How to install the box

Abstract

To provide a box body installation method capable of preventing the ground from slacking due to a defective part generated in the ground between a pipe roof and a box body.SOLUTION: The box body installation method includes: a first step of inserting multiple pipes 8 to be adjacent to each other into the ground E and building a pipe roof 8R to protect a box body 11 to be installed; and a second step of placing the box body 11 below the pipe roof 8R and installing the box body 11 in a planned box body installation area S. In the second step, a hard foam urethane UF is injected between the pipe roof 8R and the box body 11 from an injection hole 8a formed on the pipe roof 8R of the pipe 8.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for installing a box body, and to a technology for preventing loosening of the ground when installing a box body under a pipe roof constructed of multiple steel pipes inserted into the ground during underpass construction. [Background technology]

[0002] The underpass method is a construction method for building urban tunnels without excavating. In other words, it is a construction method in which the ground below is excavated while railway and road facilities remain in use, and a box structure such as a box culvert is installed to construct the tunnel. Note that the path of the railway, road, and other facilities intersects with the path of the tunnel.

[0003] One known underpass construction method involves inserting multiple steel pipes (pipes) outside the area where the box is to be installed to cover the top surface or the top surface and both sides of the box, creating a pipe roof as a protective member, and then installing the main structure, the box, below the pipe roof, to prevent sinking or deformation of the facilities above.

[0004] In this construction method, the steel pipes are arranged continuously across the width and vertical directions of the box body with as few gaps as possible, penetrating the ground from the starting side to the destination side. The steel pipes have a rectangular or circular hollow cross section, and are inserted into the ground from the inside of the hollow section while excavating the face. After one set of steel pipes has reached the destination side from the starting side (insertion is complete), the adjacent steel pipe is inserted from the starting side.

[0005] Additionally, while the steel pipe is advanced, a filler is injected into the ground through an injection hole at the top end. The filler is used to compensate for any loosening that occurs in the ground above the steel pipe due to its insertion. Therefore, a filler that has water-stopping and hardening properties is preferred. The filler is injected after the steel pipe has been inserted a predetermined distance (for example, the length of one piece of steel pipe), after which excavation and insertion are stopped, and the front is protected with retaining materials to stabilize the ground at the face.

[0006] Once the steel pipes have been inserted into the ground in this way to construct the pipe roof, a box is inserted underneath. The construction is carried out so that a specified distance is maintained between the pipe roof and the top surface of the box. The front of the box on the face side is open, with cutting edges on its periphery. The box is then advanced while excavating the face from inside the opening of the box, and construction is completed up to the end.

[0007] In addition, a technology for protecting the front of a steel pipe with a retaining member is described in Patent Publication No. 2018-172929 (Patent Document 1), and a technology for preventing the road surface from subsiding when a box is inserted under a pipe roof is described in Patent Publication No. 2003-064985 (Patent Document 2).

[0008] Patent document 1 describes a technology in which, while excavation work on a hollow pipe member (steel pipe) is suspended, an airbag member is set on the excavation cutting edge member of the hollow pipe member for which excavation work has been suspended, the airbag member is inflated to press its tip surface against the cutting edge face to make tight contact, and the side surface of the inflated airbag member is pressed against the inner surface of the excavation cutting edge member to obtain a supporting reaction force, thereby retaining soil on the cutting edge face.

[0009] Patent document 2 also describes a technology in which a fluid filler, which does not itself have the ability to solidify, is injected at a predetermined pressure between the pipe roof and the box body through an injection port provided in the box body, and a fluid sealing means provided on the outer edge of the cutting edge prevents the fluid filler from leaking out, thereby maintaining the fluid filler filled in the defect in the ground that has occurred between the pipe roof and the box body and allowing the box body to enter. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2018-172929 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-064985 Summary of the Invention [Problem to be solved by the invention]

[0011] In the underpass construction method described above, there is unexcavated (undisturbed) natural ground below the pipe roof, which supports the pipe roof from below. As the box enters, the natural ground may be carried in the direction of entry due to friction with the box body and cutting edge, or may collapse from the tip of the box, causing partial damage.

