JP2000220378A - Method for suppressing fluctuation of soil pressure in chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the change of volumes in chambers and surely prevent the fluctuation of heading soil pressure by operating the other auxiliary excavation means in the direction of increasing the volume in the chamber when one auxiliary excavation means is operated in the direction of decreasing the volume in the chamber. SOLUTION: An overbreaking devices 4, 4 of spokes 3a, 3c are gradually contracted as a cutter head 2 is rotated counterclockwise, and the overbreaking devices of spokes 3b, 3d are gradually extended. Then, the contraction amount of the overbreaking devices 4, 4 of the spokes 3a, 3c is made to substantially agree with the extension amount of the overbreaking device 4, 4 of the spokes 3b, 3d. When the cutter head 2 is further rotated, the spokes 3a, 3c comes in the direction of the minor axis of an elliptical cross section and the overbreaking devices 4, 4 are in the most construction state, the spokes 3b, 3d comes in the direction of the major axis of the elliptical cross section and the overbreaking devices 4, 4 are in the most extension state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutter head and a plurality of auxiliary excavating means provided on the cutter head for excavating a cutting face having an irregular cross section, and taking the excavated earth and sand into a chamber behind the cutter head to carry it out. The present invention relates to a method for suppressing a fluctuation in earth pressure in a chamber, which suppresses a fluctuation in earth pressure in a chamber due to an operation of an auxiliary excavating means in a tunnel machine described above.

[0002]

2. Description of the Related Art Generally, in the construction work of a tunnel using a shield machine, while excavating the ground by a disk-shaped cutter head provided in front of a cylindrical skin plate, segments are assembled in the machine, and the segments are assembled. The tunnel is excavated with substantially the same diameter as the skin plate by extending the shield jack by taking a reaction force to the tunnel.

[0003] In recent years, along with the expansion of the use range of tunnels, there has been an increasing demand for tunnel excavators that can excavate tunnels having irregular cross sections such as rectangular cross sections. As a tunnel excavator responding to such a demand, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 10-14079 and the like that a cutter head can be oscillated and the cutter head can be extended and contracted in the radial direction of the cutter head. There has already been proposed a tunnel excavator capable of digging a tunnel having a deformed cross section by providing a plurality of extra excavating devices and extending the extra excavating devices at required positions.

As described above, in a tunnel machine in which excavation equipment is extended to excavate the ground, the internal volume of a chamber for taking excavated earth and sand decreases when the extra excavation equipment is extended and contracts. It has been found that a phenomenon of sometimes increasing occurs. When such a phenomenon occurs, the earth pressure in the chamber fluctuates during excavation, and as a result, there arises a problem that the cutter head torque, the shield jack thrust, and the excavation speed fluctuate.

Accordingly, the present applicants changed the volume of a chamber or a portion communicating with the chamber in accordance with the amount of expansion and contraction of the excavation device, and suppressed the fluctuation of earth pressure in the chamber. (Japanese Patent Application No. 10-257103). According to the prior invention,
It is possible to prevent a change in the empty volume in the chamber due to the expansion and contraction of the surplus digging device, thereby suppressing a change in the face pressure, and thereby to expect an effect that stable digging can be performed.

[0006]

However, in the invention of the prior application, since it is necessary to add a special mechanism or device for suppressing fluctuations in the empty volume in the chamber, the structure of the device becomes complicated. There is a problem that the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and does not require a special device, and prevents a change in the empty volume in the chamber due to the operation of auxiliary excavating means such as an excavation device. It is another object of the present invention to provide a method for suppressing the fluctuation of the earth pressure in the chamber, which can surely prevent the fluctuation of the face pressure.

[0008]

Means for Solving the Problems and Functions / Effects In order to achieve the above object, a method for suppressing fluctuation of earth pressure in a chamber according to the present invention comprises a cutter head and a plurality of auxiliary excavating means provided on the cutter head. A method for suppressing fluctuations in earth pressure in a chamber in a tunnel excavator in which a face having an irregular cross section is excavated and the excavated earth and sand is taken into a chamber behind a cutter head and carried out, wherein When at least one auxiliary digging means is operated in a direction to decrease the volume in the chamber, another at least one auxiliary digging means is operated in a direction to increase the volume in the chamber to reduce a volume fluctuation in the chamber. It is characterized by suppressing.

