WO2017081990A1 - Precast structure, and construction method for underground structures - Google Patents

Abstract

A segment 3 is made from concrete and has an external shape substantially the same as a segment used in shield tunneling. That is, the segment 3 comprises arc-shaped curved faces that face each other and side faces to couple the curved faces to each other. That is, a precast structure 1 comprising the segment 3 has a ring shape. A ring-shaped precast structure can be formed by connecting a plurality of segments 3 in the circumferential direction. Prestressing is applied by a tensioning member that spans the entire length of the connected segments 3 in the longitudinal direction. In the same manner, prestressing is applied by a tensioning member in the circumferential direction of the connected segments 3.

Description

Construction method of precast structure and underground structure

The present invention relates to a precast structure that can be used for underground structures and the like.

Conventionally, as a method of constructing a structure underground, there is a method of excavating the ground from the ground and constructing an underground structure with cast-in-place concrete. Moreover, there exists the method of using precast concrete for the part (for example, patent document 1, patent document 2).

JP 2008-2154 A JP 2000-337092 A

However, as in Patent Document 1, the precast concrete having a substantially rectangular shape requires a wall thickness of a predetermined value or more in order to obtain a desired yield strength, and is not always efficient in the manufacturing, transportation, installation process, and the like.

Further, as in Patent Document 2, it is difficult to ensure water-stopping by a method using arch-shaped precast concrete on a cast-in-place slab.

Also, the conventional precast concrete is heavy, so it is difficult to carry and install. In addition, there is a limit to increasing the size of precast concrete due to restrictions such as transport weight.

The present invention has been made in view of the above-mentioned problems, and it is possible to reduce the thickness of a member by using an arch action, which is lightweight, excellent in water stoppage, and can significantly reduce the work period. An object of the present invention is to provide a precast structure and the like.

In order to achieve the above-described object, the first invention is a ring-shaped precast structure in which a plurality of segments having an arch shape are connected, and the segments are connected in the circumferential direction and the longitudinal direction. And prestress is applied in the circumferential direction and the longitudinal direction of the connected segments.

The segments may be connected to each other in the circumferential direction and the longitudinal direction via a water stop member.

A hollow portion of concrete may be provided inside the segment.

A foam may be embedded in the hollow portion.

A pipe may be embedded in the hollow portion.

The outer peripheral surface of the segment is provided with a first protrusion as a positioning guide in the longitudinal connection between the segments, and the first protrusions of the segments adjacent in the longitudinal direction are connecting members. It is connected and prestress may be given over the full length of the connected segment in the longitudinal direction.

In the outer peripheral surface of the segment, a second protrusion for connecting the segments in the circumferential direction is provided, and the positions of the second protrusions of the segments adjacent in the circumferential direction are aligned. The second protrusions may be tensioned by a tension member.

The end surfaces of the segments facing in the longitudinal direction may be provided with concave portions at mutually corresponding portions, and the concave portions may be filled with a filler and solidified.

According to the first invention, since the precast structure is composed of a plurality of segments having an arch shape, the member can be made thin by using the arch action. For this reason, a construction period can be shortened significantly.

Further, if the segments are connected to each other in the circumferential direction and the longitudinal direction via a water-stopping member, higher water-stopping performance can be secured in combination with the effect of prestress.

Also, if a concrete hollow is provided inside the segment, the segment can be reduced in weight. For this reason, transportation and handling are easy. Further, since the segment can be reduced in weight, the size of the segment can be increased when there is a limit on the weight. As a result, it can be applied to a large structure. Moreover, since the width of the segment can be increased, the number of segments to be used can be reduced. As a result, the number of connecting portions between the segments can be reduced to improve the water stoppage, and the number of assembly steps can be reduced.

Moreover, the hollow part can be easily formed by embedding a foam in the hollow part. That is, by placing the foam in the mold and filling the concrete, it is possible to easily form a concrete hollow body in which the foam is disposed.

