JP2003074294A - Horizontal hole excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal hole excavator enabling long-boring in soil with compressive strength not more than that of a soft rock. SOLUTION: In this horizontal hole excavator for excavating by rotating a cutter head 3 provided at the front part, at least one part of the cutter head 3 is provided with a center cutter 28 protruded in an advancing direction, and a plurality of cutter bits 29-1-29-28 disposed at the cutter head 3 in the radial positions of the cutter head 3 from the center cutter 28 so as to be successively positioned on the axially rear side off the horizontal hole excavator. These cutter bits 29-1-29-28 are shaped to enlarge the radial dimension of the cutter head 3 from the tip parts 26 provided at both circumferential side ends of the cutter head 3, to an intermediate part 25 so that an excavated face is cut wide in the radial direction of the cutter head 3 following the rotation of the cutter head 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal hole excavator for excavating with a cutter head provided in front of a shield body, for example, and more specifically, cutter bits are arranged at a plurality of radial positions of the cutter head. The present invention relates to a horizontal hole excavator.

[0002]

2. Description of the Related Art A shield machine, which is one of horizontal hole excavators, usually has a plurality of bit mounting portions arranged in the circumferential direction of a cutter head provided in front of a shield body. In a so-called earth-pressure shield machine, the bit attachment portion is configured by a Katta spoke radially extending radially from the center frame at the tip of the center shaft, and each of these Katta spokes has a plurality of radial positions. A cutter bit is installed at. Further, in a so-called muddy water shield machine, a plurality of circumferentially-corresponding positions of the Kattus pork on the substantially disk-shaped face plate are provided with bit mounting regions radially extending from the radial center side to form the bit mounting portion. Also, in these bit mounting areas, cutter bits are arranged at a plurality of radial positions. Then, by rotating the cutter head having such a structure, the cutting face is excavated by the cutter bit.

The excavated soil is agitated in the excavation chamber just behind the cutter head defined by the partition.
In the earth pressure type shield machine, mud making material is injected as needed to promote plastic fluidization of the excavated soil, and the plastic fluidized soil is discharged to the rear of the shield body by an earth discharging device such as a screw conveyor. To do. Further, in the muddy water shield machine, water is injected into the excavation chamber by using water injection means such as a water supply pipe, and the excavated earth and sand is discharged as muddy water to the rear of the shield main body by a mud discharge means such as a mud discharge pipe.

At this time, an erector is provided at the rear of the shield body, and the erector sequentially assembles the segment rings to construct a tunnel. In addition, a plurality of shield jacks for giving propulsive force in the excavation direction to the shield body are arranged in an annular shape slightly forward of the erector in the shield body.By extending these shield jacks and pressing the segment ring, The shield body is propelled forward and the cutter head is pressed against the face. A cavity is formed around the segment ring with a backfill material to fill the cavity.

In this way, the front face is excavated by excavating the face face while propelling the shield body, and the tunnel by the segment ring is constructed on the rear side. The shield construction method forms a tunnel in a predetermined underground section from one vertical shaft (starting vertical shaft) to another vertical shaft (reaching vertical shaft) that has been separately excavated by repeating the above work using a shield machine. It is a thing. By the way, generally, the soil quality (geosphere) of the ground to be excavated by the shield machine is
From hard to soft, for example, rocks, consolidated silt, dotan, cobble-mixed gravel, gravel, sand, cohesive soil (silt, clay), and the like. Usually, compressive strength 500kg / cm
Hard rocks with a compressive strength higher than that of about 2 are called soft rocks, and those with a smaller compressive strength are called soft rocks. When excavating with a shield machine, for soil types other than hard rock (in other words, soil with compressive strength of soft rock or less, hereinafter simply referred to as "soft rock or less soil"), the drilling blade was attached to the tip of the bit body. It is possible to excavate with a normal cutter bit, but when excavating hard rock, it is difficult to excavate with this ordinary cutter bit, so the shaft body whose both axial ends are connected to the cutter head, A roller bit that rotatably supports a cutting roller for cutting a face is often used.

Further, in the case of excavating soil which is hard to excavate because of its relatively high compressive strength among the hard rocks, for example, as described in JP-A-2000-64788,
In a shield machine, in which roller bits are arranged at a plurality of radial positions of a cutter head provided in front of the shield body and the cutter head is rotated to perform excavation, a roller bit located on the radial center side of the cutter head. And the roller bit at the other adjacent radial position is sequentially retracted rearward in the excavation direction and the excavation surface is formed so that the vertical cross-section has a substantially stepped shape. An excavator has been proposed.

This shield machine excavates while maintaining the vertical cross-sectional shape of the excavated surface of the ground in a substantially staircase shape (so-called undercutting), so that the substantially staircase edge ( Inducing peeling and crushing on the rear side edge of the excavation direction) reduces the excavation force (pressure) required during excavation, and enables excavation of soil with high compressive strength with a smaller excavation force than before. It is a thing.

[0008]

By the way, generally, in a shield machine, the cutter bit is worn away by sliding with a cutting face as the excavation work progresses. There is a limit. Conventionally, a shield machine has a relatively short excavation distance, and one shield machine excavates a relatively short (eg, 1 km) section from one shaft (starting shaft) to another shaft (arriving shaft). After that, a relatively short section from another shaft to another shaft (same) had to be excavated by using another shield machine or by exchanging a worn cutter bit.

