JPH10121900A - Tunnel timbering and frame for assembly thereof and construction method of the timbering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a tunnel timbering and a frame for assembly thereof easily and reinforce a tunnel wall appropriately by corresponding to the nature of the soil when a tunnel is excavated by a so-called open type excavator. SOLUTION: A timbering 10 is assembled on an inner side of a tunnel when the tunnel is excavated by an open type excavator which presses a gripper in a rear part thereof against an inner peripheral face of the tunnel. Among the timberings 10, a frame 12 made of channel steel 12a is stretched over in such a manner that many curved quadrilaterals are drawn along the inner peripheral face of the tunnel or the gripper can be pressed against the inner peripheral face of the tunnel through an inner side of a side of the quadrilateral. The channel steel 12a forms a surrounding which becomes a formwork for placing concrete at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support suitable for being provided inside a tunnel when excavating the tunnel using an excavator of a type in which a rear gripper is pressed against the inner peripheral surface of the tunnel. is there.

[0002]

2. Description of the Related Art When excavating a tunnel in an area where the geology is hard and stable, a so-called open type excavator having almost no outer shell is usually used. The open-type excavator has a rotary cutter at the front to excavate the ground, and a rear part is equipped with a gripper to obtain support for excavation from the wall of the excavated tunnel. The gripper is protruded outward from the excavator main body, pressed against the inner peripheral surface of the tunnel (usually the middle part of the left and right sides), and then the front part of the main body including the cutter is pushed forward. In this case, the gripper functions as a so-called anchor for advancing the main body forward and for fixing the main body which is to be rotated in the opposite direction to the cutter by the rotational reaction force.

[0003] If the geology is sufficiently hard and the independence of the ground is good, there is no need to provide any support inside the tunnel, but in soft fault zones that are scattered in many mountainous areas in Japan, Some kind of support (tunnel support) must be provided. Unlike a shield excavator, an open type excavator has almost no outer shell, so that the support in this case is preferably installed from the front part of the excavator.

As a support for excavating a tunnel with an open excavator, a ring-shaped steel frame (frame) has conventionally been used.
Was used. The steel frame is bridged along the inner peripheral surface of the tunnel in a ring shape, thereby preventing the collapse of the tunnel wall and the like. The reason why a segment commonly used when excavating a tunnel with a shield machine is not supported is that the gripper is pressed from the inside thereafter. In other words, since the pressure of the gripper does not always act uniformly on the entire surface of the segment, the segment may be broken or bent at that time,
It is difficult to obtain sufficient support force even as a gripper. If only a steel frame is provided in a ring shape unlike a segment, the gripper is pressed against the portion of the tunnel inner peripheral surface between the steel frame and a slit (groove) on a part of the gripper pressing surface (pressing surface). It is also possible to press the gripper against the inner peripheral surface of the tunnel so as to straddle the steel frame. In addition, in order to prevent such a steel frame from falling down and to secure a space between adjacent steel frames, generally, another beam or rod is connected and bridged between the steel frames. In addition, in places where the geology is slightly weaker and a support made of steel or the like is not sufficient, a sheet pile is also used. The sheet pile is a steel plate or a wooden plate, and is stretched between the ring-shaped steel frames so as to be wound around the entire circumference (or partly), for example, in the longitudinal direction of the tunnel.

[0005] A technical example in which a ring-shaped steel frame is provided as a support on the inner peripheral surface of a tunnel, and a sheet pile is bridged between the steel frames has already been described in Japanese Utility Model Publication No. 1-44631.

[0006]

A ring-shaped steel frame (or further including other beams and rods) is provided inside a tunnel excavated by an open-type excavator, and a sheet pile is also mounted as necessary. There is room for improvement in the support of the configuration such as handing over in the following points. That is, a) a ring-shaped steel frame is first installed in the tunnel,
The work of bridging the sheet pile later cannot be easily performed as described in the above-mentioned publication. Since the steel frame as the support is provided so as to be in contact with the inner peripheral surface of the tunnel, a special means is required to provide the sheet pile outside thereof, that is, between the steel frame and the inner peripheral surface of the tunnel.