Similarly, the hollow portion can be easily formed by embedding a pipe in the hollow portion. That is, by placing the pipe in the mold and filling the concrete, it is possible to easily form a concrete hollow body in which the pipe is disposed.

Also, if the first protrusion as a guide is provided, it can function as a positioning guide for connecting the segments in the longitudinal direction, and the segments can be easily positioned. Further, since prestress is applied over the entire length in the longitudinal direction of the segments positioned relative to each other, it is possible to increase the water stoppage.

Also, by providing a second protrusion for connecting the segments in the circumferential direction and tensioning them with a tension member, it is possible to further increase the water stoppage of the connection portion between the segments in the circumferential direction.

Also, recesses are provided on the end faces of the segments facing the longitudinal direction (width direction) perpendicular to the circumferential direction, and a predetermined number of ring-shaped structures adjacent in the longitudinal direction are connected, and then the recesses are filled with a filler from the outside. Thus, the ring-like structures can be prevented from shifting by being solidified. At this time, even when the segment construction accuracy is somewhat worse than when using a metal key member or the like, it is possible to reliably prevent displacement.

The second invention is a method for constructing an underground structure, wherein a plurality of segments are surrounded by a step of installing an arched segment in an excavated portion from the ground and a platform that moves on the segment. A step of constructing a ring-shaped structure by applying a prestress in the circumferential direction by connecting through a water stop member in a direction, and a predetermined number of the ring-shaped structures adjacent to the longitudinal direction perpendicular to the circumferential direction And a step of applying prestress in the longitudinal direction to each other through a water-stopping member, and a construction method for an underground structure.

Moreover, 2nd invention is the construction method of an underground structure, Comprising a plurality of segments which have arch shape through the water stop member in the circumferential direction, Giving prestress in the circumferential direction, Ring shape Using the pedestal that moves in the existing ring-shaped structure, adjacent to the longitudinal direction in the circumferential direction. And a step of connecting a predetermined number of the ring-shaped structures via a water-stopping member and applying prestress in the longitudinal direction.

The gantry is movable inside the ring-shaped structure, and a part of the gantry can be expanded and contracted outward, and when the gantry is moved inside the ring-shaped structure. A portion of the gantry is shrunk to prevent interference between the gantry and the inner surface of the segment, and when the gantry is moved outside the ring-shaped structure, a part of the gantry is removed from the ring. It may be possible to extend outward to the end face position of the shaped structure.

The ring-shaped structure is divided into four in the circumferential direction, and is configured by connecting a bottom segment, a pair of side segments, and a top segment, and is adjacent to the longitudinal direction perpendicular to the circumferential direction. In the structure, the bottom segments and the top segments may have different lengths.

According to the second invention, in assembling the segments, the work is easy because the gantry that can move inside the segments is used.

At this time, if the segments are assembled inside the excavation part, the work space can be used effectively because no segment assembly work area is required in any part other than the excavation part.

Also, it can be installed in the cut-out part with the segments assembled in a ring shape. By doing in this way, the assembly operation of a segment can be performed in the state which laid the segment.

In addition, if a part of the gantry can be expanded and contracted outward, the part of the gantry is moved outward to the end surface position of the ring-shaped structure with the gantry moved outside the ring-shaped structure. Can be stretched. For this reason, when applying prestress in the longitudinal direction, the work on the end surface in the width direction of the segment is easy.

In addition, in the ring-shaped structures adjacent in the longitudinal direction, the positions of the connecting portions in the circumferential direction can be shifted in the circumferential direction by changing the lengths of the bottom segments and the top segments.

According to the present invention, it is possible to provide a precast structure or the like that can reduce the thickness of a member by using an arch action, is lightweight, has excellent water-stopping properties, and can significantly shorten the work period. it can.

