a ring-shaped lining body B shown in FIG. In the lining body B, the long side joint J1 of the hexagonal segment SG is arranged so as to face the front and back of the excavation pit (that is, the face side and the wellhead side), and the inclination of the hexagonal segment SG located in the front and back direction. By alternately connecting the joints J2 to each other, a convex portion close to the face and a trapezoidal concave portion recessed by half the width of the hexagonal segment SG from this convex portion are alternately formed along the circumferential direction ( Concavo-convex formation). Then, the front half of the next hexagonal segment SG is axially inserted into the formed recess and fitted.

Further, when assembling the hexagonal segment SG, the shield excavator 1 is hexagonal while taking a reaction force by pressing the face side of the lining body B made of the hexagonal segment already assembled in an annular shape by the propulsion jack 9b. The assembly space is formed by advancing by the width of the segment SG. Further, the propulsion direction of the shield excavator 1 is controlled by the center-folding jack 9a.

By the way, in the tunnel, there is an area of a straight part without a bend and a curved part bent in the vertical direction or the horizontal direction. When the curved portion of the tunnel is constructed using the hexagonal segment, the hexagonal segment SG for the curved portion in which the long side joint J1 is tapered is used.

An example of the hexagonal segment for the curved portion is shown in FIGS. 6 and 7. In each of the hexagonal segment SGs, the long side joints J1 formed opposite to each other are tapered in a plan view, but in the hexagonal segment SG shown in FIG. 6, the vertices of the inclined joints J2 on both sides are connected. The straight line L is inclined with respect to the long side joint J1 on the wellhead side (see FIG. 6A), and the hexagonal segment SG is slightly bent at the straight line L (see FIG. 6B). The straight line L and the long side joint J1 on the face side are parallel to each other.

Further, in the hexagonal segment SG shown in FIG. 7, the long side joint J1 on the wellhead side and the long side joint J1 on the face side are tapered, but unlike the hexagonal segment SG shown in FIG. , It is not bent at the straight line L connecting the vertices of the inclined joints J2 on both sides (see FIG. 7A). Further, the end surface of the long side joint J1 on the face side is slightly inclined with respect to the front and back surfaces (see FIG. 7B).

FIG. 8 shows a tunnel of a curved portion constructed by using such a hexagonal segment SG.

Here, as shown in FIG. 9, when the tapered hexagonal segment SG is used, the pressing direction D of the propulsion jack 9b and the end surface of the long side joint J1 on the face side of the hexagonal segment SG (that is, the propulsion jack). Since the pressing surface by 9b) is not orthogonal to each other, a couple F is generated in the circumferential direction of the tunnel in the hexagonal segment SG, and a couple F'in the opposite direction paired with the couple F is generated in the propulsion jack 9b. It will occur.

As described above, in the hexagonal segment SG, the convex portions and the concave portions are alternately formed along the circumferential direction, so that the hexagonal segment forming the convex portions has a weaker binding force in the circumferential direction. Further, since the hexagonal segment is formed to be uneven in the circumferential direction, the difference in stroke length between the plurality of propulsion jacks that press the end faces of the hexagonal segment becomes large, and the balance deteriorates.

Therefore, the shield excavator 1 that presses the hexagonal segment SG to move forward is likely to be rolled due to the influence of the couple F'of the propulsion jack 9b.

Therefore, in the present embodiment, when the face side of the lining body B composed of the tapered hexagonal segment SG assembled in an annular shape is pressed by the propulsion jacks 9b, the pressing pressures of all the propulsion jacks 9b are mutual. It is adjusted so that it is the same as. Then, the hexagonal segment SG is pushed so that all the propulsion jacks 9b have the same pressing force, and the shield excavator 1 is advanced while taking a reaction force. Is in control.

Here, FIG. 10 shows a state in which the face side of the lining body B made of the tapered hexagonal segment SG assembled in an annular shape is pressed by the propulsion jack 9b. The hexagonal segment SG with hatching in FIG. 10 is a tapered hexagonal segment SG used in the curved portion of the tunnel.

As shown in FIG. 10, when the lining body B made of the tapered hexagonal segment SG is pressed by the propulsion jack 9b, the couple generated in each hexagonal segment SG is offset.

That is, the couple Fa1 generated in the hexagonal segment SG located at the top and the couple Fa2 generated in the hexagonal segment SG located at the bottom cancel each other out in opposite directions. Further, the couple Fb1 and the couple Fb2 generated in the two adjacent hexagonal segments SG forming one side surface are offset in opposite directions. Then, the couple Fc1 and the couple Fc2 generated in the two adjacent hexagonal segments SG forming the other side surface are offset in opposite directions.

In this way, the couple when the end face of the tapered hexagonal segment SG assembled in a staggered pattern is pressed by the propulsion jack 9b is canceled between the segment SGs, so that the hexagonal segment SG is used to form a tunnel. It is possible to prevent the shield excavator 1 from rolling when constructing the curved portion.

Although the invention made by the present inventor has been specifically described above based on the embodiments, the embodiments disclosed in the present specification are exemplary in all respects and are limited to the disclosed techniques. It's not a thing. That is, the technical scope of the present invention is not limitedly interpreted based on the description in the above-described embodiment, but should be interpreted according to the description of the claims, and the scope of claims. All changes are included as long as they do not deviate from the description technology and the technology equivalent to the above and the gist of the claims.

For example, the fact that the pressing forces for pressing the end faces of the tapered hexagonal segments SG by all the propulsion jacks 9b are not exactly the same does not mean that they are exactly the same, but it is sufficient if they are substantially the same.

In the above description, the case where the present invention is applied to a mud pressure type shield excavator has been described, but the present invention is not limited to this, and for example, the pump is sent to a muddy water chamber provided in the main body of the device behind the cutter head. The muddy water is pumped by a mud pump, and the pressure of the muddy water in the muddy water chamber is adjusted to the pressure commensurate with the earth pressure and ground water pressure of the face. It can also be applied to other shield excavators such as the muddy water type shield excavator to be formed.

1 Shield excavator 2 Cutter head 3 Equipment body 3a Front body 3b Rear body 6 Chamber 7 Partition 9a Center-folded jack 9b Propulsion jack 11 Electa B Lining body F, F', Fa1, Fa2, Fb1, Fb2, Fc1, Fc2 Couple J1 Long Edge Joint J2 Inclined Joint SG Hexagonal Segment

Claims (1)

A front fuselage with a cutter head, a rear fuselage with a plurality of propulsion jacks in the circumferential direction provided at the rear end of the front fuselage, and a circumference between the front fuselage and the rear fuselage. Using a shield excavator having a center-folding jack that is arranged in a plurality of directions and that flexibly connects the front body portion and the rear body portion.
The long side of a hexagonal segment having a long side joint formed so as to face each other and tapered in a plan view and a V-shaped inclined joint formed to project on both sides of the long side joint. It is a construction method of the tunnel curved part in the shield method in which the joint part is assembled in a staggered manner toward the front and back of the excavation pit to construct the curved part of the tunnel covering the inner peripheral surface of the pit.
The face side of the lining body composed of the hexagonal segments assembled in an annular shape is pressed by all the propulsion jacks with the same pressing force against each other to take a reaction force, and the shield excavator with the center-folding jack. Control the propulsion direction,
A method of constructing a tunnel curve portion in a shield method characterized by the fact that.

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