Construction method for guide pilot tunnel and steel protective shelter structure

Abstract

To provide a construction method for a guide pilot tunnel which can be easily, quickly and safely constructed.SOLUTION: A steel protective shelter consisting of a front cutting edge section, a propulsion jack installation section, and a support assembly section is used. Both the steel protective shelter and the support have an outer periphery in a lotus petal or horseshoe shape. The support is of a half-assembly type having this lotus petal or horseshoe shape. The front cutting edge section of the steel protective shelter is used to excavate, the steel protective shelter is propelled by the propulsion jack in the propulsion jack installation section, and the support is assembled in the support assembly section of the steel protective shelter. This process is repeated to gradually extend the support.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a construction method for a guide pilot tunnel, which is a small tunnel excavated at a location that will become the base of the tunnel prior to the construction of a tunnel such as a box culvert located directly beneath a railway or road. [Background technology]

[0002] Guide pilot tunnels are also shown in the following patent documents, and as shown in Figure 15, a protective pipe roof 3 is constructed between a departure shaft 21 and an arrival shaft 22, and a guide pilot tunnel 6 is excavated at a position that will become the bottom slab of the tunnel. [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-242582

[0003] The guide tunnel 6 can be constructed by a known tunnel excavation method. For example, a tunnel can be constructed by the sheet pile method, repeating the steps of assembling support structures, erecting sheet piles, excavating, and assembling support structures.

[0004] The concrete box 5 is constructed inside the departure shaft 21, and a frame member 8, which serves as a back frame, is attached to the end of the concrete box 5 opposite the excavation direction, i.e., the rear end. In addition to constructing such a concrete box 5 as a cast-in-place reinforced concrete box, it may also be constructed as a precast factory-made concrete box or a steel segment box.

[0005] One end of the traction member 71 is fixed to a fixed point 91 provided on the arrival shaft 22 side, for example, and the other end is attached to the frame material 8 via a traction jack 73.

[0006] The traction member 72 installed below the tunnel is inserted into the guide pit 6. Like the traction member 71 installed above, the traction member 72 installed below has one end fixed to a fixed point 92 and the other end attached to the frame material 8 via a traction jack 73.

[0007] Concrete box 5 Guide tunnel construction groundThe concrete box body 5 is towed by a combination of digging with an excavator or the like at the front of the concrete box body 5 (the surface in contact with the ground) and towing the concrete box body 5 by operating a jack 73.

[0008] The above has been explained in the case of the towing method, but a pushing method is also possible. As shown in Figure 16, a pushing jack 74 is installed in the starting shaft 21, and the concrete box body 5 is pushed forward using this pushing jack 74. Prior to this, a box-shaped roof 76 is installed in place of the protective pipe roof 3.

[0009] The box-shaped roof 76 has small jacks 77 housed in jack housing pipes at the base, and as each jack is used to excavate the concrete box 5 using the reaction force, the concrete box 5 is excavated.

[0010] In the figure, reference numeral 75 denotes a reaction wall provided in the departure shaft 21, and 78 denotes a support for the box-shaped roof 76 provided in the arrival shaft 22. Summary of the Invention [Problem to be solved by the invention]

[0011] As mentioned above, the guide tunnel 6 is constructed by a known tunnel excavation method, and the steel support is erected by the sheet pile method. Guide tunnel The sheet pile method is a method of supporting the excavated ground with steel supports and sheet piles, and after excavation and removal of debris, the supports are erected. However, this method requires an exposed section of about 1m for the steel supports without sheet piles. back ground Generally, chemical injection work and other ground improvement works are carried out below the back ground Although reinforcement was carried out, the workability and safety were lacking.

[0012] The object of the present invention is to provide a method for constructing a guide tunnel and a steel protective shelter structure that can eliminate the disadvantages of the above-mentioned conventional examples and can be constructed easily, quickly, and safely. [Means for solving the problem]

[0013] In order to achieve the above object, the present invention as set forth in claim 1 comprises: To prevent the face from collapsing, a tapered hood was formed so that the top of the tip protrudes. A steel protective shelter consisting of a front cutting edge section, a propulsion jack installation section, and a support assembly section is used, and both the steel protective shelter and the support have the outer periphery of a lotus petal or horseshoe shape, and the support is a half-assembled type with this lotus petal or horseshoe shape.The gist is that the front cutting edge section of the steel protective shelter is used to excavate, the steel protective shelter is propelled with the propulsion jack in the propulsion jack installation section, and the support is assembled in the support assembly section of the steel protective shelter, and this process is repeated to gradually extend the support.