The perspective view of the precast structure 1. FIG. The front view of the segment 3. FIG. The top view of the segment 3. FIG. FIG. 3 is a cross-sectional view of the segment 3 taken along the line AA in FIG. 2. Sectional drawing of the other segment 3. FIG. The front view of the precast structure 1. FIG. The front view of the precast structure 1. FIG. FIG. 4B is a sectional view taken along line BB in FIG. 4A. The front view of the precast structure 1a. The F arrow line view in the E section of FIG. FIG. 7B is a sectional view taken along line GG in FIG. 7A. The front view of the precast structure 1a. The front view of the precast structure 1a. FIG. 10 is a cross-sectional view taken along line II in the H portion of FIG. 9. The figure which shows the process of installing the lower segment 3a. The figure which shows the process of installing the lower segment 3a. FIG. 11B is a sectional view taken along line KK in FIG. 11B. The figure which shows the process of installing the upper segment 3b. The figure which shows the process of installing the upper segment 3b. The figure which shows the underground structure 43. The side view which shows the water stop structure of the precast structure 1a. FIG. 15B is a cross-sectional view taken along line LL in the M portion of FIG. 15A. The side view which shows the construction process of an underground structure. FIG. 16B is an OO arrow view of FIG. 16A. The side view which shows the construction process of an underground structure. FIG. 17B is a QQ arrow view of FIG. 17A. The side view which shows the construction process of an underground structure. FIG. 18B is an SS arrow view. The side view which shows the construction process of an underground structure. FIG. 19B is a view taken along the line U-U in FIG. 19A. The side view which shows the construction process of an underground structure. FIG. 20B is a WW arrow view of FIG. 20A. The side view which shows the construction process of an underground structure. The side view which shows the construction process of an underground structure. The figure which shows a part of mount 21. The figure which shows a part of mount 21. FIG. 4 is a partial cross-sectional view of a segment 3. FIG. 4 is a partial cross-sectional view of a segment 3. The side view which shows the construction process of another underground structure. The top view which shows the construction process of another underground structure. The side view which shows the construction process of an underground structure. The side view which shows the construction process of an underground structure. The front view which shows a double underground structure. The figure which shows the tunnel 51. FIG. The figure which shows the process of towing the precast structure 57 to the sea. The figure which shows the process of towing the precast structure 57 to the sea.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a precast structure 1. In addition, illustration of the tension member etc. which are mentioned later is abbreviate | omitted in FIG.

The precast structure 1 is composed of a plurality of segments 3. In the illustrated example, an example in which the precast structure 1 includes four segments 3 is shown. However, if the precast structure 1 includes a plurality of segments 3, the number of segments 3 is not limited. The number of connections in the longitudinal direction of each segment 3 is not limited to the illustrated example. In addition, when the precast structure 1 consists of the four segments 3, it is desirable to arrange | position the connection position of the segment 3 in the position of +/- 45 degrees with respect to a horizontal direction from the center of a ring. For example, when the precast structure 1 is buried in the basement, considering the moment distribution due to earth pressure, the position of ± 45 ° with respect to the horizontal direction becomes the part where the sign of the moment changes and becomes the part with the smallest moment. Because.

FIG. 2A is a front view of the segment 3, and FIG. 2B is a plan view of the segment 3. FIG. 3A is a cross-sectional view taken along line AA of FIG. 2A. The segment 3 is made of concrete and has substantially the same outer shape as the segment used for the shield tunnel. That is, the segment 3 is composed of arcuate (arch-shaped) curved surfaces facing each other and side surfaces connecting the curved surfaces. A ring-shaped precast structure 1 can be formed by connecting a plurality of segments 3 in the circumferential direction. That is, the precast structure 1 composed of the segments 3 has a ring shape.