[0012] In particular, when the width of the box is wide, boxes of that width will enter at the same time, so the impact on the ground between the pipe roof and the box will be greater as the boxes enter, resulting in greater damage.

[0013] Furthermore, as the length of the box increases, the accumulation of these defects will cause the ground to become looser, which may result in subsidence or deformation of facilities and equipment constructed on the ground.

[0014] The present invention has been made in light of the above-mentioned technical background, and aims to provide a technology that can prevent loosening of the ground due to defects that occur in the ground between the pipe roof and the box body. [Means for solving the problem]

[0015] In order to solve the above problem, the method for installing the box in the invention described in claim 1 is as follows: A plurality of steel pipes with injection holes formed at predetermined intervals along the axial direction are installed with the injection holes facing the area where the box is to be installed. A first step of constructing a pipe roof for protecting boxes to be installed by inserting the boxes into the ground so that they are adjacent to each other, and a second step of inserting the boxes under the pipe roof, The aforementioned and a second step of installing the case in a case installation area, wherein the second step includes: When the leading box reaches each injection hole formed in the steel pipe, A feature of the present invention is that rigid foamed urethane is injected between the pipe roof and the box body.

[0016] The method for installing a box in the invention described in claim 2 is characterized in that, in the invention described in claim 1, the pipe roof is a straight-line type in which multiple steel pipes are inserted into the ground so that they are adjacent to each other above the area where the box is to be installed, or a gate type in which multiple steel pipes are inserted into the ground so that they are adjacent to each other above and outside both sides of the area where the box is to be installed, and the rigid foamed urethane is injected between the pipe roof and the upper surface of the box in at least the part located above the box.

[0017] The method for installing boxes in the invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2, in the second step, when the leading box during its entry reaches an injection hole formed in the steel pipe, rigid foamed urethane is injected between the pipe roof and the boxes through the injection hole.

[0018] The method for installing a box body in the invention described in claim 4 is characterized in that, in the invention described in any one of claims 1 to 3, in the second step, the box body is installed under the pipe roof by a construction method in which the box body is advanced from an opening on the side in the direction of travel while excavating the ground in front of it. [Effects of the Invention]

[0019] According to the present invention, rigid foamed urethane is injected between the pipe roof and the box body, so that the rigid foamed urethane penetrates into the defect that has occurred in the ground between the pipe roof and the box body and hardens, thereby making it possible to prevent loosening of the ground. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an explanatory diagram showing a process of constructing a pipe roof on natural ground in one embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a front view showing a pipe roof constructed by the process of FIG. 1. [Figure 3] 10 is an explanatory diagram showing the process of inserting and installing a box under a pipe roof in one embodiment of the present invention. FIG. [Figure 4] 4 is an enlarged view of a main part when the box is installed in the step of FIG. 3. FIG. [Figure 5] FIG. 1 is a front view showing a pipe roof constructed according to one embodiment of the present invention and a box body installed underneath it. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally designated by the same reference numerals, and repeated description thereof will be omitted.

[0022] A method for installing a box body according to this embodiment will be described with reference to Figures 1 to 5. Figure 1 is an explanatory diagram showing the process of constructing a pipe roof on the natural ground in one embodiment of the present invention, Figure 2 is a front view of the pipe roof constructed by the process of Figure 1, Figure 3 is an explanatory diagram showing the process of inserting a box body under the pipe roof and installing it, Figure 4 is an enlarged view of the main part when installing the box body in the process of Figure 3, and Figure 5 is a front view of the constructed pipe roof and the box body installed under it. In Figures 1 and 3, the symbol R indicates a road built on the surface of the natural ground.

[0023] Here, for installation of the box body 11 in this embodiment, a construction method that combines the FJ method (front jacking method) and the ESA method (endless self advancing method) is used.

[0024] The FJ method involves drilling through holes within the installation area of the box 11 in the ground E after the construction of the pipe roof 8R (see Figure 2) is completed, installing a PC steel wire, and connecting the starting end of the PC steel wire to the box 11 and the destination end to a traction jack (front jack) J2 (see Figure 3). The box 11 is then pulled forward from the destination end. The ESA method involves connecting each box 11, consisting of three or more pieces, with PC steel wire. Jacks are installed between each piece and at the rear end. The tail of each piece is fixed, the head is advanced, and then the head is fixed and the tail is pulled. This process is repeated, allowing the box 11 to be advanced piece by piece, using the reaction force of the other boxes 11. Furthermore, by combining the FJ and ESA methods, the box 11 can be advanced efficiently by both pulling the box 11 (FJ method) and pushing the box 11 using the reaction force (ESA method).

