JP4485373B2 - Construction method of tunnel junction - Google Patents

Description

  The present invention relates to a method for constructing a junction / junction portion of a tunnel, and more particularly to a method for constructing a junction / junction portion of a tunnel that can construct a communication portion that connects adjacent tunnels at a low cost.

  Of the road tunnels, various techniques have been publicly announced and construction work has been carried out regarding the construction method of the section where the main tunnel and the ramp tunnel, which serves as the vehicle entry / exit line, merge (hereinafter referred to as the “merging / merging section”). (Patent Documents 1, 2, etc.). These construction methods include mechanically docking the composite circular shield machine that excavates the junction and the single circle shield machine that excavates the ramp tunnel and the main tunnel, or the separation and connection of the composite circular shield machine. After excavation, the shield machine is separated and the main tunnel and the ramp tunnel are excavated in parallel.

  In the construction method disclosed in the above-mentioned patent document, there is a problem that the manufacturing cost of the machine rises because the composite circular shield machine is used. Therefore, a ramp tunnel and a main tunnel are constructed with a circular shield machine at an interval, and a communication space is formed by excavating between both shield tunnels. The communication portion is formed from a ceiling slab, a ceiling beam, a column, and a wall. It is common to build a tunnel junction by forming.

  As described above, when the communicating portion is constructed by connecting the circular shield tunnels provided side by side, since both of them are circular in cross section, the extension of the beams and slabs forming the communicating portion becomes long, so these components are large. There was a problem of becoming a scale. In addition, when the merging and merging section is constructed below the groundwater level, the extension of the communication section lengthens the water stoppage construction, even if the production cost of the shield machine is reduced. There was a problem that soared.

JP-A-8-60979 JP 2002-13384 A

  The construction method of the junction / junction part of the tunnel of the present invention has been made in view of the above-mentioned problems, and the construction cost can be reduced by shortening the separation between the ramp tunnel and the main tunnel constituting the junction / confluence part as much as possible. It is an object of the present invention to provide a method for constructing a junction / junction part of a tunnel that can significantly reduce the above. This is caused by the use of a shield machine having a generally used circular cross section and the relatively small components of the communication portion connecting the lamp tunnel and the main tunnel.

  In order to achieve the above object, a method for constructing a junction / junction portion of a tunnel according to the present invention is a method of dividing a tunnel formed by connecting a first tunnel and a second tunnel provided in a direction perpendicular to both axes. A method for constructing a merge portion, a first step of constructing a first tunnel divided into two by a partition wall by a shield machine, and a second tunnel side of the first tunnel from the partition wall A second step of constructing the second tunnel with a shield machine so as to interfere with a part of the tunnel, and removing the segment constituting the partition and the second tunnel segment facing the partition, It is characterized by comprising a third step of forming a communication part space for communication between them, and constructing a ceiling, a floor, a pillar or a wall constituting the communication part.

  The first tunnel has a configuration in which at least one partition wall is provided in a well of a shield tunnel having a general circular cross section, and this partition wall is also formed of segments. In the first step, after the first tunnel is constructed, the second tunnel is attached to the first tunnel while cutting the segment on the second tunnel side of the first tunnel with a shield machine. (2nd process). Therefore, at the stage where the second step is completed, the first tunnel has a defective circular shape whose cross section is partially cut off. In this case, since the inside of the first tunnel opposite to the second tunnel from the partition is protected by the partition, a stable defect circular tunnel is formed. The shield machine used in the first process and the second process may be the same machine or a separate machine, and can be arbitrarily selected from the construction cost and the construction period.

  Next, as a third step, a communication part that communicates between both tunnels is constructed. First, by removing the partition (segment) of the first tunnel and the segment facing the partition of the second tunnel and forming a communication space, it is possible to come and go between the two tunnels. When removing the segment, it is preferable to temporarily set up an internal support for temporarily receiving earth pressure in the segment removal area of both tunnels.

