JP7842998B2 - Box-shaped roof pipe for underpass construction method - Google Patents

Description

This invention relates to a box-shaped roof pipe for underpass construction, and more particularly to a box-shaped roof pipe having a roughly quadrilateral hollow cross-section that constitutes a box-shaped roof on the top surface, replacing a box-shaped structure in an underpass construction method.

The underpass construction method is used to create underground spaces that traverse existing structures such as railways and roads, by installing a series of box-shaped pipe members in the ground beneath them. Known methods include the R&C method (registered trademark) (see, for example, Patent Document 1) and the SFT method (registered trademark) (see, for example, Patent Document 2). In the underpass construction method, for example, box-shaped pipe members are installed in a series in the ground beneath the existing structure where the underground space is to be formed, thereby forming a top and side box-shaped roof that supports the existing structure from below. Then, the formed top and side box-shaped roofs are replaced by a box-shaped structure with a rectangular cross-section that is propelled into the area where the underground space is to be formed, thereby creating the underground space with the replaced box-shaped structure.

Furthermore, in the underpass construction method, when replacing the formed box-shaped roof on the top surface or side surfaces with a box-shaped structure having a rectangular cross-section that has been propelled forward, there is a risk that the frictional force between the top surface of the box-shaped roof or box-shaped structure and the ground above them may affect the ground above as the box-shaped roof or box-shaped structure is pushed out. Therefore, a friction-cut plate, which is detachably attached to the top surface of the box-shaped roof, is left in the ground while the box-shaped roof or box-shaped structure is pushed out. This friction-cut plate reduces the frictional force with the ground above, preventing any impact on the ground above. This friction-cut plate is installed in the ground with the top surface of the box-shaped roof in place. When the box-shaped roof is replaced with the box-shaped structure, it is detached from the box-shaped roof while both ends of the ground (launching side and arrival side) are fixed, and left in the ground.

Japanese Patent Publication No. 2007-177553 Japanese Patent Publication No. 2012-144942 Japanese Patent Publication No. 2001-73670

On the other hand, in recent years, there has been a demand to create underground spaces with larger hollow cross-sections at deeper locations underground, for example, using underpass construction methods. This results in greater earth and water pressure loads being applied to the top surface of box-shaped roofs and box-shaped structures during propulsion, as well as greater frictional forces between them and the ground above. Therefore, conventional box-shaped roof construction methods make it difficult to propel the box-shaped roofs and box-shaped structures while maintaining stable friction reduction.

Furthermore, Patent Document 3 discloses a technology that enables the construction of underground structures using an underpass method even when a receiving tunnel cannot be constructed. According to Patent Document 3, when propelling an underground structure while leaving a friction-cut plate, detachably positioned at the top of the roof cylinder, in the ground, the roof cylinder, constructed by connecting short segments in the longitudinal direction, can be sequentially removed from the rear segments at the tip of the underground structure's cutting edge and recovered towards the receiving tunnel. Additionally, multiple reinforcing friction-cut steel members extending in the longitudinal direction are connected to the top of the roof cylinder and interposed between them and the friction-cut plate, preventing the friction-cut plate from deflecting under an upward load.

However, in the underpass construction method described in Patent Document 3, the cylindrical roof structure (box-shaped roof pipe) is constructed by joining multiple reinforcing friction-cutting steel members to the upper part, and then attaching a friction-cutting plate with these multiple friction-cutting steel members interposed. This results in a complex structure, and requires excavation work from inside the tip of the cylindrical roof structure, not only across its entire cross-section but also in the area of the friction-cutting steel members and friction-cutting plate above it, making such excavation work difficult. Furthermore, as the underground structure passes beneath the friction-cutting plate, a considerable amount of frictional force is still generated between the friction-cutting steel members and the top surface of the underground structure. Therefore, further improvements are needed for the box-shaped roof pipe used in the underpass construction method, particularly for the top surface box-shaped roof, to enable effective friction cutting while supporting the load from above with a simpler structure.