Here, in recent years, it is becoming difficult to install a large number of starting and reaching shafts due to the progress of urbanization, and further reduction of shaft installation cost and shield machine manufacturing cost is desired. Due to such factors, there is an increasing need to make the digging distance by one shield machine as long as possible.

The inventors of the present application have found that for the soil of soft rock or less, which is relatively widely distributed in the Japanese strata, the vertical cross-sectional shape similar to that of the above-mentioned prior art is substantially stepwise while using the ordinary cutter bit. It has been newly found that such excavation enables long-distance excavation without using a heavy equipment structure such as the roller bit.

An object of the present invention is to provide a horizontal hole excavator capable of long-distance excavation in soils having a compressive strength of soft rock or less.

[0012]

(1) In order to achieve the above object, a horizontal hole excavator according to the present invention is a horizontal hole excavator for rotating a cutter head provided at a front portion to perform excavation. At least one part of the cutter head is provided with a preceding excavating means that is provided so as to project in the propulsion direction, and a radial position of the cutter head from the preceding excavating means, and a sequential position on the axial rear side of the lateral hole excavator. A plurality of cutter bits disposed on the cutter head so that the plurality of cutter bits cut the excavation surface in the radial direction of the cutter head as the cutter head rotates. The cutter head has a shape in which the dimension on the radial side of the cutter head is increased from a substantially pointed portion provided on both ends in the circumferential direction to an intermediate portion.

In the present invention, the preceding excavation means is projected in the excavation direction at at least one location (for example, one radial direction position) of the cutter head, and a plurality of cutter bits are provided from the preceding excavation means to the cutter head radial position. It should be located sequentially on the rear side in the axial direction. As a result, it is possible to perform excavation while forming an excavation surface having a substantially stepwise vertical cross-section from the excavation surface excavated by the advance excavation means (so-called undercutting). That is, the plurality of cutter bits cause a crack on the root side of the substantially stepped edge portion (corner portion) by the pressing force in the excavation direction to propagate and cause a shear failure in a diagonal direction in most of the edge portion. Excavation is carried out by continuously performing peeling and crushing. Moreover, at this time, the plurality of cutter bits have a shape in which the dimension on the radial direction side of the cutter head increases from the substantially pointed portions provided at both ends in the circumferential direction of the cutter head to the intermediate portion. As a result, during excavation, the cutter bit bites into the face of the cutting edge by propulsion, and the cutter head rotates in the bite state, so that the diameter-enlarged cutter bit widens the excavation surface in the radial direction of the cutter head. Can be drilled in this way. Therefore, the excavation by the above-mentioned peeling and crushing is combined with the cutting and widening effect, and the excavation resistance can be significantly reduced. In particular,
The effect is great when there is an open surface on the cut-out side. In this way, the excavation force required for excavation can be reduced, excavation of the ground can be performed with a smaller excavation force compared to normal excavation, and excavation efficiency is significantly improved. As a result, it is possible to reduce wear of the cutter bit due to sliding with the face, and to improve the excavation distance. Also, instead of excavating the ground face by scraping the ground face with the cutting edge of the cutter bit as in normal excavation, the excavation is performed mainly by the separation crushing and cutting effect as described above. Even if it becomes worn and no longer sharp, excavation capacity can be secured. Therefore, also by this, the digging distance can be improved. As described above, since the excavation distance can be greatly improved as compared with the normal excavation, it is possible to excavate a sufficiently long distance in a soil condition in which the compressive strength is soft rock or less.

(2) In the above (1), preferably,
At least one of the plurality of cutter bits has a negative rake angle with respect to the excavation surface in the excavation direction.

By providing a negative rake angle with respect to the excavation surface in the excavation direction, the excavation locus of the cutter bit accompanying the circumferential rotation of the cutter head is more forward at the end of cutting than at the beginning of cutting. Due to the rotation of the cutter head, the cutter bit positively applies a pressing force to the front side in the excavation direction to the ground. As a result, (1) above
In addition to the effect of cutting and expanding the cutter head in the radial direction described above, a pressing force is applied to the front side in the excavation direction, so that the resultant force is a force that pushes the rock mass diagonally forward in the excavation rotation direction. This resultant force makes it easier to generate a crack on the root side of the substantially stepped edge portion described in (1) above, and therefore, peeling fracture can be further promoted. Therefore, the reduction of excavation can be further reduced, and the excavation distance can be more reliably improved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. An embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG.

FIG. 1 is a side sectional view showing the entire structure of an embodiment of a horizontal hole excavator of the present invention, and FIG.
It is the arrow front view seen from the direction.

1 and 2, the horizontal hole excavator of this embodiment is a so-called shield excavator, and includes, for example, soft rock, consolidated silt, dotan, cobbles-mixed gravel, gravel,
It is particularly suitable for excavating soft rocks and other soft soils (in other words, soils other than hard rocks) such as sand and cohesive soil (silt, clay), etc. It is a fuselage of a shield machine and allows the center break described later. For this reason, the shield body 1 has a structure in which the front body 1A located at the foremost portion in the excavation direction and the rear body 1B adjacent to the rear side thereof are foldably connected, and the inside of the shield body 1 and the excavation chamber P. And a cutter head 3 provided on the front side (left side in FIG. 1) in the excavation direction of the front body 1A for excavating the face face M of the natural ground and taking it into an excavation chamber P (described later), and this cutter. A cutter driving device (for example, an electric motor or a hydraulic motor) 4 that rotationally drives the head 3, and a rotation transmission mechanism 5 that is attached to the partition wall 2 and that transmits the driving force from the cutter driving device 4 to the cutter head 3.
And a soil discharging device, for example, a screw conveyor 6 that conveys and discharges the excavated earth and sand taken into the excavation chamber P to the rear side of the shield body 1 in the excavation direction, and a tunnel (see FIG. It has an erector device 9 for sequentially assembling the segment rings S lining the inner surface (not shown), and a center shaft 10 rotatably supported by the partition wall 2 via the rotation transmission mechanism 5. Front body 1
An intermediate folding mechanism 11 is provided between A and the rear body 1B so as to slidably connect them to each other. That is, a sliding portion 11a having a substantially spherical outer peripheral surface is provided at the front end of the rear body 1B, and the rear end of the front body 1A is in sliding contact with the sliding portion 11a. A substantially ring-shaped seal member 11b that seals between 11a and the rear end of the front body 1A (prevents the intrusion of earth and sand and groundwater) is provided, and the sliding portion 11a and the seal member 11b fold in the middle. The mechanism 11 is configured.

