JPH09268878A - Tunnel excavating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with the change of natural ground conditions quickly and improve the efficiency of construction and the economic efficiency by changing the support method and the form of a timbering of an excavated tunnel in advancing an excavating machine corresponding to the condition of natural ground in the process of being excavated. SOLUTION: Plural main girders 1 curved along the inner peripheral form of a tunnel have both end parts connected at a space in the longitudinal direction of the tunnel by a coupling plate 2, the central parts of the main girders 1 are connected to each other by a reinforcement plate 3 to form a frame, and the curved outer peripheral surface is formed gas a lath net structure to form a timbering material 10. The timbering material 10 is assembled like a ring, and if the natural ground is comparatively hard, the top end part is widened to form a timbering in such a manner as to closely adhere to the natural ground, and an excavator is advanced with the reaction force supported by a gripper. On the other hand, if the natural ground is a little soft, concrete is sprayed from the lath net part of the timbering 10 after closely adhering to the natural ground. If the natural ground is further soft and the gripper sinks into the natural ground, a removable thrust reinforcing fitting is inserted between the main girders 1, the excavator is advanced by a jack.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a tunnel excavation method using a mechanical excavator.

[0002]

2. Description of the Related Art Conventionally, as a tunnel excavation method using a mechanical excavator, a tunnel boring machine (hereinafter referred to as TBM) method and a shield method are known. The TBM method and the shield method are generally selected under natural conditions.

Also in the TBM method, as shown in FIG. 13, there is often used a segment type in which the support material is closed in a ring shape as used in the shield method and back-filled. Most of the segment type supports are precast products, and some are steel types, but most are concrete. Also,
A concrete segment type support is also used, in which concrete is poured into the formwork at the on-site yard and the segment structure produced by on-site curing is simplified.

Other than the ring closing / back pouring type, as shown in FIG. 6, there is also a supporting type by an expansion method in which the top end is widened with a jack or the like and closely adheres to the ground, but most supporting materials are made of concrete. Is.

In addition, after excavation by TBM, it may be supported by shotcrete.

In any case, it is common to use supports of the same structure over the entire extension line of the tunnel construction.

Supporting the segment type of precast products is expensive due to high manufacturing and freight costs. Moreover,
Since this segment type is designed on the safe side of natural conditions, it is uneconomical because it is over-designed in the Keniwa area such as an independent rock. And even in the section where the tunnel wall is self-sustaining, it is irrational to shield the inside of the tunnel by the segment and carry out back-filling, resulting in an increase in the number of processes and an increase in cost.

In addition, it is necessary to secure a sufficient stock yard for the segment, and when manufacturing a simple segment on site, it is necessary to prepare a large number of concrete formwork, considering concrete curing, and It is necessary to secure a large yard.

On the other hand, as will be described later, the support of shotcrete cannot support the jack thrust. When supporting the propulsion of the excavator by the gripper that is in contact with the inner wall surface of the tunnel, if the ground becomes soft and the gripper that is in contact with the inner wall surface of the tunnel slips into the ground,
It becomes impossible for the gripper to support the propulsion of the excavator. In addition, in such soft ground, the surrounding soil (ground) acts to tighten the excavator, so if the reaction force (by the gripper) that supports the excavator's propulsion is insufficient, There is a risk that the aircraft will be unable to move.

In consideration of such a danger, the thrust of the excavating machine M in the TBM is (generally) gripper G as shown in FIG. 4 when the ground is healthy (hard). Therefore, it is being promoted by the reaction force of natural rock E. And the ground E
When the condition of is weak, as shown in FIG.
In recent years, cases in which the reaction force of segment S is being promoted have been implemented.

Therefore, in the construction of the tunnel using the excavating machine, when the ground condition changes from the free-standing ground to the soft ground, the support pattern for switching from the gripper propulsion to the jack propulsion is checked in the field excavation situation. However, there is a demand for an excavation method that can be selected, yet can be propelled at high speed without slowing down the excavation speed, and can achieve a significant reduction in construction costs by reducing the cost of supporting materials.
However, such a tunnel excavation method has not been provided so far.

[0012]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems of the prior art, and provides a drilling machine which can quickly respond to changes in natural conditions and is excellent in workability and economy. The purpose is to provide a tunnel excavation method.