[0014] According to the present invention described in claim 1, a guide tunnel is constructed using a steel protective shelter consisting of a front cutting edge section, a thrust jack installation section, and a support assembly section, and since the support can be assembled using the support assembly section of the steel protective shelter, construction can be carried out safely and quickly.

[0015] Furthermore, both the steel protective shelter and the support have a lotus petal or horseshoe-shaped outer periphery, and the support can be easily assembled at the support assembly section of the steel protective shelter.

[0016] The present invention described in claim 2 is a half-assembled type support structure with an outer shape resembling a lotus petal or a horseshoe, in which one side is erected first, used as a temporary support, and then the other side is erected and the tops are bolted together to form a ring.

[0017] According to the present invention described in claim 2, the supports can be easily assembled in the support assembly section of the steel protective shelter, and the supports can be assembled more safely by first erecting one side, temporarily supporting it, and then erecting the other side and bolting the tops together to form a ring.

[0018] The present invention as defined in claim 3 is By forming a tapered hood, the amount of over-excavation is reduced, and by advancing the cutting edge and the steel protective shelter as a single unit without erecting shoring at the face in front of the cutting edge, the area behind the shelter where the ground is exposed is significantly reduced. The gist of this is that

[0019] According to the present invention as set forth in claim 3, by sequentially advancing the steel protective shelter in accordance with the excavation, Back of guide tunnel becomes ground The exposed section is limited to about 0.2 m, allowing for safe excavation of the face.

[0020] The present invention as set forth in claim 4 is The construction method of the guide tunnel of claim 1 It is a steel protective shelter to be used, It is shaped like a lotus petal or horseshoe, tapering at the tip. The cutting edge section, the propulsion jack installation section, and the support assembly section are assembled with bolts to create a three-part structure, with the support assembly section only having a base plate at the front, and the rear half being open underneath.

[0021] According to the present invention as set forth in claim 4, the steel protective shelter is By tapering the tip in a lotus petal shape, the strength of the tip can be increased, improving digging performance.

[0022] In addition, the support assembly section has a bottom slab only at the front, while the rear half is open at the bottom, exposing the ground. The support can be assembled in the rear part of the shelter where the ground is exposed. In order to ensure space for support assembly, no reinforcing members are provided in the support assembly section, and removable reinforcing materials with jacks incorporated in some parts can be placed as support beams to prevent deformation. This narrows the gap between the inner surface of the steel protective shelter and the support, making it possible to reduce the amount of backfill injected, ensuring safety during excavation and improving workability.

[0023] By installing removable reinforcement materials in the support assembly area inside the steel protection shelter, deformation of the steel protection shelter due to earth pressure in the guide tunnel can be suppressed without installing reinforcement materials, and the support can be assembled close to the inner surface of the steel protection shelter, so the backfill thickness can be about 50 mm. ground This minimizes excavation and reduces the amount of backfill injection. [Effects of the Invention]

[0024] As described above, the guide pilot tunnel construction method and steel protective shelter structure of the present invention enable the construction of guide pilot tunnels easily, quickly, and safely. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a vertical cross-sectional side view showing one embodiment of a guide pilot tunnel construction method of the present invention. [Figure 2] 1 is a longitudinal sectional side view showing an excavation state illustrating one embodiment of a guide pilot tunnel construction method of the present invention. [Figure 3] This is a longitudinal side view of the front cutting edge of the steel protective shelter. [Figure 4] This is a vertical cross-sectional side view of the propulsion jack installation section of the steel protective shelter. [Figure 5] This is a longitudinal side view of the support assembly part of the steel protective shelter. [Figure 6] FIG. 4 is a view taken along the line A in FIG. 3. [Figure 7] FIG. 5 is a view taken along the line B in FIG. 4. [Figure 8] FIG. 6 is a view taken along the line C in FIG. 5. [Figure 9] FIG. 1 is a cross-sectional plan view of a completed form showing one embodiment of a guide pilot tunnel construction method of the present invention. [Figure 10] This is a front view of the first step showing the procedure for erecting support structures. [Figure 11] This is a front view of the second step showing the procedure for erecting the support structure. [Figure 12] This is a front view of the third step showing the procedure for erecting support structures. [Figure 13] This is a front view of the fourth step showing the procedure for erecting support structures. [Figure 14] This is a front view of wooden sheet piles installed on the support structure. [Figure 15] FIG. 2 is a vertical cross-sectional side view showing an example of a guide tunnel. [Figure 16] FIG. 10 is a vertical cross-sectional side view showing another example of a guide tunnel. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Figure 1 is a vertical cross-sectional side view showing one embodiment of the guide pilot tunnel construction method of the present invention, in which 21 is a starting shaft and 2 is a steel protective shelter.

