JPH0431350Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shield excavator that facilitates construction of sharp horizontal curves.

[Prior Art] A shield excavator equipped with a circular cutter rotatably in the front has a shield frame formed by providing a cylindrical body with approximately the same diameter as the cutter and a required length in a straight line, and the rotation of the cutter A tunnel with a circular cross section corresponding to the outer diameter of the above-mentioned shield frame is excavated in the ground, and a large number of shield jacks provided along the inner circumference of the shield frame are extended, and the extension is extended along the inner circumferential surface of the tunnel. It is known to support the vehicle on stretched segments and propel it by the reaction force.

Incidentally, in recent years, tunnels have been constructed with partial curves, especially in the horizontal direction, due to the purpose of use and excavation conditions, etc., and conventional general shield tunneling machines have an external shape that is a straight line of the required length. Because of the shape of the rock, it is impossible to excavate in the required curve using general excavation methods.As a countermeasure, extra excavation was carried out on the inner and outer parts of the ground on the sides of the excavator. (hereinafter referred to as over-drilling), the propulsion machine is propelled with the shield jack applying propulsive force only to the outer part, and the inner part is left with no propulsive force.This allows the excavator to move without propulsive force. I tried to bend it inward. FIG. 7 shows the above state, in which a shield excavator 1 with a total length L, which is equipped with a cutter 3 driven around an axis 5 at the front end of a shield frame 2, excavates a curved tunnel B from a straight tunnel A. The over-drilling that was attempted is shown as a plane, and 6 is the outer over-drilling of a roughly elongated triangle with width 7 and length 8, which is made outside the outer locus _B3 of the curved tunnel B, and 9 is the inner side. Width 10 and length 1 made to reach trajectory B ₂
It is an almost elongated triangular inner overbore consisting of 1,
The outer overcut 6 is excavated by the face plate of the cutter 3, and the inner overcut 9 is excavated by making an overcut (not shown) attached to the cutter 3 protrude in the radial direction. Note that 2c and 2d are the front edge and rear edge of the shield frame 2, respectively.

[Problems to be solved by the invention] An example of the amount of over-excavation when excavating a curved tunnel using the above construction method is that the tunnel diameter is approximately
4.5m, the curvature R of curved tunnel B is approximately 15m, and the total length of excavator 1 is approximately 4.5m, and the width of the outer excavation amount is 7.
is approximately 560 m/m, and the width of the inner trench is approximately 780 m/m.
It will be about m. The outer over-excavation 6 forms an extra space on the outer part of the tunnel, and is a completely unnecessary work in tunnel excavation, and
It is also unfavorable from a safety point of view because the spaces are continuous. Further, although the inner over-drill 9 can be used as a tunnel, the excavated earth and sand caused by the protrusion of the overcut are not completely taken into the shield frame 2 and flow into the inner over-drill 9 portion. As a result, resistive earth pressure from the ground side prevented the shield frame 2 from digging along the inside curve locus _B2 .

Therefore, in order to reduce the amount of excess excavation and increase the efficiency of tunnel curve construction, a center-folding type shield excavator for curved construction has been developed in which the shield frame is divided into two parts at the front and back from the middle part of the length, and the shield frame is bendable. However, the problem was that the amount of folding was so small that the amount of over-drilling could only be slightly reduced, and it was not particularly effective.

This invention was devised to effectively solve the above-mentioned problems, and its purpose is to omit and abolish unnecessary external over-drilling in curved tunnel excavation, and to eliminate most of the internal over-drilling by cutting. It is an object of the present invention to provide a shield excavator suitable for curved tunnel excavation which can be carried out using a face plate part.

[Means for solving the problem] The present invention has a front end opening of the shield frame.
In a shield excavator rotatably equipped with a cutter having a cross-sectional area substantially equal to the cylindrical cross-section of the shield frame, a drive shaft of the cutter is installed in a long hole extending in the left-right direction bored in the center of the partition wall in the shield frame. In addition to placing the bearing that supports the
In order to make the cutter eccentric in the left-right direction with respect to the shield frame axis, an eccentric jack extending in the left-right direction is arranged between the outer side of the bearing and the inner wall of the shield frame, and the cutter is moved leftward. The right side arc of the cutter centered on the axis of the cutter when it is eccentric to the maximum and the right half of the opening coincides with the center of the axis of the cutter when the knife is eccentric to the right to the maximum. The opening is formed into a substantially elliptical shape by reducing the diameter of the front end of the shield frame into a conical shape only in the left-right direction so that the left side arc of the cutter matches the left half of the opening.

