JP5550879B2 - How to build a tunnel - Google Patents

Description

  The present invention relates to a method for constructing a tunnel having a tunnel widening portion such as a junction, a branching portion, or an emergency parking zone such as a road tunnel.

  The present applicant has proposed a technique for constructing a widened portion in a tunnel cross section using a shield machine provided with a widening cutter that can protrude from the peripheral surface of the main body (see Patent Document 1).

  In addition, the present applicant has proposed a technology for constructing a junction between a main tunnel and a branch tunnel (see Patent Document 2). Specifically, in the section of the junction, the main tunnel and the branch tunnel are dug so as to be close to each other, and a substantially circular lining including a segment with a protrusion at the upper part and the lower part is assembled. Next, the projections of the segments with projections are extruded to form projections on the upper and lower portions of the main tunnel and the branch tunnel. Then, a steel shell is attached so as to be bridged between these protrusions, and the space between the steel shell and the lining is filled with a filler to integrate the lining of the main tunnel and the branch tunnel. And the envelope of the cross section of the lining consisting of the branch tunnel and steel shell is constructed so as to be almost circular. According to this, without cutting from the ground, it is not necessary to devise the shield machine, and it is possible to reduce their costs. In addition, the merging part of the shield tunnel can be constructed while using the merged main tunnel.

JP 2005-54528 A JP 2008-14076 A

  By the way, in order to bridge the steel shell between the protrusions of the main line tunnel and the branch line tunnel, it is necessary to excavate the ground between the main line tunnel and the branch line tunnel. Since the water pressure is high in the deep underground, ground improvement by the freezing method is most reliable.

  In the freezing method, as shown in FIG. 18, first, a pilot tunnel 11 is formed above and below the main tunnel 1 and the branch tunnel 5. Next, the freezing pipe 12 is installed in the ground from the pilot tunnel 11 toward the main tunnel 1 and the branch tunnel 5. Thereafter, the ground is frozen by circulating antifreeze through the freezing tube 12. Then, as shown in FIG. 18, the arch-shaped frozen ground 10 is formed up and down so as to straddle the main tunnel 1 and the branch tunnel 5. By forming the frozen ground 10 in an arch shape, it can withstand earth pressure and water pressure. By excavating the ground inside the arch-shaped frozen ground 10, a space necessary for installing the steel shell can be secured.

  However, since the freezing pipe 12 is installed in the ground from the pilot tunnel 11 toward the main tunnel and the branch tunnel, it is necessary to form the pilot tunnel 11 outside the arch-shaped frozen ground as shown in FIG. . For this reason, the temporary structure requires a height due to the pilot tunnel 11, and in order to form the temporary structure deep underground, it is necessary to form the main tunnel and the branch tunnel at a deeper position. Further, the periphery of the pilot tunnel 11 is not necessary to form an arch shape, and energy for freezing unnecessary portions is generated, and the construction cost is high.

  The subject of this invention is providing the construction method of the tunnel which can form the wide part of a tunnel, and a junction part at low cost.

In order to solve the above problems, the invention according to claim 1 is a tunnel construction method,
Only the upper and lower than the main tunnel and branch tunnel is substantially parallel to excavation, drilling one by one pilot tunnel substantially parallel to the main tunnel and the branch tunnel,
Next, a freezing pipe through which antifreeze is circulated is inserted in an arch shape from the pilot tunnel to the upper and lower grounds of the main tunnel and the branch tunnel.
Next, the pilot tunnel is filled with a filler,
Only the upper and lower ground of the main tunnel and the branch tunnel are frozen in an arch shape by circulating antifreeze through the freezing pipe, and then excavated in the ground between the linings of the main tunnel and the branch tunnel And excavating the ground on the outer peripheral side of the upper and lower segments of the main tunnel and the branch tunnel to form a cavity,
Thereafter, an upper connecting member is bridged between the upper segments of the main tunnel and the branch tunnel, and a lower connecting member is bridged between the lower segments of the main tunnel and the branch tunnel.

  According to the present invention, the widened portion and the merging portion of the tunnel can be formed at low cost.

The structure of one Embodiment to which this invention is applied is shown, and it is the schematic front view which showed the integrated lining of the tunnel merge part. FIG. 2 shows an extruded segment on the main line tunnel side of FIG. 1, and is a broken front view (a) and a bottom view (b) thereof, and an enlarged sectional view (c) of an arrow C part in FIG. FIG. 2 shows an extruded segment on the branch line tunnel side of FIG. 1, and is a broken front view (a) and a bottom view (b) thereof, and an enlarged sectional view (c) of an arrow C part in FIG. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the method of constructing the wide part of a tunnel. It is explanatory drawing which shows the conventional freezing construction method.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an integrated lining of a tunnel junction as a configuration of an embodiment to which the present invention is applied.

