JP7670280B2 - Segment and method for manufacturing the segment - Google Patents

Description

The present invention relates to segments used in shield tunnel linings and a method for manufacturing the segments.

Shield tunnels, which are used as pipelines for water supply and sewage systems, utility conduits, roads, railways, etc., are constructed using the shield construction method.

In the shield method, for example, a starting shaft and a destination shaft are constructed in the ground, and while the ground is excavated from the starting shaft to the destination shaft with a shield tunneling machine, multiple segments are successively connected behind the shield tunneling machine in the circumferential and axial directions of the tunnel to construct a cylindrical tunnel structure (in other words, a lining).

One example of this type of segment is the tunnel segment described in Patent Document 1. The tunnel segment described in Patent Document 1 consists of a segment piece made of reinforced concrete and a waterproof sheet attached to the outside of the segment piece (the surface facing the ground). This waterproof sheet is intended to prevent water leakage through chips and cracks in the concrete in the segment piece.

Japanese Patent Application Publication No. 140992

However, in the tunnel segments described in Patent Document 1, the waterproof sheet is only provided on the ground-facing surface of the segment pieces, so some ingenuity may be required to prevent water that has entered the gaps between the sides of adjacent segment pieces from entering the segment pieces.

The present invention aims to provide a segment having a waterproof sheet that can prevent water from entering the segment piece from the side, and a manufacturing method thereof.

According to one aspect of the present invention, a segment is provided that has segment pieces made of precast concrete that form a tunnel structure. This segment includes a waterproof sheet that covers the surface of the segment piece, and is provided from the back surface, which is the surface of the surface facing the ground, to both side surfaces in the tunnel axial direction and both side surfaces in the tunnel circumferential direction. The waterproof sheet has a back sheet portion corresponding to the back surface, a first side sheet portion corresponding to one of the side surfaces in the tunnel axial direction, a second side sheet portion corresponding to the other side surface in the tunnel axial direction, a third side sheet portion corresponding to one of the side surfaces in the tunnel circumferential direction, and a fourth side sheet portion corresponding to the other side surface in the tunnel circumferential direction.

According to another aspect of the present invention, a method for manufacturing a segment according to the above aspect is provided. This method for manufacturing a segment includes a covering step of covering a portion of the concrete corresponding to the back surface with the back surface sheet portion after pouring concrete into a form for a segment piece and before steam curing or underwater curing of the concrete.

According to the manufacturing method of the segment according to the one aspect and the segment according to the other aspect, the waterproof sheet covering the surface of the segment piece is provided from the back surface, which is the surface of the surface of the segment piece facing the ground, to both side surfaces in the tunnel axial direction and both side surfaces in the tunnel circumferential direction, and has a back sheet portion corresponding to the back surface, a first side sheet portion corresponding to one of the side surfaces in the tunnel axial direction, a second side sheet portion corresponding to the other side surface in the tunnel axial direction, a third side sheet portion corresponding to one of the side surfaces in the tunnel circumferential direction, and a fourth side sheet portion corresponding to the other side surface in the tunnel circumferential direction. In this way, since each side surface of the segment piece is covered by the first side sheet portion, the second side sheet portion, the third side sheet portion, and the fourth side sheet portion, even if water infiltrates from the ground side into the gap between the side surfaces of adjacent segment pieces, these side sheet portions can prevent water from entering the segment piece.

In this way, it is possible to provide a segment having a waterproof sheet capable of preventing water from entering the segment piece from the side, and a method for manufacturing the segment.

And, according to the segment manufacturing method according to the other aspect, the back covering process of covering the portion of the concrete corresponding to the back surface with the back sheet portion is carried out after pouring the concrete into the formwork for the segment pieces and before steam curing or underwater curing of the concrete, so that the back sheet portion of the waterproof sheet can be used as a curing sheet for the concrete when manufacturing the segments. As a result, there is no need to prepare a separate curing sheet for the concrete when manufacturing the segments, and curing work and manufacturing costs can be reduced.