  After the segment is removed, a floor slab and a column or wall and a ceiling slab (or beam) constituting the communication part are constructed from both or one of the tunnel tunnels. The floor slab and the ceiling slab are preferably constructed so that a part of the segments constituting both tunnels is embedded, and in some embodiments, a stud diver is attached to the segment embedded in the slab in advance.

  According to the present invention, the distance between the opposing tunnel walls can be shortened by forming one of the adjacent tunnels into a deficient circle. Therefore, the constituent members of the communication portion constructed in this distance can be made relatively small. It becomes possible to use a simple member. In addition, in this communication section, a form in which the ceiling slab and floor slab overhang from the wall, and a set of pillars that support the beam on the floor slab spanning between both tunnels (ramen structure), this ramen structure is Appropriate embodiments such as a configuration constructed with an interval in the longitudinal direction of the merging / merging portion can be applied, and in principle, a structure that does not require reinforcement around the segment removal portion of the tunnel can be adopted. Therefore, compared to a structure in which the periphery of the removed portions of both tunnels is directly connected by a beam or the like while reinforcing the periphery of the segment removed portions, the constituent members of the communicating portion are small-scale.

  In another embodiment of the method for constructing a junction / merging portion of a tunnel according to the present invention, the first tunnel is a ramp tunnel and the second tunnel is a main tunnel.

  The method for constructing a junction / merging portion of the tunnel of the present invention is preferably used when constructing a junction / merging portion composed of a ramp tunnel and a main tunnel that are provided side by side. In this case, the ramp tunnel may have a structure having a partition wall only in the junction / merging section, and the other approach section to the ground may be a normal circular cross-section tunnel having no partition wall. In addition, the term “merging / merging section” here means all sections where the ramp tunnel and the main tunnel are installed side by side. It means a section.

  In a preferred embodiment of the method for constructing a junction / merging portion of a tunnel according to the present invention, the segment forming the partition wall and the segment of the main tunnel facing the partition wall are made of steel segments.

  In a general concrete segment, it is difficult to remove it after it is assembled once because of its weight. On the other hand, if it is a steel segment, it will become comparatively lightweight and the removal after attachment will become markedly easy. Therefore, in the ramp tunnel (first tunnel) and main tunnel (second tunnel), the segment to be removed is made a steel segment in advance, so that the segment removal work at the time of constructing the communication part is performed smoothly. be able to. In addition, even when using steel segments, the joint strength between the communication component parts and both tunnels is increased by adopting a configuration in which stud gibbles are attached to places embedded in slab concrete or beam concrete. It becomes possible.

  Further, in another embodiment of the method for constructing a junction / merging portion of a tunnel according to the present invention, the steel segment is composed of a plurality of main girders extending in the circumferential direction of the tunnel and a skin plate attached between the main girders. In the third step, the communication plate is constructed after removing the skin plate, and then the main girder is removed.

  The steel segment is generally composed of a plurality of main girders extending in the circumferential direction of the tunnel and skin plates attached between the main girders. Therefore, when using steel segments, in the third step, first, only the skin plate is removed to enable the traffic between the two tunnels to come and go, and the main girder is removed after the communication part is constructed. It is good to do. With this work flow, the earth pressure is supported by the main girder until the communication section is constructed, and after the communication section is constructed, the earth pressure is maintained at the communication section even if the main girder is removed. Therefore, it is not necessary to provide a temporary support for the removal of the segment.

  Further, in another embodiment of the method for constructing a junction / junction portion of a tunnel according to the present invention, a cutting portion on the side that interferes with the main tunnel among tunnel tunnels divided into two by a partition wall includes mortar. It is characterized by being filled with filling material.

  Inside the shield machine, the segment is assembled by the erector device so that the segment having a circular arc shape (super arc) and the bulkhead segment are closed, and a shield tunnel having a circular cross section is constructed in the ground, The cutting part on one side of the partition wall is filled with a backfill material such as mortar. Therefore, also in the present invention, a shield machine having a circular cross section can be used.