[0025] As shown in Figure 1, temporary earth retaining piles 1 are driven into the ground E on both sides of the planned installation area for the box body 11 (see Figures 3 and 5), and excavation is then carried out to form two shafts 2 that serve as work spaces on either side of the road R. Next, a bearing wall 3 and a launch pad 4 are constructed in one of the shafts 2, followed by the construction of a lattice frame 5. After that, a platform 6 for driving a pipe 8 (described later) is constructed, and a driving machine 7, such as a driving jack, is installed on the platform 6.

[0026] Then, a pipe (steel pipe) 8 is placed on the platform 6 using a crane or the like, and is then propelled by a propeller 7 toward the shaft 2 on the opposite side and pressed in. Excavated soil generated inside the pipe 8 during the pressing in is discharged to the outside using a conveying device such as an auger. However, if the pipe 8 is large enough that a worker can work inside it, the process of excavating the pressing surface of the pipe 8 by a worker and the process of pressing in the pipe 8 with the propeller 7 may be repeated.

[0027] In this embodiment, a pipe 8 having a circular cross section in the intersecting axis direction is used, but a pipe having a rectangular cross section in the intersecting axis direction may also be used. In addition, if one pipe 8 does not reach from one shaft 2 to the opposite shaft 2, multiple pipes 8 are connected in series and pressed in.

[0028] Here, the pipe 8 has injection holes 8a (Fig. 4) formed at predetermined intervals along the axial direction. These injection holes 8a are holes for injecting rigid urethane foam UF between the pipe roof 8R formed by press-fitting the pipe 8 into the natural ground E, as will be described later, and the box body 11. Therefore, when press-fitting the pipe 8 into the natural ground E, the injection holes 8a are oriented toward the planned box installation area S (Fig. 2).

[0029] Once the first pipe 8 has been pressed in, the next pipe 8 is pressed in adjacent to that pipe 8, and then the next pipe 8 is pressed in adjacent to that pipe 8, and this process is repeated. In this way, as shown in FIG. 2, a pipe roof 8R made up of multiple pipes 8 for protecting the box body 11 to be installed is formed (first process).

[0030] In this embodiment, the arrangement shape of the pipe roof 8R is a gate shape. That is, a plurality of pipes 8 are installed adjacent to each other along the upper side and the outer sides of the planned box installation area S. However, the arrangement shape of the pipe roof 8R is not limited to a gate shape, and may be, for example, a straight line shape in which a plurality of pipes 8 are installed adjacent to each other in a row along the upper side of the planned box installation area S.

[0031] Once the pipe roof 8R has been formed, as shown in FIG. 3, the box 11 is inserted under the pipe roof 8R and installed in the box installation area S (second step).

[0032] The box 11 is a hollow structure used to construct a tunnel, such as an underground crosswalk. As shown in FIG. 5, the box 11 is composed of an upper slab 11-1 and a lower slab 11-2 that face each other in the vertical (height) direction, and wall panels 11-3 that face each other laterally at both ends and in the middle. The front and back are open. The box 11 of this embodiment is constructed by arranging multiple pieces (boxes 11) in the axial direction with the openings of each piece communicating with each other. The box 11 also has through-holes (not shown) formed in the longitudinal direction of the pipe 8 (i.e., the direction in which the box 11 is advanced) through which PC steel wires are inserted.

[0033] In Figure 3, when the boxes 11 are advanced and installed, a PC steel wire is passed through the multiple boxes 11 from the starting shaft 2 (here, the shaft 2 on the right side in Figure 3) and connected to each other, a center push jack J1 is installed between each box 11, and an ESA jack (not shown), which is a center-hole type hydraulic jack, is installed at the rearmost part. The tip of the PC steel wire (the tip in the direction of advancement of the boxes 11) is fixed to the first box 11, and the rear end is attached to the rearmost ESA jack. In this embodiment, four pieces of boxes 11a, 11b, 11c, and 11d are shown, but it is sufficient if there are multiple boxes that can be used with the ESA construction method.

