Pipe roof installation method, pipe roof and elements constituting the pipe roof

Abstract

To allow for excellently filling tips of elements with concrete even when edge surfaces of the elements constituting a pipe roof are blocked.SOLUTION: The total aperture area of first exhaust holes VH1 for exhausting disposed on tips of standard elements Em constituting a pipe roof PR is made larger than the aperture area of one of second exhaust holes VH2 disposed at parts other than the tips of the standard elements Em. Consequently, the tips of the standard elements Em can be excellently filled with ready-mixed concrete CC even when edge surfaces of a plurality of standard elements E constituting the pipe roof PR are blocked.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a pipe roof construction method, a pipe roof, and elements constituting a pipe roof, and more particularly to a technique for filling concrete into elements constituting a pipe roof. [Background technology]

[0002] In urban areas, when constructing underground structures for forming roads, railways, etc., there is a demand for construction methods that prevent ground shifts or subsidence, because main roads, houses, etc. are densely located above ground.

[0003] The pipe roof method involves installing multiple pipes in parallel around the area where an underground structure is planned to be constructed in the ground and connecting them to construct a pipe roof (protective roof). It is used in the construction of underground structures in urban areas as a technology that can suppress or prevent ground shifts and subsidence.

[0004] Such a pipe roofing method is disclosed, for example, in Patent Document 1, which describes how the long space of an element is divided into multiple concrete pouring spaces by partition members that intersect with it, and how concrete is poured into each concrete pouring space through a concrete pressure pipe installed in each space, with the pressure pipes being left buried. Patent Document 1 also describes how, when pouring concrete, air in the concrete pouring space is released through an air vent hole formed in the partition member and from an opening in the front end face of the element (starting shaft side).

[0005] Furthermore, for example, Patent Document 2 discloses a method of filling multiple long spaces with concrete, in which a concrete inlet is provided at one end of the long spaces and an air vent hole is provided at the other end of the long spaces, and when filling with concrete, air within the long spaces is released through the air vent hole formed at the other end of the long spaces. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-104403 A [Patent Document 2] Japanese Patent Application Publication No. 10-306584 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, in order to give a pipe roof a specified strength, it is necessary to fill each of the multiple elements that make up the pipe roof with concrete without any gaps. However, in the pipe roof construction examined by the inventor, there were problems in that the total length of pouring for the multiple elements was extremely long, and there was no arrival shaft in the direction in which the elements were pressed in, and the openings on the tip faces of the elements were blocked with soil and sand, making it difficult to fill the tips of the elements with concrete.

[0008] The present invention has been made in light of the above-mentioned technical background, and aims to efficiently fill the tip of an element that constitutes a pipe loop with concrete even when the tip surface of the element is blocked. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the pipe roof construction method of the present invention described in claim 1 includes an element preparation step of preparing a plurality of rectangular tubular elements having a hollow space surrounded by a first steel plate and a second steel plate facing each other and a third steel plate and a fourth steel plate facing each other while crossing the first steel plate and the second steel plate, and in which a first end face in the axial direction of the hollow space and a second end face located opposite to the first end face are opened; an element pressing step of pressing the elements into the ground while excavating and discharging soil in front of the elements along the outer periphery of the planned underground structure on the side of the starting shaft, with the first end faces of the elements facing the side of the starting shaft, thereby installing the plurality of elements in parallel while being connected to each other via connecting spaces between adjacent elements; and a concrete filling step of filling the elements and the connecting spaces with concrete after the element pressing step, with the first end faces of the elements being closed. and in the element pressing-in process, the plurality of elements are pressed in such that the first steel plate and the second steel plate of adjacent elements face each other via the connecting space, and in the element preparation process, the first steel plate has a communication hole that communicates the hollow space with the connecting space, and the second steel plate has an exhaust hole that is formed to communicate the hollow space with the connecting space and that releases air in the hollow space and the connecting space when the concrete is poured into the element, the exhaust hole being formed at a position closer to the fourth steel plate than to the third steel plate, and having a first exhaust hole provided on the first end face side of the element and a second exhaust hole provided other than the first end face side of the element, and a total opening area of ​​the first exhaust holes is larger than an opening area per one of the second exhaust holes.

[0010] The pipe roof construction method of the present invention described in claim 2 is characterized in that, in the invention described in claim 1, during the element pressing-in process, in locations where the multiple elements are arranged in a horizontal row, the elements are pressed in so that the exhaust hole is located at the top, and in locations where the multiple elements are arranged stacked vertically, the elements are pressed in so that the communicating hole faces upward.

[0011] The pipe roof construction method of the present invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2 above, the first exhaust hole is formed by a plurality of through holes arranged at a predetermined first distance along the longitudinal direction of the element, and the second exhaust hole is formed by a plurality of through holes arranged at a second distance longer than the first distance along the longitudinal direction of the element.

[0012] The pipe roof construction method of the present invention described in claim 4 is characterized in that, in the invention described in any one of claims 1 to 3 above, the diameters of the first exhaust hole and the second exhaust hole are smaller than the diameter of the coarse aggregate of the concrete.

[0013] The pipe roof construction method of the present invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4 above, the dimensions of the first exhaust hole and the second exhaust hole are equal to each other.

[0014] The pipe roof construction method of the present invention described in claim 6, in the invention described in any one of claims 1 to 5 above, is characterized in that the concrete filling process includes a partition member installation process of forming a concrete filling space within the element by installing a partition member that separates the hollow space within the element, an inlet pipe installation process of installing the inlet pipe within the element so that the discharge portion of the inlet pipe that flows the concrete into the concrete filling space is located in the longitudinal center of the concrete filling space, and a process of pouring the concrete into the concrete filling space through the inlet pipe and filling the concrete from the first end face toward the second end face of the element.

[0015] The pipe roof construction method of the present invention described in claim 7 is characterized in that, in the invention described in claim 6 above, the partition member installation process includes a process of preparing a partition member in which a third exhaust hole for releasing air from within the element is formed in an adjustable state of opening area, and the concrete filling process includes a process of blocking all of the third exhaust holes of the partition member or making the opening area of ​​the third exhaust hole smaller than the opening area of ​​the exhaust hole of the element before the concrete is filled on the first end face side of the element, flowing the concrete into the concrete filling space with the third exhaust hole open after the concrete is filled on the first end face side of the element.

[0016] The pipe roof construction method of the present invention described in claim 8 is the invention described in claim 6 or 7, Concrete filled space The method further comprises the step of installing a filling detection sensor in the innermost part, or in the innermost part and the middle part, of the concrete filling space before pouring the concrete into the concrete filling space.

[0017] The pipe roof construction method of the present invention described in claim 9 is characterized in that, in the invention described in any one of claims 6 to 8 above, when the concrete filling space has been finished being filled with the concrete, the inlet pipe and the partition member are left embedded in the concrete, and the concrete is filled up to the inlet of the inlet pipe.

[0018] The pipe roof construction method of the present invention described in claim 10 is characterized in that, in the invention described in any one of claims 1 to 9 above, the first steel plate of the element is constructed by joining a steel plate of a predetermined width between the third steel plate and the fourth steel plate in the longitudinal direction of the element.

