JPH0913872A - Excavating construction method for tunnel with large cross section of arch type - Google Patents

Abstract

PURPOSE: To safely and quickly excavate a tunnel with a large cross section of arch type even through the un-consolidated natural ground with a thin earth cover thereon. CONSTITUTION: Leading invert concrete 15 is placed on the lower foundation 11a of a leading center guide tunnel 11 preliminarily excavated through the natural ground 1 and, then, rails 4 are laid thereon. An arch type through- channel 8 drilled through the natural ground 1 is filled with a hardenable material 9a via the through-channel excavating chain cutter 6 of an arch type tunnel excavator 5 traveling along the rails 4 and, then, the tunnel 11 is formed to divide pre-lining concrete 10 as an arch type support on the center bottom thereof. A real tunnel cutting blade 2a is separated into right and left sections 2a1 and 2a2 , for excavation, and, then, invert concrete 15, a base section 10a and a base section 10b at the other side are communicated to one another via invert concrete 15a at one side and invert concrete 15b at the other side, thereby jointing the internal surface of a tunnel 2 having large cross section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a large section tunnel (large section (excavation sectional area 100 to 150 m ² )) or an ultra large section (excavation section), even in unconsolidated ground where relatively thin soil is broken. Area larger than 150 m ² ) for excavating a large-section arched tunnel that enables safe and short-term excavation.

[0002]

2. Description of the Related Art As a method for excavating a large-section arch-shaped tunnel as described above, a proposal has been disclosed in Japanese Examined Patent Publication No. 4-63198, but in this case, FIGS.
As clearly indicated by the above, the large-section tunnel 2 to be excavated in the required ground 1 is operated by the arch-shaped tunnel excavator 5 which travels on the rail 4 on the lower plate portion 3, so that the chain cutter 6 for excavating the through groove is formed. By driving this while rotating it along the arch-shaped guide frame 7, an arch-shaped through groove 8 is bored in the soft ground 1a and the like, and a curable material injection pipe 9 separately provided therein. Therefore, as shown in FIG.
By injecting a, the prelining concrete 10 as an arch-shaped support plate is enclosed, and the face 1b having a large cross section surrounded by this is excavated at once by the full-section construction method.

[0003]

When the conventional method for excavating a large-section arch-shaped tunnel is used, a full-section method is adopted in order to make mechanized construction efficient, but a medium-section tunnel (excavation sectional area 100 m ² In the case of (below), it is the general construction method to use the full section construction method, but in the case of a large section tunnel, the self-supporting property of the face 1b can be improved by ordinary reinforcement work such as mirror spraying and mirror bolts. It becomes difficult to secure such a structure, and a large-scale reinforcement work such as a mirror pile is required. Moreover, since the cross section of the tunnel is large, the amount of earth and sand to be carried out in a single excavation increases, so that the traveling speed of the face 1b is also delayed.

Further, a serious problem in the conventional method is that the pre-lining concrete 10 has a larger cross section.
Since it is considered that the stress concentration on the ground will be increased due to the foot bases on the lower sides of both sides, reinforcement of the foot ground will not be unavoidable frequently, and if the reinforcement work is performed late, It is expected that the pre-lining concrete 10 as a whole will sink.

Therefore, as the reinforcement work, invert concrete is placed on the ground in the vicinity of the face 1b so that both leg bases of the prelining concrete 10 are connected to each other, whereby the large section is converted to the invert concrete. Although it may be possible to close the pre-lining concrete 10 at an early stage, such a process will further hinder the progress of excavation of the face face 1b, and the construction period of the large section tunnel will be prolonged. become.

In view of the drawbacks of the above conventional method, the present invention is
According to claim 1, the advanced central tunnel, which has a fast excavation speed, is previously excavated without using the full-section method.
If the preceding invert concrete is placed on the lower part, and if the pre-lining concrete that defines the area is erected in the subsequent large section tunnel, it will be placed between this and the advanced central tunnel. Without excavating the arch-shaped main shaft face formed in
Where one side half has been excavated, one side leg base of the pre-lining concrete and the preceding invert concrete are connected by the one side invert concrete, and after the other side half is excavated in the same way, the pre-lining The concrete, the leg portion on the other side, and the preceding invert concrete are connected by the other side invert concrete.