[0034] Furthermore, a cutting edge Bm for press-fitting the box body 11a while cutting the natural ground is provided at the tip of the leading box body 11a in the press-fitting direction.

[0035] Furthermore, a through hole (guide tunnel) is provided from the arrival side shaft 2 (here, the shaft 2 on the left side in Figure 3) within the installation range of the box body 11 in the ground E, and a PC steel wire is inserted through it, one end of which is fixed to the leading box body 11a, and the other end of which is connected to a towing jack J2 provided in the arrival side shaft 2 for towing the box body 11.

[0036] With this configuration, when one box body 11 is propelled, the frictional resistance due to the earth pressure and the weight of the other multiple box bodies 11 serves as a reaction force resistor. Specifically, when propelling four-piece box bodies 11a to 11d as in this embodiment, the leading box body 11a is first advanced by the center push jack J1 installed at the tail of that box body 11a. At this time, the towing jack J2 described above also pulls the box body 11a, holding that box body 11a at the advanced position to prevent it from retreating due to earth pressure. Next, the center push jack J1 that advanced the leading box body 11a is retracted, and box body 11b is advanced by the center push jack J1 installed at the tail of box body 11b. Next, the center push jack J1 that advanced box body 11b is retracted, and box body 11c is advanced by the center push jack J1 installed at the tail of box body 11c. Finally, the middle push jack J1 that advanced box body 11c is retracted, and the ESA jack installed at the rearmost position uses the reaction force of boxes 11a to 11c, which are connected by PC steel wire, to advance the rearmost box body 11d. In this way, the leading box body 11a, followed by the following boxes 11b, 11c, and 11d, are advanced piece by piece in sequence, and box body 11 is installed under the pipe roof 8R (see Figure 5).

[0037] When the case 11 is advanced, rigid urethane foam UF is injected between the pipe roof 8R and the case 11 through an injection hole 8a formed in the pipe 8, as shown in Fig. 4. In this embodiment, a worker is inside the pipe 8, and when the worker confirms that the leading case 11a being advanced has reached the injection hole 8a formed in the pipe 8, he manually injects rigid urethane foam UF between the pipe roof 8R and the case 11 through the confirmed injection hole 8a. The reason for injecting rigid urethane foam UF is as follows.

[0038] In other words, below the constructed pipe roof 8R there is unexcavated ground E that supports the pipe roof 8R, but as the box body 11 enters, the ground E is carried in the direction of entry due to friction with the box body 11 and the cutting edge Bm, or it collapses from the tip of the cutting edge Bm, causing soil and sand to flow into the box body 11 through the opening on the front side of the box body 11, resulting in partial damage.

[0039] In particular, in the case of wide boxes 11, boxes 11 of that width will enter at the same time, so the impact on the ground E between the pipe roof 8R and the boxes 11 will be greater as the boxes 11 enter, resulting in greater damage. Also, if the length of the boxes 11 becomes longer, the accumulation of damage to the ground E will cause greater loosening of the ground E, which may result in settlement or deformation of facilities, equipment, etc. constructed on the ground.

[0040] At this time, as mentioned above, by injecting rigid foamed urethane UF between the pipe roof 8R and the box body 11, the rigid foamed urethane UF penetrates into the defects that have occurred in the ground E and hardens, making it possible to prevent loosening of the ground E.

[0041] The timing of injection of the rigid urethane foam UF is not limited to when the leading box 11a reaches or passes through the injection hole 8a formed in the pipe 8, but can be determined freely. Furthermore, the injection of the rigid urethane foam UF does not have to be performed by an operator; for example, it can be performed by inserting a tube into the pipe 8 while checking the positional relationship between the injection hole 8a and the boxes 11 with a camera. When checking the positions of the boxes 11 with an operator or a camera, it is not necessary to check all boxes 11; the rigid urethane foam UF can be injected into all pipes 8 when it is confirmed from within a specific pipe 8. Furthermore, it is not necessary to provide injection holes 8a in all pipes 8; pipes 8 can be installed with injection holes 8a at intervals depending on the filling characteristics of the rigid urethane foam UF.