The present invention aims to provide a box-shaped roof pipe for underpass construction that can effectively support loads from above with a simpler configuration, without requiring reinforcing steel materials on the outside of the pipe, and can effectively cut friction without generating large frictional forces between the pipe and the underground structure (box structure) passing below.

The present invention relates to a box-shaped roof pipe for underpass construction, which is installed in advance on the ground below an existing structure and replaces the top surface of a box-shaped structure having a rectangular cross-section, thereby forming an underground space by the box-shaped structure that crosses the ground directly below the existing structure. The box-shaped roof pipe is arranged in a series in the lateral direction along the top surface of the planned installation area of the box-shaped structure on the ground below the existing structure, thereby forming the box-shaped roof. The box-shaped roof pipe has a roughly four-sided hollow cross-section and consists of a U-shaped upper flat piece and a U-shaped lower piece that are vertically separable and connected at the upper ends of the side plates on both sides. The U-shaped upper flat piece has a strip-shaped height adjustment fitting supported on the lower surface of its top plate, and the box-shaped roof pipe The above objective is achieved by providing a box-shaped roof pipe for underpass construction, which extends in the axial direction and is fixed in a position parallel to the top plate portion. After the box-shaped roof is installed on the ground beneath the existing structure, when the box structure is propelled, the U-shaped lower piece separates from the U-shaped upper flat piece and replaces the top surface of the box structure, while the U-shaped upper flat piece remains in place to function as a friction-cutting member. Furthermore, the height adjustment hardware includes a load-bearing roller member, including a rotating roller having a rotation axis perpendicular to the axial direction of the box-shaped roof pipe and parallel to the upper surface of the top plate portion of the U-shaped upper flat piece. This member is height-adjustable and interposed between the top surface of the box structure and the U-shaped upper flat piece, thereby enabling the box structure to slide while supporting an overhead load.

Furthermore, it is preferable that the box-shaped roof pipe for the underpass construction method of the present invention has the U-shaped upper flattened piece and the U-shaped lower piece connected vertically so as to be separable by pin joints.

Furthermore, it is preferable that the box-shaped roof pipe for the underpass construction method of the present invention is formed by integrating multiple unit box-shaped roof pipes, each having a roughly quadrilateral hollow cross-section, in the axial direction.

Furthermore, it is preferable that the box-shaped roof pipe for underpass construction according to the present invention is formed by connecting a plurality of shorter unit U-shaped lower pieces axially connected and integrated, so as to be separable vertically, below a unit U-shaped upper flat piece of a predetermined length.

Furthermore, it is preferable that the box-shaped roof pipe for the underpass construction method of the present invention has a hollow cross-section with approximately four sides, measuring 800 to 1400 mm in width and 800 to 1400 mm in height.

Furthermore, the box-shaped roof pipe for underpass construction according to the present invention is preferably used in the R&C (Registered Trademark) method, in which excavation work is performed at the face of the front portion of the box-shaped structure.

According to the box-shaped roof pipe for underpass construction methods of the present invention, it is possible to effectively support loads from above with a simpler configuration without providing reinforcing steel materials on the outside of the pipe, and to effectively reduce friction without generating large frictional forces between the pipe and the underground structure (box structure) passing below.

A preferred embodiment of the present invention describes a box-shaped roof pipe for an underpass construction method, where (a) is a cross-sectional view and (b) is a cross-sectional view showing the U-shaped upper flat piece and the U-shaped lower piece separated. This is a perspective view illustrating a load-bearing roller component. This is a schematic longitudinal cross-sectional view illustrating the process of propelling box-shaped roof pipes to form a box-shaped roof on the top surface. This diagram illustrates the process of forming a box-shaped roof by propelling box-shaped roof pipes. (a) is a schematic longitudinal section view, and (b) is a schematic longitudinal section view along A-A in (a). This is a schematic longitudinal cross-sectional view illustrating the process of forming a box structure inside a working shaft. This is a schematic perspective view illustrating the process of forming a box structure inside a working shaft. This is a schematic longitudinal cross-sectional view illustrating the situation in which a box-shaped structure is advanced while excavating the ground inside the box-shaped roof using the R&C method. This is a schematic perspective view illustrating the process of advancing a box-shaped structure while excavating the ground inside the box-shaped roof using the R&C method. This is a schematic longitudinal cross-sectional view illustrating the underground space created by a box-shaped structure that crosses beneath an existing structure. This is a schematic perspective view illustrating the underground space created by a box-shaped structure that crosses beneath an existing structure.