  In another embodiment of the method for constructing a junction / junction portion of a tunnel according to the present invention, a tunnel wall that interferes with a main tunnel among the lamp tunnels divided into two by a partition wall is a shield that constructs the main tunnel. It is formed from a segment that can be cut by a machine.

  Here, as an embodiment of the segment that can be cut, at least one of a segment in which a fiber reinforcing bar that can be easily cut is arranged inside a concrete segment, steel, resin, and fiber reinforced resin is used. An example is a segment made of a material obtained by kneading and adding the above-mentioned fiber reinforcing material into concrete. Here, the fiber reinforcing bars are made of plastic (generally referred to as FRP) reinforced with fibers such as glass, carbon, and aramid, and more preferably carbon fiber reinforced resin (CFRP). ). Further, as another embodiment, in the lamp tunnel, the region cut by the shield machine is a normal concrete segment, the non-cut region is a steel segment, and both are integrally formed in the ring direction to form a shield tunnel. There is also a form which constitutes.

  Further, in another embodiment of the method for constructing the junction / merging portion of the tunnel according to the present invention, in the section where the junction / merging portion is formed in the main tunnel, the tunnel wall opposite to the side facing the ramp tunnel is widened. It is characterized by being.

  In the junction part, it may be necessary to widen the main tunnel to the side opposite to the lamp tunnel. Also, in the main tunnel, it is necessary to widen the tunnel laterally in other general parts, such as in a vehicle retreat section. Therefore, in the construction of such a widening section, efficient construction is possible by using a shield machine used in advance as a machine equipped with a widening cutter.

  As described above, in the main tunnel of the junction / merging section, by widening the opposite side of the ramp tunnel, the wall that forms the portal structure in the branch / merging section is secured while securing the internal space of the main tunnel. Space for constructing pillars and ceilings can be provided (partial space of the main tunnel that has been invaded by construction of one wall or pillar that constitutes a gate-shaped structure is secured by providing a widening section. ) By constructing the communication portion from such a gate-type structure, the constituent members constituting the communication portion can be further reduced in scale.

  Furthermore, in another embodiment of the method for constructing a junction / junction portion of a tunnel according to the present invention, when the junction / junction portion of the tunnel is constructed at a groundwater level or lower, before communicating both tunnels in the third step, The water stop construction is performed on the upper ground and the lower ground of the communication part.

  The water stop construction method is not particularly limited. For example, a single pipe or double pipe is inserted into the ground from one of the pits, and a chemical solution is injected (chemical injection method). There is a method (high-pressure jet agitation method) in which a horizontal column is formed by inserting a pipe or a double pipe into the ground and injecting a hardener and compressed air into the ground.

  After implementing the above ground improvement on the upper ground and lower ground of the communication part, part of the segments of both tunnels are removed, and both tunnels are used to stop water along the outline of the part where the segments were removed There is an embodiment that connects with the plate. After installing the water stop plate, the process moves to building the housing of the communication part.