FIG. 2 is a perspective view of a segment according to an embodiment of the present invention. FIG. FIG. 2 is a perspective view of a segment piece of the segment. 4 is a perspective view of the components that constitute the waterproof sheet of the segment. FIG. 13 is a perspective view of another member constituting the waterproof sheet of the segment. FIG. FIG. 4 is a perspective view of a corner cover seal of the segment. 4A to 4C are process diagrams illustrating a method for manufacturing the segment. 7 is a process diagram continuing from FIG. 6 for explaining the method of manufacturing the segment. FIG. 8 is a process diagram continuing from FIG. 7 for explaining the method of manufacturing the segment. FIG. FIG. 4 is a partial cross-sectional view for explaining a waterproofing effect in the segment.

The following describes an embodiment of the present invention with reference to the drawings. Figure 1 is a perspective view showing the schematic configuration of a segment 1 in one embodiment of the present invention. Figure 2 is a plan view of segment 1 as viewed from the direction of arrow A (the natural ground side) shown in Figure 1.

The segment 1 shown in Figures 1 and 2 constitutes part of the tunnel structure in a shield tunnel. In the shield method for constructing a shield tunnel, while the ground is excavated with a shield machine, multiple segments 1 are successively connected behind the shield machine (the tunnel mouth side) in the tunnel circumferential and axial directions to construct a cylindrical or arch-shaped tunnel structure (lining). Specifically, at the tunnel mouth side, multiple segments 1 are connected in the tunnel circumferential direction to construct a segment ring, and the segment 1 of the next segment ring is connected to the side of this segment ring on the face side in the tunnel axial direction. By repeating this procedure, the tunnel structure is constructed inside the excavated shaft excavated by the shield machine.

The segment 1 is composed of a segment piece 2 and a waterproof sheet 3. In this embodiment, the segment 1 further includes a corner cover seal 4. Figure 3 is a perspective view of the segment piece 2, Figures 4 and 5 are perspective views of the members that make up the waterproof sheet 3, and Figure 6 is a perspective view of the corner cover seal 4.

The segment piece 2 is a precast concrete member that constitutes the tunnel structure and is the main body of the segment 1. In plan view (e.g., plan view from the ground side), the segment piece 2 is formed in a rectangular shape with the long side extending in the tunnel circumferential direction and the short side extending in the tunnel axial direction, and in side view from the tunnel axial direction, it has a predetermined thickness and is formed in an arc shape that curves to fit the inner surface of the excavation hole (see Figure 3).

The side surfaces 2a1, 2a2 on both sides of the segment piece 2 in the tunnel axial direction form connection surfaces with other adjacent segments 1 (segment rings) in the tunnel axial direction, and the side surfaces 2b1, 2b2 on both sides of the segment piece 2 in the tunnel circumferential direction form connection surfaces with other adjacent segments 1 in the tunnel circumferential direction. Although not shown in the figure, each side surface (2a1, 2a2, 2b1, 2b2) is provided with a connection structure (connector) consisting of, for example, a male joint and a female joint for connection with other adjacent segments 1.

In this embodiment, the side surfaces 2a1, 2a2 in the tunnel axial direction and the side surfaces 2b1, 2b2 in the tunnel circumferential direction of the segment piece 2 are formed with a seal groove 21 for accommodating a seal member, i.e., for accommodating a seal member 5 (see FIG. 10 described later), so as to extend in a direction parallel to the back surface 2c, which is the natural ground side surface of the segment piece 2. The seal member 5 is made of, for example, an elastic material. The seal groove 21 is recessed, for example, at two locations spaced apart in the thickness direction of the segment piece 2. The seal member 5 is a member for sealing the gap between adjacent segment pieces 2 and preventing water from entering the tunnel from the natural ground side through the gap in a tunnel structure consisting of multiple segments 1.

The waterproof sheet 3 is a sheet that covers the surface of the segment piece 2. This waterproof sheet 3 is provided from the back surface 2c, which is the surface of the segment piece 2 facing the ground, to the side surfaces 2a1 and 2a2 on both sides in the tunnel axial direction and the side surfaces 2b1 and 2b2 on both sides in the tunnel circumferential direction.

