Method for constructing underground structure

Abstract

To provide a method of constructing an underground structure, etc., which can easily construct the underground structure.SOLUTION: A tunnel is constructed by a process of constructing a bottom plate 8, a side wall 9, and a bulkhead 10 of the tunnel in an excavation part 15 of the ground 1, and a process of constructing a top plate of the tunnel using the formwork support 11 placed on the bottom plate 8 of the excavation part 15. In this process, a replacement beam 12 is placed on the formwork support 11, and a contacting member 13, which is fixed to the tip of the replacement beam 12 and extends in the direction of extension of the side wall 9, is brought into contact with the side wall 9, and the side pressure of the ground 1 acting on the side wall 9 is supported by the replacement beam 12.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for constructing an underground structure and a shoring structure used therefor.

Background Art

[0002] As a method for constructing an underground structure in the ground below a road or the like, there is an excavation method in which the ground is excavated from the ground surface and an underground structure is constructed in the excavation part. In the excavation method, retaining walls are installed on both sides of the planned excavation location of the ground, and the ground is excavated between the retaining walls. At this time, by providing a cross beam between the retaining walls, the lateral pressure of the ground acting on the retaining walls is supported by the cross beam.

[0003] In this state, the bottom plate and side walls of the underground structure are constructed in order from the bottom in the excavation part. The cross beam is removed as the underground structure is constructed. However, when the lateral pressure of the ground becomes a problem, a replacement beam is installed between the constructed side walls, and the lateral pressure of the ground acting on the side walls through the retaining walls or the like is supported by the replacement beam (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using a replacement beam, a temporary anchor is driven into the side wall of the underground structure to attach a bracket, a web is installed on the bracket, and the tip of the replacement beam is fixed to the web. However, such work is time-consuming. In addition, there is also a problem that forming holes for driving anchors into the side walls impairs the quality and aesthetics of the underground structure.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a method for constructing an underground structure that can easily construct an underground structure. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a method for constructing a pair of retaining walls on both sides of a planned excavation site of the ground, excavating the ground between the pair of retaining walls, and supporting the lateral pressure of the ground acting on the retaining walls by a brace bridged between the pair of retaining walls; It is a tunnel The side walls on both sides of the main body of the underground structure are aligned along the pair of earth retaining walls, and are vertically aligned from bottom to top. On the bottom plate of the main body of the housing and a step (c) of supporting the formwork for constructing the top slab with a formwork support having a configuration in which a horizontal member is connected midway in the height direction of a vertical member, the formwork support being provided between the side walls on both sides up to the height of the top slab of the main body of the underground structure, which is the upper part of the side walls, and constructing the top slab with concrete using the formwork. In the step (b), a horizontal temporary beam is placed on the horizontal member of the formwork support between the side walls on both sides in a vertical plane, and the temporary beam is attached to the formwork support. and after fixing a contact member extending in the extension direction of the side walls to the tip of one of the side walls of the temporary beam, an expandable member provided midway in the longitudinal direction of the temporary beam is extended to bring the contact member into contact with the head of the constructed portion of one of the side walls, and an axial force is introduced to the temporary beam by taking a reaction force from the constructed portion of the other side wall or the constructed portion of the partition wall constructed between the side walls on both sides, and the lateral pressure of the ground acting on the constructed portion of one of the side walls via the retaining wall is supported by the temporary beam. After constructing the top plate using the formwork support, the formwork support is moved on the bottom plate in the extending direction of the tunnel to the next construction section of the tunnel, and the lateral pressure of the ground acting on the side wall of the construction section is supported by the temporary beam The present invention relates to a method for constructing an underground structure.

[0008] ThisIn the invention, a temporary beam with a contact member attached to its tip and extending in the extending direction of the side wall of the underground structure supports the lateral pressure of the ground acting on the side wall of the underground structure. Since the temporary beam is placed on the formwork support and the contact member is fixed to the tip of the temporary beam, the temporary beam and the contact member can be installed without attaching brackets or the like to the side wall, facilitating the construction of the underground structure and not impairing the quality and aesthetics.

[0009] It is desirable that the temporary beam be divisible in the longitudinal direction. Thereby, each part obtained by dividing the temporary beam can be stored in the formwork support, and the temporary beam can be easily disassembled and assembled on the formwork support.

[0010] It is desirable that a plurality of the temporary beams be provided at intervals in the extending direction of the side wall, and that the contact member be provided for each of the temporary beams. By making the contact member a short one provided for each temporary beam, an excessive eccentric load is not applied to the formwork support when storing the temporary beam, preventing the formwork support from tipping over.