[0019] The pipe roof of the present invention described in claim 11 comprises a plurality of rectangular tubular elements arranged along the outer periphery of an underground structure on a side surface of a starting shaft and connected to each other via a connecting space between adjacent elements, and concrete filled in the elements and the connecting spaces, the elements have a hollow space surrounded by a first steel plate and a second steel plate facing each other and a third steel plate and a fourth steel plate facing each other while intersecting the first steel plate and the second steel plate, a first end face in the axial direction of the hollow space and a second end face located opposite to the first end face are open, and the first steel plate and the second steel plate of the plurality of elements are connected to each other via the connecting space. the first steel plate is formed with a communication hole communicating the hollow space with the connecting space, and the second steel plate is formed with an exhaust hole communicating the hollow space with the connecting space, which releases air in the hollow space and the connecting space when the concrete is poured into the element, the exhaust hole is formed at a position closer to the fourth steel plate than to the third steel plate, and has a first exhaust hole provided on the first end face side of the element and a second exhaust hole provided other than the first end face side of the element, and the total opening area of ​​the first exhaust holes is formed to be larger than the opening area per one of the second exhaust holes.

[0020] The pipe roof of the present invention described in claim 12 is characterized in that, in the invention described in claim 11 above, where the multiple elements are arranged in a horizontal row, the elements are installed so that the exhaust hole is located at the top, and where the multiple elements are stacked and arranged vertically, the elements are installed so that the communicating hole faces upward.

[0021] The pipe roof of the present invention described in claim 13 is characterized in that, in the invention described in claim 11 or 12 above, the first exhaust hole is formed by a plurality of through holes arranged at a predetermined first distance along the longitudinal direction of the element, and the second exhaust hole is formed by a plurality of through holes arranged at a second distance longer than the first distance along the longitudinal direction of the element.

[0022] The pipe roof of the present invention described in claim 14 is characterized in that, in the invention described in any one of claims 11 to 13 above, the diameters of the first exhaust hole and the second exhaust hole are smaller than the diameter of the coarse aggregate of the concrete.

[0023] The pipe roof of the present invention described in claim 15 is characterized in that, in the invention described in any one of claims 11 to 14, the first exhaust hole and the second exhaust hole have the same dimensions.

[0024] The pipe roof of the present invention described in claim 16 is characterized in that, in the invention described in any one of claims 11 to 15 above, a partition member that divides the element to form a concrete filling space within the element is embedded in the concrete.

[0025] The pipe roof of the present invention described in claim 17 is characterized in that, in the invention described in claim 16, the partition member is formed with a third exhaust hole for releasing air from the concrete-filled space.

[0026] The pipe roof of the present invention described in claim 18 is characterized in that, in the invention described in claim 16 or 17 above, an inlet pipe for injecting the concrete into the element is embedded in the concrete with the discharge portion of the inlet pipe positioned in the longitudinal center of the concrete filling space, and the inside of the inlet pipe is filled with the concrete up to the inlet of the inlet pipe.

[0027] The pipe roof of the present invention described in claim 19 is characterized in that, in the invention described in any one of claims 16 to 18 above, a filling detection sensor for detecting the filling of the concrete is embedded in the rear part, or in the rear part and middle part, of the concrete filling space.

[0028] The pipe roof of the present invention described in claim 20 is characterized in that, in the invention described in any one of claims 11 to 19 above, the first steel plate of the element is constructed by joining steel plates of a predetermined width perpendicular to the longitudinal direction of the element.

[0029] The element of the present invention described in claim 21 is a rectangular tubular element that is arranged along the outer periphery of an underground structure on the side of a starting shaft and is arranged in parallel while being connected via a connection space between adjacent elements, the element has a hollow space surrounded by a first steel plate and a second steel plate facing each other, and a third steel plate and a fourth steel plate facing each other while intersecting the first steel plate and the second steel plate, a first end face in the axial direction of the hollow space and a second end face located opposite to the first end face are opened, the first steel plate and the second steel plate of the adjacent elements are arranged to face each other via the connection space, a communication hole communicating with the hollow space and the connection space is formed in the first steel plate, and a hole communicating with the hollow space and the connection space is formed in the second steel plate, and concrete and an exhaust hole is formed to release air in the hollow space and the connecting space when air flows in the hollow space and the connecting space, the exhaust hole is formed at a position closer to the fourth steel plate than to the third steel plate, and the exhaust hole has a first exhaust hole provided on the first end face side of the element and a second exhaust hole provided other than the first end face side of the element, and a total opening area of ​​the first exhaust holes is larger than the opening area of ​​each of the second exhaust holes.

[0030] The element of the present invention described in claim 22 is characterized in that, in the invention described in claim 21, the first exhaust hole is formed by a plurality of through holes arranged at a predetermined first distance along the longitudinal direction of the element, and the second exhaust hole is formed by a plurality of through holes arranged at a second distance longer than the first distance along the longitudinal direction of the element.

[0031] The element of the present invention described in claim 23 is characterized in that, in the invention described in claim 21 or 22, the diameters of the first exhaust hole and the second exhaust hole are smaller than the diameter of the coarse aggregate of the concrete.

[0032] The element of the present invention described in claim 24 is characterized in that in the invention described in any one of claims 21 to 23, the first exhaust hole and the second exhaust hole have the same dimensions.

[0033] The element of the present invention described in claim 25 is characterized in that, in the invention described in any one of claims 21 to 24, the first steel plate is constructed by joining steel plates of a predetermined width perpendicular to the longitudinal direction of the element. Effect of the Invention

[0034] According to the present invention, even when the tip surface of the element constituting the pipe loop is blocked, it is possible to satisfactorily fill the tip of the element with concrete. [Brief description of the drawings]

[0035] [Figure 1] 1 is a cross-section of a main portion of a construction site for a pipe roof according to an embodiment of the present invention. [Diagram 2] This is a side view of the main parts of the starting shaft after the soil and sand in the element have been discharged. [Diagram 3] FIG. 3 is a cross-sectional view of a main portion of the pipe roof construction site in FIG. 2. [Figure 4]This is a side view of the main part of the starting shaft after the wires for fixing the elements have been installed. [Diagram 5] This is a side view of the main parts of the starting shaft after concrete has been filled into the elements. [Figure 6] FIG. 7 is a cross-sectional view of a main part of the pipe roof construction site in FIG. 6. [Figure 7] This is a side view of the main parts of the starting shaft after the tunnel is constructed. [Figure 8] FIG. 8 is a cross-sectional view of a main portion of the pipe roof construction site in FIG. 7. [Figure 9] FIG. 2 is a front view of a group of elements constituting a pipe roof according to an embodiment of the present invention. [Figure 10] FIG. 1 is a front view of a standard element. [Figure 11] 10, (a) is a plan view of the first steel plate of the leading standard element as viewed from the direction of arrow A1 in FIG. 10, and (b) is a plan view of the second steel plate of the leading standard element as viewed from the direction of arrow A2 in FIG. [Figure 12] 10, (a) is a plan view of the third steel plate of the leading standard element as viewed from the direction of arrow A3 in FIG. 10, and (b) is a plan view of the fourth steel plate of the leading standard element as viewed from the direction of arrow A4 in FIG. 10. [Figure 13] 10, (a) is a plan view of the first steel plate of the subsequent standard element as viewed from the direction of arrow A1 in FIG. 10, and (b) is a plan view of the second steel plate of the subsequent standard element as viewed from the direction of arrow A2 in FIG. [Figure 14] FIG. 13 is a front view of the elements showing the standard connection state between the elements. [Figure 15] FIG. 2 is a front view of the prestressing element. [Figure 16] 15. (a) is a plan view of the fifth steel plate of the element for introducing prestress, as viewed from the direction of arrow A1 in FIG. 15, and (b) is a plan view of the seventh steel plate P7b of the element for introducing prestress, as viewed from the direction of arrow A5 in FIG. 15. [Figure 17]15. (a) is a plan view of the eighth steel plate of the element for introducing prestress, as viewed from the direction of arrow A3 in FIG. 15, and (b) is a plan view of the sixth steel plate of the element for introducing prestress, as viewed from the direction of arrow A6 in FIG. 15. [Figure 18] FIG. 13 is a front view of an element showing the connection state between a prestressing element, a deformed type standard element, and a standard element. [Figure 19] A cross-sectional view of a key part of the element casting space. [Figure 20] 20(a) is a plan view of an example of a partition plate, (b) is a plan view of the partition plate shown in FIG. 20(a) with the opening / closing plate that constitutes the partition plate removed, and (c) is a plan view of the opening / closing plate that constitutes the partition plate in FIG. 20(a). [Figure 21] 20(b) is an exploded plan view of the partition plate of FIG. 20(a), and FIG. 20(b) is a cross-sectional view taken along line YY of FIG. 20(b). [Figure 22] 22(a) and (b) are plan views of modified examples of the partition plate, and (c) is a plan view of the opening / closing plate of FIGS. 22(a) and (b). [Figure 23] This is a cross-sectional view of the tip of the leading standard element during pouring. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] 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 the repeated description will be omitted.