The segment 3 is provided with a hole 11 in the width direction (vertical direction in FIG. 2B), and a tension member to be described later is inserted inside. That is, the tension member penetrates in the width direction of the segment 3. Further, in the circumferential direction of the segment 3 (left-right direction in FIG. 2B), a hole 12 is formed along the curved shape of the segment 3, and a tension member, which will be described later, is inserted therein. That is, the tension member penetrates in the circumferential direction of the segment 3. As described above, the tension member holes 11 and 12 are provided in the circumferential direction and the width direction of the segment 3 so that prestress can be applied when the segments 3 are connected in the circumferential direction and the width direction.

In the part other than the tension member of the segment 3, the foam 16 is embedded. The foam 16 is made of a lightweight resin such as polystyrene foam. That is, a hollow portion is formed inside the concrete constituting the segment 3, and the foam 16 is provided in the hollow portion. In addition, the hollow part inside the segment 3 in this invention points out a site | part without concrete, and when another member is embed | buried under the concrete, it is also called a hollow part.

As shown in FIG. 3A, holes 12 through which tension members are inserted are provided in the vicinity of the four corners of the foam 16, and the reinforcing bars 14 are arranged along the circumferential direction of the segment 3 so as to cover the periphery of the foam 16. The In the illustrated state, the tension member 27 is inserted into the hole 12. The segment 3 is formed by filling concrete with a gap and unboxing in a state where the reinforcing bars 14, the foams 16, etc. are arranged at predetermined positions inside the concrete outer shell. Such a segment 3 can be reduced in weight as compared with a solid concrete member up to the inside.

As described above, there is no problem even if it is hollow because there is generally room for a concrete cross section against compression and shearing of concrete. On the other hand, with respect to concrete tension, it is only necessary to secure a member height (member thickness) as a concrete member that allows the reinforcing bars 14 to resist tension to be disposed.

In addition, as shown to FIG. 3B, you may form the hollow part of concrete by embedding the some pipe 16a. The pipe 16a is, for example, a winding pipe, and the segment 3 can be formed by filling the concrete with the pipe 16a and the like disposed therein and then unboxing the box.

Thus, since the concrete hollow portion is provided inside the segment 3, the segment 3 can be reduced in weight. For this reason, transportation and handling are easy. Moreover, since the segment can be reduced in weight, the size of the segment 3 can be increased in the case of the same weight restriction. As a result, it can be applied to large structures. Further, since the width of the segment 3 can be increased, the number of segments 3 to be used can be reduced. As a result, it is possible to reduce the number of connecting portions and improve the water stoppage, and to reduce the number of assembly steps.

In addition, in this invention, if it is a segment which has a hollow part of concrete, about the formation method of a hollow part, it is not limited to the foam 16 and the pipe 16a mentioned above. Further, the hollow portion is not always essential, and a solid concrete segment may be used without providing the hollow portion.

FIG. 4A is a front view of the precast structure 1. As described above, the precast structure 1 becomes ring-shaped by connecting the plurality of segments 3 in the circumferential direction. Furthermore, the precast structure 1 is formed by connecting ring-shaped segment connection bodies in the width direction (longitudinal direction of the precast structure 1). In addition, about the construction method of a precast structure, a detail is mentioned later.

It is desirable that water stop members 9a and 9b are provided on both side surfaces of the segment 3 in the width direction. In this case, the segment 3 is connected via the water stop members 9a and 9b. Further, it is desirable that water stop members (not shown) are provided on both side surfaces of the segment 3 in the circumferential direction. That is, it is desirable that a water stop member is provided on the connection surface between the segments 3 and the segments 3 are connected to each other in the circumferential direction and the longitudinal direction via the water stop member.

A tension member 5 is used to connect the segments 3 in the width direction (longitudinal direction of the precast structure 1). FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4A. The hole 11 is provided at the approximate center in the thickness direction of the segment 3. The tension member 5 is inserted into the hole 11. The tension member 5 penetrates the plurality of segments 3.