In the present invention, the cutter head is rotated or reciprocated and oscillated, and a plurality of auxiliary excavating means (for example, an excavating device) provided on the cutter head are operated to excavate the face, thereby obtaining a rectangular cross section and an elliptical shape. Excavation of tunnel with irregular cross section such as cross section is performed. The earth and sand generated by the excavation is taken into a chamber provided behind the cutter head, and is carried out from inside the chamber toward the rear of the tunnel. At the time of excavation by the cutter head, when at least one auxiliary excavation means is operated in a direction to reduce the volume in the chamber, another at least one auxiliary excavation means is operated in a direction to increase the volume in the chamber. The amount of decrease in the chamber volume by the auxiliary digging means is offset by the amount of increase in the chamber volume by the other auxiliary digging means, thereby suppressing the fluctuation of the chamber volume. In this way, it is possible to prevent the occurrence of earth pressure fluctuation in the chamber due to the operation of the auxiliary excavating means, and as a result, it is possible to prevent the fluctuation of the cutter head torque, the shield jack thrust and the excavation speed, and It becomes possible to perform stable excavation without disturbance.

In the present invention, a plurality of pairs of the auxiliary digging means are provided, and when one of the pair of auxiliary digging means is operated in a direction to reduce the volume in the chamber, the other auxiliary digging means is used for the content of the chamber. It is preferable to suppress the volume fluctuation in the chamber by operating in the direction of increasing the product. This makes it easier to control the auxiliary excavating means when excavating a tunnel having a line-symmetrical cross section such as an elliptical cross section or a rectangular cross section.

Further, in the present invention, a plurality of reciprocating oscillating cutter heads are provided, and the oscillating operation is controlled so as to shift the oscillating phase of each of the cutter heads, thereby suppressing volume fluctuation in the chamber. It is also possible to adopt a configuration in which In this way, in a tunnel machine equipped with a plurality of reciprocating swing cutter heads, it is possible to greatly suppress the earth pressure fluctuation in the chamber only by a simple control of shifting the swing phase of each cutter head. Can be.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of the method for suppressing fluctuation of earth pressure in a chamber according to the present invention will be described with reference to the drawings.

(First Embodiment) FIGS. 1 (a) and 1 (b) are front views of a tunnel machine according to a first embodiment of the present invention applied to a tunnel machine for elliptical cross section excavation. . FIG. 1A shows a state in which the spoke positions coincide with the major axis and the minor axis of the ellipse, respectively. FIG. 1B shows the cutter head from the position shown in FIG. It shows a state where it is rotated by 50 ° in a counterclockwise direction.

In the tunnel machine according to the present embodiment, a skin plate 1 having an elliptical cross section is provided, and a cutter head 2 is rotatably mounted in front of the skin plate 1. A chamber (both not shown) is defined behind the cutter head 2 between the cutter head 2 and the bulk head.
The earth and sand excavated by the rotation of the cutter head 2 is taken into the chamber, and is carried out of the chamber to the rear of the tunnel by earth and sand carrying means such as a screw conveyor.

The cutter head 2 is of a spoke type, and four spokes 3a, 3b, 3c, 3d are arranged at equal intervals so that the angle between adjacent spokes is a right angle. Each of the spokes 3a to 3d has a built-in extra excavation device 4 as an auxiliary excavating means. The tip of the extra excavation device 4 protrudes outward from the tip of the spokes 3a to 3d by jack operation, so that the outer peripheral portion is The ground is excavated. A leading bit 5 is attached to the outer surface of each of the spokes 3a to 3d at the center, and a tool bit 6 is attached to both sides, and a face is excavated by each of the bits. In addition, the above-mentioned excavation device 4 has a configuration in which a plurality of specially shaped cutter bits are buried in a front portion and a top portion in the excavation direction in a cylindrical shape as a whole, and a top portion is formed in a spherical shape. I have.

In such a configuration, as shown in FIG. 1A, when the upper and lower spokes 3a and 3c, which are symmetrical with respect to the center of the tunnel, are located in the major axis direction of the elliptical cross section, The spare devices 4, 4 built in these spokes 3a, 3c are in the most extended position, and at this time, the left and right spokes 3b, 3d are located in the short axis direction and are built in the respective spokes 3b, 3d. Excavation devices 4 and 4 are in the most contracted position.