[0027] The construction method of the present invention uses a steel protective shelter 2 for constructing a guide tunnel, and the steel protective shelter 2 is a steel shell with an outer periphery having a cross section shaped like a lotus petal or a horseshoe.

[0028] The steel protective shelter 2 can also be divided to make installation and removal easier. This figure shows a structure divided into three parts: a front cutting edge section 2a, a propulsion jack installation section 2b, and a support assembly section 2c, which are assembled using flange bolts or the like.

[0029] Of these, the front cutting edge 2a has an upward facing tip to prevent the face from collapsing, as shown in Figure 3. tension The tapered hood allows for excavation with a slope at the face.

[0030] Also, By forming a tapered hood, the amount of over-excavation is reduced, and by advancing the cutting edge and the steel protective shelter as a single unit without erecting shoring at the face in front of the cutting edge, the section where the guide drift ground is exposed behind the shelter is significantly reduced. It is possible.

[0031] The propulsion jack installation section 2b has four installation stands 7 for the propulsion jacks 4 provided inside as horizontal brackets.

[0032] Both the front cutting edge section 2a and the propulsion jack installation section 2b are closed-type steel shells with a bottom plate 9, while the support assembly section 2c has a bottom plate only at the front and is open at the bottom at the rear rear half, exposing the ground. The support, described below, is assembled at this exposed ground.

[0033] Additionally, in order to ensure space for assembling the support, no reinforcing members 8 are provided in the support assembly section 2c, but removable reinforcing members 10 incorporating jacks can be placed as support beams to prevent deformation. This narrows the gap between the inner surface of the steel protective shelter and the support, reducing the amount of backfill injected.

[0034] Furthermore, lighting (LED) 11a and lighting (fluorescent lamp) 11b were installed inside the steel protective shelter 2.

[0035] A thrust reaction body 12 is formed from steel and brackets in the departure shaft 21, and the steel protective shelter 2 is excavated in sequence with struts (for thrust construction) 13 interposed between them. This excavation is carried out by digging the face of the front cutting edge part 2a by hand or with a small backhoe or shaft loader, the excavated earth and sand are sent rearward with a trolley 17, the thrust jack 4 is extended to excavate the steel protective shelter 2, and the struts 13 are added to the empty space created by retracting the thrust jack 4.

[0036] The shoring 14 is assembled in the shoring assembly section 2c of the steel protective shelter 2. This allows the shoring to be assembled in a space protected by the steel protective shelter, enabling safe shoring assembly. When assembled, the shoring 14 has an outer periphery shaped like a lotus petal or horseshoe, just like the steel protective shelter 2, and is a combination of shoring material 14a and shoring material 14b that curve together to form a shoring ring.

[0037] Figures 10 to 13 show the procedure for erecting this support 14, with one support material 14a being erected first at the support assembly section 2c of the steel protective shelter 2, and this being temporarily supported by a temporary support material 15 such as a pipe, and then the other support material 14b is erected and the tops are bolted together, and struts (support materials) 16 are placed across the bottom ends to form a ring.

[0038] The supports 14 are arranged at intervals, and wooden sheet piles 18 are attached to the outside as shown in Figure 13. The wooden sheet piles 18 arranged at the top are equipped with packers 19.

[0039] The steel protective shelter 2 was excavated in stages, ground The section where the tunnel is exposed is limited to about 0.2 m, so that excavation can be carried out while suppressing collapse of the ground of the tunnel, and backfill material 20 is injected through the gaps in the wooden sheet piles 18 of the support 14 protruding from the support assembly part 2 c of the steel protective shelter 2.