[0037] An example of the pipe roof construction method of this embodiment will be described with reference to Figures 1 to 8. Note that here, the case where the pipe roof construction method of this embodiment is applied to the construction of a tunnel (underground structure) for railroad facilities underground will be described.

[0038] FIG. 1 is a cross section of a main part of a construction site for a pipe roof according to this embodiment.

[0039] First, a starting shaft DH is constructed at the construction site G of the pipe roof. The depth of the starting shaft DH is, for example, 40 to 50 m. Next, a thruster RM and a plurality of elements E are carried into the starting shaft DH. The elements E are formed of long rectangular steel pipes for constructing the pipe roof. The elements E will be described later.

[0040] Then, the element E is set on the thruster RM. At this time, the element E is set so that its posture is horizontal, and its tip end face (first end face) in the longitudinal direction (axial direction) of the element E faces the side of the starting shaft DH. Then, the thruster RM presses the element E into the ground from the side of the starting shaft DH while excavating and removing the soil in front of the element E.

[0041] Figure 2 is a side view of the main part of the starting shaft after the element pressing process, and Figure 3 is a cross-sectional view of the main part of the pipe roof construction site in Figure 2. Although Figure 2 is a side view, the soil and sand are hatched.

[0042] As shown in Fig. 2, on the side of the starting shaft DH, for example, a plurality of elements E are arranged in parallel along the periphery of the planned tunnel site (planned underground structure) Tp so as to surround the entire area of ​​the planned tunnel site Tp. Adjacent elements E, E are connected to each other via a connection space CS. The connection state of the elements E will be explained later.

[0043] In addition, as shown in Fig. 3, a plurality of elements E are press-fitted in series into each element press-fitting portion (element row). In Fig. 3, three elements E are shown to simplify the drawing, but in reality, three or more elements E are press-fitted.

[0044] The total length of the elements E arranged in series at each element press-fitting location (total casting length described below) is, for example, 50,000 to 100,000 mm.

[0045] 2 and 3, the soil in each element E and the connection space CS is removed by an excavator (not shown) and manually. However, in this embodiment, even after the soil is removed, the tip end face (first end face) of the leading element E in each element press-in portion is still blocked by soil.

[0046] Figure 4 is a side view of the main part of the starting shaft after the wires for fixing the elements were installed. Note that although Figure 4 is a side view, the soil is hatched.

[0047] After removing the soil from each element E and the connecting space CS, the multiple elements E arranged vertically and horizontally are fixed together with steel wires W1 and W2. The wire W1 passes through the multiple elements E arranged vertically and the connecting space CS and is fixed in a tensioned state within the elements E at the corners located at the top and bottom ends. The wire W2 passes through the multiple elements E arranged horizontally and the connecting space CS and is fixed in a tensioned state within the elements E at the corners located at the left and right ends. The wires W1 and W2 are provided at predetermined distances along the longitudinal direction of the elements E (the direction perpendicular to the paper surface of FIG. 4).

[0048] Figure 5 is a side view of the main part of the starting shaft after concrete has been filled into the elements, and Figure 6 is a cross-sectional view of the main part of the pipe roof construction site in Figure 5. Although Figure 5 is a side view, the soil and concrete C are hatched to make the drawing easier to see.

[0049] As shown in Figures 5 and 6, after joining multiple elements E together by applying prestress to wires W1, W2 (see Figure 4), the elements E and the connecting space CS are filled with fresh concrete CC. This pouring work is carried out for each element press-in point (element row). After filling the elements E at all element press-in points with fresh concrete CC, the fresh concrete CC is allowed to harden after a curing period. In this way, a full-circumference pipe roof PR is constructed at the pipe roof construction site, surrounding the entire perimeter of the planned tunnel location Tp. This pouring process will be explained later.

[0050] Figure 7 is a side view of the main part of the starting shaft after the tunnel is constructed, and Figure 8 is a cross-sectional view of the main part of the pipe roof construction site in Figure 7. Although Figure 7 is a side view, the soil and concrete CC are hatched to make the drawing easier to see.

[0051] As shown in Figures 7 and 8, after constructing a pipe roof PR, soil is excavated at the planned tunnel site Tp (see Figure 5, etc.) using an excavator (not shown), and then various types of paving are applied to construct a tunnel T.

[0052] Next, examples of the configuration of the above-mentioned pipe roof PR and the elements E that constitute the pipe roof PR will be described with reference to Figs.

[0053] FIG. 9 is a front view of the element group that constitutes the pipe roof of this embodiment.

[0054] The element group EG has, for example, a perimeter-type structure and includes four casting blocks: a bottom block Bb, a ceiling block Bc, and two side blocks Bs. Here, the element E is shown after the soil has been discharged.

[0055] Moreover, the elements E of the element group EG include a standard element Em, a deformed type standard element Emc, and an element Eb for introducing prestress.

[0056] The standard element Em is the main element that is most frequently placed in the element group EG, and is placed in all four pouring blocks mentioned above.

[0057] The deformed type standard element Emc is an element in which a portion of the standard element Em is deformed in order to ensure consistency with the prestressing element Eb when filling the connecting space CS between the prestressing element Eb and the adjacent element E with concrete, and is positioned adjacent to the prestressing element Eb.

[0058] The prestressing elements Eb are mainly used to apply prestress to the wires W1 and W2 (see FIG. 4) and are arranged at the four corners of the element group EG. The prestressing elements Eb determine the casting block.

[0059] FIG. 10 is a front view of the standard element.

[0060] The standard element Em is formed of a rectangular steel pipe having a hollow space HS surrounded by first to fourth steel plates P1m to P4m. The first steel plate P1m and the second steel plate P2m are arranged to face each other, and the third steel plate P3m and the fourth steel plate P4m are arranged to face each other while intersecting (orthogonal to) the first and second steel plates P1m, P2m.