(B) At a position before the gripper at the rear of the excavator, a sheet pile cannot be wound around the entire periphery of the tunnel. Depending on the softness of the geology, it may be desirable to place sheet piles all around the tunnel.In that case, too, consider the pressing of the gripper against the inner peripheral surface of the tunnel, and place the sheet pile where the gripper should be pressed. Sheet piles cannot be wound before the gripper. Therefore, regardless of the geology, the sheet pile is wound around the entire inner peripheral surface of the tunnel near the rear end of the excavator behind the gripper. Therefore, during this time,
The soft tunnel walls will be exposed over long distances.

C) According to the above items a) and b), it is necessary for the worker to perform the difficult work of attaching a sheet pile under the long exposed wall of the tunnel while paying attention to the collapse. Burden.

According to the first to sixth aspects of the present invention, when a tunnel is excavated with a so-called open type excavator, the wall surface of the tunnel can be appropriately reinforced according to the geology.
To provide means capable of solving the problems described in (1) to (3).

[0010]

According to a first aspect of the present invention, there is provided a tunnel support for excavating a tunnel by an excavator of a type that presses a gripper against an inner peripheral surface of the tunnel (ie, a so-called open type excavator). A steel frame (frame made of shaped steel, etc.) is bridged along the inner peripheral surface of the tunnel so as to draw a number of curved polygons along the inner peripheral surface of the tunnel. The gripper is arranged so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the side of the tunnel, and forms an enclosure that can be a formwork for concrete construction.

This support functions as follows. That is, 1) Since the steel frame is bridged along the inner peripheral surface of the tunnel, the collapse of the tunnel wall and the like are prevented as in the case of the above-mentioned conventional support made of a ring-shaped steel frame.

2) Since the steel frame is arranged so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the side of the polygon, the support is assembled at a position forward of the gripper. In this case, the gripper can be pressed against the inner peripheral surface of the tunnel to provide a sufficient supporting force to the excavator, and the support itself can be prevented from being damaged during the pressing. As in the case of the conventional support, a gripper is passed through a portion between steel frames, for example, inside one polygon, or
Because it is possible to press the gripper against the inner surface of the tunnel inside several adjacent polygons (by forming a slit etc. on a part of the pressing surface of the gripper and straddling the steel frame). is there.

[0013] 3) Since the above-mentioned steel frame is formed in such a manner that a large number of curved polygons along the inner peripheral surface of the tunnel are stretched out so as to form a frame, and furthermore, it forms an enclosure that can be a formwork for concrete construction. In addition, it is possible to appropriately reinforce the tunnel wall according to the geology. If the geology is weak, for example, use the steel frame as a formwork and put concrete inside the polygon (and at the position in contact with the inner peripheral surface of the tunnel). No). In addition, in order to form an enclosure which can be a formwork with a steel frame, for example, a channel steel (or an H-shaped steel or an I-shaped steel) is used as a steel frame, and the inside of the groove between the flanges is formed by a polygonal inside. It is sufficient to form a closed polygon so that concrete can be held inside, such as turning to The concrete is filled with concrete by spraying or the like into the space surrounded by the polygon and the inner peripheral surface of the tunnel at the front or rear of the gripper. It is recommended to use stuffed concrete.

According to a second aspect of the present invention, there is provided an assembling frame for a tunnel support, in which, when an excavator that presses a rear gripper against an inner peripheral surface of the tunnel excavates the tunnel, the excavator is assembled and supported inside the tunnel. An assembling frame, which is arranged along the inner peripheral surface of the tunnel and can be arranged in contact with other assembling frames on each side, and in an assembled state of the sides of the polygon. A steel frame is provided along each side so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside, and the steel frame forms an enclosure that can be a formwork for concrete construction.