At this time, the middle folding jack bracket 12 provided inside the front case 1A and the ring girder 13 provided at the forefront part of the rear case 1B (specifically, the inner peripheral side of the sliding part 11a) are attached. A plurality of (e.g., eight) middle folding jacks (front trunk propelling jacks) 14 are provided in the circumferential direction between the folding jack bracket 13a. And
When bending a curve or correcting the direction of excavation, the center bending mechanism 11 is moved by the expansion and contraction operation of these center bending jacks 14.
The front body 1A is bent with respect to the rear body 1B via the, and the angle formed by them can be changed to change the excavation direction.

Further, a shield jack bracket 13b is provided at a circumferential position different from the center folding jack bracket 13a of the ring girder 13 provided on the rear body 1B, and this shield jack bracket 13 is provided.
A plurality of (for example, 10) shield jacks 15 are attached to b in the circumferential direction.

The shield jacks 15 are
Although not shown in detail, for example, they are arranged in an annular shape at equal intervals, and they are extended to shield the shield jack 15.
By pressing the spreader 16 connected to the rear end portion 15a in the excavation direction against the existing segment ring S, the pressing reaction force is applied to the cutter head 3 as a propulsive force in the excavation direction forward side via the front body 1A. This allows
During excavation, the cutter head 3 is pressed against the face of the natural ground.

The screw conveyor 6 has a casing 6a which internally forms an excavation route for excavated earth and sand, a screw shaft 6b axially arranged in the casing 6a, and a drive for rotationally driving the screw shaft 6b. The shield body 1 is provided with a device, for example, a hydraulic motor 6c, and the screw shaft 6b is rotated by the driving force of the hydraulic motor 6c to take in earth and sand from a suction port 6d provided at an opening below the excavation chamber P. It is designed to discharge inward.

A tail seal portion 8 having a plurality of tail packings 8a is provided at the rear end portion of the rear body 1B, whereby the rear end of the shield body 1 of the shield machine which advances. The portion and the segment ring S are sealed to prevent intrusion of water and earth from outside the shield machine into the machine.

The elector device 9 is guided by a guide roller (not shown) arranged along the inner circumference of the rear body 1B, and is turned by a turning motor (not shown). Is provided, and the segments (not shown) constituting the divided pieces of the segment ring S are lifted one by one and conveyed to a predetermined assembly position,
The segment ring S is assembled by sequentially bolting to the existing segment ring S that is adjacent to the shield body 1 in the axial direction (the front-rear direction) and the existing segment that is adjacent to the circumferential direction.

(1) Structural Features of the Shield Machine of the Present Embodiment The most important structural features of the shield machine of the present embodiment are the cut head pork shape in the cutter head 3, the cutter bit arrangement, and the cutter. It is in a bit shape.
This will be described below.

FIG. 3 is an enlarged view of an essential part in FIG. 1 showing a detailed structure of the cutter head 3. In FIG. 3 and FIG. 2 described above, the cutter head 3 has a center portion (inside) in the radial direction.
A boss 10a fixed to the front end of the center shaft 10 on the front side in the excavation direction, and a center as a cutting means fixed to the front side of the boss 10a further forward in the excavation direction, for example, via a bolt 10b. Cutter 28
And a plurality of pieces (in this example, extending radially from the boss 10a toward the outer peripheral side in the radial direction and extending backward toward the outer peripheral side in the radial direction toward the rear side in the excavation direction (right side in FIG. 3). 4) Katta Spokes 27A, 27B, 27C,
27D (see FIG. 2) and these Kattaspokes 27A-
And an annular member 27E provided so as to sequentially connect the outermost peripheral portions of 27D in the circumferential direction. At this time, the outer diameter dimension of the cutass spokes 27A to 27D (in other words, the outer diameter dimension of the annular member 27E) is substantially equal to the inner diameter dimension of the circular cross section to be excavated.

The cutter bits 29-1 and 29-2 are arranged on the respective cutas pork 27A to 27D and the annular member 27E from the inner peripheral side toward the outer peripheral side at a plurality of radial positions in the cutter head 3. , 29-3, 29-
4,29-5,29-6,29-7,29-8A, 29
-8B are arranged in this order. That is, the cut bit 29-
1,29-5 are arranged, Kattaspoke 27B
Cutter bits 29-3 and 29-7 are arranged on the Cutter Spoke 27C.
4,29-8A (However, this cutter bit 29-8A is
The annular member 27E, which will be described later, is arranged at a position slightly displaced from the cutter bit 29-8B on the radially inner side. (See FIG. 2) is arranged, the cutter bits 29-2 and 29-6 are arranged on the cutas pork 27D, and the four cutter bits 29- are arranged on the annular member 27E.
8B is arranged. This cutter bit 29-
The reason for providing four 8B is that if it becomes difficult to excavate this outermost peripheral position, it will not be possible to propel the shield body 1 forward in the excavation direction. This is to reduce the burden of excavation and to ensure the excavation capacity.