As can be seen from Figures 1 to 3, the waterproof sheet 3 has a back sheet portion 31 corresponding to the back surface 2c of the segment piece 2, a first side sheet portion 32 corresponding to one side surface 2a1 in the tunnel axial direction (hereinafter referred to as the first side surface 2a1 as appropriate), a second side sheet portion 33 corresponding to the other side surface 2a2 in the tunnel axial direction (hereinafter referred to as the second side surface 2a2 as appropriate), a third side sheet portion 34 corresponding to one side surface 2b1 in the tunnel circumferential direction (hereinafter referred to as the third side surface 2b1 as appropriate), and a fourth side sheet portion 35 corresponding to the other side surface 2b2 in the tunnel circumferential direction (hereinafter referred to as the fourth side surface 2b2 as appropriate). Although not particularly limited, in this embodiment, the one side in the tunnel axial direction is the face side, and the other side in the tunnel axial direction is the tunnel mouth side.

The back sheet portion 31 is provided along the back surface 2c of the segment piece 2 and is the portion of the waterproof sheet 3 that covers the back surface 2c of the segment piece 2, and is formed, for example, in a rectangular shape of the same dimensions as the back surface 2c when viewed in a plan view from the ground side.

Specifically, the rear sheet portion 31 is made of a film-like or thin sheet-like material that covers the entire rear surface 2c of the segment piece 2.

In this embodiment, the first side sheet portion 32 and the second side sheet portion 33 of the waterproof sheet 3 are both made of a first member formed of a member separate from the member that constitutes the back sheet portion 31. Similarly, in this embodiment, the third side sheet portion 34 and the fourth side sheet portion 35 of the waterproof sheet 3 are both made of a second member formed of a member separate from the member that constitutes the back sheet portion 31. In other words, in this embodiment, each side sheet portion (32 to 35) of the waterproof sheet 3 is each made of a member formed of a member separate from the member that constitutes the back sheet portion 31.

As shown in Figs. 4 and 5, in this embodiment, the first member constituting the first side sheet portion 32 and the second side sheet portion 33 and the second member constituting the third side sheet portion 34 and the fourth side sheet portion 35 are molded products having an L-shaped cross-sectional shape that covers the edge portion on the back surface 2c side of the segment piece 2. The first member constituting the first side sheet portion 32 and the second side sheet portion 33 is curved in an arc shape that matches the back surface 2c of the segment piece 2, and the second member constituting the third side sheet portion 34 and the fourth side sheet portion 35 extends linearly. The "edge portion" covered by the first member and the second member refers to a portion that has a predetermined width on the back surface 2c side and the side (2a1, 2a2, 2b1, 2b2) side. The first side sheet portion 32 and the second side sheet portion 33 are molded to have the same shape, and the third side sheet portion 34 and the fourth side sheet portion 35 are also molded to have the same shape.

Specifically, for the four edges on the back surface 2c side of the segment piece 2, the first side sheet portion 32 covers the portion on the first side surface 2a1 side (long side portion), the second side sheet portion 33 covers the portion on the second side surface 2a2 side (long side portion), the third side sheet portion 34 covers the portion on the third side surface 2b1 side (short side portion), and the fourth side sheet portion 35 covers the portion on the fourth side surface 2b2 side (short side portion).

In this embodiment, the rear sheet portion 31 is formed in a rectangular shape with the same dimensions as the rear surface 2c of the segment piece 2 as described above. The rear sheet portion 31 is attached to the rear surface 2c of the segment piece 2 with each edge portion sandwiched between the corresponding side sheet portion (32-35) and the rear surface 2c of the segment piece 2. Each side sheet portion (32-35) has a portion that is attached from above to the corresponding edge portion of the rear sheet portion 31 and a portion that is directly attached to the corresponding side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2, and is configured to cover the corresponding edge portion on the rear surface 2c side of the segment piece 2 by being attached in this manner.

In this embodiment, each side sheet portion (32 to 35) is provided from the edge of the back sheet portion 31 to the portion in front of the seal groove portion 21. Specifically, each side sheet portion (32 to 35) is provided up to the portion in front of the seal groove portion 21 on the natural ground side of the two seal groove portions 21.

The members (materials) used for the waterproof sheet 3 have excellent material properties, such as water resistance, alkali resistance (for example, not generally deteriorating at pH 11 to 12), damage prevention, and UV resistance. Therefore, such material properties are possessed by the film-like or sheet-like member constituting the back sheet portion 31, the first member constituting the first side sheet portion 32 and the second side sheet portion 33, and the second member constituting the third side sheet portion 34 and the fourth side sheet portion 35.