[0015] This assembling frame is a curved polygonal frame which can be arranged along the inner peripheral surface of the tunnel while being in contact with other assembling frames on each side. The support is assembled inside the tunnel similarly to the segment generally used as a support. In other words, each frame having a steel frame along each side of the polygon is assembled along the inner peripheral surface of the tunnel such that each side of the frame is in contact with another frame. It is. It is also possible to form the support in combination with frames having another configuration or the above-described ring-shaped steel frame. However, from the viewpoint of strength, it is preferable to assemble such that the entire support including these members covers the entire periphery of the tunnel.
Since each of the assembling frames has essentially no difference in shape and handling method from ordinary segments, it can be easily assembled using ordinary segment erectors or the like. However, this assembling frame has no wall made of concrete or iron plate so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the polygonal side in the assembled state, and For that reason that it is lightweight,
It is different from a general segment.

Further, since the assembling frame is assembled as described above and serves as the tunnel support of the first aspect, the functions of the above 1) to 3) are also provided.

In addition to the above, the assembling frame according to the third aspect is characterized in that a wire mesh is attached to an outward surface (convex surface outside the curve) of the steel frame along the inner peripheral surface of the tunnel. Features. Such an assembly frame is
In addition to having the functions of 1) to 4), 5) The action of the wire mesh can prevent small collapse from the inner peripheral surface of the tunnel. Therefore, when the assembling frame according to claim 3 is used, it is not sufficient to support the assembling frame using only steel frames due to the geology and the like, but it is not necessary to hit concrete (as described above). Can be reinforced. When this assembly frame is assembled in the tunnel, there will be a wire mesh inside the space surrounded by the polygon formed by the steel frame and the inner peripheral surface of the tunnel. There is also an advantage that it is held firmly.

When the gripper is pressed against the inner peripheral surface of the tunnel, a wire mesh is sandwiched between the two surfaces, but there is no inconvenience. If the wire mesh is sandwiched between them, the magnitude of the force transmitted by the contact between the pressing surface of the gripper and the inner peripheral surface of the tunnel hardly decreases, and the wire mesh is deformed by being sandwiched between the two. However, the ability of the assembly frame as a support is not impaired. In other words, it can be said that this assembly frame of the third aspect also has the function of the above 2).

The frame for assembly according to claim 4 is further characterized in that the polygon formed by the inner edge of the steel frame has the same shape and dimensions as the outer edge of the pressing surface of the gripper. When assembling the tunnel support while arranging the assembling frame on the inner peripheral surface of the tunnel where the gripper is pressed, the assembling frame has the following functions. That is, in addition to the above 1) to 4), 6) When the gripper is pressed against the inner peripheral surface of the tunnel, the gripper fills the entire inner edge of the steel frame, that is, the portion of the inner peripheral surface of the tunnel surrounded by the steel frame. It will push almost the entire surface. Therefore, as described in the above 3) and as described later (Claim 6), a method of filling a hardening bagged concrete into the inside of a steel frame and applying a gripper from above is used. To
Pressure can be applied to almost the entire area of the concrete.

According to a fifth aspect of the present invention, there is provided a method for constructing a tunnel support, wherein when an excavator of a type for pressing a rear gripper against an inner peripheral surface of the tunnel excavates the tunnel, the inside of the tunnel is located at a position forward of the gripper. By laying a steel frame over a number of curved polygons along the peripheral surface, the steel frame is arranged so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the sides of the polygon. And forming an enclosure that can be used as a formwork for concrete construction with the steel frame, and then placing concrete inside the enclosure (polygon) formed by the steel frame and in contact with the inner peripheral surface of the tunnel It is characterized by.

The bridging of the steel frame first forms a tunnel support similar to that shown in claim 1 (therefore the said
1) to 3). At that stage, a method of assembling the assembly frame according to claims 2 to 4 may be adopted (so that the functions of 4) to 6) are obtained). The concrete can be hit by a method such as spraying, and the position may be a position in front of or behind the gripper (however, when hitting in front of the gripper, it is necessary to allow some hardening time).