According to the first aspect of the present invention, by the above-described excavation process, by constructing the advanced central tunnel and its invert concrete, the self-sustaining property of the main face in the subsequent pre-lining concrete forming process is ensured and the arch is formed. The first purpose is to improve the excavation efficiency by reducing the amount of excavated soil of the main shaft face.

Further, according to claim 1, the main shaft face is not excavated all at once by the full-section construction method, but is excavated in right and left side halves, and one side invert concrete and another side invert concrete are respectively excavated. By placing
The second purpose is to enable the large-section closure as early as possible and to complete the large-section arch-shaped tunnel in a short time without any problem even on soft ground.

[0009] Next, in claim 2, in addition to the step of the above-mentioned claim 1, after injecting the preceding invert concrete on the lower plate part of the advanced central tunnel, pouring from the advanced central tunnel. By work, etc., when forming the pre-lining concrete that defines the large cross-section tunnel region in the next step, the preceding ground reinforcement treatment with mortar etc. is performed on the leg ground around which both leg bases are placed, As a result, both leg bases of the pre-lining concrete are erected on the above-mentioned ground of the reinforcing leg portion, so that the unintentional sinking of the pre-lining concrete is more effectively prevented.

[0010]

In order to achieve the above-mentioned object, the present invention is characterized in that, in claim 1, at a central bottom portion of a large cross-section tunnel region to be dug into a required ground, an advanced central conductor for a desired length is provided. A pit is dug up and, if necessary, a tunnel support work or a tunnel support work and a preliminary support work is applied to the advanced central tunnel, and a preceding invert concrete is placed on the lower part of the advanced central tunnel. After that, by laying a rail on the preceding invert concrete, guide the arch-shaped tunnel machine for the main tunnel face, which is the large cross-section tunnel area, by operating this arch-shaped tunnel machine. With the chain cutter for excavating the arc-shaped through-groove, an arch-shaped through-groove having an arc-shaped cross section is excavated, and a curable material is filled and hardened in the arch-shaped through-groove to form an arch-shaped support plate with an arc-shaped cross section. Prelining con After erected the reed in an arch shape, the arch-shaped main shaft face between this pre-lining concrete and the advanced central tunnel was excavated and removed on one side half thereof, and then with the preceding invert concrete. The one leg base of the pre-lining concrete is connected by the invert concrete on one side, and then the other half of the face of the main shaft is excavated and removed, and the space between the preceding invert concrete and the other leg base of the pre-lining concrete is removed. , Continuous with the other side invert concrete, from the standing of the pre-lining concrete, repeating the process from the other side of the invert concrete to the continuous, while the inner surface of the pre-lining concrete, the secondary lining arch concrete Excavation of large-section arch-shaped tunnel characterized by being cast It is intended to provide a method.

Further, in the excavation method for a large-section arch-shaped tunnel according to claim 2, in addition to the configuration according to claim 1, the preceding invert concrete is placed on the lower part of the advanced central tunnel. After installation, pre-reinforcing treatment was performed by pouring operation from the advanced central tunnel to the ground around both legs in the large cross-section tunnel area, and the ground location where the pre-lining concrete should be erected was hardened in advance. That is the content.

[0012]

First, according to the method for excavating a large-section arch-shaped tunnel according to claim 1, the leading advanced central tunnel can be dug in a relatively short time by the free-section excavator, and the leading invert concrete is By being cast, a part of the cross section of the large cross section tunnel will be reinforced early. Rails are laid on the preceding invert concrete, which guides the arch tunnel excavator to run and efficiently fills and cures the curable material in the arch through groove by its operation. The pre-lining concrete, which is an arch-shaped support plate having an arc-shaped cross section, can be erected so as to have an arch shape.