Some or all of the segments 3 are provided with openings through which the holes 11 are exposed on the inner surface side of the curved shape. Therefore, the internal tension member 5 is exposed at the opening. The end of the tension member 5 is fixed to the opening of the segment 3 by the anchor plate 18. Furthermore, a coupler sleeve 18a is provided at the end of the tension member 5 and can be connected via a coupler joint 18b. For this reason, every time a predetermined number of segments 3 are connected in the longitudinal direction, the tension members 5 can be inserted and connected to each other. For this reason, a prestress can be provided over the full length of the longitudinal direction of the segment 3 connected.

It should be noted that the tensioning and fixing of the tension member 5 may be performed every time one segment 3 is connected, or may be performed every time a plurality of segments 3 are connected.

Here, as described above, the water stop members 9a and 9b are arranged on the opposing surfaces (end surfaces) of the segments 3. In this way, prestress is applied over the entire length of the connected segments 3 in the longitudinal direction, and the water-stop members 9a and 9b are disposed on the contact surfaces of each other in a double manner so that the water-stop properties of the contact surfaces between the segments 3 can be reduced. Can be secured.

Similarly, the tension member 27 described above is used to connect the segments 3 in the circumferential direction. The segments 3 are tensioned and connected in the circumferential direction by the tension members 27 penetrating in the circumferential direction. That is, prestress is applied to the segments 3 connected in the circumferential direction in the circumferential direction.

As described above, when the segments 3 are connected in the circumferential direction, the precast structure 1 becomes substantially circular. For this reason, the arch action can be used from any direction. For this reason, the thickness of the precast structure 1 can be made thin.

Thus, since the segment 3 is connected via the water stop member in the circumferential direction and the longitudinal direction, and the precast structure 1 gives a prestressing force to the longitudinal and circumferential connecting portions, Aqueous property can be secured. In addition, the shape of the precast structure 1 may not be a perfect circle, and may be another shape as long as an arch action can be used, such as an ellipse.

In addition, as shown in FIG. 4B, a tension member 27 a may be disposed on the outer periphery of the segment 3. That is, instead of inserting the tension member 27 into the segment 3, the tension member 27a may be arranged on the outer periphery of the ring-shaped member in a state where the segments 3 are connected in the circumferential direction, and barrel tightened. In this case, the tension member 27a can use, for example, a steel wire coated with a resin such as epoxy.

Next, other precast structures will be described. FIG. 6 is a diagram showing the precast structure 1a. The precast structure 1 a is substantially the same as the precast structure 1, but a coupling protrusion 7 is provided at a part of the connecting portion in the circumferential direction of the segment 3. In addition, about the structure which show | plays the function similar to the precast structure 1, the code | symbol same as the precast structure 1 is attached | subjected and the overlapping description is abbreviate | omitted.

Further, in the following description, a lower segment connection body (indicated by an arrow D in the figure) composed of one or a plurality of segments is referred to as a lower segment 3a, and an upper segment connection body (indicated by an arrow C in the figure). Is referred to as the upper segment 3b. That is, in the precast structure 1a, the lower segment 3a and the upper segment 3b each have the coupling protrusion 7. A pair of coupling protrusions 7 is formed at the tip of the semicircular lower segment 3a and upper segment 3b.

FIG. 7A is a view taken in the direction of arrow F in part E of FIG. 6, and FIG. 7B is a cross-sectional view taken along the line GG of FIG. 7A. When the lower segment 3a and the upper segment 3b are combined to face each other, the coupling protrusions 7 face each other and come into contact with each other. The coupling protrusion 7 is provided with a hole 24 penetrating vertically. The number of holes 24 is not limited to the illustrated example.

In a state where the hole 24 of the coupling protrusion 7 of the lower segment 3a and the hole 24 of the coupling protrusion 7 of the upper segment 3b are arranged on a substantially straight line, the hole 24 has a tension passing through the upper and lower coupling protrusions 7. The member 27b is inserted. By fixing the tension members 27b on the upper and lower surfaces of the coupling protrusion 7 in a state where the positions of the coupling protrusions 7 of the lower segment 3a and the upper segment 3b adjacent to each other in the circumferential direction are aligned, the coupling protrusions 7 are tensioned. The member 27b is tensioned.