At this time, each cutter bit 29-1 to 29
As shown in FIG. 2, the arrangement of −8 is such that the positions of the cutter bits 29-1 to 29-8 at the eight radial positions are displaced from each other in the radial direction from the radial center side in the radial direction. It is widely arranged up to the outer peripheral side, so that when the cutter head 3 rotates, these cutter bits 29-1
.About.29-8 and the center cutter 28 make it possible to excavate a circular cross-sectional shape whose outer diameter is substantially equal to that of the annular member 27E (strictly, slightly larger, see the chain double-dashed line in FIG. 2).

The arrangement of the center cutter 28 and the cutter bits 29-1 to 29-8 in the excavation direction is shown in FIG.
As shown in, the center cutter 28 located at the center in the radial direction (positioned on the innermost radial side) is projected to the frontmost side in the excavation direction, and the radial position is set to the radial position of the center cutter 28. The cutting edges of the cutter bits 29-1, 29-2, ..., 29-7, 29-8, which are sequentially adjacent to the outer peripheral side, are respectively arranged on the cutas pork 27A to 27D so as to be sequentially retracted rearward in the excavation direction. Then, as a result, the excavation surface M having the excavation direction excavation surface Ma (see FIG. 3) and the radial direction excavation surface Mr (the same) and having a substantially vertical cross-sectional shape is formed.
(The same) is formed.

Further, the cutter bits 29-1 to 29-8
Has a radial dimension substantially equal to the radial dimension of the above-mentioned one step (see FIG. 8 described later), and the diameter between the rotational loci of the adjacent cutter bits 29 is almost equal to the radial dimension. It is arranged so that there is no directional gap.

FIG. 4 shows the cutter bits 29-1 to 29-8.
2 is a partially enlarged view showing the detailed structure of FIG. 2, FIG. 5 is a top view seen from the B direction in FIG. 4, and FIG. 6 is a bottom view seen from the C direction in FIG. 4 is a side view seen from the direction D in FIG. 4, and FIG. 8 is a cross-sectional view seen in the section VIII-VIII in FIG. In addition, in these drawings, for easy understanding of the mounting direction and the like during excavation, the excavation direction excavation surface Ma and the radial excavation surface Mr provided on the substantially stepped excavation surface M are shown together. . In these FIGS. 4, 5, 6, 7, and 8, the cutter bits 29-1 to 29-
All 8 have the same structure, and in detail, they are provided with a bit body 29B and five cemented carbide chips 29A provided so as to be embedded in the bit body 29B. The bit bodies 29B are respectively the excavation surface Ma in the excavation direction.
A substantially vertical upper edge portion (chamfered portion) 29Ba extending substantially parallel to the radial direction and having a negative rake angle γa (see FIG. 6), and the inner circumference of the cutter head 3 thereof. And a sloped portion 29Bb provided on the side thereof so as to form a predetermined inclination angle θa with respect to the excavation surface Ma in the excavation direction and to have a positive rake angle γr with respect to the excavation surface Mr in the radial direction (see FIG. 4). Is equipped with. The vertical upper edge portion 29Ba is provided in order to prevent stress from being concentrated on the sharp edge portion and lowering the durability. The cemented carbide chips 29A are arranged in the bit body 29B having the above-mentioned structure so that five cemented carbide chips 29A are embedded in the circumferential direction of the cutter head 3 at predetermined equal intervals.
As shown in FIG. 6, it is configured so as to match the shape of the chip placement portion in the bit body 29B having the above structure. As a result of the above configuration, the cutter bit 29
-1 to 29-8 as a whole are substantially pointed portions 26 provided at both ends in the circumferential direction of the cutter head, as clearly shown in FIG.
To the circumferential intermediate portion 25, the size of the cutter head in the radial direction (vertical direction in FIG. 4) is increased (in other words, the radial excavation locus is larger at the end of cutting than at the start of cutting). Shape).

The center cutter 28 is referred to as a known fish tail bit which is usually provided in the cutter head of this type of shield machine, and has a plurality of positive rake angles with respect to the excavation surface in the excavation direction. 28 square bits
a. Further, in FIG. 2, 30 is an excavation chamber P.
It is a known earth pressure gauge that detects the earth pressure inside. In the above, the center cutter 28 constitutes the preceding excavation means which is provided so as to project in the propulsion direction as described in each claim.

(2) Basic operation of shield machine The basic operation of the shield machine of the present embodiment configured as described above will be described below. The shield machine drives the cutter head 3 to rotate by the driving force of the cutter driving device 4,
Cutter bits 29-1 to 29 provided on the cut head spokes 27A to 27D and the annular member 27E of the cutter head 3.
The ground is excavated by 9-8. The propulsive force to the cutter head 3 at this time is given by extending the shield jack 15 by using the existing segment ring S as a reaction force receiving force, as described above.

The excavated earth and sand are agitated and plastically fluidized in the excavation chamber P by the cutas pork 27A to 27D of the cutter head 3, thereby preventing the ground from collapsing and stopping water. At this time, if necessary, a mud material for promoting plastic fluidization of the excavated soil is injected from the injection port 57 (see FIG. 1) provided in the cutter head 3. The plastically fluidized earth and sand is taken into the screw conveyor 6 and discharged.