Since the excavation work to be carried out next is carried out on the arch-shaped main shaft face, the excavated soil amount obtained by subtracting the excavated soil amount for the advanced central tunnel will suffice. The work speed is considerably increased, and since the mine face is divided into right and left half sections, the work can be performed efficiently. In addition, the invert concrete on one side and the invert concrete on the other side are placed each time, and early large cross-section closure is carried out, so it is possible to prevent the subsidence of the prelining concrete and the collapse of the main shaft face, which is safe. In addition, it is possible to efficiently excavate an arch-shaped tunnel having a large cross section.

According to the second aspect of the present invention, further, after the preceding invert concrete has been placed in the advanced central tunnel, the advanced central tunnel can be safely connected to the ground around the legs of the pre-lining concrete. By the injection treatment of mortar and urethane, the preceding reinforcement treatment is applied to the ground without delaying the process, so that the settlement of the pre-lining concrete can be prevented with higher reliability.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of excavating a large-section arch-shaped tunnel according to the present invention will be described below in detail with reference to the drawings according to one embodiment. As shown in FIG. A large cross-section tunnel 2 is dug into the required natural ground 1 such as a connection.
The standard excavation method for mountain tunnels (NAT)
According to M), a free section excavator (not shown) is used to excavate the advanced central tunnel 11 having a cross section of a two-lane road tunnel. This advanced central tunnel 11 is to be excavated in the central lower portion of the large-section tunnel 2 to be constructed, as understood from FIGS. 1 (B), 2 and 3. .

Here, for the above-mentioned advanced central tunnel 11, it is necessary to form a tunnel support if necessary, and as a means for this, a steel support 1 is provided on the inner surface thereof.
2 may be built, sprayed concrete may be formed, or rock bolts may be driven in. At this time, in consideration of the case of excavating the main shaft face 2a described later, fiber bolts are used for the lock bolts. Is desirable.

Further, in addition to the above-mentioned support work, the loosened region 13 caused by excavation of the advanced central tunnel 11 concerned.
However, as shown in FIG. 2, when there is a possibility that the tunnel will spread out of the area of the large cross-section tunnel 2, a pre-supporting auxiliary method will be applied, and therefore, an existing simple means, that is, a fiber bolt, will be used. Ground improvement will be carried out by a mortar-filling type forepoling using No. 14 or a urethane injection type forepoling. This ground improvement is in principle cast into the inner region of the pre-lining concrete 10, but it may be cast out of the region.

Next, the advanced central tunnel 11 which has been excavated in advance as described above has a lower plate portion 11a, as shown in FIG.
As clearly shown in FIG. 3, the preceding invert concrete 15 is placed behind it. Next, in claim 2, by using the time lag which is about several tens of days until the main shaft face 2a, which will be described later, approaches, by the work from the advanced central tunnel 11, As clearly shown in FIG. 3, the preceding reinforcement processing is performed on the leg ground areas 16a and 16b at the lower left and right sides of the large section tunnel 2.

As the preceding reinforcement treatment, the injection pipe 1 shown in FIG. 3 inserted from the inner wall surface 11b of the advanced central tunnel 11 is inserted.
The reinforcement leg grounds 18a and 18b are formed by mortar injection using 7a and 17b or urethane injection. The subsequent steps are the same in any of claims 1 and 2, so that the prelining concrete 10 is first formed on the upper face of the preceding invert concrete 15 with respect to the main shaft face 2a. The above-mentioned arch-shaped tunnel excavator 5 is laid with a rail 4 to be guided for traveling.

