JP4196290B2 - Reinforcement structure of the center pillar of a glasses tunnel and a tunnel construction method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a center pillar reinforcing structure and a tunnel construction method for a spectacle tunnel, and more particularly, a center pillar reinforcing structure for suppressing deformation of a center pillar wall column during excavation of an advanced main shaft, and a reinforcing structure thereof. It is related with the construction method of the glasses tunnel.

  For example, in road tunnels, the upper and lower lanes are very close to each other, and the central partition column (hereinafter referred to as the center pillar) made of reinforced concrete built in the central advanced guide shaft is used as a shared structure. Two main tunnels (referred to as twin tunnels, eyeglass tunnels, etc., but in this specification referred to as eyeglass tunnels) are being constructed. FIG. 4 is a cross-sectional view showing an example of the cross-sectional shape of this kind of eyeglass tunnel. The center pillar 11 built in the central advanced guide shaft 10 reliably supports the tunnel action load acting on the center side of the upper half of both main tunnels 20 and 30 and maintains the stability of the entire eyeglass tunnel. It is like that.

  As shown in FIG. 5, the center pillar 11 is constructed in the central advanced guide shaft 10 that has been excavated in advance between the two main tunnels 20 and 30 and has a horseshoe-shaped tunnel, for example. It is a wall columnar reinforced concrete structure. The cross-sectional shape is substantially inverted T-shaped following the side wall shape and invert shape of the main tunnel, and is continuously constructed along the extending direction of the tunnel. The center pillar 11 may be safe in all stress states corresponding to each construction stage of the advanced main tunnel 20 and the reverse main tunnel 30 (hereinafter referred to as the advanced main tunnel 20 and the reverse main tunnel 30). is important. For this reason, it is important to have a structure in which the top of the center pillar 11 and the top of the advanced guide shaft 10 are integrally connected. For this reason, a method for constructing the center pillar top has also been proposed (Patent Literature). 1).

  When the center pillar is constructed by the construction method disclosed in Patent Document 1, the center pillar has a configuration in which the lower end has a fixed end as the bottom plate of the entire invert in the advanced guide shaft, and the upper end is fixed to the top of the advanced guide shaft. .

See JP 2002-322898 A.

  By the way, in the glasses tunnel, the excavation timing (process) of the advanced main shaft and the reverse main shaft shown in FIG. 4 is generally different. Therefore, when excavating the advanced main mine, as shown in FIG. 6, the excavation load of the advanced main mine is shot concrete and steel arch support constructed at a predetermined pitch in the tunnel extension direction (hereinafter referred to as arch support) Supported by At this time, one side of the arch support is supported by the shoulder of the center pillar, and the tunnel excavation load is the sprayed concrete constructed at the arch of the advanced main pit and the legs of the arch support-center pillar wall column- Communicated with center pillar bottom plate.

  After that, when the advanced main mine is excavated, the support pillar axial force of the leg portion 21a of the arch support work 21 acts only on one side of the center pillar, so that the center pillar 11 is expected to be deformed as indicated by a white arrow. At this time, a bending moment M is generated in the center pillar wall column portion 11d so that the advanced main mine 20 side is in a compressive stress state and the reverse main mine shaft 12 side is in a tensile stress state.

  Conventionally, in order to suppress the deformation of the wall pillar portion of this type of center pillar and to make the stress state appropriate, the amount of reinforcing bars of the center pillar as reinforced concrete is increased or reinforcing steel materials are arranged. In order to prevent deformation of the center pillar, a countermeasure work may be considered in which the entire main shaft on the reverse main shaft side is filled with foamed mortar and closed. However, when the entire guide pit is closed with foamed mortar, it is necessary to perform excavation of the foamed mortar portion during excavation of the reverse main mine, which lowers the construction efficiency of the reverse main mine.

  However, in the case of an eyeglass tunnel with a large earth cover, the displacement and stress states of the center pillar during construction of the advanced main mine were confirmed by FEM analysis. As a result, the structural system in which the upper and lower ends were firmly held as described above. It is confirmed that the center pillar of the center pillar is close to the behavior as a fixed plate at both ends. By referring to the stress state, the stress state of the center pillar as a whole is obtained by restraining the displacement at the middle position in the height direction of the center pillar. It was confirmed that the safety of can be secured. Therefore, the object of the present invention is to eliminate the above-mentioned problems of the prior art and to suppress the displacement of the center pillar during excavation of the advanced main shaft by a simple reinforcing structure so that excessive stress is not generated in the center pillar. An object of the present invention is to provide a reinforcing structure for a center pillar of a glass tunnel and a method for constructing a glass tunnel.

  In order to achieve the above object, the present invention is a glasses tunnel constructed by using a center pillar provided in advance in an advanced guide shaft located between an adjacent advanced main shaft and a reverse main shaft as a shared support structure. The reinforcing structure of the wall pillar portion of the center pillar is provided on the backfill filler layer having a predetermined thickness in the reverse main shaft side guide shaft of the advanced guide shaft.