The box-shaped roof pipe 10 for underpass construction, as shown in Figures 1(a) and 1(b), according to a preferred embodiment of the present invention, is used as one of the box-shaped pipe members constituting the top box-shaped roof 21 in the R&C method (registered trademark), which, as an underpass construction method, for example as shown in Figures 3 to 8, can form another newly constructed underground space 26 (see Figures 9 and 10) by a box structure 15 installed across the portion directly below the existing structure 30, replacing the top box-shaped roof 21 of a previously installed box-shaped roof 20 in the ground below the existing structure 30. In this embodiment, it is not possible to secure a site large enough to form a working shaft 31, and therefore each work process of the R&C method is carried out in a working shaft 31 in a narrow space. Furthermore, since an existing equipment structure 40 (see Figures 3 and 5) is formed as an underground structure on the receiving side of the box-shaped structure 15 flanked by the existing structure 30, each work process of the R&C method can be carried out without providing a shaft on the receiving side, using only the shaft on the departure side as the work shaft 31.

The box-shaped roof pipe 10 for the underpass construction method in this embodiment consists of a U-shaped upper flat piece 11 and a U-shaped lower piece 12 that are detachably connected vertically. By leaving the U-shaped upper flat piece 11 in the ground and using it as a friction-cutting member, it is possible to effectively support loads from above with a simpler configuration without providing reinforcing steel materials on the outside of the pipe. Furthermore, it is configured to effectively cut friction without generating large frictional forces between the pipe and the box-shaped structure 15 passing below.

Furthermore, the box-shaped roof pipe 10 for the underpass construction method of this embodiment is installed in advance in the ground below the existing structure 30 in the underpass construction method, and replaces the top surface 15a of the box-shaped structure 15 which has a rectangular cross-section (see Figure 7), thereby forming an underground space 26 (see Figures 9 and 10) by the box-shaped structure 15 that crosses the ground directly below the existing structure 30. The box-shaped roof pipe 10 is a box-shaped pipe member for the underpass construction method that has a roughly quadrilateral hollow cross-section and forms a top surface box-shaped roof 21. Multiple box-shaped roof pipes 10 are arranged in a continuous manner in the lateral direction along the top surface of the planned installation area of the box-shaped structure 15 in the ground below the existing structure 30, thereby forming a top surface box-shaped roof 21 (see Figures 3 and 4(b)). As shown in Figures 1(a) and 1(b), the box-shaped roof pipe 10 has a roughly quadrilateral hollow cross-section and consists of a U-shaped upper flat piece 11 and a U-shaped lower piece 12 that are vertically separable and connected at the upper ends of the side plate portions 10a on both sides. A strip-shaped height adjustment fitting 13 is supported on the lower surface side of the top plate portion 11a of the U-shaped upper flat piece 11 and extends in the axial direction of the box-shaped roof pipe 10, and is fixed in place parallel to the top plate portion 11a. The height of the U-shaped upper flat piece 11 is lower than that of the U-shaped lower piece 12. After the box-shaped roof 21 is installed on the ground beneath the existing structure 30, when the box structure 15 is propelled, the U-shaped lower piece 12 separates from the U-shaped upper flat piece 11 and replaces the top surface 15a of the box structure 15. The U-shaped upper flat piece 11 is left in place to function as a friction-cutting member (see Figure 7). Furthermore, a load-bearing roller member 14 (see Figure 2), including a rotating roller 14a with a rotation axis perpendicular to the axial direction of the box-shaped roof pipe 10 and parallel to the upper surface of the top plate 11a of the U-shaped upper flat piece 11, is attached to the height-adjustable fitting 13. By interposing between the top surface 15a of the box structure 15 and the U-shaped upper flat piece 11, it enables the box structure 15 to slide while supporting the load from above.