In this way, after excavating a predetermined distance (for example, one stroke of the shield jack 15), the shield jack 15 is contracted to form a space between the spreader 16 and the existing segment ring S. ,
A new segment ring S is assembled and arranged by the erector device 9 and bolted to the existing segment ring S. At this time, the backfill material is injected into the cavity formed around the segment ring S by, for example, an injection means (not shown), so that the cavity is filled.

Then, the newly arranged segment ring S is used as a reaction force again to bring the shield jack 15 into the extended state and the shield body 1 is propelled forward, while the cutter head 3 is rotated to excavate the ground again. To go.

The above procedure is repeated to construct a tunnel having a circular cross section. Note that, for the earth and sand around the segment ring S after the shield machine has passed, a backfill material that is age-hardened is injected and filled by an injection means (not shown),
Fix the tunnel wall to the ground.

(3) Detailed excavation operation and action of the cutter head One of the features in the operation of the shield machine according to the present embodiment
One is from the center cutter 28 as the preceding excavating means whose radial position in the cutter head 3 is the center side and which is most protruded to the front side in the excavation direction, and the cutter bits 29-1 and 29-2 at other radial positions which are successively adjacent to each other. , ..., 29-7, 29-8
By arranging the blade edges of the so as to retreat toward the rear side in the excavation direction in sequence, excavation is performed while maintaining the vertical cross-sectional shape of the excavated surface M of the ground in a substantially stepwise manner (so-called undercutting), and at the same time, Cutter Bit 29-
1, 29-2, ..., 29-7, 29-8, the cutter head 3 is rotated in the circumferential direction to excavate the ground so as to widen the ground in the radial direction.

FIG. 9 is an explanatory view showing such excavation behavior. Of the above-mentioned cutter bits 29-1 to 29-8, the cutter bit 29-2 in FIG. 3 and its peripheral portion D are shown. The part is taken as an example and enlarged and shown.
In the shield machine of the present embodiment, the center cutter 28 that precedes the excavation direction forms a substantially conical leading excavation surface on the face, and each of the cutter bits 29-1 to 29-8 uses the preceding excavation surface as a foothold. Excavate sequentially. As a result, on the outer peripheral side of the preceding excavation surface, as shown in FIG. 9, most of the excavation surface M of the natural ground has a substantially stepwise vertical cross-sectional shape composed of the excavation surface Ma in the advancing direction and the excavation surface Mr in the radial direction. An excavation surface is formed (at this time, each cutter bit 29-1 to 29-29).
The surface Cc connecting the positions of the blade tips at -8 is a conical surface.
(Represented by a straight line in FIG. 9)). By adopting such an excavation mode, a crack Cr is generated on the root side of the substantially step-like edge portion (corner portion) Mc by the pressing force of the cutter bit 29 in the excavation direction (left direction in FIG. 9) to propagate. Thus, peeling and crushing can be performed in which most of the edge Mc (portion hatched in FIG. 9) continuously induces diagonal shear failure. Moreover, at this time, each cutter bit 29-1 to 29-2
Since 9-8 has a shape in which the radial dimension increases from the substantially pointed portions 26 provided at both ends in the circumferential direction toward the intermediate portion 25 in the circumferential direction, each cutter bit 29- 1 to 29-8 bite into the face from a substantially pointed portion 26 on one side (excavation direction side), and as the cutter head 3 rotates in the biting state, each of the cutter bits 29-1 to 29-having an enlarged diameter. 8 can excavate the excavation surface so as to widen it in the radial direction of the cutter head 3. Therefore, the excavation by the above-mentioned peeling and crushing is combined with the cutting and widening effect, and the excavation resistance can be significantly reduced. In particular, the effect is large because the radially inner peripheral side to be cut out is an open surface. In this way, since the excavation force required for excavation can be reduced, excavation of the ground can be performed with a smaller excavation force than in ordinary excavation, and excavation efficiency is significantly improved. Therefore, the wear due to the sliding of the cutter bits 29-1 to 29-8 with the natural ground face (excavation surface M) can be reduced accordingly (especially, soft rock,
Effective for soil, cobblestone, gravel, etc.), so that the digging distance can be improved. Further, instead of excavating the ground face with the cutting edge of the cutter bit as in normal excavation, excavation is mainly performed by peeling and crushing as described above. Therefore, the cutter bits 29-1 to 29
A relatively large excavating force can be secured even if the blade edge of -8 becomes worn and no longer sharp. Therefore, also by this, the digging distance can be improved. As described above, since the excavation distance can be greatly improved as compared with the normal excavation, it is possible to perform a sufficiently long distance excavation (for example, 2 km or more) in the soil having a compressive strength of soft rock or less.

Further, in the shield machine according to the present embodiment, each cutter bit 29-1 to 29-8 has a negative rake angle γa with respect to the excavation surface Ma in the excavation direction, so that the circumference of the cutter head 3 is reduced. Cutter bit 2 with direction rotation
Since the excavation loci of 9-1 to 29-8 are more forward in the excavation direction than in the beginning of cutting (see FIG. 5), the cutting bit 29-is rotated by the rotation of the cutter head 3.
1 to 29-8 positively apply a pressing force to the front side (the lower side in FIG. 5) in the excavation direction to the natural ground. As a result,
In addition to the effect of cutting and widening the cutter head 3 in the radial direction as described above, a pressing force is applied to the front side in the excavation direction, so that as a resultant force, a force is generated to push the natural ground diagonally forward in the excavation rotation direction. This resultant force makes it easier to generate the crack Cr on the root side of the above-mentioned substantially stepped edge portion Mc, so that peeling and crushing can be further promoted. Therefore, the reduction of excavation can be further reduced, and the excavation distance can be more reliably improved.