[0061] Joints J1, J1 are joined to the outer surface of the first steel plate P1m of the standard element Em near the corners of the element Em. The joints J1, J1 are made of, for example, a long, flat steel plate, and are provided so as to protrude from the outer surface of the first steel plate P1m with one end face (end face on one long side) in the width direction (short direction) joined to the first steel plate P1m.

[0062] In addition, joints J2, J2 are joined to the outer surface of the second steel plate P2m of the standard element Em near the corners of the element Em. The joints J2, J2 are made of, for example, a long, flat steel plate, and are provided so as to protrude from the outer surface of the second steel plate P2m with one end surface (end surface on one long side) in the width direction (short direction) joined to the second steel plate P2m.

[0063] Furthermore, the positions of the joint parts J1, J1 and the joint parts J2, J2 in the height direction of the element Em (the vertical direction in Figure 10) are shifted by the thickness of the joint parts J1, J2, and as described below, when the elements Em, Em are arranged side by side adjacent to each other, the joint parts J2, J2 are arranged inside the joint parts J1, J1 and are arranged so that they overlap and are in contact with each other.

[0064] The element Em has an opening at its leading end face (first end face) and its opposing rear end face (second end face) in the longitudinal direction (axial direction) of the hollow space HS. Although not particularly limited, the element Em has a width (horizontal dimension in FIG. 10) of, for example, 1000 mm and a height (vertical dimension in FIG. 10) of, for example, 800 mm at both end faces in the longitudinal direction.

[0065] In addition, at each element press-in location, there is a leading element E and a trailing element E following the leading element E. The leading element E refers to the element E that is first pressed into the side of the starting shaft, as well as the element E that is placed at the back (leading position) when concrete is poured, even if it is located midway along the entire length of multiple elements E that are arranged in series at each element press-in location. Also, the trailing element E refers to the element E that is placed in series behind the leading element E. The front view of the leading element E and the trailing element E are the same, but the side views are slightly different, so in the following explanation of the side views of element E, the leading element E and the trailing element E will be explained separately.

[0066] 11(a) is a plan view of the first steel plate of the leading standard element as viewed from the direction of arrow A1 in FIG. 10, and FIG. 11(b) is a plan view of the second steel plate of the leading standard element as viewed from the direction of arrow A2 in FIG. 10.

[0067] As shown in FIG. 11(a), the first steel plate P1m of the leading standard element Em is configured by joining steel plate parts Ps of a predetermined width perpendicularly to the longitudinal direction of the element Em. That is, the first steel plate P1m is provided with the steel plate parts Ps of the first steel plate P1m and the openings (communicating holes) TH arranged alternately along the longitudinal direction of the element Em. The area of ​​the steel plate parts Ps and the opening area of ​​the openings TH are, for example, almost the same (i.e., the opening ratio is about 50%). As will be described later, the fresh concrete that flows into the element Em during casting and the air in the element Em are designed to flow into the adjacent connecting space CS through the openings TH.

[0068] By making the first steel plate P1m into a wall column (vertical stripe structure) made of steel plate in this way, the structural stability of the element Em can be improved, and the element Em can be made lighter while maintaining its strength. In addition, the raw concrete that flows into the element Em can be smoothly and satisfactorily flowed into the connecting space CS.

[0069] As shown in Fig. 11(b), the second steel plate P2m of the leading standard element Em is formed of a flat steel plate. This second steel plate P2m is formed to communicate the hollow space HS of the standard element Em with the adjacent connecting space CS, and has an exhaust hole VH drilled therein for releasing air from the hollow space HS and connecting space CS of the standard element Em during the above-mentioned concrete pouring process.

[0070] The exhaust hole VH has a first exhaust hole VH1 provided on the front end surface (first end surface) side of the standard element Em, and a second exhaust hole VH2 provided on a side other than the front end surface side of the standard element Em. The first exhaust hole VH1 and the second exhaust hole VH2 are formed by through holes penetrating the front and back surfaces of the second steel plate P2m, and are formed side by side along the longitudinal direction of the standard element Em at a position closer to the fourth steel plate P4m than to the third steel plate P3m.

[0071] The diameters of the first exhaust hole VH1 and the second exhaust hole VH2 are equal to each other, for example, about 30 mm. The diameters of the first exhaust hole VH1 and the second exhaust hole VH2 are set to a size that allows them to be blocked by the coarse aggregate contained in the concrete. That is, the diameters of the first exhaust hole VH1 and the second exhaust hole VH2 are smaller than the diameter of the coarse aggregate contained in the concrete. As a result, the first exhaust hole VH1 and the second exhaust hole VH2 are naturally blocked by the coarse aggregate contained in the concrete, so that the concrete that has flowed into the connection space CS does not flow into the adjacent element E through the exhaust hole VH (VH1, VH2). Note that, when there are multiple diameters of the coarse aggregate, the diameters of the first exhaust hole VH1 and the second exhaust hole VH2 may be smaller than the average value of the multiple diameters of the coarse aggregate, may be smaller than the diameter of the coarse aggregate that is most contained, or may be smaller than the maximum diameter of the coarse aggregate.

[0072] However, in this embodiment, the total opening area of ​​the first exhaust holes VH1 is set to be larger than the opening area of ​​each of the second exhaust holes VH2. That is, the first exhaust holes VH1 are drilled close together on the tip surface side of the standard element Em, for example, six in number. In contrast, only one second exhaust hole VH2 is drilled in a location other than the tip surface side of the standard element Em.

[0073] The second exhaust holes VH2 are arranged at a distance L1 longer than the adjacent distance of the first exhaust holes VH1 in terms of design, but the distance between the second exhaust hole V2 and the rearmost first exhaust hole VH1 is set to a distance L2 that is twice the distance L1. This is to ensure that the exhaust at the tip of the standard element Em is performed well and that the tip is filled with concrete well. In this example, the total length of the standard element Em is short, and the length from the second exhaust hole VH2 to the rear end of the element Em is not even the distance L1, so only one second exhaust hole VH2 is arranged. The distance L1 is, for example, 1 m.

[0074] Furthermore, a plurality of through holes WH are drilled in the second steel plate P2m of the leading standard element Em at a position close to the third steel plate P3m. These through holes WH are holes for passing the above-mentioned wires W1 and W2, and are drilled at predetermined intervals along the longitudinal direction of the element Em.

[0075] In addition, Fig. 11 illustrates the element Em that is the first to be pressed into the side of the starting shaft among the leading standard elements Em. In the case of this leading element Em, the tips of the first steel plate P1m and the second steel plate P2m are inclined with respect to the longitudinal direction of the element Em to facilitate pressing into the side of the starting shaft. However, in the leading standard element Em that is arranged midway along the entire length of the multiple elements Em arranged in series, the tips of the first steel plate P1m and the second steel plate P2m are not inclined with respect to the longitudinal direction of the element Em, but are perpendicular thereto.

[0076] 12(a) is a plan view of the third steel plate of the leading standard element as viewed from the direction of arrow A3 in FIG. 10, and FIG. 12(b) is a plan view of the fourth steel plate of the leading standard element as viewed from the direction of arrow A4 in FIG. 10.