Since an enclosure which can be used as a formwork for concrete construction is formed by the above-mentioned steel frame, it is still easy to put concrete inside the enclosure as described above. According to this method, it is possible to appropriately reinforce the tunnel wall surface even in the case where the geology is considerably soft, and to construct a tunnel support having sufficient strength. Therefore, this construction method realizes the function of the above 1), even when digging into soft ground despite starting to excavate the tunnel with a so-called open type excavator, the same excavator Excavation can be continued smoothly.

According to a sixth aspect of the present invention, in the method of the fifth aspect of the present invention, in the step of hitting the concrete, the concrete in a bag, which is immediately hardened by pressing and dewatering, is placed at a position forward of the gripper, The inside of the enclosure formed by the steel frame is filled into a portion in contact with the inner peripheral surface of the tunnel, and the gripper is pressed against the inner peripheral surface of the tunnel via the bagged concrete. Such a method has the following operation.

7) A high-strength support for providing a concrete wall on the inner peripheral surface of the tunnel can be extremely simply constructed at the position of the gripper (that is, in front of the conventional rear of the gripper with a sheet pile). can do. Since the above bagged concrete hardens quickly by being strongly pressed and dewatered by the gripper,
The support is completed in a short time and immediately begins to exert its strength. Filling the inside of the steel frame with bagged concrete is a simple task, so it is not difficult to automate by machine.

8) Since the gripper at the rear of the excavator is used as a pressurizing and dewatering means for hardening the above bagged concrete, only the pressurizing and hardening means for hardening the concrete are used.
There is no need to provide dehydration means. Also, by pressing the above-mentioned gripper against the inner peripheral surface of the tunnel through the same concrete for both pressurization and dehydration, a sufficiently strong supporting force is provided to the gripper. When the concrete is sandwiched between the gripper and the inner surface of the tunnel,
This is because both the surfaces are brought into close contact with each other to transmit a force, and curing starts during pressurization.

[0026]

1 to 5 show an embodiment of the present invention. FIG. 1 is a perspective view showing a support 10 assembled along the inner peripheral surface of a tunnel and an assembling frame 12 incorporated therein. 2 and 3 are a side view and a cross-sectional view, respectively, showing the entire excavator 1 used to excavate the tunnel. FIG.
FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 2, showing the vicinity of the inner peripheral surface of the tunnel. FIG. 5 is a perspective view of another support 20 that is partially different from the support 10.

As shown in FIG. 2, the excavator 1 has a rotary cutter 2 having a large number of disk roller cutters for crushing rock and a driving means 2a at its forefront. Since it is intended to excavate a ground having a hard geology and good autonomy, the outer shell 6 for covering the inside is small and only slightly covers the periphery of the driving means 2a and the like. A simple type such as the excavator 1 having a small outer shell (or no at all) and exposing many equipments (and therefore, lower in cost than a general shield excavator) is generally an open type. being called.

The rear part of the excavator 1 is equipped with a gripper (main gripper) 3 which is pressed against the inner peripheral surface of the tunnel to obtain a supporting force for excavation. The gripper 3 projects left and right as the jack 3a shown in FIG. 3 is extended, and the outer pressing surface 3b is pressed against and fixed to the inner peripheral surface of the tunnel, so that the excavator 1 retreats or rotates due to the excavation reaction force. An anchor that prevents you from doing so.
After the gripper 3 is fixed to the inner peripheral surface of the tunnel in this way, the beam 4 is pushed forward by extending the propulsion jack 5 shown in FIG. The face 2 can be dug forward by the cutter 2 at the front end. When the stroke of the jack 5 is exhausted, the front gripper and the movable roof at the front of the beam 4 are spread out and fixed to the inner peripheral surface of the tunnel, and the support 4a at the rearmost portion is extended downward so that the beam 4 is extended. To support,
In this state, the rear gripper 3 is retracted and the propulsion jack 5 is contracted to move the gripper 3 forward. When the gripper 3 moves forward, the gripper 3 is again extended and fixed to the inner peripheral surface of the tunnel,
Excavate forward. The excavator 1 can dig a long tunnel by repeating intermittent digging as described above.