The shape of the cutter bits 29-1 to 29-8, which is one of the features of the present invention, is not limited to that of the above-mentioned one embodiment, and its spirit and technical idea are not deviated. Various modifications are possible within the range. Hereinafter, modifications of such a cutter bit shape will be sequentially described.

(Variation 1) Structure without chamfer FIG. 10 shows cutter bits 29-1 and 29-2 according to this modification.
9-8 is an enlarged front view showing the detailed structure of 9-8 seen from the face side, and FIG. 11 is a top view seen from the E direction in FIG.
12 is a bottom view seen from the F direction in FIG.
3 is a side view seen from the direction G in FIG. 10, and is a view corresponding to FIG. 4, FIG. 5, FIG. 6, and FIG. 7 in the embodiment of the present invention. It should be noted that in FIGS. 10 to 13, the cemented carbide alloy chip 29A is not shown for the purpose of preventing the illustration from being complicated and clarifying the structure,
Further, the same parts as those shown in FIGS. 4 to 8 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

As shown in FIGS. 10 to 13, this modification has a shape in which the substantially vertical upper edge portion 29Ba as the chamfered portion shown in FIGS. 4 to 8 is omitted. Other than that, the cutter bits 29-1 to 29-8 are shaped so that the radial dimension increases from the substantially pointed portions 26 provided at both ends in the circumferential direction toward the intermediate portion 25 in the circumferential direction. The structure is substantially the same as that shown in FIGS.

Similar to the above-described embodiment of the present invention, this modification has the effect of improving the excavation distance, simplifying the shape of the cutter bit, and facilitating the processing.

(Variation 2) Structure in which the radial dimension of the chamfered portion is enlarged. FIG. 14 shows cutter bits 29-1 to 29-2 according to this modification.
9-8 is an enlarged front view showing the detailed structure of 9-8 seen from the face side, and FIG. 15 is a top view seen from the H direction in FIG.
16 is a bottom view seen from the direction I in FIG.
7 is a side view seen from the direction J in FIG. 14, and is a view corresponding to FIG. 10, FIG. 11, FIG. 12, and FIG. 13 in the modified example of (variation 1). Note that these FIG.
17A to 17C, the cemented carbide tip 29A is not shown, and the same parts as those shown in FIGS. 4 to 8 and FIGS. Is omitted.

As shown in FIGS. 14 to 17, in this modification, the substantially vertical upper edge portion 29Ba as the chamfered portion shown in FIGS. 4 to 7 is in the radial direction (vertical direction in FIGS. 14 and 17).
In addition to expanding the dimensions,
6 in the left-right direction) has a reduced size. Other than that, the cutter bits 29-1 to 29-8 are shaped so that the radial dimension increases from the substantially pointed portions 26 provided at both ends in the circumferential direction toward the intermediate portion 25 in the circumferential direction. The structure is substantially the same as that shown in FIGS.

In this modified example, as in the above-described embodiment of the present invention, the effect of improving the excavation distance can be obtained, and the chamfered portion is increased in size to further increase the cutter bit 2.
There is also an effect that the durability of 9-1 to 29-8 can be improved.

(Variation 3) Structure in which the chamfered portion is inclined FIG. 18 shows cutter bits 29-1 to 29-2 according to this modification.
FIG. 19 is an enlarged front view showing the detailed structure of 9-8 seen from the face side, and FIG. 19 is a top view seen from the K direction in FIG.
20 is a bottom view seen from the direction L in FIG.
1 is a side view seen from the N direction in FIG. These are shown in FIG. 14 and FIG.
FIG. 18 is a view corresponding to FIG. 5, FIG. 16 and FIG.
The same parts as 7 are designated by the same reference numerals.

As shown in FIGS. 18 to 21, in the present modification, the structure shown in FIGS. 14 to 17 extends in a substantially vertical direction (in particular, see FIG. 17). Instead of the upper edge 29Ba, the excavation surface Ma in the excavation direction
(In other words, it has a shape in which an inclined upper edge portion 29Ba ′ that is inclined at an inclination angle θb with respect to the vertical surface is provided. Other than that, the cutter bits 29-1 to 29-8
14 to 17, including the point that the radial dimension increases from the substantially pointed portions 26 provided at both ends in the circumferential direction toward the intermediate portion 25 in the circumferential direction as a whole. It is almost the same.

In this modified example, as in the above-described embodiment of the present invention, the effect of improving the excavation distance can be obtained, and the inclined arrangement of the chamfers reduces the force for cutting into the ground face. Since it is completed, it is possible to excavate the ground with a smaller excavation force, and it is possible to improve the excavation distance.

(Variation 4) A structure in which the inner circumference side and the outer circumference side are positively cut out in the radial direction. One embodiment of the present invention and the above-mentioned (variation 1) to (variation 3).
The structure of the cutter bits 29-1 to 29-8 in FIG. 2 has a radially expanded shape extending from the substantially pointed portion 26 toward the circumferential intermediate portion 25. More specifically, regarding the radial outer circumferential side, The excavation locus having a substantially arcuate shape is configured to more actively push the ground only on the radially inner side, and as a result, the excavation surface is widened in the radial direction during excavation.

In this modified example, not only the above-mentioned radial inner peripheral side but also the radial outer peripheral side is more actively pushed to expand the ground, thereby further increasing the cutting and expanding effect. It is something to try. FIG. 22 is an enlarged front view showing the detailed structure of the cutter bits 29-1 to 29-8 according to this modified example, as seen from the cutting face side.
FIG. 24 is a top view seen from the Q direction in FIG. 22, and FIG.
FIG. 25 is a bottom view seen from the R direction in FIG. 22, and FIG.
2 is a side view seen from the S direction in 2 and is a view corresponding to FIG. 4, FIG. 5, FIG. 6, and FIG. 7, respectively, in the embodiment of the present invention. 22 to 25, the cemented carbide tip 29A is not shown, and the same parts as those of the structure shown in FIGS. Omit it.

As shown in FIGS. 22 to 25, in this modification, a cemented carbide tip 29A (not shown) is provided on the substantially rhomboidal bit main body 29B '. With such a structure, the cutter bit 2 is similar to the above-described embodiment of the present invention and the modified examples of (variation 1) to (variation 3).
9-1 to 29-8 as a whole have such a shape that the radial dimension increases from the substantially pointed portions 26 provided at both ends in the circumferential direction toward the intermediate portion 25 in the circumferential direction. Note that, unlike the embodiment of the present invention and the modified examples of (Variation 1) to (Variation 3), a negative rake angle γr is provided with respect to the radial excavation surface Mr (see FIG. 22) and the excavation direction. The rake angle is zero with respect to the excavated surface Ma (see FIG. 23).

In this modified example, the effect of improving the excavation distance by the radial dimension expansion can be obtained as in the above-described embodiment of the present invention, and as described above, not only the radial inner peripheral side but also the radial direction can be obtained. Since the ground can be more positively expanded on the outer peripheral side in the direction as well, it is possible to further increase the cutting and expanding effect and further improve the excavation distance.

(Variation 5) Structure in which chamfered portion is inclined FIG. 26 shows cutter bits 29-1 and 29-2 according to this modification.
FIG. 29 is an enlarged front view showing the detailed structure of 9-8 seen from the face side, and FIG. 27 is a top view seen from the T direction in FIG. 26.
28 is a bottom view seen from the direction U in FIG.
9 is a side view seen from the V direction in FIG. 26. These are shown in FIG. 22 and FIG. 2 in the modified example of (Variation 4).
It is a figure corresponding to FIG. 3, FIG. 24, and FIG.
The same reference numerals are given to the same parts as 5.

As shown in FIGS. 26 to 29, in this modification, the rake angle is zero with respect to the excavation surface Ma in the excavation direction in the structure shown in FIGS. 22 to 25 (FIG. 23).
However, the bit body 29B ′ has a negative rake angle γ.
It has a convex shape to the front side in the excavation direction with a. Further, at this time, as shown in FIG. 29, it is shaped so as to incline with respect to the excavation surface Ma in the excavation direction at a predetermined inclination angle θc both on the outer peripheral side in the radial direction and on the inner peripheral side in the radial direction. As a result, as shown in FIGS. 26 and 29, the cutter bits 29-1 to 29-8 as a whole have a shape that can be called a sword type similar to the shape of a sword. Other than that, the cutter bits 29-1 to 29-8
22 to 25, including a shape in which the radial dimension increases from the substantially pointed portions 26 provided at both ends in the circumferential direction toward the intermediate portion 25 in the circumferential direction as a whole. It is almost the same.

In this modification, the effect of improving the excavation distance can be obtained as in the above case. In addition, the excavation direction M
By providing a negative rake angle γa with respect to a, unlike the modified example of (Variation 4) described above, peeling is performed in the same manner as in the embodiment of the present invention and the modified examples of (Variation 1) to (Variation 3). Crushing can be promoted more. Therefore, the reduction of excavation can be further reduced, and the excavation distance can be more reliably improved.

In the above description, at one radial position of the cutter head 3, the center cutter 28 is provided so as to project to the front side in the excavation direction, and the cutter bit 29 is provided at another radial position successively adjacent to the radial position. When the cutting edges are sequentially retracted rearward in the excavation direction, the cutass pork 27 is also arranged to be receded rearward toward the outer peripheral side in correspondence with the arrangement on the cutting edge side, but the invention is not limited to this. That is, the Kattaspoke side is configured to simply extend radially in a radial direction like a normal shield machine, and the axial length of the cutter bit attached to this is changed for each radial position, You may implement | achieve such the aspect of arrangement | positioning of a cutting edge position. It goes without saying that the same effect can be obtained in this case as well.

Further, in the above, the mud taken in the excavation chamber P is discharged by the screw conveyor 6, and
The case where the present invention is applied to a so-called earth pressure shield excavator that opposes the earth pressure of the face by the pressure of the mud in the excavation chamber P has been described as an example, but the present invention is not limited to this. That is, the present invention is applied to a so-called muddy water shield machine in which water is injected into the excavation chamber P by using a water injection means such as a water pipe, and the excavated soil is discharged as muddy water by a mud discharge means such as a mud discharge pipe. Is also good. Also in this case, the same effect is obtained.

Further, although the case where the present invention is applied to the shield machine for excavating by rotating the cutter head 3 provided in front of the shield body 1 has been described above as an example, the present invention is not limited to this. The cutter head structure of the present invention can be applied to a horizontal pipe excavator such as a push tube shield, a small diameter propulsion machine, and a TBM. In this case, the same effect can be obtained.