[0077] 12(a) and 12(b), the third steel plate P3m and the fourth steel plate P4m are formed, for example, from long, flat steel plates. The above-mentioned joints J1 and J2 are provided so as to protrude outward from both long sides of the third steel plate P3m and the fourth steel plate P4m, and extend along the longitudinal direction of the third steel plate P3m and the fourth steel plate P4m.

[0078] 13(a) is a plan view of the first steel plate of the subsequent standard element as viewed in the direction of arrow A1 in FIG. 10, and FIG. 13(b) is a plan view of the second steel plate of the subsequent standard element as viewed in the direction of arrow A2 in FIG. 10.

[0079] As shown in Fig. 13(a), the first steel plate P1m of the following standard element Em is a wall-pillar structure (vertical stripe structure) made of steel plates, similar to the first steel plate P1m of the leading standard element E. Also, as shown in Fig. 13(b), the second steel plate P2m of the following standard element Em is formed of a flat steel plate, similar to the second steel plate P2m of the leading standard element E.

[0080] The second exhaust holes VH2 described above are drilled at the positions close to the fourth steel plate P4m in the second steel plate P2m of the following standard element Em at the distance L1 along the longitudinal direction of the element Em. However, the first exhaust holes VH1 (see FIG. 11(b)) described above are not drilled in the second steel plate P2m of the following standard element Em.

[0081] Furthermore, in the second steel plate P2m of the following standard element Em, at a position close to the third steel plate P3, through holes WH for passing the above-mentioned wires W1, W2 (see FIG. 4) are drilled at predetermined intervals along the longitudinal direction of the element Em. Note that the configurations of the third steel plate P3m and the fourth steel plate P4m of the following standard element Em are the same as those of the third steel plate P3m and the fourth steel plate P4m shown in FIG. 10, and therefore description thereof will be omitted.

[0082] FIG. 14 is a front view of the elements showing the standard connection state of the elements.

[0083] As shown in Fig. 14, adjacent standard elements Em, Em are connected to each other by a joint J1 of one standard element Em and a joint J2 of the other standard element Em with a connection space CS between them. The joints J1, J1 are arranged on the outside, and the joints J2, J2 are arranged on the inside of the joints J1, J1. The joints J1, J1 and the joints J2, J2 overlap each other in contact with each other. In addition, by applying prestress to the wires W1, W2 (see Fig. 4), the tip surface of the joint J1 is abutted against the opposing second steel plate P2m, and the tip surface of the joint J2 is abutted against the opposing first steel plate P1m.

[0084] Furthermore, as shown in FIG. 14, in the bottom block Bb and ceiling block Bc (where elements Em are arranged side by side horizontally) of the element group EG shown in FIG. 9, of the adjacent standard elements Em, Em, the first steel plate P1m of one standard element Em is arranged to face the second steel plate P2m of the other standard element Em through the connecting space CS, and the fourth steel plate P4m is arranged on the ceiling side so that the exhaust holes VH (first exhaust hole VH1 and second exhaust hole VH2) drilled in the second steel plate P2m are located at the top.

[0085] The second steel plate P2m acts as a retaining wall to prevent the ground from collapsing and flowing into the element Em when the soil in front of the element Em is excavated and removed while it is pressed into the ground. For this reason, the element Em that was pressed in first is positioned with the second steel plate P2m side facing outward, and the next element Em to be pressed in is pressed in with the first steel plate P1m facing this face and with the second steel plate P2m side facing outward.

[0086] In the two side blocks Bs (where elements Em are stacked vertically) of the element group EG shown in Fig. 9, the first steel plate P1m of one of the adjacent standard elements Em, Em is arranged to face the second steel plate P2m of the other standard element Em through the connecting space CS, and the first steel plate P1m is arranged to face the ceiling side and the opening TH formed in the first steel plate P1m faces upward, as in the case of rotating Fig. 16 90 degrees to the left. The second steel plate P2m is arranged to face downward, and serves as a work floor when performing excavation work etc. within the element Em.

[0087] FIG. 15 is a front view of the prestressing element.

[0088] The prestressing element Eb is formed of a rectangular steel pipe having a hollow space HS surrounded by the fifth to eighth steel plates P5b to P8b. The fifth steel plate P5b and the sixth steel plate P6b are arranged to face each other, and the seventh steel plate P7b and the eighth steel plate P8b are arranged to face each other while intersecting (orthogonal to) the fifth and sixth steel plates P5b and P6b. The front end face (first end face) in the longitudinal direction (axial direction) of the hollow space HS of the prestressing element Eb and its opposite rear end face (second end face) are also open, similar to the standard element Em.

[0089] Joints J2, J2 are joined to the outer surface of the fifth steel plate P5b near the corners of the element Eb. Also, joints J2, J2 are joined to the outer surface of the seventh steel plate P7b near the corners of the element Eb.

[0090] Figure 16(a) is a plan view of the fifth steel plate of the prestressing element as viewed from the direction of arrow A1 in Figure 15, and Figure 16(b) is a plan view of the seventh steel plate P7b of the prestressing element as viewed from the direction of arrow A5 in Figure 15.

[0091] As shown in Fig. 16(a) and (b), the fifth steel plate P5b and the seventh steel plate P7b are formed of flat steel plates. The fifth steel plate P5b and the seventh steel plate P7b have the above-mentioned through holes WH for wire insertion drilled at predetermined intervals along the longitudinal direction of the fifth steel plate P5b and the seventh steel plate P7b, but the above-mentioned exhaust holes VH are not drilled. This is because the prestressing element Eb is cast after concrete is cast in the standard element Em, so there is no place for the air in the prestressing element Eb to escape. For this reason, an air vent pipe with openings at predetermined intervals is installed in the prestressing element Em. The air vent pipe may have openings at predetermined intervals in the longitudinal direction of the prestressing element Eb, or multiple pipes may be arranged so that the positions of the tip openings are different.

[0092] 17(a) is a plan view of the eighth steel plate of the prestressing element as viewed from the direction of arrow A3 in FIG. 15, and FIG. 17(b) is a plan view of the sixth steel plate of the prestressing element as viewed from the direction of arrow A6 in FIG. 15.

[0093] 17(a) and 17(b), the sixth steel plate P6b and the eighth steel plate P8b are formed of flat steel plates. The sixth steel plate P6b and the eighth steel plate P8b do not have the above-mentioned through holes WH and exhaust holes VH.

[0094] FIG. 18 is a front view of the element showing the connection state between the prestressing element, the modified type standard element, and the standard element.

[0095] In the deformed type standard element Emc, the second steel plate P2m of the normal standard element Em is not provided, and the portion of the second steel plate P2m of the standard element Em is composed of the first steel plate P1m. That is, in the deformed type standard element Emc, the pair of first steel plates P1m, P1m are arranged to face each other.

[0096] This is because, if a normal standard element Em is placed next to the prestressing element Eb, a second steel plate P2m will be placed on the side facing the prestressing element Eb, and as a result, when fresh concrete is poured into the normal standard element Em, it will be obstructed by the second steel plate P2m of the normal standard element Em, and the fresh concrete will not flow into the connecting space CS between the prestressing element Eb and the adjacent normal standard element Em, and the connecting space CS will remain empty.

[0097] In contrast, if a deformed type standard element Emc is placed next to a prestressing element Eb, when fresh concrete is poured into the deformed type standard element Emc, the fresh concrete will flow into the connecting space CS between the prestressing element Eb and the adjacent normal standard element Em through the opening TH of the first steel plate P1m of the deformed type standard element Em, so that concrete can be filled into the connecting space CS.