The members that make up the waterproof sheet 3 are elastic. Therefore, the back sheet portion 31 and each side sheet portion (32-35) can expand and contract in response to displacements such as cracks in the concrete that makes up the segment piece 2. In other words, the waterproof sheet 3 is a crack-compacting sheet. Furthermore, when connecting to another adjacent segment 1, each side sheet portion (32-35) is pressed by the other segment 1 and elastically deforms together with the sealing member 5.

In this embodiment, the members (materials) constituting the waterproof sheet 3 have material properties that allow them to be attached to the surface of the concrete through alkaline bleeding water that rises from within the concrete constituting the segment piece 2 to the surface of the concrete during the manufacturing process of the segment piece 2. The members constituting the waterproof sheet 3 attached to the surface of the segment piece 2 can be firmly attached without peeling off from the segment piece 2 not only when the segment 1 is in use, but also during the steam curing process of the concrete, the underwater curing process, and when the segment 1 is stored, which will be described later. The attachment (joining) of each side sheet portion (32 to 35) to the corresponding edge portion of the back sheet portion 31 is performed, for example, by adhesive. In addition, in cases where the amount of bleeding water is insufficient when the side sheet portions (32 to 35) are attached to each side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2, the attachment (joining) of each side sheet portion (32 to 35) to each side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2 may also be performed by adhesive.

As shown in Figures 1, 2 and 6, the corner cover seals 4 are formed to cover the parts of the waterproof sheet 3 that correspond to the four corners C on the back surface 2c side of the segment piece 2. In other words, the segment 1 has four corner cover seals 4. Each corner cover seal 4 is attached (joined) to each side sheet portion (32-35) by, for example, an adhesive. The corner cover seals 4 have the same material properties as the first member and the second member (each side sheet portion (32-35)). These corner cover seals 4 can protect the parts of the waterproof sheet 3 that correspond to the four corners C on the back surface 2c side of the segment piece 2, and can also close the gaps between the side sheet portions that may occur in these areas from above.

Next, the manufacturing method of the segment 1 in this embodiment will be described below mainly with reference to Figs. 7 to 9. Figs. 7 to 9 are each an example of a process diagram for explaining the manufacturing method of the segment 1, and in this embodiment, the process proceeds in the order of Figs. 7(a) to 7(c), Figs. 8(d) to 8(f), and Figs. 9(g) to 9(i).

In this embodiment, the manufacturing method of the segment 1 includes a formwork assembly process (see FIG. 7(a)), a concrete pouring process (see FIG. 7(b)), a surface finishing process (see FIG. 7(c)), a back surface coating process (see FIG. 8(d)), a steam curing process (see FIG. 8(e)), a demolding process (see FIG. 8(f)), a side surface coating process (see FIG. 9(g)), a corner coating process (see FIG. 9(h)), and an underwater curing process (see FIG. 9(i)).

In the formwork assembly process shown in FIG. 7(a), the formwork M is assembled. In this embodiment, the formwork M is positioned so that the portion of the formwork M that corresponds to the ground side of the segment 1 when in use, i.e., the portion that corresponds to the back surface 2c of the segment piece 2, faces vertically upward. In this embodiment, the portion of the formwork M that corresponds to the back surface 2c of the segment piece 2 is open and not closed by a formwork member.

In the concrete pouring process shown in FIG. 7(b), the concrete that will form the segment piece 2 is poured into the formwork M. Although not shown in the figure, a pre-assembled reinforcing bar cage is inserted into the formwork M before pouring the concrete. The concrete is then poured and compacted.

In the surface finishing process shown in FIG. 7(c), the exposed surface of the concrete poured into the formwork M is smoothed and finished evenly with a wooden trowel or metal trowel. Because the poured concrete has low fluidity, this surface finishing process finishes the exposed surface of the concrete into a curved surface.

In the back surface covering process shown in FIG. 8(d), the portion of the concrete in the formwork M that corresponds to the back surface 2c of the segment piece 2 (i.e., the curved surface that was finished in the surface finishing process) is covered (wrapped) with the back surface sheet portion 31.