Next, the above-mentioned arch tunnel excavator 5 is operated to form the pre-lining concrete 10 as described above with reference to FIGS. 5 to 8.
Here, the process will be described in detail with reference to the same drawing. In particular, as clearly shown in FIG. 8, with respect to the moving frame 19 supporting the chain cutter 6 for arc-shaped see-through groove excavation,
After this is moved forward by the cutter advancing / retreating drive device 21 along the arcuate guide member 20, the movable boom 22 supporting the arcuate guide member 20 moves along the arched guide frame 7. By this, the chain cutter 6 for excavating the through groove excavates the arch through groove 8 having an arcuate section in which the longitudinal middle portion is curved so as to be convexly curved toward the outside of the large section tunnel. .

Next, the curable material 9a is filled and cured in the arch-shaped through groove 8 through the curable material injection pipe 9 to pre-concrete concrete 10 which is an arch-shaped supporting plate having an arc-shaped cross section. 7 is formed in an arched shape as clearly shown in FIG. 7, and in FIGS. 5 to 7, 23 is a drive device for the chain cutter 6 for see-through groove excavation, 24 is an injection device for moving the injection pipe, and 25 is movable. A drive device for moving the frame 22, 20a is an arcuate rack of the arcuate guide member 20,
7a is an arcuate rack of the arch-shaped guide frame 7, and 26
8 is a wheel traveling on the rail 4, 27 is a traveling drive device for driving the wheel 26, and 28, 29, 30, in FIG.
Reference numerals 31a and 31b respectively denote a sprocket, an excavating blade, a link, and a pair of connecting links in the arc-shaped see-through groove excavating chain cutter 6.

Then, again, the step of forming the prelining concrete 10 which is an arch-shaped supporting plate having an arcuate cross section by the arcuate through groove excavation chain cutter 6 is repeatedly performed to bring them closer to each other or to each other. A large number of joined pre-lining concretes 10 are sequentially constructed in the longitudinal direction.

Here, of course, the above-mentioned rail 4 is laid on the lower board 3 in the conventional example, whereas it is installed on the preceding invert concrete 15 in the present invention.
And FIG. 9 is related with the said Japanese Patent Publication No. 4-63198, and regarding the said arc-shaped through groove excavation chain cutter 6, it is not provided with only one,
A conventional example in which a pair is provided side by side is shown (JP-A-2-167994). That is, in FIG. 9, a double chain cutter mechanism is proposed in which the above-mentioned pre-lining concrete 10 can be formed more efficiently. In this case, the groove-shaped cover 32 is arched. The shape through groove 8 is opened in the groove cutting direction D and is movable in the longitudinal direction of the large cross section tunnel 2 together with the double chain cutter.

Further, inside the groove-shaped cover 32, a pair of through-groove excavating chain cutters 6a which can be driven environmentally,
6b is not only arranged vertically in the radial direction of the large cross-section tunnel 2, but also from the front to the rear in the groove cutting direction D,
The installation is inclined so as to approach the width center of the arch-shaped through groove 8, and only the front portions of these chain groove excavating chain cutters 6a, 6b are exposed from the groove cover 32,
The other portions are in a state of being housed and protected in the groove-shaped cover 32.

Therefore, if the arch-shaped through-groove 8 is cut in the main shaft face 2a by the above-mentioned double chain cutter mechanism as described above, the earth and sand collapsed at the time of the cutting can be removed through the through-groove. The chain cutters 6a, 6b for piercing through-grooves are arranged so as not to fall into the returning movement portions of the chain cutters 6a, 6b and apply an excessive load, and as described above. Since the groove-shaped cover 32 does not hinder this during the excavation, the arch-shaped see-through groove 8 can be efficiently excavated. In FIG. 9, reference numerals 29a and 29b denote excavation blades of the chain cutters 6a and 6b for excavating the through groove.

Here, in practice, the central bottom of the arched tunnel machine 5 is inside the arched guide frame 7 and is suitable, as understood from FIG. 7 and shown in FIG. 1 (B). It is preferable that the approach space S is formed under the fall protection cover, and this allows the face of the advanced central tunnel 11 to be dealt with even when the arched tunnel machine 5 is in operation or at rest. It becomes possible to carry out the excavated earth and sand of the face concerned and carry in the materials without any breaks, and the work efficiency can be improved.