  As a construction method of the eyeglass tunnel, a center pillar is built in advance as a shared support structure in the advanced guide shaft located between the adjacent advanced main shaft and the reverse main shaft, and the reverse main shaft of the advanced guide shaft is constructed. A backfill filler layer having a predetermined thickness is formed in the side guide mine, and a reinforcing structure for the wall pillar portion of the center pillar is provided thereon to excavate the advanced main mine, and then the reverse main mine side guide mine. The reverse main shaft is excavated while removing the reinforcing structure of the main shaft, the invert of the main tunnel is excavated, and the secondary lining of each main tunnel is performed. At this time, it is preferable that a filling solidified body having a predetermined layer thickness fills the backfill reinforcing portion as the reinforcing structure of the wall pillar portion of the center pillar.

  As the reinforcing structure of the wall pillar portion of the center pillar, it is preferable that a filling solidified body having a predetermined layer thickness is filled on the backfilling filler layer.

  Moreover, it is also preferable that a steel assembly reinforcing member is installed on the backfill reinforcing portion as the reinforcing structure of the wall pillar portion of the center pillar.

  Furthermore, it is also preferable that a foamed resin block structure is installed on the backfill reinforcing portion as the reinforcing structure of the wall pillar portion of the center pillar.

  According to the present invention, in the construction of a spectacle tunnel, the deformation of the wall pillar portion of the center pillar accompanying excavation of the advanced main mine can be prevented with a simple reinforcement structure, and the reinforcement structure can be easily removed in a subsequent process. Therefore, the reverse main pit can be efficiently excavated, and the effect of being able to construct a glasses tunnel is achieved.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, the following embodiments will be described with reference to the accompanying drawings as the best mode for carrying out the center pillar reinforcing structure and the tunnel construction method of the present invention.

  Hereinafter, a method for constructing a glasses tunnel using the reinforcing structure of the center pillar of the present invention will be described with reference to FIGS. As shown in FIG. 1A, for example, a central advanced guide shaft 10 having a horseshoe-shaped cross section is excavated at an intermediate position between an advanced main shaft and a reverse main shaft constructed in a subsequent process. This central advanced guide shaft 10 functions as a pilot tunnel in the tunnel construction section, changes its support pattern as appropriate according to the ground conditions, and is constructed later such as a drainage method, a preceding reinforcement method, etc. It can also be used to apply preparatory work so that the advanced main shaft 20 and the reverse main shaft 30 can be smoothly excavated.

  Next, the center pillar 11 made of reinforced concrete having a cross-sectional shape considering the separation between the main mines and the side wall shapes 11a and invert shapes 11b of the main mines is constructed (FIG. 1 (b)). The wall pillar 11d and the bottom slab 11e of the center pillar 11 are designed so as to be always safe in the temporary stress state generated in each construction stage as described above and in the permanent stress state after completion. Therefore, it has a reinforced concrete structure in which necessary reinforcing materials (reinforcing bars, shaped steel) are arranged. It is also preferable to dispose a reinforcing steel material in the concrete in the center pillar 11 in order to alleviate stress concentration at the shoulder 11c where the leg 21a of the arch support 21 is installed.

Prior to excavation of the advanced main mine 20, the backfill main lining 12 is filled with a backfill material to a predetermined thickness to form a backfill filler layer 13. In addition, as a backfill material of this backfill filler layer 13, a part of locally generated soil generated by blasting and mechanical excavation originally carried out of the mine is used (FIG. 1 (c)). Further, the backfill filler layer 13 is filled with concrete 14 as a filling solidified body that is solidified after filling as a reinforcing structure of the wall pillar portion 11d of the center pillar 11 by a predetermined layer thickness. In this example, an air mortar (an air-drying specific gravity of about 1.2, 4 weeks strength of 1 to ² N / mm ² ) manufactured by introducing a foaming agent at a field plant outside the mine is used. It is preferable that the concrete layer thickness and the concrete strength are determined in advance by FEM analysis in consideration of the tunnel shape and the ground state, and a reinforcing pattern such as a layer thickness according to the ground state is set. As will be described later, since the concrete 14 portion and the backfilling filler layer 13 are removed together with the natural ground when excavating the reverse main pit 30, the concrete 14 portion can be excavated by a used excavating machine. It is necessary to set the strength. As the filled solidified body, in addition to air mortar, cellular concrete, porous concrete, or soil cement that exhibits a predetermined strength can be used.

  The excavation procedure of the main shafts 20 and 30 with the reinforcing structure of the reverse main shaft side guide shaft 12 as described above will be described with reference to FIGS. As shown in FIG. 2 (a), while removing a part of the support work of the central advanced guide shaft 10, the upper half of the advanced main mine 20 is excavated to form the legs 21 a of the upper half arch support work 21. Is supported by the shoulder 11c of the wall pillar 11d of the center pillar 11. The excavation load acting on the advanced guide shaft 10 side is transmitted to the bottom slab 11e through the wall pillar portion 11d of the center pillar 11, and at this time, the reinforcing structure (backfill filler 13, concrete) is provided in the reverse main shaft guide shaft 12. 14), the deformation of the wall pillar portion 11d of the center pillar 11 can be minimized. Next, the lower half of the advanced book 20 is excavated. In the lower half excavation, a maximum bending moment is generated in the center pillar 11, but the deformation of the center pillar 11 can be sufficiently suppressed by the reinforcing structure in the reverse main shaft side guide shaft 12.