In this embodiment, the back covering process is performed after pouring concrete into the formwork M for the segment piece (more specifically, after the surface finishing process) and before steam curing of the concrete (steam curing process), in which the portion of the concrete that corresponds to the back surface 2c of the segment piece 2 is covered with the back sheet portion 31.

Specifically, the material constituting the back sheet portion 31 is prepared, for example, by cutting a rolled film or sheet material according to the dimensions of the back surface 2c. The material constituting the back sheet portion 31 is then placed on the curved surface of the concrete by a worker or the like, and is finished (laminated) uniformly over the entire surface using a wooden trowel or metal trowel to prevent wrinkles or air pockets.

Here, conventionally, in order to prevent drying shrinkage of the exposed surface of the poured concrete, the exposed surface of the concrete is covered with a curing sheet immediately after pouring the concrete, and this curing sheet is then removed, for example, after the concrete has hardened. On the other hand, the back sheet portion 31 functions as a sheet to prevent drying shrinkage of the concrete during the manufacturing process in place of the conventional curing sheet, and is not peeled off even after the concrete has hardened, and furthermore, it is not peeled off even when the segment 1 is in use, but rather covers the back surface 2c as it is and functions as part of the waterproof sheet 3.

In this embodiment, the back sheet portion 31 adheres to the surface of the concrete via bleeding water in the surface layer of the concrete. In other words, the back sheet portion 31 is placed on the portion of the concrete that corresponds to the back surface 2c of the segment piece 2, and the back sheet portion 31 is adhered (joined) to the surface of the concrete using bleeding water.

The steam curing process shown in Figure 8 (e) is a process in which the formwork M into which concrete has been poured is stored in a high-temperature steam chamber filled with high-temperature steam for a specified period of time, thereby quickly increasing the strength of the concrete. In this process, for example, the concrete develops the strength required for demolding the formwork M.

As such, in this embodiment, the back coating process and steam curing (steam curing process) are carried out before the formwork is removed (demolding process).

In the demolding process shown in FIG. 8(f), the formwork M is removed (disassembled) after the concrete has developed a predetermined strength. Note that instead of disassembling the formwork M, the demolding process may involve removing the concrete (more specifically, the integrated body of the segment piece 2 and the back sheet portion 31) from the formwork M that has developed a predetermined strength.

In the side covering process shown in FIG. 9(g), the edges on the back surface 2c side of the segment piece 2 formed by the formwork M are covered (wrapped) with the remaining members constituting the waterproof sheet 3. Specifically, for the four edges on the back surface 2c side of the segment piece 2, the portion on the first side surface 2a1 side is covered with the first side surface sheet portion 32, the portion on the second side surface 2a2 side is covered with the second side surface sheet portion 33, the portion on the third side surface 2b1 side is covered with the third side surface sheet portion 34, and the portion on the fourth side surface 2b2 side is covered with the fourth side surface sheet portion 35.

In this embodiment, each side sheet portion (32-35) is attached from above to the corresponding edge portion of the back sheet portion 31 and directly to the corresponding side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2, so that each side sheet portion (32-35) covers the corresponding edge portion on the back surface 2c side of the segment piece 2. The attachment (joining) of each side sheet portion (32-35) to the corresponding edge portion of the back sheet portion 31 is performed, for example, by an adhesive. Also, when attaching each side sheet portion (32-35) to the corresponding side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2, the amount of bleeding water may be insufficient. In this case, the attachment (joining) of each side sheet portion (32-35) to the corresponding side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2 may also be performed by an adhesive.

In the corner covering process shown in FIG. 9(h), the portions of the waterproof sheet 3 that correspond to the four corners C on the back surface 2c side of the segment piece 2 are covered with corner cover seals 4. Specifically, each corner cover seal 4 is attached (joined) to each side sheet portion (32-35) with an adhesive.

In the underwater curing process shown in FIG. 9(i), the integrated body of the segment piece 2 and waterproof sheet 3 is stored underwater for a specified number of days. Specifically, the integrated body of the segment piece 2 and waterproof sheet 3 is lifted and stored underwater in an upright position as shown in FIG. 9(i). In this process, for example, the segment piece 2 develops the concrete strength and quality required as part of the tunnel structure.