  As can be understood from the above description, according to the method for constructing a junction / merging portion of the tunnel according to the present invention, both tunnels are installed side by side with one of the two tunnels constituting the junction / merging portion having a cross section of a defective circle shape. Therefore, the communication portion can be made small, and therefore the construction period can be shortened and the construction cost can be reduced. In particular, by widening the opposite side of the main tunnel to the main tunnel in the branch section, it is possible to configure the communication section from a gate-type structure while securing the internal space of the main tunnel. The constituent members of the communication part can be made smaller. Further, according to the method for constructing the junction / merging portion of the tunnel of the present invention, the portion to be removed is a steel segment, and the communication portion is constructed after the skin plate constituting the steel segment is removed, and thereafter By removing the main girder constituting the steel segment, it is possible to realize an efficient construction that does not require a support work. In addition, according to the method for constructing a junction / junction part of the tunnel of the present invention, a main tunnel and a ramp tunnel including the junction / junction part can be constructed using a single circular cross-section shield machine. Can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view illustrating an outline of a junction / merging portion of a tunnel according to the present invention, FIG. 2 is a sectional view illustrating a first step, and FIG. 3 is a perspective view illustrating a steel segment. Yes. 4 is a cross-sectional view illustrating the second step, FIG. 5 is a cross-sectional view illustrating the third step, and FIG. 6 is a cross-sectional view illustrating the third step following FIG. . FIG. 7 is a cross-sectional view showing one embodiment of the completed junction / merging portion, and FIG. 8 shows another embodiment of the completed junction / merging portion. In addition, although embodiment shown in figure has shown the case where a divergent junction part is constructed | assembled below a groundwater level, when constructed below a groundwater level, the water stop construction by ground improvement etc. is not required. Furthermore, it goes without saying that the housing of the communication portion may have a structure other than the illustrated embodiment, such as another wall type structure. Further, in the illustrated embodiment, all the sections where the ramp tunnel and the main tunnel are provided are assumed to be branching / merging portions.

  FIG. 1 is a plan view showing an outline of a junction / merging portion 3 of a tunnel. A shield machine (not shown) is started from the vertical shaft 7 communicating with the ground, and the ramp tunnel 1 is constructed while the shield machine excavates in the ground G. In the illustrated embodiment, the lamp tunnel 1 is constructed by the shield machine excavating between the start shaft 7 and the arrival shaft 7. The ramp tunnel 1 starts and arrives from an appropriate depth of the shaft 7, and the approach section to the ground is constructed by a shield machine that travels further from the shaft 7 toward the ground. In a certain section of the ramp tunnel 1, a main tunnel 2 is built along with the ramp tunnel 1. In this fixed section, the merging and merging portion 3 is constructed according to the construction direction described later.

Next, a method for constructing the junction / junction portion of the tunnel will be described with reference to FIGS.
In the first step, the shield machine started from the start shaft 7 constructs the ramp tunnel 1. FIG. 2 shows a cross section of a section of the lamp tunnel 1 that is provided with the main tunnel 2, that is, a section that forms the branching / merging portion 3. The lamp tunnel 1 in this section includes a general part 11 that is not cut by a shield machine that constructs the main tunnel 2, a partition wall 12, and a backfilling material 13 that is filled closer to the main tunnel side than the partition wall 12. The general part 11 is constructed by a normal concrete segment, and the partition wall 12 is constructed by steel segments 12a and 12b. The construction of the lamp tunnel 1 is performed using a shield machine having a normal circular section. Inside the shield machine, the general part 11 and the partition wall 12 are assembled by an erector device so as to be closed, and a segment (cross-sectional view is a circular shape in cross section) installed in the ground G is installed. Since the cross section of the ground G is cut into a circular shape by the circular face plate, a cavity is formed between the partition wall 12 and the ground G on the main tunnel side (the side opposite to the general portion 11) from the partition wall 12. . The inside of this cavity is filled with a backfilling material 13 such as mortar from the inside of the shield machine, whereby the lamp tunnel 1 having the cross section shown in FIG. 2 can be constructed. Note that, in the section of the lamp tunnel 1 where the split junction 3 is not formed, a general circular cross-section shield tunnel having no portion filled with the partition wall 12 and the backfill material 13 is constructed.

  FIG. 3 shows an embodiment of the steel segment 12a among the steel segments constituting the partition wall 12 in FIG. The steel segment 12a includes a plurality of main girders 12a1, 12a1,... Extending in the circumferential direction of the tunnel and a skin plate 12a2 attached between the main girders 12a1, 12a1. As will be described later, since the skin plate 12a2 is detached from the main girders 12a1 and 12a1 during the construction, the main girder 12a1 and the skin plate 12a2 are preferably attached by, for example, bolt joining, Good.