As shown in the drawing, the main tunnel 1 is covered with a general segment 2 on the opposite side to the ramp tunnel 5 and upper and lower extruded segments 3 at the tunnel junction.
The ramp tunnel 5, which is a branch tunnel that is dug almost parallel to the main tunnel 1, has a general segment 6 on the opposite side of the main tunnel 1 and upper and lower extruded segments 7. The

The upper and lower connecting members 9 are bridged between the upper and lower extrusion segments 3 of the main tunnel 1 and the upper and lower extrusion segments 7 of the ramp tunnel 5. The connecting member 9 has an arch shape as shown in the figure, and specifically includes a steel support 91 and a synthetic segment 92 inside thereof.
The connecting member 9 having an upper and lower arch shape, and the general segments 2 and 6 and the extruded segments 3 and 7 that are continuous on both sides of the connecting member 9 form an elliptical tunnel joining portion that is resistant to external pressure.

The extruded segment 3 of the main line tunnel 1 is made of steel, and as shown in FIG. 2, a box-shaped protruding portion 33 protrudes in the inner and outer peripheral directions into a rectangular opening 32 formed in a part of the middle portion of the segment body 31. It is fitted and assembled as possible.
The box-shaped projecting portion 33 is composed of an upper surface portion and four side surfaces, and has a thickness approximately double the thickness of the segment main body 31. Like the segment main body 31, the box-shaped protruding portion 33 has reinforcing ribs 34 inside. . The box-shaped projecting portion 33 is temporarily assembled to the segment main body 31 with the temporary fixing bolt 35 abutting against the small recess 36 in the opening 32 in a state where the outer peripheral surface of the box main body 31 is substantially flush with the segment main body 31. In this temporarily assembled state, a bolt hole 37 for the actual assembly at the time of completion of extrusion is formed in a portion of the box-shaped projecting portion 33 projecting from the segment body 31 to the inner peripheral side.

The extruded segment 7 of the lamp tunnel 5 is made of steel, and, as shown in FIG. 3, a box-shaped protruding portion 73 protrudes in the inner and outer peripheral directions into a rectangular opening 72 formed in a part of the middle portion of the segment main body 71. It is fitted and assembled as possible.
The box-shaped projecting portion 73 is composed of an upper surface portion and four side surfaces, and has a thickness approximately double the thickness of the segment main body 71. Like the segment main body 71, the box-shaped protrusion 73 has reinforcing ribs 74 inside. . The box-shaped projecting portion 73 is temporarily assembled to the segment main body 71 by abutting the temporary fixing bolt 75 against the small recess 76 in the opening 72 in a state where the outer peripheral surface is substantially flush with the segment main body 71. In this temporarily assembled state, a bolt hole 77 is formed in the portion of the box-shaped protruding portion 73 that protrudes from the segment main body 71 toward the inner peripheral side when the extrusion is completed.

  On the outside of the upper and lower connecting members 9, frozen grounds 10 and 10 having a substantially arched cross section are formed so as to straddle the main tunnel 1 and the ramp tunnel 5 by a freezing method at the time of construction. Specifically, pilot tunnels 11 and 11 are formed outside the upper and lower connecting members 9. A freezing tube 12 is inserted from the pilot tunnels 11, 11 toward the main segments 2 and 6 of the main tunnel 1 and the ramp tunnel 5. The pilot tunnels 11 and 11 are filled with a filler 13. The antifreeze is circulated through the freezing pipe 12 and the surrounding ground is cooled, so that frozen grounds 10 and 10 having a substantially arched cross section are formed.

Next, a method for constructing the widened portion of the tunnel will be described with reference to FIGS.
First, as shown in FIG. 4, the main tunnel 1 is formed in the ground. At this time, the main tunnel is formed from the general segment 2, the extruded segment 3, and the cutting segment 4. The cutting segment 4 may be thinner than the general segment 2 and the extruded segment 3. The cutting segment 4 is made of a material that can be excavated by a cutter of a shield excavator that excavates the ramp tunnel 5.
Next, in the extrusion segment 3, the box-shaped protrusion 33 is pushed out to the outer peripheral side by using an extrusion device such as a hydraulic unit (not shown).
Then, after the extrusion of the box-shaped projecting portion 33 is completed, the box-shaped projecting portion 33 is assembled to the peripheral wall of the opening 32 of the segment main body 31 in a bolt hole 37 in a fixed state with a bolt. Next, the partition segment 14 is installed between the upper and lower extruded segments 3.

  Next, as shown in FIG. 5, an internal support 15 is installed in the space between the partition wall segment 14 and the general segment 2. Next, the backfill material 16 is backfilled into the space between the partition wall segment 14 and the cutting segment 4.

Next, as shown in FIG. 6, the ramp tunnel 5 is formed in the ground. At this time, the ramp tunnel 5 is formed from the general segment 6, the extrusion segment 7, and the removal segment 8.
The cutting segment 4 is cut by a cutter of a shield excavator that excavates the ramp tunnel 5.

Next, in the extrusion segment 7, the box-shaped protrusion 73 is pushed out to the outer peripheral side using an extrusion device such as a hydraulic unit (not shown).
Prior to this extrusion, the temporary fixing bolt 75 is removed beforehand. After the extrusion of the box-shaped protrusion 73 is completed, the box-shaped protrusion 73 is assembled to the peripheral wall of the opening 72 of the segment body 71 in a bolt hole 77 in a fixed state with a bolt.