After a certain number of days have passed, the integrated segment piece 2 and waterproof sheet 3 are pulled out of the water and stored (stocked) on land until they are shipped. This completes the manufacture of the segment 1 consisting of the segment piece 2 and waterproof sheet 3.

Next, the waterproofing effect of segment 1 will be described with reference to FIG. 10. FIG. 10 is a partial cross-sectional view for explaining the waterproofing effect of segment 1. FIG. 10(a) shows the connection state of segments 1 adjacent to each other in the tunnel axis direction, and FIG. 10(b) shows the connection state of segments 1 adjacent to each other in the tunnel circumferential direction.

When adjacent segments 1 are connected by a connection structure (connector) not shown, each side sheet portion (32-35) is pressed by the other segment 1 and elastically deforms together with the seal member 5. At this time, the first side sheet portion 32 of the waterproof sheet 3 of one segment 1 and the second side sheet portion 33 of the waterproof sheet 3 of the other segment 1 are crushed and in close contact with each other (see FIG. 10(a)). Then, the third side sheet portion 34 of the waterproof sheet 3 of one segment 1 and the fourth side sheet portion 35 of the waterproof sheet 3 of the other segment 1 are crushed and in close contact with each other (see FIG. 10(b)). As a result, the ground side area of the gap between adjacent segment pieces 2 is generally sealed by each side sheet portion (32-35). As a result, water is prevented from entering through the gap between adjacent segment pieces 2. In addition, by providing a seal member 5 on the tunnel center side as in this embodiment, water is more reliably prevented from entering through the gap between adjacent segment pieces 2.

The back surface 2c of the segment piece 2 is covered by the back surface sheet portion 31 of the waterproof sheet 3, which prevents water from the ground side from reaching the back surface 2c of the segment piece 2 and from entering the segment piece 2 from the back surface 2c side. In addition, the portions of each side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2 in front of the ground-side seal groove portion 21 (ground side) are all covered by the corresponding side surface sheet portions (32-35), and the ground-side seal member 5 prevents water from the ground side from reaching the remaining portions of each side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2 that are not covered by the side surface sheet portions (32-35). This prevents water on the natural ground side from reaching each side (2a1, 2a2, 2b1, 2b2) of the segment piece 2, and prevents water on the natural ground side from entering the segment piece 2 from each side (2a1, 2a2, 2b1, 2b2).

In addition, when the segment 1 is in use, even if minute cracks or other such defects that do not affect strength occur in the surface layer on the back surface 2c side or the surface layer on the side surfaces (2a1, 2a2, 2b1, 2b2) of the segment piece 2, the back sheet portion 31 and each side sheet portion (32-35) will not break and will expand and contract in response to the displacement of the cracks in the surface layer. Therefore, water on the ground side is prevented from passing through the waterproof sheet 3 and entering the segment piece 2 through minute cracks that may occur in the surface layer of the segment piece 2. As a result, the durability and water resistance of the segment piece 2 are further improved.

According to the segment 1 and its manufacturing method of this embodiment, the waterproof sheet 3 is provided from the back surface 2c of the segment piece 2 to the side surfaces 2a1, 2a2 on both sides in the tunnel axial direction and the side surfaces 2b1, 2b2 on both sides in the tunnel circumferential direction, and has a back surface sheet portion 31 corresponding to the back surface 2c, and a first side surface sheet portion 32, a second side surface sheet portion 33, a third side surface sheet portion 34, and a fourth side surface sheet portion 35 corresponding to each side surface (2a1, 2a2, 2b1, 2b2). In this way, since each side surface (2a1, 2a2, 2b1, 2b2) of the segment piece 2 is covered by the first side surface sheet portion 32, the second side surface sheet portion 33, the third side surface sheet portion 34, and the fourth side surface sheet portion 35, even if water infiltrates from the ground side into the gap between the side surfaces of adjacent segment pieces 2, these side surface sheet portions (32 to 35) can prevent water from infiltrating into the segment piece 2.

In this way, it is possible to provide a segment 1 having a waterproof sheet 3 capable of preventing water from entering the segment piece 2 from the sides 2a1, 2a2, 2b1, 2b2) of the segment piece 2, and a manufacturing method thereof.