From this state, as the cutter head 2 rotates counterclockwise in the figure, the spokes 3a,
3c is gradually contracted (see arrow P in FIG. 1 (b)), while spokes 3b and 3d are
4 is gradually extended (see arrow Q in FIG. 1 (b)). At this time, the amount of contraction of the extra digging devices 4 and 4 of the spokes 3a and 3c is substantially equal to the amount of extension of the extra digging devices 4 and 4 of the spokes 3b and 3d. Thus, when the cutter head 2 is further rotated from the position shown in FIG. 1 (b), the spokes 3a, 3c come in the short-axis direction of the elliptical cross section, and the overhanging devices 4, 4 are in the most contracted state. Spoke 3b,
3d comes in the direction of the major axis of the elliptical cross section, and the overhanging devices 4, 4 are in the most extended state.

As described above, the extra volume of the spokes 3a, 3c is contracted, and the extra volume of the interior of the chamber is increased by the contraction of the extra volume of the spokes 3b, 3d. Will be reduced,
The volume in the chamber is always kept substantially constant. Therefore, it is possible to prevent the fluctuation of the earth pressure in the chamber due to the expansion and contraction of the excavation device 4 and to prevent the fluctuation of the cutter head torque, the shield jack thrust and the excavation speed.

(Second Embodiment) FIG. 2 is a front view of a tunnel machine according to a second embodiment of the present invention. The second embodiment is applied to a tunnel machine for a rectangular section tunnel.

In the tunnel machine according to the present embodiment, the cutter head 10 has eight spokes 11a, 11b, 11
c, 11d, 11e, 11f, 11g, 11h are arranged so as to be point-symmetric with respect to the center of the tunnel,
Each of the spokes 11a to 11h has a structure in which the same excavation device 12 as that of the first embodiment is incorporated.

In the case of this embodiment, each of the spokes 11a to 11a
h is an angle between adjacent spokes of 45 °
Spokes arranged at equal intervals in the circumferential direction so as to be orthogonal to each other, in other words, every other set of spokes 11a, 11c, 11e, 11g (or 11
(b, 11d, 11f, 11h).

That is, as shown in FIG. 2, when a set of spokes 11a, 11c, 11e, 11g is located in a direction orthogonal to each side of the rectangular cross section, these spokes 11a, 11c, 11e, 11g is in the most retracted position, and the other set of spokes 11b, 11d, 11f, 11h is located in the direction toward the corner of the rectangular cross-section. , 11d, 11f, and 11h are in the most extended position. From this state, as the cutter head 10 rotates in the counterclockwise direction in the figure, each of the spare devices 12 of the spokes 11a, 11c, 11e, and 11g is gradually extended, while the spokes 11b, 1
Each of the over-drilling devices 12 of 1d, 11f, and 11h is gradually contracted. At this time, the spokes 11a, 11c, 11e, 1
The extension amount of each of the over-digging devices 12 of 1 g and the spokes 11 b, 1
The contraction amounts of the respective over-drilling devices 12 of 1d, 11f, and 11h are made to substantially match. Thus, the cutter head 2
Are further rotated, and spokes 11a, 11c, 11e, 11
When g comes to the position facing the corner of the rectangular cross section and the overdigging device 12 is in the most extended state, the spokes 11b,
11d, 11f, and 11h are located at positions orthogonal to each side of the rectangular cross section, and the over-digging device 12 is in the most contracted state.

As described above, also in this embodiment, the first
As in the embodiment, a set of spokes 11a, 11c, 11
e and 11g, the spokes 11b and 11g are reduced by an amount corresponding to the reduction of the internal volume of the chamber due to the extension of each of the excavating devices 12.
The shrinkage of each of the over-drilling devices 12 of d, 11f, and 11h increases the volume in the chamber, so that the volume in the chamber is kept substantially constant, and it is possible to prevent earth pressure fluctuations in the chamber. .

(Third Embodiment) FIG. 3 is a front view of a tunnel machine according to a third embodiment of the present invention. The third embodiment is similar to the second embodiment, and is applied to a tunnel machine for a tunnel having a rectangular cross section.