In this embodiment, prior to the work of forming an underground space 26 by a box structure 15 in the ground below the existing structure 30, preferably using the R&C method, a work shaft 31 (see Figure 3) serving as a work base is formed on one side of the existing structure 30. In this embodiment, as described above, since other existing equipment structures 40 are formed on the other side of the existing structure 30, the work shaft 31 is formed on only one side, and each work process is carried out. The work shaft 31 can be easily formed, for example, in the same way as a shaft formed in the shield tunneling method using a shield tunneling machine, by forming a retaining wall 32 using sheet piles and ground improvement with excellent watertightness, preferably by the SMW method, and excavating to a predetermined depth while retaining the inside of this wall. The surface on the side of the work shaft 31 is protected by sheet piles and supported by shoring such as bracing. The formed working shaft 31 will be appropriately equipped with propulsion equipment for moving the box-shaped roof pipe 10 and the box-shaped structure 15, as well as removal equipment for removing the U-shaped lower piece 12 of the box-shaped roof pipe 10 (see Figure 5).

Furthermore, in this embodiment, as shown in Figures 3 and 4(a) and (b), a known propulsion device (not shown) is installed in the formed working shaft 31. Similar to the conventional R&C method, multiple box-shaped roof pipes 10 forming the top box-shaped roof 21, and box-shaped roof pipes 10' and 10'' forming the side box-shaped roofs 22 and bottom box-shaped roofs 23, are arranged in a continuous line along the top, both side, and both ends of the bottom portion of the planned installation area of the box structure 15, aligning them in the circumferential direction of the cross-section perpendicular to the transverse direction of the box structure 15 in the planned installation area. This allows the pipes to be propelled and pushed from the working shaft 31 into the ground below the existing structure 30. This makes it possible to form a box-shaped roof 20 that includes, preferably, the bottom box-shaped roofs 23 at the corner portions of both ends, in addition to the top box-shaped roof 21 and side box-shaped roofs 22 that traverse the portion directly below the existing structure 30.

Here, the box-shaped roof pipes 10 forming the top box-shaped roof 21 each preferably have a roughly quadrilateral hollow cross-section (roughly square hollow cross-section in this embodiment) with a width of 800 to 1400 mm and a height of 800 to 1400 mm, and have an internal space large enough for workers to enter and work inside. The box-shaped roof pipes 10' and 10'' forming the side box-shaped roof 22 and bottom box-shaped roof 23 have, for example, a roughly square hollow cross-section with dimensions of approximately 800 to 1400 mm in both length and width, and in this embodiment, they are buried underground without being recovered into the work shaft 31 (see Figure 10). These box-shaped roof pipes 10, 10', and 10'' are installed underground with a sufficient length to traverse the ground directly beneath the existing underground structure 30, by sequentially joining unit pipes divided into appropriate lengths.

Furthermore, the box-shaped roof pipe 10 of this embodiment, which forms the top box-shaped roof 21, has a hollow cross-section with a roughly quadrilateral (roughly square) shape, as described above. It consists of a U-shaped upper flat piece 11 and a U-shaped lower piece 12, which are vertically separable and connected at the upper ends of the side plate portions 10a on both sides. A strip-shaped height adjustment fitting 13 is supported on the lower surface of the top plate portion 11a of the U-shaped upper flat piece 11, extending axially along the box-shaped roof pipe 10 and fixed parallel to the top plate portion 11a.