[0011] In the present invention After constructing the top slab using the formwork support, the formwork support is moved to the next construction section of the underground structure, and the lateral pressure of the ground acting on the side wall of the construction section is supported by the temporary beam. To do Thereby, the temporary beam, the contact member, and the formwork support can be collectively moved to the next construction section and reused.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide a construction method of an underground structure that can easily construct the underground structure.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiment for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0016] In the present embodiment, an example of constructing a concrete tunnel as an underground structure by excavating the ground below a road or the like will be described. Here, first, as shown in Fig. 1(a), a pair of earth retaining walls 2 are constructed on both sides of the planned excavation location of the ground 1, and intermediate piles 3 are driven into the ground 1 between the earth retaining walls 2. The earth retaining walls 2 are, for example, soil-cement wall bodies, but are not limited thereto, and various known wall bodies can be used.

[0017] Also, the ground 1 between the earth retaining walls 2 is shallowly excavated, and upper diaphragms 4 are installed inside both earth retaining walls 2. Steel materials such as H-shaped steel are used for the diaphragms 4, for example. The diaphragms 4 are installed on brackets 21 fixed inside the earth retaining walls 2 and are arranged along the extending direction of the earth retaining walls 2 (corresponding to the normal direction of the paper surface in Fig. 1(a)).

[0018] Furthermore, a bearing girder 6 is spanned between the tops of both earth retaining walls 2, and a covering board 7 is installed on the bearing girder 6. The covering board 7 is provided to ensure traffic on the excavation part 15.

[0019] In the present embodiment, a reaction force receiving member 17 is fixed to the lower surface of the bearing girder 6, and the reaction force receiving member 17 and the diaphragm 4 are connected via a jack 18. Thereby, the lateral pressure of the ground 1 acting on the earth retaining wall 2 can be transmitted to the bearing girder 6 via the reaction force receiving member 17, and the bearing girder 6 functions as an upper cutting beam that supports the lateral pressure. Steel materials such as H-shaped steel are used for the bearing girder 6, for example.

[0020] After that, as shown in FIG. 1(b), excavation of the ground 1 between the retaining walls 2 is advanced, and the lower abdominal reinforcements 4 are provided inside both retaining walls 2 in the same manner as described above. Then, a cross beam 5 is installed between the lower abdominal reinforcements 4. Steel materials such as H-shaped steel are used for the cross beam 5.

[0021] Next, as shown in FIG. 2(a), a tunnel bottom slab 8 is constructed on the bottom surface of the excavation part 15 between both retaining walls 2. After the concrete of the bottom slab 8 has sufficiently hardened, the lower abdominal reinforcements 4, the cross beam 5, etc. are removed.

[0022] After that, as shown in FIG. 2(b), tunnel side walls 9 are constructed on the bottom slab 8 at positions along both retaining walls 2 on both sides of the bottom slab 8. Also, between both side walls 9, a tunnel partition wall 10 is constructed on the bottom slab 8.

[0023] In this embodiment, in order to construct the tunnel top slab which is the upper part of these wall bodies, as shown in FIG. 3(a), a formwork support structure 11 is assembled on the bottom slab 8 of the excavation part 15. The formwork support structure 11 is for supporting a formwork (not shown) during the construction of the top slab, and is provided by being divided on both sides thereof while avoiding the positions of the intermediate piles 3 between each side wall 9 and the partition wall 10.

[0024] Also, a replacement beam 12 (temporary beam) in the tunnel width direction (corresponding to the left - right direction in FIG. 3(a)) is assembled between each side wall 9 and the partition wall 10 so as to be arranged straddling the formwork support structures 11, 11 on both sides of the intermediate pile 3.

[0025] Steel materials such as H-shaped steel are used for the replacement beam 12, and its longitudinal direction can be divided at the dividing part 121. The replacement beam 12 is composed of connecting the respective parts divided at the dividing part 121, and a jack 122 is provided in the middle of the longitudinal direction of the replacement beam 12. The jack 122 is a telescopic member that expands and contracts in the longitudinal direction of the replacement beam 12. The replacement beam 12 is carried into the formwork support structure 11 in a divided state at the dividing part 121 and assembled on the formwork support structure 11.

[0026] In this embodiment, as shown in Fig. 3(b), abutting members 13 that abut against the side wall 9 and the partition wall 10 are fixed to both ends of the replacement beam 12.