In the tunnel excavator of this embodiment, the cutter head 20 has four spokes 21a, 21b, 21
c and 21d are arranged so as to be point-symmetrical with respect to the center of the tunnel, and each of the spokes 21a to 21d has a structure in which the same over-drilling device 22 as in the first embodiment is incorporated. Each of the spokes 21a to 21d has an angle formed by the spokes 21a and 21b and the spokes 21c and 2c.
The angles made by 1d are each 45 °, and the spokes 21b,
The spokes 21a, 21c (or 21) are arranged such that the angle formed by the spokes 21c and the spokes 21d, 21a is 135 °, respectively, and are aligned with each other.
b, 21d), each of the over-mining devices 22 performs the same expansion and contraction operation.

With such a configuration, it is also possible to excavate a tunnel having a rectangular cross section similar to that of the second embodiment, and at the time of excavation, each of the overdigging devices 22 of the set of spokes 21a and 21c is extended. As the volume in the chamber is reduced, the volume of the chamber is increased by the contraction of each of the spare devices 22 of the other sets of spokes 21b and 21d, so that the volume in the chamber is maintained substantially constant and the soil in the chamber is maintained. Pressure fluctuations are prevented.

(Fourth Embodiment) FIG. 4 is a front view of a tunnel machine according to a fourth embodiment of the present invention. 4A shows a state in which one spoke is facing upward, and FIG. 4B shows a state in which the spoke is rotated approximately 60 ° counterclockwise from the position shown in FIG. 4A. I have. This embodiment is applied to a tunnel machine for a tunnel having a substantially elliptical cross section in which a circular cross section is slightly shifted in one direction.

In this embodiment, three spokes 31a, 31b and 31c are arranged on the cutter head 30 at equal intervals in the circumferential direction so that the angle between adjacent spokes is 120 °. , Each spoke 31
a to 31c are the same as the first embodiment.
Is built in.

In the case of this embodiment, each of the spokes 31a to 31
c, in the upper half of the excavation cross section, excavation is performed with the excavation device 32 in the most contracted position, and after passing through the center line L, the extra excavation device 32 is gradually extended, and the spokes 31 a to 3 c
When 1c comes directly below, the extra excavation device 32 is brought into the most extended state (see FIG. 4B). After that, after passing directly below the position, the excavation device 32 is gradually contracted, and the spokes 31a-31
When 31c comes to a position corresponding to the center line L, it is set to the most contracted state.

As described above, as the cutter head 30 rotates counterclockwise in the drawing, the excavating device 32 (see the arrow R in FIG. 4A) that is being extended and the excavating device that is being contracted are being excavated. The device 32 (see the arrow S in FIG. 4A) is present as a pair, and the amount of extension of the excavating device 32 and the amount of contraction of the contracting extra device 32 are substantially the same. By doing so, the volume inside the chamber can be kept substantially constant, and fluctuations in earth pressure inside the chamber can be prevented. According to the tunnel machine of the present embodiment,
A tunnel with a substantially elliptical cross-section in which a circular cross-section having a radius r is slightly shifted downward is excavated.

(Fifth Embodiment) FIG. 5 is a front view of a tunnel machine according to a fifth embodiment of the present invention. FIG. 5 (a) shows a state in which one spoke is upward, and FIG. 5 (b) shows a state in which the spoke is rotated approximately 36 ° counterclockwise from the position shown in FIG. 5 (a). I have.

In this embodiment, the cutter head 40 has five spokes 41a, 41b, 41c, 41d, 41
e is an angle between adjacent spokes of 72 °
Are arranged at equal intervals in the circumferential direction so that
Each of the spokes 41a to 41e has a structure in which the same over-digging device 42 as that of the first embodiment is incorporated. Further, in the present embodiment, similarly to the fourth embodiment, the present invention is applied to a tunnel machine for a tunnel having a substantially elliptical cross section in which a circular cross section is slightly shifted in one direction.

In the case of this embodiment, each of the spokes 41a to 41
In the upper half of the excavated cross section, excavation is performed with the excavation device 42 in the most contracted position, and after passing through the center line L, the extra excavation device 42 is gradually extended, and the spokes 41 a to 41
When 1e comes directly below, the overdigging device 42 is brought into the most extended state (see FIG. 5B). After that, after passing directly below the position, the excavation device 42 is gradually contracted, and the spokes 41a to
When 41e comes to a position coinciding with the center line L, it is set to the most contracted state.