[0098] Near the corner of the element group EG shown in Figure 9, the adjacent prestress introduction element Eb and the deformed type standard element Emc are arranged so that the first steel plate P1m of the deformed type standard element Emc faces the fifth steel plate P5b of the prestress introduction element Eb through the connecting space CS.

[0099] In addition, near the upper corner of the element group EG shown in Figure 9, the adjacent prestress introduction element Eb and standard element Em are arranged so that the first steel plate P1m of the standard element Em faces the seventh steel plate P7b of the prestress introduction element Eb through the connecting space CS.

[0100] The connection state at the joints J1, J2 between the adjacent prestress-introducing elements Eb and the deformed type standard elements Emc and standard elements Em is the same as that explained in Figure 14 etc., so the explanation will be omitted.

[0101] Next, the process of filling the element with ready-mixed concrete will be described with reference to FIG. 9 and FIGS. 19 to 23.

[0102] First, the sequence of pouring work for filling the elements E and the connection spaces CS with fresh concrete will be described with reference to Fig. 9. Pouring is carried out for each press-in location of the element group EG. The pouring time for one location is, for example, about one hour, and pouring is carried out at 5 to 6 locations per day.

[0103] In the bottom block Bb and the ceiling block Bc of the element group EG, concrete is poured in order from the prestressing elements Eb at both corners to the other prestressing element Eb. In the side blocks Bs of the element group EG, concrete is poured in order from the closing element Ec at the bottom to the standard element Em at the top. Finally, the prestressing element Eb is poured.

[0104] Next, FIG. 19 is a cross-sectional view of a main portion of the element casting space.

[0105] As described above, the tip end of the casting space formed by the multiple elements E is blocked by earth and sand. In this embodiment, the total casting length is, for example, 50,000 to 100,000 mm as described above, but this is too long to be completed in one casting, so for example, a partition plate (partition member) PP is installed at a position 1 / 2 (25,000 to 50,000 mm) or 1 / 3 (16,000 to 33,000 mm) of the total length to divide the casting space, thereby forming a one-time casting space (concrete filling space) L3. Note that here, the length of the casting space L3 is, for example, 25,000 to 50,000 mm.

[0106] The partition plate PP is installed so as to close the opening of the element E. Here, as described above, the partition plate PP is installed in the center of the total pouring length, so the total pouring length is divided into two pouring spaces arranged in series. When pouring the rear pouring space after pouring the front one of these two pouring spaces, the tip face of the rear pouring space is blocked by the partition plate PP, so the leading element E having the above-mentioned exhaust hole VH1 is also arranged at the tip of the rear pouring space. The configuration of the partition plate PP will be explained later.

[0107] A filling detection sensor FD is installed at the innermost part (i.e., the tip of the element E) and the middle part of the pouring space L3. The filling detection sensor FD is a sensor that detects whether concrete has been filled at the sensor installation location in the pouring space L3, and is electrically connected to an external detection device via wiring (not shown).

[0108] In addition, a pressure pipe (inlet pipe) ST is installed in the casting space L3 to allow the fresh concrete to flow into the casting space L3. If the discharge port of the pressure pipe ST is installed in the innermost part of the casting space L3, the innermost part can be reliably filled with the fresh concrete. However, if the fresh concrete is pressure-fed to the innermost part and pushed out to the front side (inlet side), the capacity of the pump vehicle for pressure-fed becomes too large. Therefore, in this embodiment, the discharge port of the pressure pipe ST is arranged at approximately the center position of the casting space L3. This reduces the burden on the pump vehicle for pressure-fed, and therefore there is no need to use a pump vehicle with a large capacity. The distance L4 is half the length of the casting space L3.

[0109] Next, Figure 20(a) is a plan view of an example of a partition plate, Figure 20(b) is a plan view of the partition plate showing the state in which the opening and closing plates that make up the partition plate in Figure 20(a) have been removed, Figure 20(c) is a plan view of the opening and closing plates that make up the partition plate in Figure 20(a), Figure 21(a) is a cross-sectional view along line YY in Figure 20(b), and Figure 21(b) is a plan view showing the partition plate in Figure 20 disassembled.

[0110] 20 and 21, the partition plate PP is formed by joining two rectangular steel plates PP1 and PP2, which are butted together in the height direction when viewed from above. A through hole Hst for passing the pressure pipe ST is drilled in the partition plate PP.

[0111] In addition, a manhole Hh is drilled in the partition plate PP directly above the through hole Hst. This manhole Hh is a passage hole for workers to enter and exit the casting space L3, and is drilled, for example, in a rectangular shape in a plan view. The manhole Hh can be opened and closed freely by attaching and detaching the opening and closing plate BP.

[0112] The opening / closing plate BP is attached to the partition plate PP in a detachable state by the bolt Bt. Before pouring, the opening / closing plate BP is removed from the partition plate PP, and the pouring space L3 can be accessed through the manhole Hh. During pouring, the opening / closing plate BP is attached to the partition plate PP, and the manhole Hh is blocked.

[0113] Furthermore, in this embodiment, an expanded metal structure EX is provided on the upper layer of the partition plate PP and the opening / closing plate BP. This expanded metal structure EX has a plurality of through holes (third exhaust holes) He regularly arranged and drilled therein. The expanded metal structure EX is a structure for monitoring the state of the casting space L3 and releasing the air in the casting space L3 to the outside through the plurality of through holes He. The opening area (total area) of the plurality of through holes He of the expanded metal structure EX can be adjusted by covering the expanded metal structure EX with a steel plate (not shown). The diameter of each through hole He is, for example, 12 mm.

[0114] Such a partition plate PP1 is installed, for example, as follows. That is, as shown in Fig. 21(b), first, the lower steel plate PP1 is installed with the semicircular recess Hst1 on the upper side of the lower steel plate PP1 facing upward. Next, the pressure feed pipe ST is installed in the semicircular recess Hst1 of the lower steel plate PP1, and then the upper steel plate PP2 is butted against the lower steel plate PP1 with the semicircular recess Hst2 on the lower side of the upper steel plate PP2 aligned with the pressure feed pipe ST. Then, the upper steel plate PP1 and the lower steel plate PP2 are butted against each other and the butted portion is welded to install the partition plate PP.

[0115] 22(a) and (b) are plan views of modified examples of the partition plate, and FIG. 22(c) is a plan view of the opening and closing plate of FIGS. 22(a) and (b).

[0116] The configuration of the partition plate PP is not limited to the above and can be modified in various ways. For example, as shown in Fig. 22(a), a manhole may be drilled in the lower part of the partition plate PP, and a through hole Hst for the pressure pipe may be drilled diagonally above the manhole Hh. Also, as shown in Fig. 22(b), both the through hole Hst for the pressure pipe and the manhole Hh may be drilled in the lower part of the partition plate PP. In this case, the boundary between the upper and lower steel plates PP1 and PP2 is located midway in the height direction of the manhole Hh. In these cases, as shown in Fig. 22(c), no through hole He is drilled in the opening and closing plate BP.

[0117] Next, a method for filling the above-mentioned casting space with concrete will be described with reference to Figs.