In this embodiment, each of the side sheet portions (32-35) in the waterproof sheet 3 is made of a material formed by a material separated from the material constituting the back sheet portion 31. This allows each of the side sheet portions (32-35), which have a more complex shape than the back sheet portion 31, to be formed separately from the back sheet portion 31, which has a simple shape, making it possible to manufacture the waterproof sheet 3 extremely easily compared to the case where the entire waterproof sheet 3 is integrally formed. In particular, the first side sheet portion 32 and the second side sheet portion 33 in the tunnel axis direction are three-dimensionally curved and have a more complex shape than the other side sheet portions (34, 35). Therefore, it is preferable in manufacturing the segment 1 if the first side sheet portion 32 and the second side sheet portion 33 of each of the side sheet portions (32-35) are made of a material formed by a material separated from the material constituting the back sheet portion 31.

In this embodiment, each side sheet portion (32-35) is provided from the edge of the back sheet portion 31 to the portion in front of the seal groove portion 21. In other words, only the portion of the corresponding side (2a1, 2a2, 2b1, 2b2) that is likely to be reached by water on the natural ground side is covered by each side sheet portion (32-35), and as a result, the material cost of the waterproof sheet 3 can be reduced.

According to the manufacturing method of the segment 1 in this embodiment, the back covering process is performed after pouring concrete into the formwork M for the segment pieces and before steam curing of the concrete, so the back sheet portion 31 of the waterproof sheet 3 can be used as a curing sheet for the concrete during segment manufacturing, particularly during steam curing. As a result, there is no need to prepare a separate curing sheet for the concrete during steam curing, which reduces the curing work and manufacturing costs.

According to the manufacturing method of the segment 1 in this embodiment, the portion of the formwork M that corresponds to the back surface 2c of the segment piece 2 is configured to be open, and the back surface covering process and steam curing (steam curing process) are performed before the formwork M is removed. As a result, immediately after pouring the concrete (more specifically, immediately after the surface finishing process), the surface of the concrete in the formwork M can be quickly covered with the back surface sheet portion 31, and the process can proceed directly to the steam curing process.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and variations are possible based on the technical concept of the present invention.

For example, each side sheet portion (32-35) of the waterproof sheet 3 is provided from the edge of the back sheet portion 31 to the portion just before the seal groove portion 21 on the ground side, but this is not limited thereto, and each side sheet portion may be provided over the entire corresponding side surface (2a1, 2a2, 2b1, 2b2).

In addition, each of the side sheet portions (32-35) in the waterproof sheet 3 is made of a member (first member, second member) formed by a member separate from the member constituting the back sheet portion 31, but this is not limited to this. For example, if at least one of the side sheet portions (32-35) is made of a member formed by a member separate from the member constituting the back sheet portion 31, the waterproof sheet 3 can be manufactured more easily than when the entire waterproof sheet 3 is formed integrally. In other words, it is preferable for the manufacturing of the segment 1 if at least one of the first side sheet portion 32 and the second side sheet portion 33 is made of the first member, and/or at least one of the third side sheet portion 34 and the fourth side sheet portion 35 is made of the second member. In this case, since some of the side sheet portions (32-35) are formed integrally with the member constituting the back sheet portion 31, they cannot be attached (joined) by pasting them to the corresponding parts of the concrete before the formwork M is removed. Therefore, in this case, for example, the steam curing process can be carried out with only the back sheet portion 31 attached to the concrete, and then, after the demolding process is completed (after demolding), the side coating process can be carried out.

In addition, the first member constituting the first side sheet portion 32 and the second side sheet portion 33 and the second member constituting the third side sheet portion 34 and the fourth side sheet portion 35 are molded products having an L-shaped cross-sectional shape that covers the edge of the back surface 2c side of the segment piece 2, but they are not limited to this and may be members formed by hardening a resin-based lining material applied to the corresponding side surfaces (2a1, 2a2, 2b1, 2b2). Even in this case, a film-like or sheet-like material (member) can be used for the back sheet portion 31, which occupies the majority of the waterproof sheet 3, so that the quality of the waterproof sheet 3 can be uniformed. If the back sheet portion 31 is also coated with a resin-based lining material to form it as part of the waterproof sheet 3, two to three layers of coating are required, a curing period is required for each coating, and the segment piece 2 needs to be erected multiple times. Considering these points, constructing at least the back sheet portion 31 of the waterproof sheet 3 by laminating a film or sheet-like material (component) to the back surface 2c is extremely advantageous in terms of standardizing the quality of the waterproof sheet 3 and manufacturing the segment 1.