Here, water stop members 9c and 9d (see FIG. 7B) are arranged on the opposing surfaces (end surfaces) of the lower segment 3a and the upper segment 3b. In this way, the lower segment 3a and the upper segment 3b connected in the circumferential direction are connected by being tensioned by the tension member 27b, and the water stop members 9c and 9d are disposed on the contact surfaces of the lower segment 3a. It is possible to ensure the water stoppage of the contact surface between 3a and the upper segment 3b.

Further, when the precast structure 1a uses the arch action, a tensile force is applied to the outer peripheral surface side in the vicinity of the coupling protrusion 7 of the precast structure 1a. However, since the coupling protrusion 7 is disposed on the outer peripheral surface of the lower segment 3a and the upper segment 3b, not only is the connection easy, but a compressive force can be applied to the outer peripheral surface side of the precast structure 1a. . For this reason, the connection part of the lower segment 3a and the upper segment 3b does not open, and a high water stoppage can be ensured.

Next, still another precast structure will be described. FIG. 8 is a perspective view showing the precast structure 1b, and FIG. 9 is a front view. In addition, illustration of a tension member etc. is abbreviate | omitted in FIG. 8, FIG.

The precast structure 1b is substantially the same as the precast structure 1a, but is different in that a guide protrusion 8 is further provided. In addition, in this embodiment, about the structure which show | plays the function similar to the precast structure 1a, the code | symbol same as the precast structure 1a is attached | subjected, and the overlapping description is abbreviate | omitted.

The precast structure 1b includes a lower segment 3a and an upper segment 3b. The lower segment 3a and the upper segment 3b have an arch shape. In the illustrated example, the precast structure 1b is an example including two segments (the lower segment 3a and the upper segment 3b). However, the precast structure 1b may be composed of three or more segments. That is, also in the present embodiment, the lower segment 3a and the upper segment 3b may each be composed of a plurality of segments 3, as in the above-described embodiment.

Each of the lower segment 3a and the upper segment 3b has a guide protrusion 8 that is a first protrusion and a coupling protrusion 7 that is a second protrusion. A pair of guide protrusions 8 are formed on the semicircular lower segment 3a and upper segment 3b on the arc. Further, like the precast structure 1a, a pair of coupling protrusions 7 are formed at the distal ends of the lower segment 3a and the upper segment 3b.

FIG. 10 is a cross-sectional view taken along the line II in H part of FIG. Although FIG. 10 shows an example of the lower segment 3a, the upper segment 3b has the same structure. The guide protrusion 8 is formed on the outer peripheral surface of the segment 3. The guide protrusions 8 are formed on both sides of the segment 3 in the width direction (longitudinal direction of the precast structure 1b). That is, when the segments 3 are adjacent to each other in the width direction, the guide protrusions 8 face each other and contact each other.

A hole 8 a is formed in the guide protrusion 8. By aligning the positions of the holes 8a of the segments 3 adjacent in the width direction, the holes 8a are arranged on a substantially straight line. In this state, the connecting member 8b is inserted through the holes 8a of the guide protrusions 8 of the segments 3 adjacent in the width direction. The guide protrusions 8 are connected to each other by the connecting member 8b.

In addition, the connection of the segments 3 by the connecting member 8b is for positioning the segments 3. That is, the guide protrusion 8 functions as a positioning guide for connecting the segments 3 in the longitudinal direction. Since the guide protrusion 8 is disposed on the outer peripheral surface of the segment 3, positioning is easy.

As described above, the segment 3 is provided with the hole 11 penetrating in the width direction. The holes 11 are provided at substantially the same pitch in the circumferential direction. The hole 11 is provided at the approximate center in the thickness direction of the segment 3. The tension member 5 is inserted into the hole 11. The tension member 5 penetrates the plurality of segments 3. As described above, since the segments 3 are previously positioned by the guide protrusions 8, the holes 11 are positioned and the tension member 5 can be easily inserted.