[0040] The timing for excavating the steel protective shelter 2 and assembling the shoring 14 is as follows: once two rings of shoring 14 have been constructed and some of the wooden sheet piles 18 have been placed, the steel protective shelter 2 is excavated; once the shoring 14 has emerged from the shoring assembly section 2c of the steel protective shelter 2, the remaining wooden sheet piles 18 are placed and backfill material 20 is injected.

[0041] Instead of injecting the backfill material 20, backfill soil may be used to fill the gap.

[0042] In this way, as the steel protective shelter 2 is excavated, the support structure is gradually extended and a guide tunnel is constructed.

[0043] In addition, the front cutting edge is advanced by gradually inserting a steel protective shelter according to the excavation. Ground behind the guide tunnel This will significantly reduce the areas where the equipment is exposed.

[0044] This will allow the construction of steel protective shelters to be advanced in stages as the excavation progresses. Guide tunnel becomes back ground The exposed section is limited to about 0.2 m, allowing for safe excavation of the face.

[0045] In addition, the back of the support and Ground behind the guide tunnel gap of As a result, by installing removable reinforcement materials in the support assembly area inside the steel protective shelter, deformation of the steel pilotage shelter due to earth pressure on the guide pilotage can be suppressed without installing reinforcement members, and because the support can be assembled close to the inside of the steel protective shelter, the backfill thickness can be kept to around 50 mm, minimizing excavation of the ground and reducing the amount of backfill injection.

[0046] The completed form is shown in Figure 9, and once the steel protective shelter 2 reaches the arrival shaft 22, it is retrieved. [Explanation of symbols]

[0047] 1… Guide tunnel construction ground 2...Steel protective shelter 2a…Front edge part 2b…Propulsion jack installation part 2c...Shoring assembly section 3...Protective pipe roof 4...Pushing jack 5...Concrete box 6... Guide tunnel 7... Jack support member 8...Frame material 9...Bottom plate 10...Detachable reinforcement 11a...Lighting (LED) 11b...Lighting (fluorescent lamp) 12...Propulsion reaction body 13...Strut (for tunneling work) 14...Support 14a…Shoring material 14b…Shoring material 15...Temporary support material 16...Strut (support material) 17... Cart 18... Wooden board 19...Packer 20...Backfill material 21...Departure shaft 22...Arrival shaft 71, 72... Towing member 73... Towing jack 74...Propulsion jack 75...Reaction wall 76...Box roof 77...Small jack 78…Cradle

Claims

1. A guide tunnel construction method characterized by using a steel protective shelter consisting of a front cutting edge section, a thrust jack installation section, and a support assembly section, where the steel protective shelter and the support both have the outer periphery of a lotus petal or horseshoe shape, and the support is a half-assembled type with this lotus petal or horseshoe shape, and by repeating the process of excavating with the front cutting edge section of the steel protective shelter, thrusting the steel protective shelter with the thrust jack in the thrust jack installation section, and assembling the support in the support assembly section of the steel protective shelter, the support is gradually extended.

2. A construction method for a guide tunnel as described in claim 1, in which one half of a half-assembled support structure with a lotus petal or horseshoe-shaped outer shape is erected first, used as a temporary support, and then the other half is erected and the tops are bolted together to form a ring.

3. A construction method for a guide tunnel as claimed in claim 1 or claim 2, in which the steel protective shelter is advanced in sequence as the front cutting edge portion is excavated, thereby significantly reducing the section in which the ground behind the tunnel is exposed.

4. This is a steel protective shelter used in the construction of guide tunnels. The steel protective shelter is divided into three parts by assembling the cutting edge section, the thrust jack installation section, and the support assembly section with bolt connections. The support assembly section has a bottom plate only at the front, and the rear half is open at the bottom, exposing the ground. The support is assembled at this exposed point. The support assembly section is not equipped with reinforcing members to ensure space for support assembly, and removable reinforcing members with jacks incorporated in some parts can be placed as support beams to prevent deformation. This narrows the gap between the inner surface of the steel protective shelter and the support, making it possible to reduce the amount of backfill injected. This is a steel protective shelter structure characterized by this.

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