  Next, it transfers to a 2nd process and the main line tunnel 2 is built with a shield machine. FIG. 4 shows a cross section of a section where the main tunnel 2 is provided with the lamp tunnel 1. When the main tunnel 2 is constructed, the main tunnel 2 is constructed by cutting a portion filled with the backfill material 13 constituting the lamp tunnel 1 by a shield machine. Here, the lamp tunnel 1 is structurally stable by the general part 11 and the partition wall 12.

  When the main tunnel 2 is widened laterally in this tunnel section (widening portion 23), a known widening cutter (not shown) that is mounted on the side surface of the shield machine and can expand and contract in the radial direction of the face plate. )) Can be operated easily. Note that one or more shield machines may be used. That is, when using one shield machine, the procedure is to construct the ramp tunnel 1 first and then construct the main tunnel 2. For example, when using two shield machines, The construction will be preceded, and the main tunnel 2 will be constructed with a separate shield machine after a delay. When construction is performed by one shield machine, it is preferable to use a shield machine provided with the above-described widening cutter. When two or more shield machines are used, at least the main tunnel 2 is constructed. What is necessary is just to equip the shield machine with the widening cutter.

  After the ramp tunnel 1 and main line tunnel 2 are installed side by side, the process proceeds to the third step. First, as shown in FIG. 5, the ground improvement 4 is created from the inside of one tunnel toward the other tunnel. The ground improvement 4 is created in the ground above and below the communication part to be constructed. This ground improvement includes a method of injecting a chemical solution by inserting a single pipe or double pipe into the ground from one mine (chemical solution injection method), or a single pipe or double pipe inserted into the ground from the pit and hardening. An appropriate method such as a method of forming a horizontal column while jetting an agent and compressed air into the ground (high pressure jet stirring method) can be used.

  After the ground improvement 4 is created, the steel segment skin plates constituting both tunnels are removed, and the backfill material 13 is cut, thereby allowing the two tunnels to come and go. The backfilling material 13 is surely performed until the ground improvement 4 portion is exposed, the water stop plate 5 is brought into contact with the ground improvement 4 portion exposed on the inner wall surface of the communication portion, and both the tunnel and the water stop plate 5 Are welded together. The ground improvement 4 and the water stop plate 5 provide double water stop measures.

  Next, the housing of the communication part 6 is constructed. As shown in FIG. 6, the frame of the communication portion 6 includes a floor slab 63 straddling both tunnels, pillars 61, 61,... Constructed in one tunnel, and the other tunnel from the pillars 61, 61,. .. Are extended from the beams 62, 62,. Here, the main girder 12b1 of the steel segment on the side of the lamp tunnel 1 and the main girder 22a1 of the steel segment on the side of the main tunnel 2 are left, and the floor slab 63 so as to wind up the main girder 12b1, 22a1. A beam 62 is constructed. The floor slab 63, the beam 62, and the pillar 61 are made by a method of hitting concrete on the spot. However, since the main girders 12b1 and 22a1 remain, until the concrete develops strength, the main girders 12b1 and 22a1 It becomes possible to support the earth pressure acting on the communication part 6.

  In addition, the strength of the junction part of the communication part 6 and both tunnels can be improved by attaching a stud diver beforehand to the place embedded by the floor slab 63 and the beam 62 among the main girders 12b1 and 22a1. .

  By removing the main girders 12b1 and 22a1 at the stage where the frame strength of the communication portion 6 has been developed to a predetermined strength, the construction of the communication portion 6 is completed. When the construction of the communication unit 6 is completed, the construction of the branching unit 3 is completed (see FIG. 7).