[Operation] The cutter is made eccentric in the left-right direction with respect to the axis of the shield frame, and in this state, the cutter is driven to excavate the earth face, thereby constructing the inner over-drilling. After applying propulsion, the excavator easily changes direction. In addition, by forming the front end of the shield frame into a substantially elliptical shape with a conical diameter reduced only in the left-right direction, unnecessary over-excavation on the outside of the curve (outside over-excavation) can be reduced, and the excavator can be When propelling to the left, the shape from the upper end of the cutter to the right end to the lower end matches the shape of the corresponding part on the right side of the front part of the shield frame without any step. match),
A large warping effect can be obtained, and the ground reaction force in the unexcavated area can effectively generate a rotational force that changes direction to the inside of the curve.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

As shown in FIGS. 1 to 4, the shield frame 2 of the shield tunneling machine 1 includes a cylindrical main body portion 2a that occupies most of its length;
It is formed integrally with the front portion 2b, which has a diameter reduced in a conical shape only in the left-right direction, and has an opening formed by the front end edge 2c in a substantially elliptical shape. In the present invention, the cutter 3 is configured to be eccentric in the left-right direction (horizontal direction) with respect to the axis 5 of the shield frame 2 (details will be described later). It is desirable that the above-mentioned substantially elliptical shape be formed by circular arcs of right and left mutual radii r centered on the cutter axis 5' when the cutter is maximally eccentric in the direction. The cutter 3 is connected to a drive shaft 4 which is provided with a cutter bit, a slit, an over cutter, etc. (not shown) and is arranged coaxially with the axis 5 of the shield frame 2, and the drive shaft 4 is connected to a drive motor, a drive pinion, and the like (not shown). The cutter 3 is driven and rotated by a drive means such as a cutter gear.
It is designed so that it can be rotated.

Inside the shield frame 2, there are elongated holes 14a, 1 in the left and right directions in the center at required positions on the rear side of the cutter 3.
A bearing 1 which supports a drive shaft 4 in the elongated holes 14a and 15a, wherein a front partition wall 14 and a rear partition wall 15 having a diameter of 5a are appropriately spaced apart so as to face each other in the direction of the axis 5.
3 is placed through it. A rectangular box 16 that is short vertically and long horizontally is fixed on the outer periphery of the bearing 13, and the box 16 is connected to the front and rear partition walls 1.
The long holes 14a and 15a are closed between the boxes 1 and 15, and the boxes 1 and 15 are arranged so as to be slidable in the left and right direction.
The eccentric jacks 17 and 18 for eccentrically moving the cutter 3 from the shaft center 5 through the sliding motion of the bearing 1
3 and the inner wall of the shield frame 2, passing through the box 16 and facing each other in the left and right direction, guide plates 19 are provided on the upper and lower surfaces of the box 16 to guide the sliding movement of the box 16 from above and below. ，
20, and the peripheral edges of the guide plates 19, 20 are joined to the partition walls 14, 15 and the inner wall of the shield frame 2.

Thus, a cutter chamber 12 is formed in a space surrounded by the rear surface of the cutter 3, the front partition wall 14, the front face of the box 16, and the shield frame front portion 2b, and the cutter chamber 12 retains the excavated soil while disposing of the soil on the ground (not shown). The mud water sent from the plant is discharged and transferred to the above-mentioned plant from the mud drainage pipe as mud water of a required concentration. The excavator is also equipped with a generally known ring girder, erector, shield jack, tail seal, etc., but these are not shown.

Next, the operation will be explained.

When continuing to excavate the curved tunnel B from the state shown in FIG. 7, by extending the eccentric jack 17 and contracting the eccentric jack 18, the bearing 13
The drive shaft 4 is moved horizontally to the tunnel locus B ₂ side via the drive shaft 4, and the drive shaft 4 is eccentric from the shaft center 5. As a result, the cutter 3 similarly moves eccentrically, and assumes the planar state shown in FIG. 5 (cutter axis 5', eccentricity X).
The movement of the bearing 13 is performed within the range of the elongated holes 14a and 15a of the front and rear partition walls 14 and 15. Also, at this time, as the bearing 13 moves, the box 16 moves against the partition wall 14,
15, but since the box 16 is configured to always close the elongated holes 14a, 15a, watertightness is maintained. Due to the above-mentioned eccentricity, the right end 3b of the cutter 3 can be positioned on the outer locus _B3 , and the left end 3c moves toward the inner locus _B2 and approaches it, thereby reducing the required amount of extra drilling on the inside of the curve. However, when the planned curve R is small, the eccentricity X is smaller than the required over-excavation width 10, so an unreached portion Y remains between the inner locus _B2 .