Next, the construction method of the underground structure using the precast structure will be described. In addition, although the following description demonstrates the example to which the precast structure 1a is applied, you may use the precast structure 1 and 1b. In this case, all the segments 3 may be assembled on site, or some or all of the segments 3 may be connected in advance to assemble a ring-shaped or semi-ring-shaped member on-site.

FIG. 11A is a diagram showing a process of arranging and connecting the lower segments 3a. In the following description, illustration of Yamatome etc. is omitted. The lower segment 3a is composed of a plurality of segments 3 in advance, and is laid below (under the ground) the excavation part 31. As shown in FIG. 11A, supporters 33 are arranged in the cut portion 31 at a predetermined interval. Therefore, the lower segment 3 a is suspended from the gap of the support 33 by the crane. A rail 35 is laid along the longitudinal direction of the cut portion 31 below the cut portion 31.

The lower segment 3a arranged on the rail 35 by the crane can be moved by the winch 37 (in the direction of arrow J in the figure). Therefore, the lower segment 3a can be moved in the direction of the already installed lower segment 3a and connected in the longitudinal direction. At this time, the water stop members 9 a and 9 b are arranged between the lower segments 3 a and are tensioned by the tension member 5.

When the connection of the lower segment 3a having a predetermined length is completed, the fluidized soil 39 may be filled around the lower segment 3a as shown in FIG. 11B.

FIG. 12 is a cross-sectional view taken along the line KK of FIG. 11B. As described above, since the lower segment 3a has an arc shape, the gap with the bottom surface of the cut portion 31 is large, and the fluidized soil 39 can be easily filled. At this time, the fluidized soil 39 may be filled with a predetermined amount of fluidized soil 39 in the lower segment 3a. By doing in this way, the lower segment 3a (precast structure) can be prevented from being lifted, and a scaffold in the lower segment 3a can be secured. At least a part of the lower segment 3 a installed in this way is backfilled with the fluidized soil 39.

Next, as shown in FIG. 13A, the upper segment 3b composed of a plurality of segments 3 is suspended in advance. At this time, as shown in FIG. 13B, the rail 35 is laid on the fluidized soil 39 inside the lower segment 3 a, and the gantry 41 is further installed on the rail 35. Therefore, the gantry 41 is movable along the rail 35 in the longitudinal direction of the cut portion 31.

When the upper segment 3b is suspended from the gantry 41 by the crane, the gantry 41 on which the upper segment 3b is placed is moved by the winch 37 in the direction of the upper segment 3b that has already been installed, and the lower segments 3a are moved in the longitudinal direction. Can be linked to. At this time, the water stop members 9 a and 9 b are arranged between the upper segments 3 b and are tensioned by the tension member 5.

Further, the upper segment 3b is connected to the lower segment 3a. Under the present circumstances, the water stop members 9c and 9d are arrange | positioned between the lower segment 3a and the upper segment 3b. Thus, the precast structure 1a is constructed by connecting the lower segment 3a and the upper segment 3b in the circumferential direction and the longitudinal direction.

FIG. 14 is a diagram showing the underground structure 43 constructed as described above. In addition, although the underground structure 43 shows the example which is an underground tunnel, at least one part of a precast structure, such as a water and sewage storage part and an underground parking lot, is buried underground, and is a structure built underground. Any of them can be applied. Further, the precast structures 1, 1a, 1b may be substantially circular, or may have a form in which a plurality of circular cross sections are connected.

In addition, in order to ensure the water-stop property of the precast structure 1a, as shown in FIG. 15A, a coating film 45 may be applied to the connecting portion. The coating film 45 is formed, for example, by spraying an ultrafast curing polyurethane resin. For example, the coating film 45 is applied to the outer periphery of the connecting portion in the longitudinal direction between the segments 3, the connecting portion in the circumferential direction (the connecting portion of the coupling protrusion 7), or the like.