[0027] When the concrete of the side wall 9 and the partition wall 10 has sufficiently hardened, the jack 122 is extended, and the abutting members 13 at both ends are brought into contact with the side wall 9 and the partition wall 10 respectively to introduce axial force into the replacement beam 12.

[0028] Fig. 4 is a diagram showing a horizontal cross-section along line A-A in Fig. 3(b). As shown in Fig. 4, the abutting member 13 is a short member extending in the extending direction of the side wall 9 (corresponding to the vertical direction in Fig. 4), and a steel material such as H-shaped steel is used. A plurality of replacement beams 12 are provided at intervals in the extending direction of the side wall 9, and the central portion of the abutting member 13 is fixed to the tip of each replacement beam 12.

[0029] Thereby, a shoring structure is formed in which the I-shaped replacement beam 12 and the abutting member 13 are placed on the formwork shoring 11. The lateral pressure of the ground 1 acts on the side wall 9 via the earth retaining wall 2, and the replacement beam 12 functions as a crossbeam to support this lateral pressure. The replacement beam 12 is placed on the formwork shoring 11, and the self-weight of the replacement beam 12 is supported by the formwork shoring 11.

[0030] Thereafter, the covering plate 7, the receiving girder 6, the upper web girder 4, the jack 18, etc. are removed, and while supporting the lateral pressure of the ground 1 by the replacement beam 12, the tunnel roof slab 14 is constructed using the formwork shoring 11 as shown in Fig. 5(a).

[0031] After the concrete of the roof slab 14 has sufficiently hardened, the jack 122 is contracted to release the axial force of the replacement beam 12. Also, the replacement beam 12 is divided at the position of the dividing portion 121 and placed on the formwork shoring 11, and the formwork shoring 11 is moved to the next construction section (see reference symbol B in Fig. 4) where the construction of the bottom slab 8 and the side wall 9 is completed. Then, as shown in Fig. 5(b), the ground 1 on the roof slab 14 is backfilled.

[0032] The tunnel is constructed by dividing it into a plurality of construction sections. Even in the next construction section, each process described with reference to FIGS. 2 to 5 is carried out with a time lag. Therefore, if the formwork support 11 is moved on the base plate 8, the installation of the formwork support 11 in the next construction section is completed, and the replacement beam 12 and the contact member 13 can be diverted for construction in the next construction section, and the lateral pressure of the ground 1 acting on the side wall 9 of the construction section can be supported by the replacement beam 12.

[0033] Thus, in the present embodiment, the replacement beam 12 having the contact member 13 attached to its tip and extending in the extending direction of the side wall 9 of the tunnel supports the lateral pressure of the ground 1 acting on the side wall 9. Since the replacement beam 12 is placed on the formwork support 11 and the contact member 13 is fixed to the tip of the replacement beam 12, the replacement beam 12 and the contact member 13 can be installed without attaching brackets or the like to the side wall 9, facilitating the construction of the tunnel without impairing the quality and aesthetics.

[0034] Also, in the present embodiment, since the replacement beam 12 can be divided at the dividing portion 121, each part of the divided replacement beam 12 can be stored in the formwork support 11, and the replacement beam 12 can be easily disassembled and assembled on the formwork support 11.

[0035] After the replacement beam 12 is used, by moving the formwork support 11 to the next construction section, the replacement beam 12, the contact member 13, and the formwork support 11 can be moved and diverted to the next construction section all together. By previously dividing the replacement beam 12 on the formwork support 11, the replacement beam 12 does not interfere with the intermediate pile 3 when the formwork support 11 is moved.

[0036] Also, in the present embodiment, the contact member 13 is provided as a short one for each replacement beam 12. If the contact member 13 is a long one and the tips of the respective replacement beams 12 are connected to one contact member 13, a large eccentric load may occur on the contact member 13 side by the formwork supports 11, 11 on both sides of the intermediate pile 3 when the replacement beam 12 is stored, and there is a possibility that the formwork support 11 may fall over. However, in the present embodiment, by making the contact member 13 short, it is possible to suppress the occurrence of such a large eccentric load when the replacement beam 12 is stored.

[0037] However, the present invention is not limited to the above-described embodiments. For example, in the above-described embodiment, the receiving girder 6 is made to function as the upper cut beam, but this is not essential, and an upper cut beam may be separately provided below the receiving girder 6.