In addition, in the manufacturing method of the segment 1, steam curing and underwater curing are performed, but this is not limited to this. For example, only steam curing or only underwater curing may be performed, taking into consideration the design strength, design quality, manufacturing period, manufacturing costs, etc. For example, if only underwater curing is performed, the back coating process does not have to be performed before demolding, but may be performed after demolding. In other words, the back coating process may be performed after pouring the concrete and before steam curing or underwater curing of the concrete.

In addition, the portion of the formwork M that corresponds to the back surface 2c of the segment piece 2 is open, but this is not limited to this and may be closed. In other words, the formwork M is not limited to an open-top structure, but may be a completely sealed structure that has a formwork member that contacts the portion that corresponds to the back surface 2c of the segment piece 2. In this case, for example, after only the formwork member of the completely sealed formwork M that corresponds to the back surface 2c of the segment piece 2 is removed, the back surface covering process may be performed. And, the corner cover seal 4 does not need to be provided.

1...segment,
2...segment piece,
2a1, 2a2...side surfaces on both sides of the tunnel axial direction,
2a1...first side (side),
2a2...second side (side),
2b1, 2b2...side surfaces on both sides in the circumferential direction of the tunnel,
2b1...Third side (side),
2b2...Fourth side (side),
2c…back,
21...seal groove portion,
3. Waterproof sheet,
31... rear sheet portion,
32...first side sheet portion,
33...second side sheet portion,
34...third side sheet portion,
35...fourth side sheet portion,
4...Corner cover seal,
5...sealing member,
C...corner,
M: Formwork

Claims (5)

In a segment having a tunnel structure and a segment piece made of precast concrete formed to fit the inner periphery of an excavation hole ,
A waterproof sheet covering the surface of the segment piece, the waterproof sheet being provided from a back surface, which is a surface of the surface facing the ground, to both side surfaces in the tunnel axial direction and both side surfaces in the tunnel circumferential direction,
Including,
The waterproof sheet has a back sheet portion which is a member attached to the back surface, a first side sheet portion attached to the back sheet portion and one of the side surfaces in the tunnel axial direction, a second side sheet portion attached to the back sheet portion and the other side surface in the tunnel axial direction, a third side sheet portion corresponding to one of the side surfaces in the tunnel circumferential direction, and a fourth side sheet portion corresponding to the other side surface in the tunnel circumferential direction,
the first side sheet portion and the second side sheet portion are made of a first member which is a molded product having an L-shaped cross-sectional shape covering an edge portion on a rear side of the segment piece,
a portion of an edge of the back sheet portion corresponding to the first member is sandwiched between the back surface of the segment piece and a portion of the first member forming one side of the L-shape;
segment. At least one of the third side surface sheet portion and the fourth side surface sheet portion is made of a second member having an L-shaped cross section covering an edge portion on a rear side of the segment piece,
a portion of an edge of the back sheet portion corresponding to the second member is sandwiched between the back surface of the segment piece and a portion of the second member forming one side of the L-shape;
The segment of claim 1 . At least one of the third side sheet portion and the fourth side sheet portion is a member formed by hardening a resin-based lining material applied to the corresponding side surface,
The segment of claim 1 . A seal groove for accommodating a seal member is formed on the side surface so as to extend in a direction parallel to the back surface,
the first side sheet portion, the second side sheet portion, the third side sheet portion, and the fourth side sheet portion are provided from an edge portion of the back sheet portion to a portion in front of the seal groove portion,
A segment according to any one of claims 1 to 3. A corner cover seal is provided which is a molded product that is capable of covering the portions of the waterproof sheet that correspond to the four corners of the back side of the segment piece,
The segment according to any one of claims 1 to 4, comprising: