JP2002371789A - Lateral hole boring machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lateral hole boring machine making boring possible over a long distance in soil with compressive strength not higher than that of soft rocks. SOLUTION: The lateral hole boring machine performs boring by rotating a cutter head 3 provided at its front. The cutter head 3 includes a plurality of cutter spoke parts 27A to D extending radially from the radial center thereof; a surface plate part 17 disposed to approximately close gaps among the cutter spoke parts 27A to D; sediment holes 19 and 20 provided in the surface plate part 17 for taking in the sediment excavated; a center cutter 28 provided in at least one position of the cutter spoke parts 27A to D to protrude in jacking direction; and a plurality of cutter bits 29-1 to 29-10 disposed at the cutter spoke parts 27A to D, from the center cutter 28 to radial positions of the cutter head 3 in such a way that the cutter bits are located in sequence at the rear of the boring machine along the axis of the machine.

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, for example, in front of a shield body, and more particularly, to a cutter bit provided at a plurality of radial positions of the cutter head. It relates to a horizontal hole excavator.

[0002]

2. Description of the Related Art A shield excavator, which is one of the horizontal hole excavators, usually has a plurality of bit attachment portions arranged in a circumferential direction of a cutter head provided in front of a shield body, and a center excavator at a tip of a center shaft. The bit attachment portion is constituted by a cut-spoke portion radially extending from the frame in a radial direction, and each of the cut-spoke portions is provided with a cutter bit at a plurality of radial positions. At this time, in the so-called muddy shield excavator, the face plate is arranged so as to almost close the gap between those cut spokes,
Further, a sediment intake port (slit) for taking excavated sediment is provided in the face plate portion. By rotating the cutter head having such a structure, the cutting face is excavated by the cutter bit.

[0003] The excavated earth and sand is agitated in the excavation chamber immediately behind the cutter head defined by the partition wall.
In a muddy shield excavator, water is injected into a drilling chamber using a water injection means such as a mud pipe, and excavated earth and sand is discharged in a muddy state to the rear of the shield body by a mud draining means such as a mud 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. Also, slightly ahead of the erector in the shield body, a plurality of shield jacks for giving propulsive force in the excavation direction to the shield body are arranged in a ring, and 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 backing material is injected into a hollow portion formed around the segment ring, and the hollow portion is filled.

[0005] In this manner, the front face is excavated and excavated while the shield body is propelled, and a tunnel is constructed on the rear side by a segment ring. In the shield method, a tunnel is formed in a predetermined underground section from one excavated shaft (starting shaft) to another shaft (reaching shaft) by repeating the above operation using a shield excavator. Things. By the way, in general, the soil (stratum) of the ground to be excavated by the shield machine is:
From hard to soft, there are, for example, rock, consolidated silt, clay, sandstone, cobblestone, sand, cohesive soil (silt, clay), and the like. Normally, compressive strength 500kgf / c
hard rock things than compressive strength it larger the m ² degree as a boundary,
Small ones are called soft rocks. When excavating with a shield machine, for soil other than hard rock (in other words, soil with compressive strength equal to or lower than soft rock, hereafter simply referred to as “soil below soft rock” as appropriate), a carbide tip as an excavation blade is used for the bit body. It is possible to drill with a normal cutter bit attached to the tip of the blade, but when drilling hard rock, it is difficult to drill with this normal cutter bit, so both ends in the axial direction are connected to the cutter head. In many cases, a roller bit rotatably supporting a cutting roller for cutting a face is used for the shaft.

In the case of excavating a hard rock which has relatively high compressive strength and is difficult to excavate 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 a shield body and excavation is performed by rotating the cutter head, a roller bit located at a radially most central side of the cutter head is provided. , Projecting to the front in the digging direction, and arranging the roller bits at other adjacent radial positions to be sequentially retracted to the rear in the digging direction to form a digging surface such that the vertical cross-sectional shape becomes substantially step-shaped. An excavator has been proposed.

In this shield machine, excavation is performed while maintaining the vertical cross-sectional shape of the ground excavation surface in a substantially stepped shape (so-called undercutting), so that the substantially stepped edge portion (during excavation) is formed. Inducing exfoliation and crushing in the back edge of the excavation direction), thereby reducing the excavation force (pressure) required for excavation and enabling excavation of high compression strength soil with less excavation force than before. Things.

[0008]

In general, in a shield excavator, the cutter bit is worn by sliding with a face as the excavation work progresses. There are limitations. Conventionally, a shield excavator has a relatively short excavation distance, and a relatively short section (for example, 1 km) from one shaft (starting shaft) to another shaft (reaching shaft) is excavated by one shield excavator. After that, the relatively short section from the other shaft to the further shaft (the same) had to be excavated using another shield machine or after replacing worn cutter bits.

[0009] In recent years, it has become difficult to install a large number of starting and reaching shafts based on the background of the progress of urbanization and the like, and further reduction in the cost of excavating and installing shafts and the cost of manufacturing shield machine is desired. As a result, there is a growing need to increase the excavation distance by one shield excavator as much as possible.

[0010] The inventors of the present application have proposed that the same vertical cross-sectional shape as that of the above-mentioned prior art is substantially stepped, using the normal cutter bit, for the soil of the soft rock or lower which is relatively widely distributed in the stratum of Japan. By newly excavating, it was newly found that long-distance excavation is possible without using a heavy equipment structure such as the roller bit.

An object of the present invention is to provide a horizontal hole excavator which enables excavation over a long distance in soil having a compressive strength of soft rock or less.

[0012]

Means for Solving the Problems (1) In order to achieve the above object, the present invention relates to a horizontal hole excavator for performing excavation by rotating a cutter head provided at a front part, wherein the cutter head has a diameter. A plurality of cut-spoke portions extending radially from the direction center side, a face plate portion arranged to substantially close a gap between the plurality of cut-spoke portions, and a sediment intake port provided in the face plate portion to take in excavated sediment, At least one of the plurality of cut-spoke portions or the face plate portion, a leading excavating means provided so as to protrude in the propulsion direction, and a radial position of the cutter head from the leading excavating means, and A plurality of cutter bits arranged on the plurality of cutter spoke portions or the face plate portion so as to be sequentially located on the rear side in the axial direction.

According to the present invention, the leading excavation means is projected in at least one position (for example, one radial position) of the plurality of cut-spoke parts or the face plate part, and the plurality of cutter bits are moved from the leading excavation means. It is arranged on the cutter spoke portion or the face plate portion so as to be sequentially located at the radial position of the cutter head and the rear side in the axial direction. Thus, excavation can be performed (so-called undercutting) while forming an excavation surface such that the vertical cross-sectional shape becomes substantially stepwise from the excavation surface excavated by the advance excavation means. That is, the plurality of cutter bits generate cracks at the root side of the substantially stepped edge (corner) by the pressing force and cause the crack to propagate, and continuously perform oblique shear failure on most of the edge. Excavation is carried out by performing induced delamination and crushing. Therefore, the excavation force required at the time of excavation can be reduced, and the excavation of the ground can be performed with a small excavation force as compared with normal excavation. Thereby, the wear of the cutter bit caused by sliding with the cutting face can be reduced, and the excavation distance can be improved. Also, rather than excavating the ground face with the cutting edge of the cutter bit as in ordinary excavation, excavation is performed mainly by peeling and crushing as described above, so the cutting edge of the cutter bit is worn and sharpened. Excavation capacity can be secured. Therefore, the excavation distance can be improved also by this. As described above, the excavation distance can be greatly improved as compared with normal excavation, so that a sufficiently long excavation can be performed on soil having a compressive strength of soft rock or less.

When undercutting is performed from the preceding excavation surface as described above, the excavation surface is formed such that the vertical cross-sectional shape becomes substantially stepwise from the preceding excavation surface as described above (for example, the preceding excavation means). Is located in the center in the radial direction, the face is excavated like an umbrella)
In some cases, the face collapse may be more likely to occur than in the normal case.However, in the present invention, the gap between the plurality of cut-spoke parts is almost completely closed by the face plate, thereby possibly causing the face collapse. Can be reduced, and the stability of the face can be improved.

(2) In order to achieve the above object, the present invention relates to a horizontal hole excavator for excavating by rotating a cutter head provided at a front portion, wherein the cutter head is radially arranged from a radially central side. And several Kataspoke parts extending to
A face plate portion arranged to substantially close the gap between these plurality of cut-spoke portions, a sediment intake port provided in the face plate portion for taking in excavated sediment, and at least one of the plurality of cut-spoke portions or the face plate portion. A protruding excavating means provided to protrude in the propulsion direction, and sequentially positioned radially from the precedent excavating means at a radial position of the cutter head and axially rearward of the horizontal hole excavator, and excavated by the precedent excavating means. And a plurality of cutter bits disposed on the plurality of cut-spoke portions or the face plate portion so as to exfoliate and crush sequentially from the preceding excavation surface.

(3) In the above (1) or (2), preferably, a water injection means for injecting the soil excavated with the cutter head, and the injected excavated earth and sand is sucked and discharged in a muddy state. And a sludge discharging means.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing the entire structure of an embodiment of a horizontal hole excavator according to the present invention.
FIG. 2 is a front view as viewed in the direction of arrow A in FIG. 1.

In FIG. 1 and FIG. 2, the horizontal hole excavator of the present embodiment is a so-called shield excavator, for example, soft rock, consolidated silt, dotan, cobblestone-bearing gravel, gravel,
It is particularly suitable for excavation of soft soils such as sand and cohesive soil (silt, clay) and the like (in other words, soils other than hard rocks). For this reason, a shield body 1 having a structure in which a front body 1A located at the forefront in the excavation direction and a rear body 1B adjacent to the rear side thereof are connected in a bendable manner, and the inside of the shield body 1 and the excavation room P 2, a cutter head 3 provided on the front side (left side in FIG. 1) of the front body 1A in the excavation direction, excavating the ground face M and taking it into the excavation chamber P (described later); A cutter driving device (for example, an electric motor or a hydraulic motor) 4 that rotationally drives the head 3, and a so-called peripheral support type rotation that is attached to the partition wall 2 and transmits a driving force from the cutter driving device 4 to the cutter head 3. Transmitter 5, a mud pipe 6 for injecting excavated sediment taken into an excavating chamber P formed immediately behind the cutter head 3, and a drilling sediment injected into the excavating chamber P. Suck in muddy water,
A mud pipe 7 which is conveyed and discharged to the opposite side (right side in FIG. 1) of the excavation direction of B, and a segment ring S provided in the rear trunk 1B and lining the inner surface of a tunnel (not shown) are sequentially provided. And an erector device 9 to be assembled.

The rotation transmission mechanism 5 includes a cutter head 3
Four cutter arms 3 respectively connected to radial outer peripheral portions of the cut-spoke portions 27A to 27D (details will be described later).
5, a substantially annular cutter ring 34 disposed through the partition wall 2, and a bearing 33 having an inner ring 33a fixed to the cutter ring 34. A gear 32 is provided on the inner ring 33a of the bearing 33, and the pinion 31 attached to the cutter driving device 4 is provided.
Are engaged. These cutter driving devices 4 are fixed to the mounting portion 2a provided on the partition 2 together with the outer ring 33b of the bearing 33. Although not shown, they are annularly arranged at equal intervals.

In the center of the partition wall 2 in the radial direction, a through hole 2 is provided.
b is formed in the through hole 2b.
A communication pipe 36 is provided through the connection pipe 8. This communication pipe 3
Numeral 6 is for making the cutter head 3 communicate with the rear side of the shield machine (i.e., the inside of the machine) with respect to the partition wall 2. A substantially cylindrical center cutter guide member 37 having a slightly smaller diameter than the communication pipe 36 is provided at the radial center of the cutter spokes 27A to 27D. The rear end of the center cutter guide member 37 is It is fixedly connected to the front end of the tube 36.

At this time, a center cutter 28 as a cutting means is disposed so as to be located at the center (inside) in the radial direction and protrude forward in the digging direction. The center cutter 28 is located at a rear portion thereof and has a cutter support portion 28A having an outer diameter slightly smaller than the inner diameter of the center cutter guide member 37, and is located at a further rear portion of the cutter support portion 28A. And a substantially disc-shaped center cutter mounting member 28B having an outer diameter larger than the inner diameter of the communication pipe 36 and smaller than the inner diameter of the communication pipe 36. The center cutter 28 is fixed to the radial center of the cutter head 3 as shown in FIG. 1 by fastening the center cutter mounting member 28B to the rear end of the center cutter guide member 37 with a bolt 28C. Have been. By removing the bolt 28C, the center cutter 28 and the cutter support 28 are removed.
A and the center cutter mounting member 28B are integrally connected to the communication pipe 3.
6 has a structure capable of being collectively extracted to the rear side.
Between the front body 1A and the rear body 1B, there is provided a center-bending mechanism 11 for slidably connecting them to each other.
That is, a sliding portion 11a whose outer peripheral surface is substantially spherical is provided at the front end of the rear body 1B, and the rear end of the front body 1A is slidably in contact with the sliding portion 11a. 11a and front body 1
A substantially ring-shaped seal member 11b (to prevent intrusion of earth and sand, groundwater) that seals between the rear end portion A is provided, and the sliding portion 11a and the seal member 11b constitute the center-bending mechanism 11. are doing.

At this time, the center bending jack bracket 12 provided inside the front body 1A and the ring girder 13 provided at the foremost part of the rear body 1B (specifically, the inner peripheral side of the sliding portion 11a) are provided. A plurality (for example, eight) of middle folding jacks (front trunk propulsion jacks) 14 are provided in the circumferential direction between the folding jack bracket 13a. And
At the time of constructing a curve or correcting the direction of excavation, the extension and contraction operation of the middle folding jack 14 causes the middle folding mechanism 11 to move.
The front trunk 1A is bent with respect to the rear trunk 1B through the through hole, and the angle formed by them can be changed to change the excavation direction.

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

These shield jacks 15
Although not particularly shown in detail, they are arranged, for example, at equal intervals in a ring shape, and are extended to form a 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 via the front body 1A as propulsion force forward in the excavation direction. This allows
During the excavation, the cutter head 3 is pressed against the face of the ground. The distal ends of the mud pipe 6 and the drain pipe 7 are exposed from the inside of the shield body 1 to the excavation chamber P through the partition wall 2 from the inside of the shield main body 1, and the mud holes 6 a and the mud suction pipes are respectively provided at the distal ends. The mouth 7a is provided. The mud port 6a of the mud pipe 6 is open at the top of the excavation chamber P, and the mud suction port 7a of the mud pipe 7 is open at the bottom of the excavation chamber P.

The rear ends of the mud pipe 6 and the drain pipe 7 are
The rear trunk 1B extends further rearward (that is, outside the shield machine). At this time, the rear end of the drainage pipe 7 is connected to a suction pump (not shown) provided at a predetermined position, and the suction force of the suction pump causes the muddy water in the excavation chamber P to be sucked as described above. It sucks in from the opening 7a, and conveys it to the opposite side (right side in FIG. 1) with the excavation direction through the drainage pipe 7. The conveyed muddy water is finally subjected to a predetermined treatment (for example, purification treatment) in a muddy water treatment facility (not shown) provided outside the tunnel pit, and then sent to the mud feed pipe 6. The water is again fed into the shield machine via the mud pipe 6 by the discharge force of a mud pump (not shown), and is returned to the excavation chamber P from the mud port 6a at the tip.

A tail seal portion 8 having a plurality of tail packings 8a is provided at the rear end of the rear trunk 1B, whereby the rear end of the shield body 1 of the shield excavator moving forward is provided. A seal is formed between the section and the segment ring S to prevent intrusion of water and earth and sand from outside the shield machine into the machine.

The above-mentioned erector device 9 is provided with an erector ring 18 which is guided by a guide roller 10 arranged along the inner periphery of the rear trunk 1B and is driven to turn by a turning motor (not shown). The segments (not shown) constituting the divided pieces of the segment ring S are lifted one by one, transported to a predetermined assembly position, and the existing segment rings S adjacent to the shield body 1 in the axial direction (the front-rear direction of excavation) and The segment ring S is assembled by sequentially fastening bolts to the existing segments adjacent in the circumferential direction.

(1) Structural features of the shield machine according to the present embodiment The most structural features of the shield machine according to the present embodiment are the shape of the cutter spoke in the cutter head 3 and the arrangement of the cutter bits. Hereinafter, this will be described.

In FIG. 2, the cutter head 3 is radially extended from the center cutter 28 and the center cutter guide member 37 toward the radially outer peripheral side, and the radially outer circumferential side is more rearward in the excavation direction. Side (right side in FIG. 1)
(4 in this example) extended so as to retract
Cutout spokes 27A, 27B, 27C, 27D
(See FIG. 2) and these cut-spoke portions 27A-27.
An annular member 27E provided so as to sequentially connect the outermost peripheral portions of D in the circumferential direction;
A plurality of face plates (four face plates 17 in this example, and each face plate extending radially outward from the center cutter guide member 37 toward the radially outer side from the center cutter guide member 37) are disposed so as to substantially close a gap between adjacent ones of the 7Ds. A plurality (four in this example) of reinforcing members 18 fixed to the back surface (the excavation chamber P side) of the portion 17, a sediment intake hole 19 provided on the outer peripheral portion of each face plate portion 17, and a cut-spoke portion 27 A And a sediment intake hole (cutting slit) 20 provided on the side of the cut-spoke portions 27A to 27D (in other words, the outer diameter of the annular member 27E) is to be excavated. It is substantially equal to the inner diameter of the circular cross section.

The center cutter guide member 37, the respective cutter spoke portions 27A to 27D, the annular member 27E, and the reinforcing member 18 are provided with a plurality of radial positions on the cutter head 3 from the inner peripheral side to the outer peripheral side. Toward the cutter bits 29-1, 29-2, 29-3, 29-4, 2
9-5, 29-6, 29-7, 29-8, 29-9, 2
9-10A and 29-10B are arranged in this order. That is, the cutter bits 29-3 and 29 are provided in the cut spoke portion 27A from the inner peripheral side toward the outer peripheral side.
-7 are arranged in this order, and the center cutter guide member 37 and the cutter spoke portion 27B are provided with cutter bits 29-1, 29-5, and 2 from the inner peripheral side toward the outer peripheral side.
9-9 are arranged in this order, and the cutter bits 29-2, 29-6, and 29-10 are provided on the cutter spoke portion 27C and the annular member 27E from the inner peripheral side toward the outer peripheral side.
A (however, the cutter bit 29-10A is arranged at a position slightly shifted inward in the radial direction from the cutter bit 29-10B described later; see FIG. 2), and is arranged in this order. The cutter bits 29-4 and 29-8 are arranged in this order on the spoke portion 27D from the inner peripheral side to the outer peripheral side, and the reinforcing member 18 and the annular member 2 are arranged.
In 7E, four cutter bits 29-10B are arranged. The four cutter bits 29-10B are provided because if it becomes difficult to excavate the outermost peripheral position, the shield body 1 cannot be propelled forward in the excavation direction itself. Cutter bit 29
This is in order to reduce the excavation load per -10B and to ensure the excavation capacity.

At this time, each of the cutter bits 29-1 to 29
As shown in FIG. 2, the positions of −10 are shifted slightly from each other in the radial direction, and the cutter bits 29-1 to 29-10 at these 10 radial positions are all radially shifted from the radial center side. The cutter bits 2 are arranged so as to extend to the outer peripheral side in the direction, so that when the cutter head 3 rotates, these cutter bits 2
By 9-1 to 29-10 and the center cutter 28, it is possible to excavate a circular cross-sectional shape having an outer diameter substantially equal to the annular member 27E (strictly, slightly larger, see the two-dot chain line in FIG. 2).

The arrangement of the center cutter 28 and the cutter bits 29-1 to 29-10 in the digging direction is located at the radial center (as shown in FIG. 1). ) The center cutter 28 is made to protrude to the foremost side in the excavation direction, and the cutter bits 29-1, 29-2,..., 29-9, the radial positions of which are sequentially adjacent to the outer peripheral side of the radial position of the center cutter 28. The cut-spoke portion 27A is configured to sequentially retreat the cutting edge 29-10 (a substantially vertical blade surface portion 29Aa to be described later) rearward in the excavation direction.
To 27D. Thus, the excavation surface M having the excavation direction excavation surface Ma (see FIG. 6 described later) and the radial direction excavation surface Mr (same as above) and having a substantially stepwise vertical cross-sectional shape is provided.
(Same as above).

FIG. 3 shows the cutter bits 29-1 to 29-1.
FIG. 4 is a partially enlarged view showing a detailed structure of FIG.
FIG. 5 is a top view as viewed from a direction B in FIG. 3, and FIG.
It is the side view seen from the direction. In these figures, the excavation direction excavation surface Ma and the radial direction excavation surface Mr provided on the substantially stepped excavation surface M are also shown for easy understanding of the mounting direction at the time of excavation. .

In FIGS. 3, 4 and 5, the cutter bits 29-1 to 29-10 have the same structure, and include a bit main body 29B and a digging blade provided so as to be embedded in the bit main body 29B. (Carbide chip) 29A.

The cemented carbide tip 29A is provided with a digging surface Ma
A substantially vertical blade surface portion 29Aa which is substantially parallel to the inner surface of the cutter head 3, an inclined blade surface portion 29Ab provided on the inner peripheral side of the cutter head 3 and having a predetermined inclination angle θa with respect to the excavation direction excavation surface Ma, and a radial direction excavation surface Mr. A substantially horizontal blade surface portion 29Ac that is substantially parallel to the
And an inclined blade surface portion 29Ad provided on the rear side in the excavation direction and forming a predetermined inclination angle θr with respect to the radially excavated surface Mr.

With the above structure, the cutter bit 2
9 has a negative rake angle γa with respect to the digging surface Ma as shown in FIG. 4, and also has a negative rake angle γr with respect to the radial digging surface Mr as shown in FIG. .

The center cutter 28 is a so-called known fish tail bit usually provided in a cutter head of this type of shield machine, and has a plurality of positive rake angles with respect to a digging surface in a digging direction. 28 square bits
a. In the above, the center cutter 28
The preceding excavation means provided so as to protrude in the propulsion direction described in each claim is constituted, and the sediment intake holes 19 and 20 constitute sediment intake ports provided in the face plate portion to take excavated sediment.

The mud pipe 6 and the mud pump constitute water injection means for injecting water excavated by the cutter head. The mud pipe 7 and the mud pump pump the injected excavated mud into muddy water. In this state, a discharging means for sucking and discharging is constituted.

(2) Basic Operation of Shield Machine The basic operation of the shield machine according to the present embodiment configured as described above will be described below. The shield machine rotates the cutter head 3 with the driving force of the cutter driving device 4,
The cutter bits 29-1 to 29-1 provided on the cutter spoke portions 27A to 27D of the cutter head 3 and the annular member 27E.
The ground is excavated according to 29-10. At this time, the propulsive force to the cutter head 3 is given by extending the shield jack 15 with the existing segment ring S as a reaction force receiver as described above.

The excavated earth and sand is taken into the excavation chamber P from the earth and sand intake holes 19 and 20 of the face plate portion 17 and then injected into the mud pipe 6a of the mud pipe 6 to form muddy water. In this state, the air is sucked from the mud suction port 7a, and is conveyed and discharged through the mud discharge pipe 7.

After digging a predetermined distance (for example, a distance corresponding to one stroke of the shield jack 15) in this way, the shield jack 15 is contracted, and the space created between the spreader 16 and the existing segment ring S is removed. ,
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, a backing material is injected into a hollow portion formed around the segment ring S by, for example, an injection means (not shown), thereby filling the hollow portion.

Then, the newly arranged segment ring S is again used as a reaction force, the shield jack 15 is extended, the shield body 1 is propelled forward, and 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. The earth and sand around the segment ring S after the shield machine has passed is injected and filled with, for example, an age hardening backfill material by an injection means (not shown).
Fix the tunnel wall to the ground.

(3) Detailed Excavation Operation and Operation of Cutter Head The greatest feature of the operation of the shield excavator according to the present embodiment is that the radial position of the cutter head 3 is the center side and most protrudes forward in the excavation direction. From the center cutter 28 as the excavating means, the cutter bits 29-1, 29-2,.
By arranging the cutting edges of 0 in the excavation direction rearward in order, the excavation is performed (so-called undercutting) while maintaining the vertical cross-sectional shape of the excavated surface M of the ground in a substantially stepped shape. .

FIG. 6 is an explanatory diagram showing a state in which the undercutting is being performed. Among the aforementioned cutter bits 29-1 to 29-10, the cutter bit 2 in FIG.
9-4 and a portion D representing the peripheral portion thereof are extracted and enlarged. In the shield machine according to the present embodiment, a substantially conical preceding excavation surface is formed on a face by the center cutter 28 preceding in the excavation direction, and each of the cutter bits 29-1 to 29-10 is formed using the preceding excavation surface as a foothold.
Will excavate sequentially. As a result, on the outer peripheral side of the preceding excavation surface, as shown in FIG. 6, the vertical cross-sectional shape is substantially stepwise formed of the excavation direction excavation surface Ma and the radial direction excavation surface Mr over most of the excavation surface M of the ground. An excavation surface is formed (at this time, a surface Cc connecting the positions of the cutting edge tips of the cutter bits 29-1 to 29-10 is a conical surface (represented by a straight line in FIG. 6)). With such an excavation mode, a crack Cr is formed on the root side of the substantially stepped edge (corner) Mc by the pressing force of the cutter bit 29 in the excavation direction (left direction in FIG. 6), and the crack bit Cr advances. By doing so, it is possible to perform peeling and crushing that continuously induces shear failure in an oblique direction on a large part of the edge Mc (portion hatched in FIG. 6). This makes it possible to reduce the excavation force required for excavation, so that excavation of the ground can be performed with a smaller excavation force than in ordinary excavation.

(4) Effects of the Shield Machine of the Present Embodiment The effects obtained by the shield machine of the present embodiment having the above-described configuration and operation will be sequentially described below.

(4-1) Effect of improving excavation distance by peeling and crushing As described in (3) above, in the shield excavator of the present embodiment, the cutter bits 29-1 to 29-10 are mainly used.
By excavating by exfoliation crushing in the above, the excavating force required for excavation can be reduced, and the excavation of the ground can be performed with a small excavating force as compared with ordinary excavation. Therefore, the wear of the cutter bits 29-1 to 29-10 due to sliding with the ground face (excavation surface M) can be reduced accordingly (especially for soft rock, dotan, cobblestone, gravel, sand, etc.). Effective), the excavation distance can be improved. Also,
Rather than excavating the ground face with the cutting edge of the cutter bit as in ordinary excavation, excavation is performed mainly by peeling and crushing as described above, so that the cutter bits 29-1 to 29-10 A relatively large excavation ability (efficiency) can be ensured even when the cutting edge is worn and no longer sharp. Therefore, the excavation distance can be improved also by this. As described above, the excavation distance can be greatly improved as compared with ordinary excavation. Therefore, in a soil where the compressive strength is equal to or less than soft rock, excavation sufficiently long (for example, 2 k
m or more).

(4-2) Effect of Reducing Cutter Drive Torque by Peeling and Crushing Excavation by peeling and crushing is more efficient than ordinary digging by cutting the ground face with the cutting edge of the cutter bit. (The ratio of the excavation amount) is greatly improved, so that the same excavation as before can be performed with a small driving torque. That is, energy saving can be achieved, and the load on the cutter driving device 4 for rotatingly driving the cutter head 3 can be reduced, and the life thereof can be improved.

(4-3) Further Improvement Effect of Excavation Distance by Inclination Angle θa to Excavation Surface Ma As described in the above (4-1), in the shield excavator of the present embodiment, the cutter bit 29 is excavated during excavation. -1 to 29
A large part of the excavation surface edge (corner) Mc is obliquely shear-ruptured by a pressing force of −10 to perform peeling and crushing. At this time, the carbide tips 2 of the cutter bits 29-1 to 29-10 are cut.
While the substantially vertical blade surface portion 29Aa of 9A is arranged almost parallel to the excavation surface Ma in the excavation direction, the inclined blade surface portion 29Ab is obliquely arranged so as to form a predetermined inclination angle θa with the excavation surface Ma in the excavation direction. I have. Thereby, as the vehicle advances in the excavation direction, the pressing force is applied to the edge Mc in a direction (in this case, toward the radially inner peripheral side) in such a direction as to promote the shear failure as shown by a thick arrow in FIG. It is possible to add. As a result, it becomes possible to excavate the ground with a smaller excavation force, so that the wear of the cutter bits 29-1 to 29-10 can be reduced, and the excavation distance can be further improved.