After the pre-lining concrete 10 is constructed, as shown in FIG. 1 (B), the main shaft face 2a is to be excavated by a large-section free-section excavator. Since it will be carried out between the guide shaft support and the pre-lining concrete 10 in the pit 11, since the height of the main pit face 2a is considerably smaller than the height of the large section tunnel 2, The face is stable and the amount of excavated soil is small.

In the present invention, instead of excavating the entire cross section of the main shaft face 2a, one side half portion 2a ₁ on the right or left side is excavated _first , and in this state. Is a monopod base portion 10a of the pre-lining concrete 10, and in the claim 1, is on the leg ground periphery 16a,
In claim 2, since it is erected on the reinforcing leg ground 18a, in either case the prelining concrete 1
The subsidence of 0 is suppressed, and under this condition, the preceding invert concrete 15 and the monopod base 10a are connected by the one-side invert concrete 15a.

Next, the other half 2a of the main shaft face 2a
_{For 2} , the excavation is performed, and when this is completed, the other side invert concrete 15b is connected between the preceding invert concrete 15 and the other leg base 10b of the prelining concrete 10 in the same manner as described above, whereby the large amount to be excavated. The pre-lining concrete 10, the preceding invert concrete 15, the one-side invert concrete 15a, and the other-side invert concrete 15b are used to close the tunnel lining cross section early on the entire inner circumferential surface of the cross section tunnel 2.

Here, in the final stage of the excavation cycle for the main shaft face 2a, the arch-shaped tunnel excavator 5 advances to form the next pre-lining concrete 10. The guide shaft support is removed, but the steel support structure 12 can be reused. Since the inner surface of the pre-lining concrete 10 is exposed in this manner, the
As shown in (B), the secondary lining arch concrete 33 will be constructed.

[0031]

EFFECTS OF THE INVENTION Since the present invention can be carried out as described above, according to claim 1, an advanced central tunnel is excavated in advance, and rails are laid on the preceding invert concrete that is placed therein. After that, the arch-type tunnel excavator running on the rail was used to build the pre-lining concrete in the large cross-section tunnel area. It is possible to reduce the amount of soil to be excavated when excavating the arch-shaped main shaft face and improve the excavation efficiency.

Furthermore, the digging face of the main shaft is divided into two parts on the right and left sides, and at the stairs after one digging, the leg bases of the preceding invert concrete and the pre-lining concrete are respectively inverted on one side. Since the concrete and the invert concrete on the other side are connected to each other, the subsidence of the pre-lining concrete can be prevented early without delay.

Further, in the second aspect, in addition to the process of the first aspect, the advanced reinforcement is applied to the periphery of the leg ground of the pre-lining concrete after the laying of the preceding invert concrete from the advanced central tunnel. As a result, the undesired settlement of the pre-lining concrete can be suppressed with a higher probability.

[Brief description of the drawings]

FIG. 1 (A) is a schematic vertical cross-sectional side view showing the forming process of pre-lining concrete in the excavation method for a large-section arch-shaped tunnel according to the present invention, and FIG. It is a cross-sectional schematic front view of the ground in the state where the concrete and the other side invert concrete are cast.

FIG. 2 is an explanatory cross-sectional front view of the ground showing the pre-supporting auxiliary construction method applied to the loosened area of the main shaft face, which is carried out as necessary, in the excavation method of the present invention.

FIG. 3 is a cross-sectional explanatory view of the natural ground showing the preceding reinforcement treatment applied to the periphery of the leg ground of the prelining concrete in the excavation method according to the second aspect of the invention.

FIG. 4 is a flowchart showing a process sequence of the excavation method according to the second aspect of the present invention.

FIG. 5 is a schematic vertical cross-sectional side view of the ground showing one usage mode of the arch tunnel excavator used for forming the pre-lining concrete according to the present invention.