As described above, even in the case of the cutter head 40 having five spokes as in this embodiment, as the cutter head 40 rotates counterclockwise in FIG. Device 42 (see arrow T)
And the over-mining device 42 (see arrow U) being contracted are present as a pair, and the extension amount of the extending over-mining device 42 and the contraction amount of the contracting over-mining device 42 are determined. By making them substantially coincide with each other, the volume in the chamber can be kept substantially constant, and the fluctuation of the earth pressure in the chamber can be prevented.

As is apparent from the above description, the number of spokes provided on the cutter head may be even or odd depending on the cross-sectional shape of the excavation. However,
It is necessary that an excavation device (auxiliary excavation means) operated in the direction of decreasing the volume in the chamber and an excavation device (auxiliary excavation means) operated in the direction of increasing the volume in the chamber are paired It is.

(Sixth Embodiment) FIG. 6 shows a front view (a) of a tunnel machine according to a sixth embodiment of the present invention and a partial cross-sectional view (b) of a spoke portion of a cutter head thereof. I have.

The tunnel excavator 50 of the present embodiment has a skin plate 53 having a substantially rectangular cross section as a whole, in which two corner portions 51 and 52;
53A are arranged in parallel, and each skin plate 53, 53
In front of A, the cutter head 54, which can swing back and forth,
54A are arranged. Here, each of the cutter heads 54, 54A is a spoke type cutter head, and has four spokes 55, 56, 57, 5 respectively.
8; 55A, 56A, 57A, 58A are arranged at an angle of 90 ° between adjacent spokes. In front of each spoke 55-58; 55A-58A, a cutter bit 59 for excavating a face is provided, and three spokes 55-57, excluding the inner spokes 58, 58A, are provided with over-drilling devices. 60 is built-in. These excavating devices 60 are provided with spokes 55 to 5 by a telescopic jack 61 built in the spokes.
7; the tunnels are projected and retracted from the outer peripheral edges of 55A to 57A in the radial direction of the tunnel (see the solid line position and the chain line position in FIG. 6B). The inner spokes 58, 58A are shorter than the other spokes 55-57; 55A-57A so that the inner spokes 58, 58A do not interfere with each other.

Next, with reference to FIGS. 7 to 9, the operation of the excavation device which comes and goes with the reciprocation of the spokes will be described. In the following description, “left” and “right”
“Left” and “right” in terms such as “left rotation” and “right rotation” refer to “left” and “right” in the figure, respectively.

First, assuming that the state shown in FIG. 7A is an initial state, in this initial state, the left cutter head 54 oscillates in the left rotation direction and reaches its most oscillating end. In this state, the extra digging device 60 of the spoke 57 is in the most extended state, and the extra digging device 60 of the spokes 55 and 56 is in the middle extended state. On the other hand, the right cutter head 54A is in the middle of swinging in the left rotation direction as shown by the arrow A, and the spokes 56A and 58A are oriented horizontally, and the spoke 5
5A and 57A are oriented vertically, and each of the overdigging devices 60 is in the most contracted state.

From this state, as shown in FIG. 7 (b), the spokes 55, 56, and 57 change as the left cutter head 54 rotates in the right rotation direction (the direction of arrow B). Each of the over-mining devices 60 gradually contracts. On the other hand, as the right cutter head 54A further rotates in the left rotation direction, the respective excavating devices 60 of the spokes 55A, 56A, and 57A gradually extend to excavate the corner portion.

As the excavation proceeds further, as shown in FIG. 7 (c), the left cutter head 54 swings in the clockwise direction as shown by the arrow B, and the spokes 56, 58
Is oriented horizontally, and the spokes 55 and 57 are oriented vertically, so that each of the extra excavation devices 60 is in the most contracted state. On the other hand, the cutter head 54A on the right side rotates and swings in the left rotation direction to reach its most swinging end, and the extra digging device 60 of the spoke 55A is in the most extended state, and the extra digging device 60 of the spokes 56A and 57A is It is in the middle extension state.

As the excavation proceeds further, as shown in FIG. 8 (a), as the left cutter head 54 further rotates clockwise (arrow B direction), the spokes 55, Each of the 56 and 57 extra excavating devices 60 gradually extends. On the other hand, as the right cutter head 54A changes its direction of rotation in the right rotation direction (the direction of arrow C) and rotates, each of the spare parts 60 of the spokes 55A, 56A, and 57A gradually contracts.