[0013]

A tunnel excavation method of the present invention is a tunnel excavation method in which an excavation machine is propelled in the ground to excavate the tunnel. The tunnel excavation method corresponds to the state of the ground excavation by the excavation machine. Therefore, it is characterized in that the support method when propelling the excavating machine and the form of support of the excavated tunnel are changed.

In carrying out the present invention, when the ground is extremely strong and the soil and rocks constituting the ground do not drop from the inner wall surface of the tunnel excavated by the excavator, the excavator is supported by the gripper without any support work. It is preferable to promote.

With such a natural ground, the gripper abutting on the inner wall of the tunnel can support the reaction force of the excavation machine propulsion without slipping into the natural ground. Further, since the cost and labor required for supporting work are unnecessary, it is possible to greatly contribute to cost reduction.

On the other hand, without support, when soil or rocks forming rocks fall from the inner wall surface of the tunnel, causing so-called "skin peeling" or collapse of the inner wall surface of the tunnel, support work is required. According to the invention, the supporting member can be used in common for various states of the ground as much as possible.

That is, a plurality of main girders curved so as to follow the inner peripheral shape of the tunnel, and a joint plate connecting the both ends of the main girders at intervals in the longitudinal direction of the tunnel,
A frame is formed by a reinforcing plate that connects the central portions of the main girders, and the curved outer peripheral surface of the frame has a lath mesh structure to form a supporting member, and the supporting member is bent and holed to form the supporting member. Prepared in a state, assembled the supporting material in the field yard, carry the supporting material into the mine, connect the joint plate parts to each other and assemble them in a ring shape, widen the top end part, and rock the ground. It is designed to be adhered to and to form a support work.

As will be described later, the excavator can be used even for soft ground where a closed ring-shaped support structure must be employed. In other words, it is possible to share the supporting material or the supporting work for a plurality of types of natural ground. At the time of construction, if the support materials are carried into the mine, connected to each other and assembled in a ring shape, and the top end portion is widened (so-called "expansion"), the radial dimension of the ring-shaped support material is also expanded, The outer peripheral surface is pressed against the inner wall surface of the tunnel and fixed.

Here, if the ground is relatively hard and only the skin is removed, it is sufficient to assemble the supporting material in a ring shape and widen the top end portion of the support material to bring it into close contact with the ground. Since the lath net on the curved outer peripheral surface of the frame is in close contact with the inner wall surface of the tunnel, skin removal is prevented. In this case, the propulsion of the excavating machine is performed by supporting the reaction force with the gripper.

When the ground becomes slightly soft and there is a risk that not only the skin will be removed but also a small-scale tunnel collapse will occur, the support material is assembled in a ring shape, and the top end portion is widened. It is preferable that concrete is sprayed from the lath net portion of the support material to the ground to form a support work, and the excavating machine is propelled by a gripper.

When the ground becomes softer than the ground like this, a rock bolt is driven toward the ground from the concrete sprayed portion of the support to form the support. It is preferable to apply it.

When the ground becomes even softer and the gripper that abuts the inner wall surface of the tunnel gets into the ground, a detachable thrust reinforcing metal fitting is inserted between the main girders of the supporting member in the longitudinal direction of the tunnel. The jacking machine will be used to drive the excavating machine. Here, it is an emergency that the gripper slips into the ground, and the excavating machine is often unable to escape at this stage. Therefore, there is no choice but to carry out propulsion of the excavating machine with a jack, but since the supporting material cannot withstand the reaction force of the propulsion jack acting in the longitudinal direction of the tunnel in the state as it is, it supports the reaction force. I don't get it. On the other hand, if a detachable thrust reinforcing metal fitting is inserted between the longitudinal main girders of the tunnel of the supporting member, the thrust reaction metal fitting bears the propulsive reaction force received by the jack.
It becomes possible to escape by excavating the excavating machine with a jack. In other words, if this method is adopted, in an emergency (or emergency) when the excavator cannot escape, the propulsion by the gripper is immediately switched to the propulsion by the jack, and the excavator becomes immovable and the tunnel becomes unexcavable. It is possible to avoid the worst case of becoming.