[0118] As shown in FIG. 19, when pouring, fresh concrete is discharged from the discharge port of the pressure pipe ST and filled from the back of the pouring space L3. At this time, all the through holes He of the partition plate BP are blocked with a steel plate (not shown) or the like. Alternatively, the total opening area of ​​the multiple through holes of the partition plate BP is made smaller than the total opening area of ​​the exhaust hole VH of the element E. In other words, when pouring, the air in the pouring space L3 is restricted from being exhausted from the multiple through holes He of the partition plate BP, and is encouraged to be exhausted from the exhaust hole VH (especially the first exhaust hole VH1) of the element E. This allows the fresh concrete to be preferentially filled at the back of the pouring space L3.

[0119] Next, when the rear side of the casting space L3 is filled with fresh concrete, all of the through holes He of the partition plate BP are opened. This allows the air in the casting space L3 to be exhausted through the second exhaust hole VH2 of the element E and the through holes He of the partition plate BP, while fresh concrete is filled in the front side of the casting space L3.

[0120] In this way, the pouring space L3 is filled with fresh concrete. In this case, the press-in pipe ST and the partition plate PP are left buried in the concrete. The concrete is filled up to the inlet of the press-in pipe ST. If concrete is to be poured further into the front half of the pouring space, a separate press-in pipe ST is placed.

[0121] Figure 23 is a cross-sectional view of the tip of the leading standard element during casting. Figure 23 illustrates an example where three standard elements Em are arranged side by side. Also, here, the leftmost standard element E is already filled with fresh concrete CC, and the example illustrates how fresh concrete CC is being poured into the central standard element Em. Note that the location where multiple standard elements Em are stacked vertically is the same as when Figure 23 is rotated 90 degrees to the left, and they are cast in order from the bottom.

[0122] First, fresh concrete CC is poured into the hollow space HS of the central standard element Em. Then, the fresh concrete CC that has flowed into the hollow space HS of the central standard element Em and the air in the hollow space HS of the central standard element Em flow into the connecting space CS adjacent to the right side of the central standard element Em through the opening TH of the first steel plate P1m of the central standard element Em.

[0123] Furthermore, the air flowing into the connecting space CS adjacent to the right side of the central standard element Em escapes into the hollow space HS of the rightmost standard element Em through the exhaust holes VH (first exhaust hole VH1 and second exhaust hole VH2) drilled in the second steel plate P2m of the rightmost standard element Em.

[0124] In this embodiment, as described above, the first exhaust hole VH1 drilled at the tip of the standard element Em is arranged closer to the second exhaust hole VH2 drilled at a part other than the tip of the element Em, so that air can be efficiently released at the tip of the standard element Em. This makes it possible to speed up the filling of the raw concrete CC into the innermost part of the hollow space HS of the standard element Em, and even when the tip face of the standard element Em is blocked, the raw concrete CC can be satisfactorily filled into the innermost part of the hollow space HS of the standard element Em without creating gaps or air pockets. Therefore, the strength of the pipe roof PR shown in FIG. 7 can be improved.

[0125] Furthermore, as described above, the exhaust holes VH (first exhaust hole VH1 and second exhaust hole VH2) drilled in the second steel plate P2m of the standard element Em are naturally blocked by the coarse aggregate contained in the fresh concrete CC, so that the fresh concrete CC that has flowed into the connecting space CS will not flow through the exhaust holes VH (first exhaust hole VH1 and second exhaust hole VH2) into the hollow space HS of the standard element Em adjacent to the right side of the standard element Em to be poured.

[0126] 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 in the above embodiments, but should be interpreted strictly according to the description in the claims, and includes technologies equivalent to the described technologies in the claims and all modifications that do not deviate from the gist of the claims.

[0127] In the above embodiment, a case has been described in which a full-circumference type pipe roof is constructed in which elements surround the entire periphery of an underground structure, but the present invention is not limited to this and can be applied in various ways, for example, it can be applied to the construction of a sector-shaped, semicircular, portal-shaped or linear-shaped pipe roof.

[0128] In the above embodiment, the first steel plate of the element is described as having a wall column structure (vertical stripe structure) made of steel plate, but the present invention is not limited to this. For example, the first steel plate may be a flat plate with an opening in a part of it. In this case, the opening is formed in the upper part of the first steel plate. Also, the steel plate part Ps of the first steel plate P1m may be arranged obliquely rather than perpendicularly to the longitudinal direction of the element Em, and may be arranged in a truss shape, for example. [Industrial Applicability]

[0129] In the above explanation, the present invention has been described as being applied to the construction of a tunnel for railway facilities, but the present invention is not limited to this and can also be applied to the construction of other underground structures, such as underground shopping malls. [Explanation of symbols]

[0130] PR Pipe Roof EG Elements Bb Bottom Block Bc Ceiling block Bs Side Block E-Element Em Standard Elements Standard elements of emc variants Eb Prestressing element P1m First Steel Plate Ps steel plate part P2m Second Steel Plate P3m 3rd steel plate P4m 4th steel plate P5b 5th Steel Plate P6b 6th Steel Plate P7b 7th Steel Plate P8b 8th Steel Plate HS hollow space CS connected space J1, J2 joint TH opening VH exhaust hole VH1 First exhaust hole VH2 Second exhaust WH through hole CC Concrete W1, W2 Wire PP Partition Board PP1.PP2 Steel plate EX Expanded metal structure He through hole Hst through hole Hh person hole BP opening and closing plate L3 Pouring space FD filling detection sensor ST Pressure Pipe G Construction site DH starting shaft RM propulsion machine Tp Tunnel planned location T-Tunnel

Claims

1. an element preparation process for preparing a plurality of rectangular tubular elements having a hollow space surrounded by a first steel plate and a second steel plate facing each other and a third steel plate and a fourth steel plate facing each other while intersecting the first steel plate and the second steel plate, the elements having a first end face in the axial direction of the hollow space and a second end face opposite to the first end face, the first end face being open; an element pressing process in which, with the first end face of the element facing the side of the starting shaft, the soil in front of the element is excavated and discharged along the outer periphery of the planned underground structure on the side of the starting shaft, and the element is pressed into the ground, thereby installing the multiple elements in parallel while being connected to each other via a connecting space between adjacent elements; a concrete filling step of filling the inside of the element and the connection space with concrete in a state in which the first end surface of the element is closed after the element press-in step; having In the element press-fitting process, the elements are press-fitted such that the first steel plate and the second steel plate of the adjacent elements face each other via the connection space, In the element preparation process, a communication hole that communicates the hollow space with the connecting space is formed in the first steel plate, and an exhaust hole that is formed to communicate the hollow space with the connecting space and that releases air in the hollow space and the connecting space when the concrete is poured into the element is formed in the second steel plate, the exhaust hole is formed at a position closer to the fourth steel plate than to the third steel plate, and has a first exhaust hole provided on the first end face side of the element and a second exhaust hole provided on a side other than the first end face side of the element, and a total opening area of ​​the first exhaust holes is larger than an opening area per one position of the second exhaust hole, A pipe roof construction method comprising the steps of:

2. 2. The pipe roof construction method according to claim 1, characterized in that, in the element pressing-in process, in locations where the multiple elements are arranged in a horizontal row, the elements are pressed in so that the exhaust holes are located at the top, and in locations where the multiple elements are stacked in a vertical row, the elements are pressed in so that the communication holes face upward.