[0038] Also, as shown in a horizontal cross-section similar to FIG. 4 in FIG. 6, the intermediate pile 3 may be omitted. In this case, there is no need to divide and arrange the formwork support 11 while avoiding the position of the intermediate pile 3 between each side wall 9 and the partition wall 10. Further, the abutting member 13a may be made long, and a plurality of replacement beams 12a can be connected to one abutting member 13a. The replacement beam 12a is not provided with the above-described dividing portion 121. After the use of the replacement beam 12a, by contracting the jack 122 and moving the formwork support 11 to the next construction section B, the integral replacement beam 12a and the abutting member 13a move together with the formwork support 11.

[0039] In addition, the cross-section of the tunnel is not limited to that shown in FIG. 5(a) or the like. For example, as shown in FIG. 7, it may not have the partition wall 10, or may have two or more partition walls 10. The configuration of the support is not particularly limited either. As long as the abutting member at the tip of the replacement beam abuts against the side wall 9 of the tunnel on which the lateral pressure of the ground 1 acts, and the lateral pressure of the ground 1 acting on the side wall 9 is supported by the replacement beam. For example, in the example of FIG. 7, the abutting members 13 at both ends of the replacement beam 12 abut against each of the side walls 9 on both sides of the tunnel where the lateral pressure acts.

[0040] Also, the side wall 9 is not limited to being in contact with the earth retaining wall 2 as shown in FIG. 5(a) or the like. For example, as shown in Patent Document 1, the side wall 9 may be provided at a distance from the earth retaining wall 2, and in some cases, concrete or the like may be provided between the earth retaining wall 2 and the side wall 9 to transmit the lateral pressure of the ground 1 to the side wall 9.

[0041] Also, the underground structure constructed using the method of the present embodiment is not limited to a tunnel, and the same method can be applied when constructing other underground structures.

[0042] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the technical idea disclosed in the present application, and it is naturally understood that those also belong to the technical scope of the present invention.

Explanation of Signs

[0043] 1: Ground 2: Retaining wall 3: Intermediate pile 4: Bulge 5: Cross beam 6: Girder 7: Formwork support 8: Bottom slab 9: Side wall 10: Partition wall 11: Formwork support and protection work 12, 12a: Replacement beam 13, 13a: Contact member 14: Top slab 15: Excavation part 17: Reaction receiving member 18, 122: Jack 21: Bracket 121: Division part

Claims

1. Constructing a pair of earth retaining walls on both sides of the planned excavation area of the ground, excavating the ground between the pair of earth retaining walls, and supporting the lateral pressure of the ground acting on the earth retaining walls by a cross beam spanned between the pair of earth retaining walls (step (a)); Removing the cross beam, and constructing the side walls on both sides of the body of the underground structure which is a tunnel, on the bottom plate of the body, in the height direction from bottom to top, at positions along the pair of earth retaining walls, between the pair of side walls (step (b)); Supporting the formwork during the construction of the top plate with a formwork support structure having a configuration in which a horizontal member is connected in the middle of the height direction of a vertical member provided up to the height of the top plate of the body of the underground structure which is the upper part between the side walls on both sides, and constructing the top plate with concrete using the formwork (step (c)); comprising: In the step (b), Between the side walls on both sides, placing a temporary beam in the horizontal direction in the direction connecting the side walls on both sides on the horizontal member of the formwork support structure in the vertical plane, and supporting the temporary beam vertically by the formwork support structure; After fixing a contact member extending in the extending direction of the side wall to the tip of one side wall side of the temporary beam, by extending a telescopic member provided in the middle of the longitudinal direction of the temporary beam, bringing the contact member into contact with the head of the constructed part of one side wall, taking a reaction force on the constructed part of the constructed part of the other side wall or the partition wall constructed between the side walls on both sides to introduce an axial force into the temporary beam, and supporting the lateral pressure of the ground acting on the constructed part of one side wall via the earth retaining wall by the temporary beam; After constructing the top plate using the formwork support structure, moving the formwork support structure on the bottom plate in the extending direction of the tunnel to the next construction section of the tunnel, and supporting the lateral pressure of the ground acting on the side wall of the construction section by the temporary beam. A method for constructing an underground structure, characterized by this.

2. The method for constructing an underground structure according to claim 1, characterized in that the temporary beam is longitudinally divisible.

3. A plurality of the temporary beams are provided at intervals in the extending direction of the side wall, The method for constructing an underground structure according to claim 2, characterized in that the contact member is provided for each of the temporary beams.

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