In this embodiment, as shown in Figures 1(a) and 1(b), the box-shaped roof pipe 10 has a roughly square hollow cross-section, for example, with a width of about 1400 mm and a height of about 1400 mm. For example, at the upper end portion of the side plate portions 10a on both sides, at a height of about 1250 mm from the bottom plate portion 10b, a U-shaped upper flat piece 11 and a U-shaped lower piece 12 are connected as a single unit so as to be easily detachable, preferably by pin joints. That is, a lower flange 12a is fixed to the upper end edge of the U-shaped lower piece 12 by welding or the like, so as to protrude inward, and engaging pins 12b are erected at predetermined intervals along the length of the box-shaped roof pipe 10, protruding upward from the lower flange 12a. An upper flange 11b is fixedly attached to the lower edge of the U-shaped upper flat piece 11 by welding or the like, so as to protrude inward. The upper flange 11b has engagement holes for engaging the engagement pins 12b of the lower flange 12a, arranged at predetermined intervals along the length of the box-shaped roof pipe 10, corresponding to the engagement pins 12b of the lower flange 12a. By engaging the engagement pins 12b of the lower flange 12a with the engagement holes of the upper flange 11b, the U-shaped upper flat piece 11 and the U-shaped lower piece 12 can be connected as a single unit, while remaining easily separable.

Furthermore, in this embodiment, a pair of linear convex ribs 11c are fixed to the central part in the lateral direction of the lower surface of the top plate portion 11a of the U-shaped upper flat piece 11 by welding or the like, and are attached in the longitudinal direction of the box-shaped roof pipe 10, extending parallel to each other. A strip-shaped height adjustment fitting 13 is attached to the linear convex ribs 11c by welding or the like, supported on the lower surface side of the top plate portion 11a via these linear convex ribs 11c. The height adjustment fitting 13 extends in the longitudinal direction of the box-shaped roof pipe 10, similar to the linear convex ribs 11c, and is positioned parallel to the top plate portion 11a, and is attached at a height position that does not protrude downward beyond the upper flange 11b. On the lower side of the height adjustment fitting 13, the U-shaped lower piece 12 is separated from the U-shaped upper flat piece 11. When the U-shaped upper flat piece 11 functions as a friction-cutting member, the load-bearing roller member 14 shown in Figure 2 is attached at predetermined intervals along the length of the box-shaped roof pipe 10 prior to the top surface 15a of the box structure 15 passing below it. The load-bearing roller member 14 is attached to the lower side of the height adjustment fitting 13 with its height adjusted so that the lower end of the rotating roller 14a is preferably positioned below the upper flange 11b, for example, at a height of approximately 200 mm from the top plate portion 11a.

In this embodiment, the box-shaped roof pipe 10 is formed by axially connecting and integrating multiple unit box-shaped roof pipes, each preferably having a hollow cross-section with a substantially quadrilateral (substantially square) shape and a length of approximately 3 m, using known joining means such as bolt joints or pin joints, to create a predetermined length.

Furthermore, in this embodiment, the unit box-shaped roof pipe is formed by connecting multiple unit U-shaped lower pieces 12c (see Figures 7 and 8), each shorter than a unit U-shaped upper flat piece (for example, 1 m in length), to the lower part of a unit U-shaped upper flat piece (for example, 3 m in length), with these pieces axially connected and integrated, and detachably connected vertically. This allows the box-shaped roof pipe 10 forming the top box-shaped roof 21 to be removed sequentially from the rear end of each unit U-shaped lower piece 12c, while leaving each of the unit U-shaped upper flat pieces constituting the U-shaped upper flat piece 11 (which acts as a friction-cutting member) in the ground. These unit U-shaped lower pieces 12c can be axially connected and integrated using known joining means such as bolt joints or pin joints.