Subsequently, as shown in FIG. 8 (b), the left cutter head 54 swings clockwise in the clockwise direction to reach its most swinging end, so that the spoke 55 is left over. The device 60 is in the most extended state, and the spare devices 60 of the spokes 56 and 57 are in the intermediate extended state. On the other hand, while the right cutter head 54A swings clockwise in the right rotation direction as shown by the arrow C, the spokes 56A and 58A are oriented horizontally.
The spokes 55A and 57A are oriented vertically, and each of the extra excavation devices 60 is in the most contracted state.

Subsequently, as shown in FIG. 8 (c), the left cutter head 54 changes the direction of rotation in the left rotation direction (the direction of arrow D) and rotates as the spokes 55, 5 rotate.
Each of the 6, 57 extra digging devices 60 gradually contracts. On the other hand, as the right cutter head 54A further rotates in the clockwise direction (the direction of arrow C), each of the spare devices 60 of the spokes 55A, 56A, and 57A gradually extends for excavation of the corner.

When the excavation proceeds further, as shown in FIG. 9 (a), the left cutter head 54 swings in the leftward rotation direction as shown by the arrow D, and the spokes 56, 58
Is oriented horizontally, and the spokes 55 and 57 are oriented vertically, so that each of the extra excavation devices 60 is in the most contracted state. On the other hand, the cutter head 54A on the right side rotates and oscillates in the clockwise direction to reach its most oscillating end, and the extra boring device 60 of the spoke 57A is in the most extended state. It is in the middle extension state.

Subsequently, as shown in FIG. 9B, the left cutter head 54 is further rotated leftward (in the direction of arrow D).
, Each of the over-drilling devices 60 of the spokes 55, 56, and 57 gradually extends for excavation of the corner portion. On the other hand, as the right cutter head 54A changes the direction of rotation in the left rotation direction (the direction of arrow A) and rotates, each of the over-drilling devices 60 of the spokes 55A, 56A, and 57A gradually contracts. After the operation state shown in FIG. 9B, the operation state returns to the operation state shown in FIG. 7A again, and the above-described operation states are sequentially repeated.

As is apparent from the above description of the operation, in the tunnel machine 50 of this embodiment, two oscillating cutter heads 54 and 54A are arranged in parallel to excavate a tunnel having an irregular cross section. In this case, the left and right cutter heads 54, 54A are not synchronized with each other and are not swung in the left-right direction.
The swing operation is controlled so that the phase of the swing of 4A is shifted. Here, the adjustment of the phase difference between the cutter heads 54 and 54A is preferably performed by a control program that controls the driving mechanism of each of the cutter heads 54 and 54A.

Also in the present embodiment, the extra cutting device 54A (or 54A) in the other cutter head 54A (or 54A) is extended by the extension of the extra cutting device 60 in the one cutter head 54 (or 54A). When the device 60 contracts, the volume in the chamber increases, and the volume in the chamber is kept substantially constant, so that fluctuations in earth pressure in the chamber can be prevented.

FIG. 10 shows the relationship between the swinging state of the cutter head shown in FIGS. 7 to 9 and the rate of volume change with respect to the volume in the chamber in order to confirm the effect of the tunnel machine of this embodiment. Are shown together with the comparative examples. Here, in the present embodiment, the left and right cutter heads 54, 54
A is provided with a phase difference of 47.5 °, whereas the comparative example swings the left and right cutter heads 54 and 54A in synchronization without providing a mutual phase difference. In this example, the volume in the chamber is 82.1 m ³ . In FIG. 10, the swing patterns 1, 2, 3, 4,
5, 6, 7, and 8 (0) correspond to FIG. 7A and FIG.
(B), FIG. 7 (c), FIG. 8 (a), FIG. 8 (b), FIG.
9C, and correspond to the respective states of FIGS. 9A and 9B.

When the volume fluctuation width is obtained based on the graph shown in FIG. 10, the volume fluctuation width in this embodiment is 0.0
In contrast to 6%, the variation in volume in the comparative example is 0.54%. As is clear from this result, it can be seen that the volume fluctuation range of the present example is significantly improved as compared with the comparative example.