3. A pipe roof construction method as described in claim 1 or 2, characterized in that the first exhaust hole is formed by a plurality of through holes arranged at a predetermined first distance along the longitudinal direction of the element, and the second exhaust hole is formed by a plurality of through holes arranged at a second distance along the longitudinal direction of the element that is longer than the first distance.

4. 4. The pipe roof construction method according to claim 1, wherein the diameters of the first exhaust hole and the second exhaust hole are smaller than the diameter of the coarse aggregate of the concrete.

5. 5. The pipe roof construction method according to claim 1, wherein the first exhaust hole and the second exhaust hole have the same dimensions.

6. In the concrete filling process, a partition member installation step for installing a partition member that partitions the hollow space within the element to form a concrete filling space within the element; an inlet pipe installation process in which an inlet pipe for injecting the concrete into the concrete filling space is installed within the element such that a discharge portion of the inlet pipe is located at a longitudinal center portion of the concrete filling space; pouring the concrete into the concrete filling space through the inlet pipe and filling the concrete from the first end surface of the element toward the second end surface; The pipe roof construction method according to any one of claims 1 to 5, further comprising the steps of:

7. In the partition member installation process, preparing a partition member having a third exhaust hole for releasing air from within the element, the third exhaust hole being formed in an adjustable state in terms of opening area; In the concrete filling process, a step of filling the concrete into the concrete filling space while blocking all of the third exhaust holes of the partition member or making the opening area of ​​the third exhaust holes smaller than the opening area of ​​the exhaust holes of the element before the concrete is filled into the first end surface side of the element; After the concrete is filled on the first end surface side of the element, the concrete is poured into the concrete filling space while the third exhaust hole is open.

7. The pipe roof construction method according to claim 6.

8. 8. A pipe roof construction method as claimed in claim 6 or 7, characterized in that it further comprises a step of installing a filling detection sensor to detect that the concrete has been filled in the inner part, or in the inner part and the middle part, of the concrete filling space before pouring the concrete into the concrete filling space.

9. A pipe roof construction method as described in any one of claims 6 to 8, characterized in that when the concrete filling space has been filled with the concrete, the inlet pipe and the partition member are left buried in the concrete, and the concrete is filled up to the inlet of the inlet pipe.

10. The pipe roof construction method according to any one of claims 1 to 9, characterized in that the first steel plate of the element is constructed by joining a steel plate of a predetermined width between the third steel plate and the fourth steel plate in the longitudinal direction of the element.

11. A plurality of rectangular tubular elements are arranged on a side surface of the starting shaft along the outer periphery of the underground structure and are arranged in parallel with each other in a connected state with a connecting space between adjacent elements; Concrete filled in the elements and in the connecting spaces; Equipped with The element has a hollow space surrounded by a first steel plate and a second steel plate facing each other, and a third steel plate and a fourth steel plate facing each other while intersecting the first steel plate and the second steel plate, and a first end face in an axial direction of the hollow space and a second end face located opposite to the first end face are open, The plurality of elements are arranged such that the first steel plate and the second steel plate of the adjacent elements face each other via the connection space, A communication hole that communicates the hollow space and the connection space is formed in the first steel plate, the second steel plate is formed with an exhaust hole that is formed so as to communicate with the hollow space and the connecting space and that releases air from the hollow space and the connecting space when the concrete is poured into the element; the exhaust hole is formed at a position closer to the fourth steel plate than to the third steel plate, and includes a first exhaust hole provided on the first end face side of the element, and a second exhaust hole provided on a side other than the first end face side of the element, A pipe roof characterized in that a total opening area of ​​the first exhaust holes is formed to be larger than an opening area per one of the second exhaust holes.

12. In a portion where the plurality of elements are arranged side by side in the horizontal direction, the elements are installed so that the exhaust hole is located at the upper portion, The pipe roof according to claim 11, characterized in that in a location where the plurality of elements are stacked vertically, the elements are installed so that the communication holes face upward.

13. the first exhaust hole is formed by a plurality of through holes arranged at a predetermined first distance along a longitudinal direction of the element, The pipe roof according to claim 11 or 12, characterized in that the second exhaust hole is formed by a plurality of through holes arranged at a second distance longer than the first distance along the longitudinal direction of the element.

14. The pipe roof according to any one of claims 11 to 13, characterized in that the diameters of the first exhaust hole and the second exhaust hole are smaller than the diameter of the coarse aggregate of the concrete.

15. The pipe roof according to any one of claims 11 to 14, characterized in that the first exhaust hole and the second exhaust hole have the same dimensions.

16. A pipe roof as described in any one of claims 11 to 15, characterized in that a partition member that divides the inside of the element to form a concrete filling space within the element is embedded in the concrete.

17. 17. The pipe roof according to claim 16, wherein the partition member is formed with a third exhaust hole for releasing air from the concrete filled space.

18. A pipe roof as described in claim 16 or 17, characterized in that an inlet pipe for injecting the concrete into the element is embedded in the concrete with the discharge portion of the inlet pipe positioned in the longitudinal center of the concrete filling space, and the inside of the inlet pipe is filled with the concrete up to the inlet of the inlet pipe.

19. A pipe roof as described in any one of claims 16 to 18, characterized in that a filling detection sensor for detecting the filling of the concrete is buried in the back part, or in the back part and middle part, of the concrete filling space.

20. The pipe roof according to any one of claims 11 to 19, characterized in that the first steel plate of the element is constructed by joining steel plates of a predetermined width perpendicular to the longitudinal direction of the element.

21. Rectangular tubular elements are arranged on the side of the starting shaft along the outer periphery of the underground structure and are arranged side by side in a state where they are connected to each other via a connecting space between adjacent elements, The element has a hollow space surrounded by a first steel plate and a second steel plate facing each other, and a third steel plate and a fourth steel plate facing each other while intersecting the first steel plate and the second steel plate, and a first end face in an axial direction of the hollow space and a second end face located opposite to the first end face are open, The first steel plate and the second steel plate of the adjacent elements are arranged to face each other via the connection space, The first steel plate has a communication hole that communicates with the hollow space and the connecting space, the second steel plate is formed with an exhaust hole that is formed so as to communicate with the hollow space and the connecting space and that releases air from the hollow space and the connecting space when concrete is poured into the element; the exhaust hole is formed at a position closer to the fourth steel plate than to the third steel plate, and includes a first exhaust hole provided on the first end face side of the element, and a second exhaust hole provided on a side other than the first end face side of the element, An element constituting a pipe roof, characterized in that the total opening area of ​​said first exhaust holes is greater than the opening area of ​​each of said second exhaust holes.

22. the first exhaust hole is formed by a plurality of through holes arranged at a predetermined first distance along a longitudinal direction of the element, An element constituting a pipe roof as described in claim 21, characterized in that the second exhaust hole is formed by a plurality of through holes arranged at second distances longer than the first distance along the longitudinal direction of the element.

23. 23. An element constituting a pipe roof according to claim 21 or 22, characterized in that the diameters of the first exhaust hole and the second exhaust hole are smaller than the diameter of the coarse aggregate of the concrete.

24. 24. An element for constructing a pipe roof according to any one of claims 21 to 23, characterized in that the first exhaust hole and the second exhaust hole have the same dimensions.

25. The element constituting a pipe roof described in any one of claims 21 to 24, characterized in that the first steel plate is constructed by joining steel plates of a predetermined width perpendicular to the longitudinal direction of the element.

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