Next, as shown in FIG. 7, a shield excavator for the pilot tunnels 11, 11 is started from the ramp tunnel 5 to form the pilot tunnels 11, 11.
Next, as shown in FIG. 8, the freezing tube 12 is inserted into the ground from the pilot tunnels 11 and 11 toward the main segments 1 and 6 of the main tunnel 1 and the ramp tunnel 5. Thereafter, the filler 13 is filled into the pilot tunnels 11 and 11. Next, the ground is frozen by circulating antifreeze through the freezing tube 12. Then, as shown in FIG. 8, the arch-shaped frozen ground 10 is formed up and down so as to straddle the main tunnel and the branch tunnel. Since the pilot tunnels 11 and 11 are filled with the filler 13, the pilot tunnels 11 and 11 form an arch with the frozen ground 10. For this reason, it is possible to withstand earth pressure and water pressure when excavating the ground inside the frozen ground 10 in the subsequent steps. Thereafter, the circulation of the antifreeze liquid is circulated until the widened portion of the tunnel is completed, and the ground is continuously cooled.
Next, an internal support 18 is also installed inside the lamp tunnel 5.

  Next, as shown in FIG. 9, a work gantry 17 is installed inside the lamp tunnel 5. Then, a part of the upper removal segment 8 is removed. Next, as shown in FIG. 10, the upper ground between the linings of the main tunnel 1 and the ramp tunnel 5 is excavated to form a cavity. At this time, since the arch-shaped frozen ground 10 is formed, the ground can be excavated by bare digging. In addition, the part which removed the segment 8 for removal becomes an entrance / exit to a cavity part.

  Next, as shown in FIG. 11, a steel support 91 is formed by a long steel pipe fore-piling work or the like at the ceiling of the excavated upper cavity. Next, as shown in FIG. 12, a synthetic segment 92 is attached to the lower part of the steel support 91. Next, as shown in FIG. 13, the support 19 that supports the composite segment 92 is assembled. Next, concrete 93 is placed between the composite segment 92 and the box-shaped protrusions 33 and 73.

  Thereafter, as shown in FIG. 14, the support 19, the backfill material 16 between the removal segment 8 and the partition segment 14 is removed. Further, as shown in FIGS. 15 and 16, the ground between the removal segment 8 and the cutting segment 4 is excavated and the cutting segment is removed. Then, an internal support 20 is installed between the removal segment 8 and the partition wall segment 14.

  Next, as shown in FIG. 17, the steel support 91 is formed also by the long steel pipe fore-pyring construction etc. also in the bottom part of the hollow part excavated. Next, the synthetic segment 92 is attached to the upper part of the steel support 91. Next, concrete 93 is placed between the composite segment 92 and the box-shaped protrusions 33 and 73.

Thereafter, the internal support members 15, 18, 20, the removal segment 8 and the partition segment 14 are completely removed. Thus, the widened portion of the tunnel is constructed as shown in FIG.
As described above, by providing the frozen ground 10 having a substantially arched cross section on the ground outside the position where the upper and lower connecting members 9 are formed, when excavating the ground in the portion inside the frozen ground 10, Can withstand pressure and water pressure.

  Moreover, since the inside of the pilot tunnels 11 and 11 is filled with the filler 13, and the pilot tunnels 11 and 11 form an arch with the frozen ground 10, the height of the temporary structure can be suppressed. Further, since the portion unnecessary for forming the arch-shaped frozen ground 10 is not frozen, there is no waste of energy, the construction period can be shortened, and the construction cost can be kept low.

1 Main tunnel 2, 6 General segment 3, 7 Extrusion segment 4, 8 Removal segment 5 Branch line tunnel 9 Connecting member 10 Frozen ground 11 Pilot tunnel 12 Freezing pipe 13 Filler 14 Bulkhead segments 15, 18, 19 Internal support 16 Back Filling material 17 Work gantry 31, 71 Segment main body 32, 72 Opening 33, 73 Box-shaped protrusion 34, 74 Reinforcing rib 35, 75 Temporary fixing bolt 36, 76 Small recess 37, 77 Bolt hole 91 Steel support 92 Synthesis segment

Claims (1)

Only the upper and lower than the main tunnel and branch tunnel is substantially parallel to excavation, drilling one by one pilot tunnel substantially parallel to the main tunnel and the branch tunnel,
Next, a freezing pipe through which antifreeze is circulated is inserted in an arch shape from the pilot tunnel to the upper and lower grounds of the main tunnel and the branch tunnel.
Next, the pilot tunnel is filled with a filler,
Only the upper and lower ground of the main tunnel and the branch tunnel are frozen in an arch shape by circulating antifreeze through the freezing pipe, and then excavated in the ground between the linings of the main tunnel and the branch tunnel And excavating the ground on the outer peripheral side of the upper and lower segments of the main tunnel and the branch tunnel to form a cavity,
Thereafter, an upper connecting member is bridged between the upper segments of the main tunnel and the branch tunnel, and a lower connecting member is bridged between the lower segments of the main tunnel and the branch tunnel. How to build.

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