(4-4) Effect of Negative Rake Angle γa on Excavation Surface Ma in Excavation Direction The shield excavator of the present embodiment performs excavation by peeling and crushing as described in (4-1). It is not necessary to provide a positive rake angle with respect to the excavation surface Ma in the excavation direction.
Therefore, as described above, in the present embodiment, the cutter bits 29-1 to 29-10 are provided with the excavation surface Ma
Has a negative rake angle γa (see FIG. 4). Thus, both the forward-direction excavation cutter bit and the reverse-direction excavation cutter bit are arranged corresponding to the forward / reverse bidirectional rotation of the cutter head like a normal excavation cutter bit having a positive rake angle. It is no longer necessary, and as shown in FIG. 2, the cutter head is provided by simply providing one cutter bit 29-1 to 29-9, 29-10A at each circumferential position of the cutter bit 3 in each of the cutter spoke portions 27A to 27D. 3 (the four cutter bits 29-10B provided on the annular member 27E are all of the same shape, and each of them can be rotated in any direction in the same manner). Compatible). This allows
Since the number of cutter bits can be greatly reduced as compared with the conventional structure, the sliding resistance with the ground face (excavation surface M) can be reduced to further reduce the cutter head driving torque.

When both the cutter bit for forward rotation and the cutter bit for reverse rotation are arranged to have a positive rake angle as in the conventional structure described above, excavated earth and sand adhere between the cutter bits on both sides thereof. By doing so, the cutter head driving torque may be increased in some cases, but such a phenomenon can be prevented beforehand (in particular, it is effective for soil, clay, etc.).

As described above, since the cutter head driving torque can be further reduced, the load on the cutter driving device 4 can be further reduced.

Further, the number of cutter bits can be reduced by reducing the number of cutter bits as compared with the conventional structure, or the number of cutter bits can be increased, for example, twice without increasing the cost.

(4-5) Effect of the Face Plate Portion When undercutting is performed from the preceding excavation surface as described above, the excavation surface M is formed such that the vertical cross-sectional shape from the preceding excavation surface is substantially stepwise. Since the face is excavated in an umbrella shape), there is a case where the concern about collapse of the ground is more likely to occur than in the normal case. Correspondingly,
In the present embodiment, the cut-spoke portions 27A-2
By substantially closing the gap between the 7Ds with the four face plate portions 17, the possibility of the ground collapse of the face can be reduced,
The stability of the face can be improved.

(4-6) Effect in Side Drilling As described above, the cutter bit 29 of the present embodiment forms each of the cutter bits 29-1 and 29-1 so as to form the substantially stepped excavation surface M. 29-2,..., 29-9, 29-10 are arranged so that the cutting edges (approximately vertical blade surface portions 29Aa) are sequentially retracted rearward in the excavation direction. For this reason, when correcting the direction of the excavation direction or performing a curve construction, excavation (so-called side excavation) in a direction (radial direction) perpendicular to the excavation direction is required. To cope with this, in the present embodiment, in addition to the substantially vertical blade surface portion 29Aa and the inclined blade surface portion 29Ab for excavating in the excavation direction, the substantially horizontal blade surface portion 29Ac and the inclined blade surface portion 29Ad for the side digging are provided. ing. At this time, the inclined blade surface portion 29Ad forms a predetermined inclination angle θr with respect to the radially excavated surface Mr (see FIG. 5). Thus, when performing lateral digging in the radial direction, the same principle as in the above (4-3) is used, and in the case of curve construction and direction correction, similar to the above (4-3), As the digging is performed, it is possible to apply a pressing force to the edge Mc in a direction that promotes the shear fracture, so that the digging of the ground can be performed with a small digging force.

In the embodiment of the present invention, the inclined blade surface portion 29Ab of the carbide tip 29A of each of the cutter bits 29-1 to 29-10 has a predetermined inclination angle θa with respect to the excavation surface Ma in the excavation direction. And the cutter bits 29-1 to 29-10 are provided with a negative rake angle γa with respect to the excavation surface Ma in the digging direction. It is not always necessary to provide these structures as long as the effects of 4-1) and (4-2) are obtained. That is, the cutter bits 29-1 to 29-
All of the ten carbide tips 29A in the digging direction are substantially vertical blade surface portions 29Aa, and the entire surface in the digging direction is arranged substantially parallel to the digging direction digging surface Ma, or each of the cutter bits 29-1 to 29-10. A positive rake angle may be provided to the excavation surface Ma in the excavation direction. Also in this case, the effect of improving the excavation distance and the effect of reducing the cutter driving torque by performing peeling and crushing can be obtained.

In the above-described embodiment of the present invention, the center cutter 28 is provided at the center in the radial direction as one preceding excavation part, but is not limited to this. That is, a first-stage excavation portion is provided in which the center cutter 28 at the center in the radial direction projects to the foremost side in the excavation direction and the cutting edge of the cutter bit adjacent to the outer peripheral side is sequentially retracted rearward in the excavation direction. The middle part in the radial direction of the cutter head radially outer side of the one-stage excavation part is protruded to the foremost side in the excavation direction (that is, this position becomes the second preceding excavation part). A second-stage excavation portion that is retracted backward in the direction may be provided.