While excavating a sufficiently hard and stable ground, no support is required in the tunnel, but some support is provided when the excavator 1 enters a soft ground such as a fault zone. There is a need. In this case, since the outer shell is small as described above, a support must be provided from a portion considerably ahead of the excavator 1 for safety. However, it is not preferable to use a general segment commonly used by shield excavators in relation to the gripper 3 disposed at the rear part (described above).

Therefore, taking into account the feature of the excavator 1 that the gripper 3 functions, a support 10 shown in FIG. 1 is formed inside a tunnel formed by the excavator 1. As shown in FIG. 1 (b), the support 10 is such that a frame 12 in which a grooved steel 12a is integrated into a curved quadrilateral shape (that is, a quadrilateral shape) (with the groove facing inward) is disposed on the left and right sides of the tunnel. In the lower and upper parts, liner frames 11 and 13 each having a thin iron plate attached to the outer surface of a similar curved quadrilateral frame are connected to each other, and they are connected in the longitudinal direction of the tunnel to form a cylindrical shape. is there. In addition, the support 10 does not push in the longitudinal direction of the tunnel unlike the segment, and furthermore, the excavation path may include a soft ground that requires further reinforcement partially. Circumstances are also taken into account.

Since both the liner frames 11, 13 and the frame 12 are quadrilateral-shaped assembling pieces,
The cylindrical support 10 can be formed by assembling the above-described general segments. Specifically, the erector 7 of the excavator 1 shown in FIG. 2 (having the same structure as a general segment erector) starts to assemble them immediately after the outer shell 6 in front (the ground is not solid). If stable, the erector 7 can start to assemble inside the outer shell 6
Can be changed). In the tunnel, the liner frame 11 (3 pieces) of FIG. 1 is first placed at the bottom, and then the frame 12 (1 piece on each side) is connected to the side,
Finally, the liner frame 13 (3 pieces) is connected to the upper part. Pieces adjacent to each other in the circumferential and longitudinal directions of the tunnel are connected by bolts and nuts.

Since the support 10 is not pushed in the longitudinal direction of the tunnel by the excavator 1 or the like, the number of strength members in that direction is small, and all the pieces are lightweight and easy to assemble. However, since there are many strength members in the circumferential direction and the whole is connected in a cylindrical shape, it has necessary strength against a radial force.

As described above, the gripper 3 of the excavator 1 is pressed against the side of the tunnel in which the frame 12 is disposed, and the frame 12 formed into a quadrilateral shape by the channel steel 12a is pressed by the gripper 3 (pressing force). The pressing surface 3b (FIG. 3 and the like) has the same shape and size as the pressing surface 3b so as not to receive the force. That is, the inner edge of the channel steel 12a of the frame 12 forms a quadrilateral similar to the pressing surface 3b, and the length of the inner edge in the circumferential direction of the tunnel is smaller than that of the pressing surface 3b as shown in FIG. 2 and the length in the longitudinal direction as shown in FIG.
It is determined that the gripper 3 just fits inside the inside 2. As shown in FIG. 4, a slit 3 c is formed in the middle of the gripper 3 to avoid contact with the channel steel 12 a (a pair joined back to back) of the frame 12. It is also possible to put the gripper 3 in the.

Since the support 10 has the liner frame 11 with an iron plate disposed thereon as shown in FIG. 1, it has a higher capacity as a support than a case where only a steel frame or the like is provided, and has a relatively soft ground portion. It is preferable to provide the
As described above, the iron plate corresponding to the conventional sheet pile already exists at the upper part when assembled at the portion immediately behind the roof 6 and assembled into a cylindrical shape, so that a stable working space is secured. Another advantage is that the work load is reduced.

However, this support 10 has an outstanding feature that enables appropriate reinforcement in accordance with the geology even when the geology greatly changes, for example, including a soft portion. Since the frame 12 arranged on the side is formed by integrating the channel steel 12a so that the groove is directed inward and forms a quadrilateral enclosure, it can be used as a formwork for concrete construction. That's why. In other words, concrete can be held in the channel steel 12a with the groove facing inward. Therefore, in places where geology is particularly unstable, the frame 12 is used as a formwork (but not removed) in the tunnel. A concrete wall can be easily constructed on the peripheral surface. The concrete wall is filled with concrete by spraying or other means on the inner peripheral surface of the tunnel surrounded by the channel steel 12a. The filling position may be in front of or behind the gripper 3.