Similarly, when the gripper abutting against the inner wall surface of the tunnel gets into the ground, the support work is assembled by the support material in which the concrete embedded in the frame of the support material is placed, and the support of the excavating machine is assembled. Propulsion is done with a jack. Here, the reaction force of the propulsion by the jack acting in the longitudinal direction of the tunnel is supported by the support material in which the above-mentioned embedded concrete is placed. For example, when the gripper slips into the ground, a detachable thrust reinforcing metal fitting is inserted between the longitudinal main girders of the tunnel of the supporting material to switch the excavation machine propulsion to jack propulsion. When the propulsion is secured, it is preferable to use a support material that is cast with embedded concrete.

Even if the supporting material is assembled into a ring shape and the top end of the support material is widened to be in close contact with the ground, the expansion is poor due to the soft ground (insulation failure of the natural support). If the square pipe or the like cannot be refilled later, or if the sand and sand flow in from the widened top end, the support material is assembled into a closed ring shape and so-called back pouring is performed. Specifically, a plurality of main girders curved so as to follow the inner peripheral shape of the tunnel, a joint plate that connects the two ends of the main girders at intervals in the longitudinal direction of the tunnel, and a main girder A frame body is formed by a reinforcing plate connecting the central portions, and a curved outer peripheral surface of the frame body constitutes a supporting member having a lath net structure, and an injection hole for back pouring is formed in the frame body of the supporting member. , Prepare the supporting material that has been subjected to bending and hole processing in a component state, assemble the supporting material in the field yard and pour infill concrete, and place the supporting material with the infill concrete placed in the mine Carrying in, connecting the joint plate parts to each other and assembling them into a ring shape to close them in a ring shape, back-filling from the injection hole and closely contacting with the ground to form a support work, and jacking the excavation machine It is promoted at J and constructed.

According to this structure, by assembling the supporting member in the closed ring shape, even if the ring cannot be stabilized by expansion, it can be stabilized by closing the ring. In this case, it is necessary to fix the closed ring-shaped support material to the inner wall of the tunnel. However, if back-filling is performed from the injection hole, cement milk or the like will be filled by back-filling between the closed ring-shaped support material and the inner wall of the tunnel, and this will solidify to fix the support material. Is done.

As described above, according to the present invention, even if the condition of the ground changes, it is possible to quickly select a construction method corresponding to the ground condition and carry out construction without delaying the excavation speed. It is not necessary to make the entire length the same structure, and it is possible to reduce the construction cost by implementing rational support work that meets the natural conditions.

In carrying out the present invention, in order to reduce the weight, it is preferable that the supporting member is made of steel.

The buried concrete is preferably fiber reinforced concrete or reinforced concrete by reinforcing steel for the purpose of increasing bending rigidity.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

1 and 2, a supporting material 1 used in the present invention.
0 is shown. A U-shaped steel material (which is merely an example and does not limit the technical scope of the present invention to a U-shaped steel material) is curved along the inner peripheral shape of the tunnel to be excavated. Two main girders 1, 1 divided in the circumferential direction are spaced apart in the longitudinal direction of the tunnel, both ends of which are connected by joint plates 2 and 2, and a central part is connected by a reinforcing plate 3 to form a frame body. Has been done. A lath net 4 is stretched on the curved outer peripheral surface of the frame body. The joint plate 2 is provided with a bolt hole 2a for connecting these supporting members 10,
Further, the reinforcing plate 3 is provided with a hanging hole 3a for transportation.

These supporting members 10 are made by bending a steel material,
Drilling work is done at the factory, and the parts are delivered to the construction site without being assembled. However, this is not applicable when it is desirable to carry out assembly and processing at the factory based on comprehensive judgment.

The support material 10 is assembled by welding, bolt joining, etc. in the field yard, carried into the mine, and assembled in a ring shape as described later.

Then, as shown in FIG. 3, the excavation is carried out by selecting the following construction method according to the conditions of the natural ground, or changing the construction timely while confirming the construction situation. The natural conditions shown here are general examples, and the construction method is selected as appropriate depending on the construction situation.

When the natural condition is Keniwa part and it is independent, A1
The support is not carried out as indicated by, and only the sprayed concrete is supported if necessary, and the excavating machine M takes the propulsion reaction force from the ground E with the gripper G and promotes it (first construction method).

When the natural condition is skin peeling, as shown in A2 of FIG. 3, the support member 10 assembled only from the above steel material is used as a ring-shaped support member by the expansion method as shown in FIGS. 6 and 7. Assemble it in the process 11. That is, the support material 10
The joint plates 2 are connected to each other by bolts or welding (not shown) to form a ring shape, and the top end U of the joint plate 2 is widened by the jack T to be in close contact with the ground E. Then, the excavating machine M takes a propulsive reaction force from the natural ground E with the gripper G (second construction method).

Here, in the case shown in FIG. 6, the jack T is replaced by a square pipe or the like (in other words, the member indicated by reference numeral 7 in FIG. 6 is a square pipe or the like used in the conventional expansion system. Is). On the other hand, in the embodiment shown in FIG. 7, the refill metal 7 is used for refill.

14 to 26 show a refill fitting 7 and a mode in which the jack T (FIG. 7) and the fitting 7 are refilled using the refill fitting 7. The refill metal fitting shown in FIG. 14 as a whole by reference numeral 7A is composed of two L-shaped steels 30, 30, a square pipe 32 connecting them, and a lath net 34. FIG.
The replacement metal fitting 7B shown by 5 has a structure in which the L-shaped steels 30 and 30 of the metal fitting 7A of FIG. 14 are replaced with H-shaped steels 36 and 36, and an overhanging iron plate 38 is provided above the H-shaped steel 36. Here, the overhanging iron plate 38 is hooked on the open end of the ring-shaped supporter 11 to prevent the refill metal fitting 7B from freely falling.

The refill metal fitting 7C shown in FIG.
The structure is simplified as compared with A and 7B, and the flat plate 42 is arranged on the square pipe 40, and the lath net 44 is further arranged thereon. Here, the lath net 44 is the metal fitting 7B.
The same effect as the overhanging iron plate 38 in FIG.

The refill metal fitting 7D shown in FIGS. 17 and 18 has a further simplified structure. That is, H-shaped steel 46
To 46C shown by a dotted line in FIG. Then, the non-cut-off portions 46D, 46D of the upper portion of the H-shaped steel 46 have the same action as the projecting iron plate 38 in the metal fitting 7B.

The refill fitting 7 (7A, 7
B, 7C, 7D) is the top end U of the ring-shaped supporter 11.
(See FIG. 6), it is difficult to insert from the bottom to the top. Therefore, as shown by an arrow I in FIG. 19, it is optimal to insert the top end portion U from the face side.

Here, as shown in FIG. 20, the height dimension h of the refill fitting 7 (7A, 7B, 7C, 7D) is made smaller than the thickness dimension H of the ring-shaped supporting member 11. By setting the insertion position of the jack T1 to a position lower than the metal fitting, it is possible to prevent the jack and the metal fitting from interfering with each other when the refill metal fitting is inserted from the face side shown in FIG. It In this case, it is not necessary to dispose one jack T and one refill metal fitting 7. Two jacks T2 and one metal fitting 7 may be used as shown in FIG. 21, or two metal fittings 7 and one jack T3 may be used as shown in FIG.

23 and 24 show another method of refilling by the refilling metal fitting 7. As shown in FIG. 23,
A blind hole 50 is formed in the support material 11. Then, as shown in FIG. 24, if a projection 52 is formed on the jack T4 and the projection 52 is fitted in the blind hole 50, even if the metal fitting 7 is inserted while the jack T4 is extended, both of them are Do not interfere.

25 and 26 show another method of rearrangement. As shown in FIG. 25, as shown in FIG.
And the jack T5 is configured to abut the shoulder portion 54. Even with this structure, the jack and the refill metal do not interfere with each other.

When the ground condition is disintegrating and hard, concrete C is sprayed onto the ground E from the lath net 4 of the support structure 11 assembled by the second construction method as shown by A3 in FIG. To reinforce. The excavating machine M is basically based on the reaction force of the gripper G from the ground E, but depending on the situation, the support J
It is also possible to take a reaction force at and use it together to promote it (the third construction method).

When the ground condition is weaker than that in the case of the third construction method, as shown by A4 in FIG. 3, the rock bolt 8 is further attached to the ground E from the concrete C spraying portion by the third construction method. To strengthen the support work 11. The excavating machine M is basically driven by the reaction force of the gripper G from the natural ground E, but depending on the situation, the reaction force is taken by the jack J from the support work.
It is also possible to promote them together. (Fourth construction method).

8 and 9 when the ground condition is further weak and thrust by the jack J is required (A5 in FIG. 3).
As shown in FIG. 2, a thrust-transmitting force is transmitted by inserting a detachable thrust-reinforcing metal fitting 5 such as a telescopic jack between the main beams 1, 1 in the longitudinal direction of the tunnel of the steel support member 10. The excavating machine M is propelled by the thrust of the jack J (fifth construction method). In this case, the thrust reinforcing metal member 5 is removed at a point where the thrust transmission is no longer necessary, and the thrust reinforcing metal fitting 5 is diverted for reuse.

To explain this fifth construction method more concretely, if the ground E becomes softer and the gripper G gets into the ground E, the gripper G cannot support the reaction force of propulsion. The excavating machine M cannot be propelled. On the other hand, since the soft ground E acts to tighten the excavating machine M, the excavating machine M cannot escape at that stage. In order to escape, the excavation machine M can only be propelled by the jack J, but the supporting member 10 can withstand the reaction force of the propulsion jack J acting in the longitudinal direction of the tunnel (not shown) as it is. Therefore, the reaction force cannot be supported.

However, when the detachable thrust reinforcing metal fitting 5 is inserted between the main girders 1 and 1 of the supporting member 10, the thrust reinforcing metal fitting 5 takes charge of the propulsive reaction force received by the jack J, so that the excavating machine M is jacked. You can use J to escape. In other words, the propulsion of the excavating machine M can be immediately switched from the propulsion by the gripper G to the propulsion by the jack J, and the worst situation in which the tunnel cannot be excavated due to the immovable state of the excavating machine M can be avoided.

When reinforcement is required between the rings in the tunnel longitudinal direction, adjacent main girders 1, 1 may be fastened with bolts 9a, 9b, etc. as shown in FIG. You may connect between rings.

When the ground condition is weaker than the above condition and the expansion method is possible, concrete is placed in the frame of the steel supporting material 10 in the frame of the steel supporting material 10 at a site yard described later as shown by A6 in FIG. The support material 10A in which 6 is embedded and buried is carried into the mine and assembled in a ring shape by the expansion method. The excavating machine M is propelled by the thrust of the jack J (sixth construction method). The filling of the concrete 6 into the steel support material 10 may be performed in the mine,
Alternatively, it may be filled with shotcrete C.

For example, the gripper G sinks into the ground,
When the excavating machine M becomes unable to escape, first, by the fifth construction method described above, the main girder 1 of the supporting member 10,
Inserting the detachable thrust reinforcing metal fitting 5 between the 1 and the gripper G
Immediately switch from propulsion by J to propulsion by Jack J. Then, if the propulsion of the excavating machine M is secured, the method is switched to the sixth construction method, and the supporting material 10A in which the embedded concrete is poured is used.

When the ground condition is soft ground, that is, when the support work cannot be brought into close contact with the ground by the expansion method (A7 in FIG. 3), the ring blocking method is used as shown in FIG. Assemble Process 11A. The supporting material 10A used here has a hole 6a for back pouring in the embedded concrete 6, through which the back pouring B is performed by pouring between the ring back surface and the ground E. The excavating machine M is propelled by the thrust of the jack J (seventh construction method).

A supporting material 10A used in the sixth and seventh construction methods is shown in FIGS. Steel support material 1
The inside of the frame of No. 0 is filled with concrete 6 inside, and a bolt box 6b for bolt fastening is provided along the joint plate 2, and when the main girder portion is also bolt fastened similarly, a bolt box (not shown) is also provided. ) Is provided. Further, a box 6c is also provided in the hanging portion of the reinforcing plate 3 in the same manner. Then, a back pouring injection port 6a is provided so as to penetrate through the embedded concrete 6. The back injection port 6
a is unnecessary in the case of the expansion system. The bolt boxes 6b and 6c and the holes 6a are formed by using a punch when the concrete 6 is poured.

The embedded concrete 6 may be ordinary concrete or aerated concrete for weight reduction. Further, in order to shorten the curing time, it is possible to use super fast-hardening concrete or super early-hardening concrete, and various admixtures such as expansion material, quick setting material, shrinkage reducing material, etc. may be mixed. Further, fiber-reinforced concrete or reinforced concrete may be used for the purpose of increasing bending rigidity.

According to this seventh construction method, the supporting material 10A
By assembling the closed ring into a closed ring shape, the closed ring assembled with the support material 10A is fixed to the inner wall of the tunnel for stabilization even if the expansion method is defective. The ring is stabilized / fixed by back-injecting cement milk or the like through the injection hole 6a, filling it with the inner wall of the tunnel, and solidifying the filler.

[0056]

As described above, according to the present invention, the following effects can be obtained. (1) It is possible to easily change the form of support, while checking the construction status at the site based on the natural conditions. (2) Since the supporting materials are brought in as parts on site, it is possible to reduce freight costs, reduce the size of the stockyard, and divert parts to other sites. (3) Conventionally, the support structure of the same structure (tunnel liner) was used for the entire extension line of the tunnel construction, but since the support structure of high rigidity type can be used to the minimum required, the construction cost will be drastically reduced. Can be reduced. (4) The expansion type support ring can greatly improve the working environment compared to the general sprayed concrete support used in mountain tunnels, and the divided support materials have excellent workability. (5) Steel support materials are used to connect the rings with reinforcing bolts,
Alternatively, reinforcement work by welding is easy, and since the concrete-filled concrete type is also held by steel,
Less likely to cause cracks or chips during handling. And, the support with the lath net can be easily reinforced by spraying concrete if necessary. (6) As a tunnel construction method for advanced tunnels for TBM,
This is the most suitable method because it is easy to disassemble and remove the supporting material and the processing cost is reduced. (7) The work environment is extremely good compared to the tunnel excavation work by blasting. (8) Regardless of the condition of the ground, it is possible to measure the common use of main components. (9) Since the steel material supports the corners of the concrete when the embedded concrete is filled in the frame of the support material, “cracking” and “chips” are less likely to occur during handling of the support material. (10) Since all sides of the supporting material are made of steel,
Reinforcement between rings (the support material is assembled in a ring shape) can be easily performed by bolt connection, or various welding can be performed for reinforcement work. (11) Compared with the case where a segment type tunnel liner is used over the entire construction extension line, by minimizing the use of a jack type jacking machine and the use of a high-rigidity type filled with embedded concrete, Construction costs can be reduced significantly.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a support material used in the present invention.

FIG. 2 is a perspective view seen from the opposite side of FIG.

FIG. 3 is an explanatory view of an excavation method according to the present invention.

FIG. 4 is an explanatory view of propulsion by a gripper.

FIG. 5 is an explanatory view of propulsion by a jack.

FIG. 6 is an explanatory diagram of an expansion system.

FIG. 7 is an explanatory view of a widening portion of the expansion system.

FIG. 8 is a perspective view showing a support member having thrust reinforcement fittings inserted therein.

9 is a perspective view seen from the opposite side of FIG. 8. FIG.

FIG. 10 is a perspective view showing reinforcement fastening between rings.

FIG. 11 is a perspective view showing a support material in which infill concrete is placed.

FIG. 12 is a perspective view seen from the opposite side of FIG. 11.

FIG. 13 is an explanatory diagram of a ring closing method.

FIG. 14 is a perspective view showing an example of a refill fitting.

FIG. 15 is a perspective view showing another example of the refill fitting.

FIG. 16 is a perspective view showing another example of the refill fitting.

FIG. 17 is a perspective view showing still another example of the refill fitting.

18 is a side view showing a method of processing the refill fitting shown in FIG.

FIG. 19 is a side view showing an example of the inserting or refilling direction of the refill fitting.

FIG. 20 is a side view showing one mode of refilling by the refilling metal fitting.

FIG. 21 is a view of another aspect of the refilling using the refilling metal as viewed from below the top end portion.

FIG. 22 is a view of another aspect of the refilling using the refilling metal as viewed from below the top end portion.

FIG. 23 is a side view showing still another mode of the refilling by the refilling metal fitting.

FIG. 24 is a view of the refilling mode shown in FIG. 23 as viewed from below the top end portion.

FIG. 25 is a side view showing another aspect of the refilling by the refilling metal fittings.

FIG. 26 is a view of the refilling mode shown in FIG. 25 viewed from below the top end portion.

[Explanation of symbols]

1 ... Main girder 2 ... Joint plate 3 ... Reinforcement plate 4 ... Lass mesh 5 ... Thrust reinforcement metal fitting 6 ... Infill concrete 7,7A, 7B, 7C, 7D ... Refill metal fittings 8 ・ ・ ・ Lock bolts 9a, 9b ・ ・ ・ Bolts 10, 10A ・ ・ ・ Supporting materials 11, 11A ・ ・ ・ Supporting work E ・ ・ ・ Solid ground B ・ ・ ・ Backing C ・ ・ ・ Spraying Concrete M ・ ・ ・ Drilling machine J ・ ・ ・ Jack G ・ ・ ・ Gripper T, T1, T2, T3, T4, T5 ・ ・ ・ Jack for expansion

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroaki Suzuki 1 Kanda Mitoshiro-cho, Chiyoda-ku, Tokyo Sumitomo Osaka Cement Co., Ltd. (72) Inventor Kaname Aoyama 1-8 Kandanishiki-cho, Chiyoda-ku, Tokyo Sumitomo Osaka Cement Co., Ltd. Tokyo Branch

Claims (9)

[Claims] 1. In a tunnel excavation method for excavating a tunnel by propelling the excavation machine in the ground, a support method for propelling the excavation machine in accordance with the state of the ground being excavated by the excavation machine, and A method of excavating a tunnel characterized by changing the form of support of the excavated tunnel. 2. The excavating machine is propelled by the gripper without supporting work when the soil and rocks forming the natural ground do not fall from the tunnel inner wall surface excavated by the excavating machine because the ground is very strong. Excavation method for tunnel 1. 3. A plurality of main girders curved so as to follow the inner peripheral shape of the tunnel, a joint plate connecting the both ends of the main girders at intervals in the longitudinal direction of the tunnel, and a main girder of the main girder. A frame is formed by a reinforcing plate that connects the central portions, and a supporting member is formed by using the curved outer peripheral surface of the frame as a lath net structure, and the supporting member that is bent and drilled is prepared in a component state. Then, the support material is assembled in the field yard, the support material is carried into the mine, the joint plate parts are connected to each other and assembled into a ring shape, and the top end portion is widened to be closely attached to the natural ground. The method for excavating a tunnel according to claim 1, wherein the method is constructed by forming a support work. 4. The method of excavating a tunnel according to claim 3, wherein the propelling of the excavating machine is performed by supporting a reaction force with a gripper. 5. The tunnel excavation method according to claim 3, wherein concrete is sprayed from the lath net portion of the support material to the ground to form a support work, and the excavation machine is propelled by gripper propulsion. 6. The method of excavating a tunnel according to claim 5, wherein the support bolt is formed by further driving a rock bolt from the concrete sprayed portion of the support bolt toward the ground. 7. The method of excavating a tunnel according to claim 3, wherein a detachable thrust reinforcing metal fitting is inserted between the longitudinal main girders of the supporting member tunnel, and the excavating machine is propelled by a jack. 8. The method of excavating a tunnel according to claim 3, wherein a supporting work is assembled by a supporting material in which concrete is embedded in the frame of the supporting material, and a jack is used to propel the excavating machine. 9. A plurality of main girders curved so as to follow the inner peripheral shape of the tunnel, a joint plate connecting the both ends of the main girders at intervals in the longitudinal direction of the tunnel, and a main girder of the main girder. A frame body is formed by a reinforcing plate connecting the central portions, and a curved outer peripheral surface of the frame body constitutes a supporting member having a lath net structure, and an injection hole for back pouring is formed in the frame body of the supporting member. , Prepare the supporting material that has been subjected to bending and hole processing in a component state, assemble the supporting material in the field yard and pour infill concrete, and place the supporting material with the infill concrete placed in the mine Carrying in, connecting the joint plate parts to each other and assembling them in a ring shape, forming backing by back-filling from the injection hole and making close contact with the ground, propelling the excavating machine with a jack The excavation method according to claim 1.