[0042] In this embodiment, for example, Set Foam (registered trademark of Nisshinbo Chemical Inc.) is used as the rigid urethane foam UF. This rigid urethane foam UF starts foaming 12 seconds after injection, hardens quickly in about 1 minute, and reaches a final strength (1 N / mm) in about 30 minutes. 2 However, the type of rigid urethane foam UF used is not particularly limited.

[0043] As described above, the pipe roof 8R of this embodiment has a gate-like configuration, with multiple pipes 8 installed adjacent to one another along the upper and outer sides of the planned box installation area S. In such a gate-like pipe roof 8R, rigid urethane foam UF may be injected only between the portion of the pipe roof 8R located above the box body 11 and the upper surface of the box body 11, so that the pipe roof 8R is supported by the upper surface of the box body 11 into which the rigid urethane foam UF has been injected. Furthermore, as shown in FIG. 5, rigid urethane foam UF may also be injected between both sides of the pipe roof 8R and the side surfaces of the box body 11, so that the soil pressure acting on the sides of the pipe roof 8R is supported by the side surfaces of the box body 11.

[0044] The invention made by the inventor has been specifically described above based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects and are not limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the description of the above embodiments, but should be interpreted solely in accordance with the claims, and includes technologies equivalent to the technologies described in the claims and all modifications that do not deviate from the gist of the claims.

[0045] For example, in this embodiment, a construction method that combines the FJ method and the ESA method is used, but this is not limited to this, and any construction method can be used as long as it is an underpass construction method that uses a pipe roof 8R (a construction method in which a box body 11 is pushed forward to the underside of the pipe roof 8R to build a tunnel), such as a construction method that uses the FJ method or the ESA method alone, or a construction method in which a reaction wall is provided on the starting shaft side and the box body 11 is pushed forward using the reaction force from the reaction wall.

[0046] In addition, in this embodiment, the pipe 8 is pressed into the ground E so that the injection hole 8a faces the intended box installation area S, but the injection hole 8a does not need to be positioned strictly opposite the box 11; it is sufficient that the injection hole 8a faces a position where the rigid foamed urethane UF is injected between the pipe roof 8R and the box 11. [Industrial Applicability]

[0047] In the above explanation, the present invention has been described as being applied to a method of installing a box for forming an underground pedestrian crossing, but it can also be applied to a method of installing boxes for other purposes, such as sewers, water conduits, or road culverts. [Explanation of symbols]

[0048] 1 Temporary retaining piles 2 Shaft 8 Pipes (Steel Pipes) 8a injection hole 8R pipe roof 11,11a,11b,11c,11d Box Bm blade mouth E. Natural ground J1 Center jack J2 Towing Jack S. Planned area for installing the box UF rigid urethane foam

Claims

1. A first step of constructing a pipe roof to protect the box to be installed by inserting multiple steel pipes, each having injection holes formed at predetermined intervals along the axial direction, into the ground so that the injection holes face the area where the box is to be installed and are adjacent to each other; A second step of inserting the box under the pipe roof and installing the box in the box installation area; and In the second step, When the leading box during its advance reaches each injection hole formed in the steel pipe, rigid foamed urethane is injected between the pipe roof and the box through the injection hole. A method for installing a box, comprising:

2. The pipe roof is a straight-line type in which a plurality of steel pipes are inserted into the ground so as to be adjacent to each other above the area where the box is to be installed, or a portal type in which a plurality of steel pipes are inserted into the ground so as to be adjacent to each other above and outside both sides of the area where the box is to be installed, The rigid urethane foam is injected between the pipe roof and the upper surface of the box at least in a portion located on the upper side of the box.

2. The method for installing a box according to claim 1.

3. In the second step, When the leading box during its advance reaches an injection hole formed in the steel pipe, rigid foamed urethane is injected between the pipe roof and the box through the injection hole.

3. The method for installing a box according to claim 1 or 2.

4. In the second step, The box is installed under the pipe roof by a construction method in which the box is advanced from the opening on the traveling direction side while excavating the ground in front of the box.

4. The method for installing the box according to claim 1, wherein the method comprises:

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