In this embodiment, after forming a box-shaped roof 20, including a top box-shaped roof 21, side box-shaped roofs 22, and bottom box-shaped roof 23, in the planned installation area of the box-shaped structure 15 that crosses the portion directly beneath the existing structure 30, the box-shaped structure 15 is propelled from the work shaft 31 towards the ground directly beneath the existing structure 30 by a propulsion device 27 installed in the work shaft 31, while preferably leaving the side box-shaped roofs 22 and bottom box-shaped roofs 23 in the ground, replacing only the top box-shaped roof 21 with the top portion 15a. This allows for the formation of an underground space 26 by the box-shaped structure 15 (see Figures 7 to 10).

In this embodiment, as described above, since the work takes place in the narrow space of the working shaft 31, the box structure 15 is formed by multiple precast concrete unit box bodies 16 that are continuously connected and integrated in the axial direction. Furthermore, the unit box body 16 is formed by assembling multiple precast pieces 16a, which are divided pieces in the circumferential direction, as a single unit in the working shaft 31, thereby achieving a thickness of approximately 1 m, corresponding to, for example, the jack stroke of the propulsion equipment 27. That is, as shown in Figures 5 and 6, each unit box body 16 is formed by assembling precast pieces 16a that have been suspended from the ground into the working shaft 31. The formed unit box bodies 16 are then sequentially connected in the axial direction and propelled as the box structure 15 toward the ground directly beneath the existing structure 30 by the propulsion equipment 27 installed in the working shaft 31 (see Figure 7).

In this way, for example, the unit box bodies 16 formed for each jack stroke of the propulsion equipment 27 are assembled sequentially from the rear side in the propulsion direction of the box structure 15, as components of the box structure 15, similar to the conventional R&C method. The resulting box structure 15, as shown in Figure 7, is propelled from the working shaft 31 towards the ground directly beneath the existing structure 30, while the top surface 15a replaces the U-shaped lower pieces 12 of each box-shaped roof pipe 10 of the top box-shaped roof 21, leaving each U-shaped upper flat piece 11 in the ground as a friction-cutting member. This makes it possible to form the underground space 26 created by the box structure 15 across the ground directly beneath the existing structure 30 (see Figures 9 and 10).

Furthermore, in this embodiment, as described above, preferably using the R&C method for underpass construction, as shown in Figure 7, the box structure 15 is advanced while excavating the ground inside the box-shaped roof 20 at the face 28. Since only the launching shaft is used as the working shaft 31, as shown in Figure 8, the U-shaped upper flat piece 11 and U-shaped lower piece 12 of the box-shaped roof pipe 10 constituting the top box-shaped roof 21 are separated by pulling out the engagement pin 12b. Each unit U-shaped lower piece 12c is then collected in the working shaft 31, while the box structure 15 is advanced into the ground below the existing underground structure 30.

In other words, in this embodiment, a roof support steel shell 17 is installed at the leading end of the box structure 15 in the direction of propulsion, interposed between it and the box-shaped roof 20, and comprising a pair of rectangular frames 18a and 18b having an outer circumference shape that follows the cross-sectional shape of the box structure 15 (see Figures 5 and 6). The roof support steel shell 17 is composed of a roof-side rectangular frame 18a and a box-side rectangular frame 18b, and a plurality of connecting steel members 19 that join and integrate these rectangular frames 18a and 18b in a parallel arrangement. The presence of the roof support steel shell 17 maintains a gap between the rectangular frames 18a and 18b that allows the unit U-shaped lower piece 12c of the box-shaped roof pipe 10 to pass through and allows workers to enter. Furthermore, the roof support steel shell 17 supports the rear end portion of the box-shaped roof on the upper steel portion of the roof-side rectangular frame 18a by placing it on the upper steel portion of the frame, and the box-side rectangular frame 18b is in contact with the front surface of the box structure 15, allowing the shell to move forward together with the box structure 15 as it propels itself.

In this embodiment, while excavating the ground inside the box-shaped roof 20 at the excavation face 28 and propelling the box-shaped structure 15, the unit U-shaped lower pieces 12c at the rear ends of each box-shaped roof pipe 10 constituting the top surface box-shaped roof 21, which protrude directly above the gap between the roof-side rectangular frame 18a and the box-shaped structure-side rectangular frame 18b, can be collected into the inside of the box-shaped structure 15 via these gaps and sequentially removed (see Figures 7 and 8).