  Next, as shown in FIG. 2 (b), the upper half of the reverse main mine 30 is excavated, and the legs of the upper half arch supporting work 31 are attached to the wall pillars of the center pillar 11 as in the advanced main mine. Support on the shoulder. At this time, since the load acting on the wall pillar portion 11d of the center pillar 11 is bilaterally symmetric, the stress state of the wall pillar portion 11d is stabilized. Then, the lower half of the reverse main mine is excavated together with the reinforcing structure (backfill filler 13, concrete 14). Further, the inverts 22 and 32 of the main tunnels 20 and 30 are excavated to complete a predetermined spectacle tunnel cross section (FIG. 2C). Thereafter, upper lining to lower halving and invert secondary linings 23, 24, 33, and 34 are performed to complete the tunnel cross section (FIG. 4).

  3 is a cross-sectional view of the central advanced guiding shaft 10 showing a modification of the reinforcing structure of the wall pillar portion 11d of the center pillar 11. As shown in FIG. When excavation of the advanced main pit 20 and excavation of the reverse main pit 30 proceed with a short time difference, the reinforcing structure of the wall pillar portion 11d of the center pillar 11 can be replaced and used. In such a case, for example, as shown in FIG. 3 (a), an advanced main pit 20 is provided by installing a structural steel assembly reinforcing member 15 on the backfill filler layer 13 backfilled to a predetermined height. It is possible to function as a reinforcing structure for suppressing deformation of the wall pillar portion 11d of the center pillar 11 during excavation. FIG. 3 shows a reinforcing structure of the wall pillar portion 11d of the center pillar 11 by placing the expanded polystyrene block structure 16 on the backfilling filler layer 13 and further laminating the upper backfilling material 17. is there. Also in this case, there is an advantage that the reinforcing members 15 and 16 can be replaced and used repeatedly in the reinforcing structure portion as the face of the advanced main pit 20 advances.

The tunnel sectional view showing the construction procedure of the reinforcement structure in the reverse main shaft side guide shaft of the advanced guide shaft of the eyeglass tunnel of the present invention. The tunnel sectional view which showed the excavation procedure of the advanced main shaft of the eyeglass tunnel of this invention, and a reverse main shaft. Tunnel sectional drawing which showed the modification of the reinforcement structure in a reverse main mine side guide shaft. The tunnel sectional view showing an example of the completed shape of the glasses tunnel. A tunnel sectional view showing an example of a center pillar in an advanced guide shaft for construction of a glasses tunnel. The tunnel sectional view which showed typically the deformation state of the wall pillar part of the center pillar at the time of excavation of an advanced main mine.

Explanation of symbols

10 Central advanced shaft 11 Center pillar 11d Wall pillar 13 Backfill filler layer 14 Concrete 20 Advanced main shaft 21 Arch support 30 Reverse main shaft

Claims (6)

  The reverse main shaft side of the above-mentioned advanced guide shaft of the glasses tunnel constructed as a shared support structure center pillar provided in advance in the advanced guide shaft located between the adjacent advanced main shaft and the reverse main shaft A reinforcing structure for a center pillar of a spectacle tunnel, wherein a reinforcing structure for a wall pillar portion of the center pillar is provided on a backfilling filler layer having a predetermined thickness in a shaft.   A center pillar is constructed in advance as a shared support structure in the advanced guiding pit located between the advanced main shaft and the reverse main shaft that are parallel to each other, and a predetermined thickness is embedded in the backward main shaft side guiding shaft of the advanced guiding mine. A back filler layer is formed, and a reinforcing structure for the wall pillar portion of the center pillar is provided thereon to excavate the advanced main shaft, and then the reinforcing structure for the reverse main shaft is removed. A construction method for a spectacle tunnel, wherein the reverse main shaft is excavated, an invert of the main shaft tunnel is excavated, and secondary lining of each main shaft tunnel is performed.   The reinforcement of the center pillar of the eyeglass tunnel according to claim 1, wherein a filling solidified body having a predetermined layer thickness is filled on the backfill filler layer as a reinforcing structure of the wall pillar portion of the center pillar. Construction.   The reinforcing structure of the center pillar of the eyeglass tunnel according to claim 1, wherein a steel assembly reinforcing member is installed on the backfill reinforcing portion as the reinforcing structure of the wall pillar portion of the center pillar.   The reinforcing structure of the center pillar of the eyeglass tunnel according to claim 1, wherein a foamed resin block structure is installed on the backfill filler layer as a reinforcing structure of the wall pillar portion of the center pillar.   The construction method of the eyeglass tunnel according to claim 2, wherein a filling solidified body having a predetermined layer thickness is filled on the backfilling filler layer as a reinforcing structure of the wall pillar portion of the center pillar.

Images