Inner locus B of cutter 3 above Unreached portion Y to ₂
In order to excavate, the overcut cutter is made to face and protrude from the cutter 3 toward the inner locus _B2 . Next, the cutter 3 is rotated to excavate the earth face. In this excavation, the ground face appeared to be elongated only on the inner locus _B2 side,
In unnecessary parts such as outer locus B ₃ , all parts except the protruding part Y of the overcut cutter, which has a mechanism to sink into the cutter 3 (known technology), touch the face plate part of the cutter 3, and excavation is carried out by this, so the excavation is not performed. The earth and sand is taken into the cutter chamber 12 through the slits provided in the face plate of the cutter 3, and the earth and sand excavated by the over cutter also reaches the slits along the face plate of the cutter 3, and most of it is taken into the cutter chamber 12, and the inside excess excavation is carried out. The amount flowing into 9 will be very small. As a result of the above, it may be possible to omit the outer over-drilling 6 to zero. FIG. 6 is a front view of the above state seen from the front side, and 3a indicates the outer edge of the cutter 3.

Further, in the above-mentioned excavation, the cutter 3 may be moved further eccentrically so that its left end portion 3c is in contact with the inner locus B ₂ , and in this case, the outer locus B ₃
Excavation is carried out with the overcutter protruding to the side, thereby eliminating the inflow of excavated soil into the inner over-excavation 9.

As described above, the shield jack is extended while excavating the required amount of the earth face, and thrust is applied to the excavator 1 to move it forward. There is no over-drilling on the outer locus B ₃ side, but the front part 2 of the shield frame 2
Since b has a conical diameter reduced only in the left-right direction, it is possible to move forward along the excavation hole from this part.
Since the necessary over-drilling 9 has been constructed on the inner locus _B2 side, it is possible to move forward by the above-mentioned thrust.
By repeating the above steps, the curved tunnel B is excavated with high efficiency.

In the above-mentioned curved propulsion, the front portion 2b of the shield frame 2 is reduced in diameter in a conical shape only in the left-right direction, so when the excavator 1 is propelled in a left-hand curve as shown in FIG. Right side end 3
Shape and shield frame 2 reaching the lower end via b
The shape of the right corresponding part of the front part 2b matches without a step (the left side matches when propelling to the right), and a large warping effect is obtained. It is possible to effectively generate rotational force for changing direction.

In the above embodiment, a single cylindrical shield frame was described, but if a center-folding shield frame is used, the curved excavation effect can be further improved.
Furthermore, since the cutter can be made eccentric, it can also be used for corrective control of the propulsion direction.

[Effects of the invention] As explained above, the shield tunneling machine of the invention can produce the following excellent effects.

() The cutter can be moved eccentrically in the left and right directions using the left and right eccentric jacks, and the front part of the shield frame is reduced in diameter into a conical shape only in the left and right directions, so the outer edge of the cutter face plate follows the outer trajectory of the curved tunnel. This makes it possible to omit and abolish outside over-drilling, and to reduce the inside over-drilling as much as possible.In addition, a large warpage effect can be obtained in curved propulsion, and the ground reaction in unexcavated areas is reduced. The force can effectively generate a rotational force that changes the direction to the inside of the curve.

() Due to the eccentric movement of the cutter, the entire surface of the cutter face plate can be effectively used during curved excavation, so most of the excavated soil can be taken into the shield frame, and the problem of poor intake of excavated soil is improved as much as possible. .

() Modification control of the excavation direction can be reliably and easily performed not only in curved excavation but also in tunnel excavation.

() Due to the effects described in each section above, tunnel excavation can be carried out with high efficiency and construction costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a cutaway plan view of the shield tunneling machine of the present invention, Fig. 2 is a - arrow view of Fig. 1, Fig. 3 is a - arrow view of Fig. 1, and Fig. 4 is a - arrow view of Fig. 1. Fig. 5 is a plan view of the shield tunneling machine of the present invention with the cutter moved eccentrically;
The figure is a view taken along the - arrow in FIG. 5, and FIG. 7 is a plan view showing curved tunnel excavation by the conventional method. 1 is a shield excavator, 2 is a shield frame,
2a is the main body part, 2b is the front part, 3 is the cutter,
4 is a drive shaft, 5 is an axis, 13 is a bearing, 14, 15
14a and 15a are long holes, 16 is a box, and 17 and 18 are eccentric jacks.

Claims (1)

[Scope of utility model registration request] In a shield excavator which is rotatably equipped with a cutter having a cross-sectional area substantially equal to the cylindrical cross-section of the shield frame at the front end opening of the shield frame, a length extending in the left-right direction is bored at the center of the partition wall in the shield frame. A bearing that supports the drive shaft of the cutter is disposed through the hole, and a bearing is provided between the outer side of the bearing and the inner wall of the shield frame so that the cutter can be eccentric in the left-right direction with respect to the shield frame axis. An eccentric jack extending in the left-right direction is arranged in such a way that when the cutter is maximally eccentric to the left, the right side arc of the cutter centered on the cutter axis coincides with the right half of the opening, and the cutter The front end of the shield frame is reduced in diameter into a conical shape only in the left-right direction so that the left half of the opening matches the left-hand arc of the cutter centered on the cutter axis when the cutter is maximally eccentric to the right. A shield excavator characterized in that the opening is formed into a substantially elliptical shape.