Furthermore, when removing the unit U-shaped lower piece 12c, the load from above in the portion between the tip of the box structure 15 and the face 28 is supported from below by the U-shaped upper flat piece 11, which functions as a friction-cutting member and whose tip portion is placed on the top surface 15a of the box structure 15 via the load-bearing roller member 14. In this embodiment, as shown in Figures 1(a) and (b), the U-shaped upper flat piece 11 has a flat U-shaped cross-sectional shape with both sides bent downwards, which provides considerable rigidity compared to a flat friction-cutting plate, making it possible to support the load from above in a stable state. In addition, in this embodiment, the U-shaped upper flat piece 11 has a strip-shaped height adjustment fitting 13 fixed to the underside of its top plate portion 11a via a pair of linear convex ribs 11c. Therefore, the rigidity is further enhanced by these height adjustment fittings 13 and linear convex ribs 11c, making it possible to support loads from above in a more stable state.

Furthermore, in this embodiment, after separating and sequentially removing the unit U-shaped lower piece 12c at the rear end of each box-shaped roof pipe 10 constituting the top box-shaped roof 21 from the unit U-shaped upper flat piece 11, the load-bearing roller member 14 is attached to the lower side of the height adjustment fitting 13 attached to the lower surface of the top plate portion 11a of the remaining U-shaped upper flat piece 11, preferably by working in the space between the roof-side rectangular frame 18a and the box-side rectangular frame 18b of the roof support steel shell 17, so that it is positioned at a predetermined distance in the axial direction of the box-shaped roof pipe 10. The load-bearing roller member 14 can preferably be mounted with its height adjusted by interposing a height adjustment plate, such that the lower end of the rotating roller 14a, which has a rotation axis perpendicular to the axial direction of the box-shaped roof pipe 10 and parallel to the upper surface of the top plate portion 11a of the U-shaped upper flat piece 11, is positioned at a height of approximately 200 mm from the top plate portion 11a. This allows the U-shaped upper flat piece 11, which functions as a friction-cutting member, to be placed on the top surface portion 15a of the box structure 15 with the rotating roller 14a of the load-bearing roller member 14 interposed. By preventing large frictional forces from occurring between them, the box structure 15, composed of multiple unit boxes 16, can be smoothly moved and propelled while the U-shaped upper flat piece 11 functions as a friction-cutting member.

These features allow the box-shaped roof pipe 10 for underpass construction in this embodiment to effectively support loads from above with a simpler configuration, without requiring reinforcing steel materials on the outside of the pipe. Furthermore, it enables effective friction reduction without generating large frictional forces between the U-shaped upper flat piece 11, which functions as a friction-cutting member, and the box-shaped structure 15 passing beneath it. Additionally, there is no need to excavate beyond the entire cross-section of the box-shaped roof pipe 10.

In this embodiment, the box-shaped structure 15 is propelled into the ground, and its tip reaches, for example, the improved ground at the tip end on the forward side of the propulsion direction, sandwiching the existing structure 30. This creates an underground space 26 formed by the box-shaped structure 15, which is installed across the portion directly beneath the existing underground structure 30 (see Figures 9 and 10). The formed underground space 26 can be used in communication with the existing equipment structure 40 by, for example, removing the side wall 40a in the portion corresponding to the underground space 26 of another existing equipment structure 40 (see Figure 9).

Furthermore, the present invention is not limited to the above embodiments and various modifications are possible. For example, the existing structure in which the underground space formed by the box-shaped structure is created in the ground below may be an existing structure for subways or roads, or other various existing structures such as building basements or sewer pipes. Also, the box-shaped roof section using the box-shaped roof pipe for the underpass construction method of the present invention, or the box-shaped structure that replaces it, may be propelled toward a working shaft on the receiving side, with a working shaft provided on the receiving side, on either side of the existing structure. If a working shaft is also provided on the receiving side, the box-shaped roof section using the box-shaped roof pipe of the present invention can also be adopted in the SFT method (registered trademark), which involves removing the ground and soil remaining inside the box-shaped roof at the working shaft on the receiving side, as an underpass construction method.