[0061]

EFFECTS OF THE INVENTION According to the present invention, since excavation by peeling and crushing and the effect of cutting and cutting are combined with each other, the excavation resistance can be remarkably reduced. In addition, the excavation efficiency can be significantly improved. As a result, it is possible to reduce wear of the cutter bit due to sliding with the face, and to improve the excavation distance. Further, since the excavation ability can be secured even when the cutting edge of the cutter bit is worn out and is not sharp, the excavation distance can also be improved. Therefore, sufficient long-distance excavation can be performed in soils with a compressive strength of soft rock or less.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an overall structure of an embodiment of a horizontal hole excavator of the present invention.

FIG. 2 is a front view seen from the direction A in FIG.

FIG. 3 is an enlarged view of a main part in FIG. 1 showing a detailed structure of a cutter head.

FIG. 4 is a partially enlarged view of FIG. 2 showing a detailed structure of a cutter bit.

5 is a top view seen from the direction B in FIG. 4. FIG.

FIG. 6 is a bottom view seen from the direction C in FIG.

FIG. 7 is a side view seen from the direction D in FIG.

8 is a cross-sectional view taken along the line VIII-VIII in FIG.

FIG. 9 is an explanatory diagram showing excavation behavior of the embodiment of the horizontal hole excavator of the present invention.

FIG. 10 is an enlarged front view showing the detailed structure of a modified example in which the chamfered portion of the cutter bit constituting the embodiment of the lateral hole excavator of the present invention is eliminated, as seen from the cutting face side.

11 is a top view seen from the direction E in FIG.

FIG. 12 is a bottom view seen from the F direction in FIG.

13 is a side view seen from the direction G in FIG.

FIG. 14 is an enlarged front view showing the detailed structure of a modified example in which the radial dimension of the chamfered portion of the cutter bit constituting one embodiment of the lateral hole excavator of the present invention is enlarged, as seen from the cutting face side.

FIG. 15 is a top view seen from the direction H in FIG.

16 is a bottom view seen from the direction I in FIG.

FIG. 17 is a side view seen from the J direction in FIG.

FIG. 18 is an enlarged front view showing the detailed structure of a modified example in which the chamfered portion of the cutter bit that constitutes one embodiment of the lateral hole excavator of the present invention is inclined, as seen from the cutting face.

FIG. 19 is a top view as seen from the direction K in FIG.

20 is a bottom view seen from the direction L in FIG.

FIG. 21 is a side view seen from the N direction in FIG.

FIG. 22 is a side view showing a detailed structure of a modified example in which the cutter bit that constitutes one embodiment of the lateral hole excavator of the present invention is configured to positively open to both the radially inner peripheral side and the outer peripheral side. FIG.

23 is a top view seen from the Q direction in FIG. 22. FIG.

FIG. 24 is a bottom view seen from the R direction in FIG. 22.

FIG. 25 is a side view seen from the S direction in FIG. 22.

FIG. 26 is an enlarged front view showing the detailed structure of a modified example in which the chamfered portion of the cutter bit that constitutes one embodiment of the lateral hole excavator of the present invention is inclined, as seen from the cutting face.

FIG. 27 is a top view seen from the direction T in FIG. 26.

FIG. 28 is a bottom view seen from the direction U in FIG. 26.

FIG. 29 is a side view seen from the direction V in FIG. 26.

[Explanation of symbols]

1 Shield body 3 cutter head 25 Circumferential middle part 26 Approximate point 28 Center cutter (preceding excavation means) 29 cutter bits 29-1 Cutter Bit 29-2 Cutter Bit 29-3 Cutter Bit 29-4 Cutter Bit 29-5 Cutter Bit 29-6 Cutter Bit 29-7 Cutter Bit 29-8A Cutter Bit 29-8B Cutter Bit M excavation surface Ma Excavation direction Excavation surface Mr radial excavation surface Rake angle to the excavation surface

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenji Yamashita             2-15-2 Konan, Minato-ku, Tokyo Co., Ltd.             Obayashi Tokyo Main Office (72) Inventor Hiroshi Kimura             2-15-2 Konan, Minato-ku, Tokyo Co., Ltd.             Obayashi Tokyo Main Office (72) Inventor Kiyoshi Tsuchiya             Hitachi Construction Machinery Co., Ltd.             Ceremony Company Tsuchiura Factory (72) Inventor Masakazu Fukai             Hitachi Construction Machinery Co., Ltd.             Ceremony Company Tsuchiura Factory F term (reference) 2D054 AC04 AC05 BA03 BB05

Claims (2)

[Claims] 1. A horizontal hole excavator for excavating by rotating a cutter head provided at a front portion, and a pre-excavating means provided at least at one location of the cutter head so as to project in a propulsion direction. From the means at a radial position of the cutter head, and a plurality of cutter bits arranged on the cutter head so as to be sequentially positioned on the axial rear side of the horizontal hole excavator, and the plurality of cutter bits are A dimension of the cutter head in the radial direction from a substantially pointed portion provided at both ends in the circumferential direction of the cutter head to an intermediate portion so that the excavated surface is widened in the radial direction of the cutter head as the cutter head rotates. The horizontal hole excavator is characterized in that it has a shape that expands. 2. The horizontal hole excavator according to claim 1, wherein at least one of the plurality of cutter bits has a negative rake angle with respect to the excavation surface in the excavation direction. Hole excavator.