  On the other hand, the completed junction part 3 in the case where the widened part 23 is formed on the side of the main tunnel 2 is shown in FIG. By forming the widened portion 23, the communication portion is constructed with the gate-shaped structure 7 (the structure composed of the ceiling 73 and the columns 71 and 72) while securing the initial internal space of the main tunnel 2. Can do. As is clear from the figure, the internal space of the main tunnel 2 eroded by the construction of the pillar 72 is secured by the widened portion 23. By constructing the communication part from such a gate-shaped structure 7, it is possible to reduce the size of each component member and further reduce the member specifications, thereby further reducing the construction cost. It becomes.

  According to the above-described method for constructing the junction / junction part of the tunnel according to the present invention, the size of the communication part can be made relatively small by shortening the separation between adjacent tunnels as much as possible, The ground improvement range of can also be reduced. In addition, a shield machine having a general circular cross section can be used. In some cases, it is possible to perform all construction of the lamp tunnel to the main line tunnel and the merging / merging portion by using only one shield machine. Therefore, the construction cost can be significantly reduced as compared with the conventional construction method.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

The top view explaining the outline | summary of the junction part of the tunnel of this invention. Sectional drawing explaining the 1st process. The perspective view explaining the steel segments. Sectional drawing explaining the 2nd process. Sectional drawing explaining the 3rd process. Sectional drawing explaining the 3rd process following FIG. Sectional drawing which showed one Embodiment of the completed junction part. Sectional drawing which showed other embodiment of the completed junction part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lamp tunnel (1st tunnel), 11 ... General part, 12 ... Bulkhead, 12a ... Steel segment, 12a1, 12b1, 22a1 ... Main girder, 12a2 ... Skin plate, 13 ... Backing material, 2 ... Main line tunnel (Second tunnel), 21 ... general part, 22 ... removal part, 23 ... widening part, 3 ... merging / merging part, 4 ... improved ground, 5 ... stop plate, 6 ... communication part, 61 ... pillar, 62 ... Beam, 63 ... Floor slab, 7 ... Gate-type structure

Claims (7)

A method for constructing a merging and merging portion of a tunnel formed by connecting a first tunnel and a second tunnel to be provided in a direction perpendicular to both axial centers,
A first step of constructing a first tunnel in which a mine is divided into two by a partition wall by a shield machine;
A second step of constructing the second tunnel by a shield machine so as to interfere with a part of the first tunnel on the second tunnel side from the partition;
The segment constituting the partition and the segment of the second tunnel facing the partition are removed to form a communication space that communicates between the adjacent tunnels, and the ceiling, floor, column, or wall constituting the communication and the third step to build, Ri Tona,
A method for constructing a junction / merging portion of a tunnel, wherein the first tunnel is a ramp tunnel and the second tunnel is a main tunnel . 2. The method for constructing a junction / merging portion of a tunnel according to claim 1 , wherein the segment forming the partition wall and the segment of the main tunnel facing the partition wall are made of steel segments. The steel segment is composed of a plurality of main girders extending in the circumferential direction of the tunnel, and a skin plate attached between the main girders. In the third step, the communication portion is removed after the skin plate is removed. And then removing the main girder. 3. A method for constructing a junction / merging portion of a tunnel according to claim 2 , wherein the main girder is removed. Of the tunnel underground divided into two by a partition wall, wherein the cutting portion of the main tunnel and the interfering side, any one of the preceding claims, characterized in that the back-filling material containing mortar is filled The construction method of the junction part of the tunnel as described in 2. The tunnel wall which interferes with the main tunnel among the lamp tunnels divided into two by the partition walls is formed from segments that can be cut by a shield machine that constructs the main tunnel . The construction method of the junction part of the tunnel in any one of 3 . 6. The tunnel according to claim 1 , wherein a tunnel wall on the side opposite to the side facing the ramp tunnel is widened in a section of the main tunnel forming the junction part. How to build a junction. When the junction part of the tunnel is constructed below the groundwater level, before the both tunnels communicate with each other in the third step, water stop construction is performed on the upper ground and the lower ground of the communication part. The construction method of the junction part of the tunnel in any one of Claims 1-6 .

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