10 Box-shaped roof pipes 10', 10" for underpass construction Box-shaped roof pipe 10a Side plate section 10b Bottom plate section 11 U-shaped upper flat piece 11a Top plate section 11b Upper flange 11c Linear convex rib 12 U-shaped lower piece 12a Lower flange 12b Engagement pin 12c Unit U-shaped lower piece 13 Height adjustment hardware 14 Load-bearing roller member 14a Rotating roller 15 Box structure 15a Top surface section 16 Unit box 16a Precast piece 17 Roof support steel shell 18a Roof side rectangular frame 18b Box side rectangular frame 19 Connecting steel material 20 Box-shaped roof 21 Top surface box-shaped roof 22 Side surface box-shaped roof 23 Bottom surface box-shaped roof 26 Underground space 27 Tunneling equipment 28 Face section 30 Existing structure 31 Working shaft 32 Retaining wall 40 Existing equipment structure 40a Side wall of the portion corresponding to the underground space

Claims (6)

In an underpass construction method, a box-shaped roof pipe for an underpass construction method, having a roughly quadrilateral hollow cross-section, is installed in advance on the ground below an existing structure and replaces the top surface of a box-shaped structure having a rectangular cross-section, thereby traversing the ground directly below the existing structure and forming an underground space by the box-shaped structure, wherein the top surface of the box-shaped roof is formed by the box-shaped structure,
The box-shaped roof pipes are arranged in a series in the lateral direction along the top surface of the planned installation area of the box-shaped structure in the ground below the existing structure, thereby forming the top surface box-shaped roof.
The box-shaped roof pipe has a hollow cross-section with approximately four sides, and consists of a U-shaped upper flat piece and a U-shaped lower piece that are detachably connected vertically at the upper ends of the side plates on both sides. A strip-shaped height adjustment fitting is supported on the underside of the top plate of the U-shaped upper flat piece, extending in the axial direction of the box-shaped roof pipe, and is fixed in place parallel to the top plate.
A box-shaped roof pipe for underpass construction, wherein, after the box-shaped roof top is installed on the ground below the existing structure, when the box structure is propelled, the U-shaped lower piece is separated from the U-shaped upper flat piece and replaced with the top surface of the box structure, while the U-shaped upper flat piece is left in place to function as a friction-cutting member, and a load-bearing roller member, including a rotating roller having a rotation axis perpendicular to the axial direction of the box-shaped roof pipe and parallel to the upper surface of the top plate of the U-shaped upper flat piece, is attached to the height adjustment hardware in an adjustable height manner, interposed between the top surface of the box structure and the U-shaped upper flat piece, thereby enabling the box structure to slide while supporting a load from above. The box-shaped roof pipe for underpass construction according to claim 1, wherein the U-shaped upper flattened piece and the U-shaped lower piece are connected so as to be separable vertically by a pin joint. A box-shaped roof pipe for underpass construction according to claim 1 or 2, formed by connecting and integrating multiple unit box-shaped roof pipes having a roughly quadrilateral hollow cross-section in the axial direction. The box-shaped roof pipe for underpass construction according to claim 3, is formed by connecting a plurality of shorter unit U-shaped lower pieces axially connected and integrated, so as to be separable vertically, below a unit U-shaped upper flat piece of a predetermined length. A box-shaped roof pipe for underpass construction according to claim 1 or 2, having a roughly quadrilateral hollow cross-section with dimensions of 800 to 1400 mm in width and 800 to 1400 mm in height. A box-shaped roof pipe for an underpass construction method according to claim 1 or 2, used in the R&C method (registered trademark) for excavation work performed at the face of the front portion of the aforementioned box-shaped structure.