In each of the embodiments described above, the excavation device is expanded and contracted by the jack operation from the spoke tip, but various types of auxiliary excavation means other than the above type are employed. can do. FIG. 11 shows another example of the auxiliary digging means. In this example, the jack knife type auxiliary digging means 70 swings from the outer peripheral portion of the cutter head 71 in the direction shown by the arrow E. It is operated to excavate the ground on the outer periphery. Even in such a type, when one auxiliary excavating means 70 is operated in the protruding direction, the other one auxiliary excavating means 70 is operated in the storing direction, whereby This has the same effect as the example.

In the first to fifth embodiments,
Although the cutter head has been described as being of a rotary type, the cutter head may be of an oscillating type.

[Brief description of the drawings]

FIGS. 1A and 1B are front views of a tunnel machine according to a first embodiment.

FIG. 2 is a front view of a tunnel machine according to a second embodiment.

FIG. 3 is a front view of a tunnel machine according to a third embodiment.

FIGS. 4A and 4B are front views of a tunnel machine according to a fourth embodiment.

FIGS. 5A and 5B are front views of a tunnel machine according to a fifth embodiment.

FIG. 6 is a front view (a) of a tunnel machine according to a sixth embodiment and a partial cross-sectional view of a spoke portion of the cutter head thereof (b).

FIGS. 7A, 7B and 7C are explanatory diagrams (1) of an excavating operation in a sixth embodiment.

FIGS. 8A, 8B, and 8C are explanatory diagrams (2) of an excavation operation in a sixth embodiment.

FIGS. 9A and 9B are explanatory diagrams (3) of the excavation operation in the sixth embodiment.

FIG. 10 is a graph showing the relationship between the swing of the cutter head and the volume change rate.

FIG. 11 is a diagram showing another example of the auxiliary excavation means.

[Explanation of symbols]

1,53,53A Skin plate 2,10,20,30,40,54,54A, 71
Cutter head 3a-3d, 11a-11h, 21a-21d, 31a
~ 31c, 41a ~ 41e, 55 ~ 58, 55A ~ 58
A Spokes 4, 12, 22, 32, 42, 60 Excavation equipment 5 Lead bit 6 Tool bit 59 Cutter bit 61 Telescopic jack 70 Auxiliary drilling means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Junkichi Onoe 3-12-10 Hakata-ekimae, Hakata-ku, Fukuoka City Kashima Construction Co., Ltd.Kyushu Branch (72) Inventor Hiroshi Matsuo Hakata-ekimae, Hakata-ku, Fukuoka City, Fukuoka Prefecture 3-12-10 Kashima Corporation Kyushu Branch (72) Inventor Takashi Minami 5 Yokaichi-cho, Komatsu-shi, Ishikawa Prefecture Komatsu Plant Komatsu Plant (72) Inventor Hideo Kambayashi 2067 Sekigahara-cho, Fuwa-gun, Gifu Prefecture Komatsu Ltd. Sekigahara Business Room (72) Inventor Kazunari Kawai 5 Yokaichi-cho, Komatsu-shi, Ishikawa Prefecture Komatsu Ltd. Komatsu Plant

Claims (3)

[Claims] 1. A tunnel excavator for excavating a face having an irregular cross section by a cutter head and a plurality of auxiliary excavating means provided on the cutter head, and taking in the excavated earth and sand into a chamber behind the cutter head and carrying it out. The method according to claim 1, wherein at least one of the plurality of auxiliary digging means is operated in a direction to reduce the volume in the chamber, and at least one other auxiliary digging is performed. A method for suppressing fluctuation in earth pressure in a chamber, characterized in that means is operated in a direction to increase the volume in the chamber to suppress fluctuation in volume in the chamber. 2. A plurality of pairs of the auxiliary digging means are provided, and when one of the pair of auxiliary digging means is operated in a direction to reduce the volume in the chamber, the other auxiliary digging means reduces the volume in the chamber. The method according to claim 1, wherein a volume fluctuation in the chamber is suppressed by operating in an increasing direction. 3. A reciprocating swing type cutter head is provided.
The method according to claim 1 or 2, wherein the fluctuation of the volume in the chamber is suppressed by controlling the rocking operation of each cutter head so as to shift the rocking phase.