In this embodiment, as a means for hitting concrete, as shown in FIG.
Is pressed by the force of the gripper 3. The bag-packed concrete 15 is formed by packing a concrete material having a property of being immediately cured by dehydration under pressure in a water-permeable bag. Such concrete 15
Is put inside the frame 12 at a position immediately before the gripper 3, and the concrete 15 is
And between the inner surface of the tunnel (wall A) and receives pressure, dehydrated and hardened quickly. As described above, since the inner size of the frame 12 surrounded by the channel steel 12a is close to the size of the pressing surface 3b of the gripper 3, the concrete 15 contacts the gripper 3 widely and is pressed in a preferable state. The gripper 3 is pressed against the inner peripheral surface of the tunnel through the concrete 15. The concrete 15 comes into close contact with both the pressing surface 3b of the gripper 3 and the wall A of the tunnel, and hardens during pressurization. , The gripper 3 is provided with a sufficiently strong supporting force.

The support 10 can be further reinforced according to the geology and the like. For example, in the case where the structure shown in FIG. 1A is insufficient in capacity as a support but it is not necessary to hit concrete as described above, the frame 12 (FIG. 1B) may be used instead of the frame 12 (FIG. 1B). ) Is placed on the side of the tunnel. The frame 14 is formed by stretching a wire mesh 14b on the outer surface of a quadrangular frame formed of the same channel steel 14a as the frame 12. When this is used, small collapse from the inner peripheral surface of the tunnel can be prevented by the action of the wire mesh 14b. Also, in the portion where the frame 14 is arranged, it is possible to use the grooved steel 14a as a formwork to strike concrete as described above.

In addition, in places where the geology is rather stable, the support 10 may be changed to a support 20 as shown in FIG. The support 20 has the same liner frame 11 and frame 12 as the support 10 shown in FIG. In locations where the geology is stable, such supports 20 that are lightweight and easy to assemble are suitable (although supports are not necessary in rock parts where stability is particularly high).

[0039]

The tunnel support according to the first aspect of the present invention prevents the collapse of the tunnel wall and the like, and prevents the function of the gripper in the so-called open type excavator, similarly to the conventional support made of a ring-shaped steel frame. It has the following effects in addition to the absence. A) Since the steel frame is hung so as to form an enclosure that also serves as a formwork for concrete construction, concrete can be struck inside the steel frame to reinforce the tunnel wall, and it is easy and easy. is there. Therefore, while the same support is formed along the inner peripheral surface of the tunnel, the strength of the support can be appropriately increased according to the geological condition.

The frame for assembling the tunnel support according to the second aspect becomes the tunnel support of the first aspect by being assembled to provide the effect of the above a), and b) a general shield machine is commonly used as the support. Since there is no essential difference in shape and assembling method from the segment, it can be easily assembled by a normal segment erector or the like. In addition, since there is no thick wall made of concrete or iron plate to press the excavator gripper against the inner peripheral surface of the tunnel through the inner edge of the steel frame, the segment is considerably lighter than the above segment.
Because it is lightweight, it is manufactured at low cost and is easy to handle.

According to the third aspect of the present invention, in addition to the effects of a) and b), since the c) having the wire mesh can prevent a small collapse from the inner peripheral surface of the tunnel, the tunnel wall can be formed in accordance with the geology and the like. It can be suitably reinforced. In addition, because of the presence of a wire mesh, when concrete is hit as in the above a), it is excellent in holding the concrete, which is preferable.

The frame for assembly according to claim 4 d) allows the gripper of the excavator to pass all the way through the inner edge of the steel frame, and presses almost the entire surface of the inner peripheral surface of the tunnel surrounded by the steel frame against the pressing surface. Therefore, when a method is used in which bagged concrete is filled into the inside of a steel frame and a gripper is applied thereon, pressure can be suitably applied to the concrete.

According to the construction method of the tunnel support described in claim 5, in addition to the effect of the above a), e) when the geology is considerably unstable, etc., the tunnel wall surface can be easily and appropriately made of concrete. High strength tunnel support can be constructed by reinforcement. Therefore, even when soft ground appears even though the tunnel has been excavated by the open excavator, excavation can be smoothly continued by the same excavator.

According to the construction method of the sixth aspect, in addition to the above-mentioned a) and e), f) a high-strength support including a concrete wall can be very easily formed at a relatively forward position in the excavator. . Based on the immediate hardening of concrete, high-strength supports can be completed in a short time, and it is also possible to automate the concrete placing operation. Since the gripper of the excavator is used, there is an advantage that it is not necessary to provide a dedicated pressurizing / dehydrating means.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating one embodiment of the present invention. FIG. 1A is a perspective view of a support 10 assembled along the inner peripheral surface of the tunnel, FIG. 1B is a perspective view of an assembly frame 12 incorporated in the support 10, and FIG. Is another assembly frame 1 which can also be incorporated into the support 10
FIG.

FIG. 2 is a side view showing the entire excavator 1 used for excavating the tunnel.

FIG. 3 is a cross-sectional view of the excavator 1 of FIG. The LL section in FIG. 2 is shown in the left half, and the RR section is shown in the right half.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2, showing the vicinity of the inner peripheral surface of the tunnel.

FIG. 5 is a perspective view of another support 20 which is partially different from the support 10 of FIG. 1 (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Excavator 2 Cutter 3 Gripper 10.20 Tunnel support 12.14 Assembly frame 12a / 14a Channel steel (steel frame) 14b Wire mesh 15 Bagged concrete

Claims (6)

[Claims] When an excavator of the type that presses a gripper against the inner peripheral surface of a tunnel excavates a tunnel, the excavator is a support that is assembled inside the tunnel and has a number of curved multi-pieces along the inner peripheral surface of the tunnel. A steel frame is bridged over the side of the polygon, and the steel frame is arranged so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the side of the polygon and a formwork for concrete construction. A tunnel support characterized by forming an enclosure that can be used. 2. An excavator of the type for pressing a gripper against an inner peripheral surface of a tunnel, when excavating a tunnel, is an assembling frame that is assembled and supported inside the tunnel, and is provided on an inner peripheral surface of the tunnel. Forming a curved polygon that can be arranged along each side with another assembly frame while being along, and in the assembled state, the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the side of the polygon. A steel frame along each side as described above, and the steel frame forms an enclosure that can be used as a formwork for concrete construction. 3. The frame for assembling a tunnel support according to claim 2, wherein a wire mesh is attached to an outer surface of the steel frame along the inner peripheral surface of the tunnel. 4. A polygon formed at an inner edge of a steel frame,
The frame for assembling a tunnel support according to claim 2 or 3, wherein the frame has the same shape and dimensions as the outer edge of the pressing surface of the gripper. 5. An excavator that presses a rear gripper against an inner peripheral surface of a tunnel when excavating a tunnel, a plurality of curved multi-sides along the inner peripheral surface of the tunnel at a position forward of the gripper. By bridging the steel frame so as to draw the shape, the steel frame is arranged so that the gripper can be pressed against the inner peripheral surface of the tunnel through the inside of the side of the polygon, and it becomes a formwork for concrete construction. A method for constructing a tunnel support, comprising: forming an enclosure to be obtained from the steel frame; and thereafter, placing concrete inside a portion of the enclosure formed by the steel frame and in contact with an inner peripheral surface of the tunnel. 6. A bag-filled concrete that is immediately hardened by pressurization and dehydration is filled in a portion in front of the gripper and inside the enclosure formed by the steel frame and in contact with the inner peripheral surface of the tunnel. The method according to claim 5, wherein the concrete is struck by pressing the gripper against the inner peripheral surface of the tunnel through the bagged concrete.