Further, in the embodiment of the present invention, a center cutter 28 is provided so as to protrude forward in the digging direction at the center of the cutter head 3 in the radial direction. When the cutting edge of the cutter bit 29 is sequentially retracted rearward in the excavation direction at the position, the cut-spoke portion 27 is also arranged in such a manner that the outer peripheral side also retracts rearward in correspondence with such an arrangement on the cutting edge side. Not limited to That is, the cut-spoke side is configured to simply extend radially in the radial direction like a normal shield machine, and the axial length of the cutter bit attached thereto is changed for each radial position, and Such an arrangement mode of the cutting edge position may be realized. It goes without saying that a similar effect can be obtained in this case as well. Furthermore, in the above, the preceding excavation part and the cutter bit 29 sequentially adjacent to this radial position are connected to the cut-spoke parts 27A-27.
Instead of being provided on D, it may be provided on the face plate 17. In this case, a similar effect is obtained.

In one embodiment of the present invention, the present invention is applied to a mud shield excavator in which water is injected into the excavating chamber P using a water injection means, and excavated earth and sand is discharged in a muddy state by the mud discharging means. However, the present invention is not limited to this, and the mud taken in the excavation chamber P is discharged by a screw conveyor, and the so-called mud pressure in the excavation chamber P is used to oppose the earth pressure of the face. The present invention may be applied to an earth pressure shield machine. In this case, a similar effect is obtained.

Further, in the above, the shield body 1
The present invention is applied to a shield machine that excavates by rotating a cutter head 3 provided in front of a pipe. However, the present invention is not limited to this. For example, a push pipe shield, a small-diameter thruster, a TBM, etc. The cutter head structure of the present invention can be applied to the horizontal hole excavator described above, and in this case, the same effect can be obtained.

[0061]

According to the present invention, the excavation is performed by so-called undercutting, so that the excavation force required for excavation can be reduced, and the excavation of the ground can be performed with a small excavation force as compared with ordinary excavation. Becomes possible. Therefore, the wear of the cutter bit due to sliding with the face can be reduced, and the life of the cutter bit can be improved. As a result, the excavation distance can be greatly improved as compared with the normal excavation, and therefore, a sufficiently long excavation can be performed on the soil whose compressive strength is equal to or less than soft rock.

[Brief description of the drawings]

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

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

FIG. 3 is a partially enlarged view of FIG. 2 showing a detailed structure of a cutter bit constituting the horizontal hole excavator of the present invention.

FIG. 4 is a top view as viewed from a direction B in FIG. 3;

FIG. 5 is a side view as viewed from a direction C in FIG. 3;

FIG. 6 is an explanatory diagram showing a state in which excavation is being performed in one embodiment of the horizontal hole excavator of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield main body 3 Cutter head 6 Mud feed pipe (water injection means) 7 Drain pipe (mud discharge means) 17 Face plate part 19, 20 Sediment intake hole (sediment intake port) 27A-D cutter spoke part 28 Center cutter (preceding) Excavation method) 29 cutter bits M Excavation surface Ma Excavation surface in excavation direction Mr Excavation surface in radial direction

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshifumi Fukawa 2-1-2-2 Konan, Minato-ku, Tokyo Obayashi Corporation Tokyo Head Office (72) Inventor Yoichi Moriya 2-5-2-1, Konan, Minato-ku, Tokyo Obayashi Corporation Tokyo Main Office (72) Inventor Kenji Yamashita 2-2-1 Konan, Minato-ku, Tokyo Obayashi Gumi Tokyo Main Office (72) Inventor Miya Kiyoshi 2-2-1 Konan, Minato-ku, Tokyo Co., Ltd. Obayashi Corporation Tokyo head office F-term in the factory (reference) 2D054 AC05 AD19 BA04 CA03 CA04 DA33

Claims (3)

[Claims] 1. A cross hole excavator for excavating by rotating a cutter head provided in a front part, wherein the cutter head comprises: a plurality of cutter spoke portions extending radially from a radially central side; A face plate portion arranged to substantially close the gap between the portions, a sediment intake port provided in the face plate portion for taking in excavated sediment, and protruding in a propulsion direction at at least one of the plurality of cut-spoke portions or the face plate portion. And a plurality of cut-spoke portions or face plate portions arranged so as to be sequentially located radially from the preceding excavation means at the radial position of the cutter head and axially rearward of the horizontal hole excavator. And a plurality of cutter bits disposed in the excavator. 2. A horizontal hole excavator for excavating by rotating a cutter head provided at a front portion, wherein the cutter head comprises: a plurality of cut-spoke portions extending radially from a radially central side; A face plate portion arranged to substantially close the gap between the portions, a sediment intake port provided in the face plate portion for taking in excavated sediment, and protruding in a propulsion direction at at least one of the plurality of cut-spoke portions or the face plate portion. Leading digging means provided in this order, sequentially from the preceding digging means at the radial position of the cutter head and axially rearward of the horizontal hole digging machine, sequentially from the preceding digging surface digged by the preceding digging means A horizontal hole excavator, comprising: a plurality of cutter bits arranged on the plurality of cut-spoke portions or the face plate portion so as to perform exfoliation and crushing. 3. A side hole excavator according to claim 1, wherein said water injection means is for injecting earth and sand excavated by said cutter head, and said mud is sucked and discharged in a state of muddy water. Means for excavating a lateral hole.