FIG. 6 is an explanatory plan view showing the arch tunnel machine shown in FIG. 5;

7 is a cross-sectional front view showing the arch tunnel excavator of FIG.

8 is a partial perspective view of a chain cutter for digging a through groove in the arch-shaped tunnel machine of FIG.

FIG. 9 is a partial cross-sectional front view showing a chain cutter for see-through groove excavation in an arch type tunnel excavator having a different color from that in FIG. 5.

[Explanation of symbols]

1 Ground 2 Large section tunnel 2a Main pit face 2a ₁ Half on one side 2a ₂ Half on the other side 4 Rail 5 Arch tunnel excavator 6 Chain cutter for excavating through groove 8 Arch through groove 9a Hardening material 10 Pre-lining concrete 10a One-leg base 10b Other-leg base 11 Advanced central tunnel 11a Lower part 15 Leading invert concrete 15a One-side invert concrete 15b Other-side invert concrete 16a Leg ground around 16b Leg ground around 18a Reinforcement leg ground 18b Reinforcement leg ground

Claims (2)

[Claims] 1. An advanced central tunnel is excavated by a desired length at a central bottom portion of a large-section tunnel region to be excavated in a required ground, and if necessary, a shaft support or a tunnel for the advanced central tunnel. After carrying out support work and pre-supporting work, after placing the preceding invert concrete on the lower part of this advanced central tunnel, a rail is laid on the preceding invert concrete and the large section tunnel area The arch tunnel excavator for the main pit face is guided to run, and by the operation of this arch tunnel excavator, the arc-shaped see-through groove excavated by the chain cutter for excavating arc-shaped sections After excavating a groove and filling and hardening it with a curable material, the pre-lining concrete, which is an arch-shaped support plate with an arc-shaped cross section, is erected in an arch shape and then Note: After excavating and removing one half of the arch-shaped main tunnel face with the advanced central tunnel, one side invert concrete was used to connect between the preceding invert concrete and the base of the monopod of the pre-lining concrete. Installed, then excavating and removing the other half of the main face, between the other leg bases of the preceding invert concrete and pre-lining concrete, the other-side invert concrete is used to connect them, A large cross-section characterized by repeating the process from standing up to the continuous installation of the other side invert concrete, and at the same time, the inner surface of the prelining concrete is subjected to the placement of secondary lining arch concrete at appropriate times. Excavation method for arched tunnels. 2. An advanced central tunnel is excavated by a desired length at a central bottom portion of a large-section tunnel region to be excavated in a required ground, and, if necessary, a shaft support or a tunnel for the advanced central tunnel. After performing support work and pre-supporting work, and placing the preceding invert concrete on the bottom plate of this advanced central tunnel, pouring operation from the advanced central tunnel to the ground around both legs in the large section tunnel area. Then, a rail is laid on the preceding invert concrete, and the arch tunnel excavator for the main tunnel face, which is the large cross-section tunnel area, is guided to drive the arch tunnel. By operating the excavator, the arched through-groove chain cutter for excavating the arc-shaped through-groove is used to excavate an arch-shaped through-groove with an arc-shaped cross section, and a curable material is filled and hardened in the arch-shaped through-groove. A The pre-lining concrete, which is a torch-type supporting plate, is erected on the ground of the reinforced legs formed by the preceding reinforcement treatment, and then the arch-shaped main shaft between the pre-lining concrete and the advanced central tunnel. After excavating and removing one side half of the cutting face, connect the preceding invert concrete and the monopod base of the pre-lining concrete with one side invert concrete, and then connect the other half of the main face cutting face. Excavate and remove, and connect between the other leg bases of the preceding invert concrete and the pre-lining concrete by the other-side invert concrete, and from the standing of the pre-lining concrete to the above-mentioned other-side invert concrete While repeating the process, the secondary lining arch concrete is timely applied to the inner surface of the pre-lining concrete. Excavation method of large cross-section arcuate tunnel, characterized in that the pouring of over bets were to be applied.