FIG. 15B is a cross-sectional view taken along line LL in part M in FIG. 15A. It is difficult to spray the coating film 45 below the precast structure 1a. For this reason, the waterproof sheet 47 may be further sandwiched between the opposing surfaces of the lower segments 3a. Moreover, you may provide the coating film 45 in the inner surface side of the precast structure 1a. Thus, if the coating film 45 etc. are used, even if the positional accuracy of segments is low compared with the case where the water stop members 9a and 9b etc. are used, a water stop can be ensured.

As described above, according to the precast structure 1, 1a, 1b of the present embodiment, the precast structure is composed of a plurality of segments 3 having an arch shape, so that the member is thinned by using the arch action. Can do. For this reason, a construction period can be shortened significantly.

Moreover, since the segments 3 are connected to each other in the circumferential direction and the longitudinal direction via the water-stopping member, it is possible to secure higher water-stopping performance together with the effect of the prestress.

Also, since the concrete hollow is provided inside the segment, the segment can be reduced in weight. For this reason, transportation and handling are easy. Further, since the width of the segment 3 can be increased, the number of segments 3 to be used can be reduced. As a result, the number of connecting portions between the segments 3 can be reduced to improve the water stoppage, and the number of assembling steps can be reduced. *

Also, if the guide protrusion 8 is provided, it can function as a positioning guide for connecting the segments 3 in the longitudinal direction, and positioning of the segments 3 is facilitated. Further, since prestress is applied over the entire length in the longitudinal direction of the segments 3 positioned relative to each other, it is possible to increase the water stoppage.

Also, by providing the coupling protrusion 7 for connecting the segments in the circumferential direction and tensioning them with a tension member, the water stoppage of the connection part between the segments 3 in the circumferential direction can be further increased.

Next, the construction method of other underground structures will be explained. 16A is a side view showing the construction process of the underground structure, and FIG. 16B is a view taken along the line OO in FIG. 16A.

FIG. 16A is a diagram showing a state in which the bottom segment 4a is further arranged on the extension of the existing ring-shaped structure 10 (P portion) in the longitudinal direction. The bottom segment 4a, the side segment 4b, and the top segment 4c are collectively referred to as a segment 3.

The bottom segment 4a, the side segment 4b, and the top segment 4c are made of precast concrete and each have an arch shape. The ring-shaped structure 10 can be formed by connecting the bottom segment 4a, the side segment 4b, and the top segment 4c in the circumferential direction. In the present embodiment, the ring-shaped structure 10 is divided into four in the circumferential direction, and is configured by connecting a bottom segment 4a, a pair of side segments 4b, and a top segment 4c.

First, as shown in FIGS. 16A and 16B, the bottom segment 4a is installed on the excavation part 31 by a crane or the like not shown from the ground. In the excavation part 31, a retaining wall and a supporting work (not shown) are installed. The bottom segments 4a adjacent to each other in the longitudinal direction of the underground structure (the horizontal direction in FIG. 16A and the width direction perpendicular to the circumferential direction of each segment) have different circumferential lengths.

The water stop member 2a is disposed on the circumferential end surface of the bottom segment 4a. Moreover, the hole 11 and the recessed part 13 are provided in the width direction (longitudinal direction of an underground structure) end surface of the bottom part segment 4a. The holes 11 and the recesses 13 of the bottom segments 4a adjacent to each other in the longitudinal direction of the underground structure (the left-right direction in FIG. 16A) are formed at positions corresponding to each other. Further, a water stop member 2b (corresponding to the water stop members 9a and 9b in FIG. 4A) is arranged on the end surface in the width direction of the bottom segment 4a.

FIG. 17A is a view showing a state in which the gantry 21 is moved on the installed bottom segment 4a, and FIG. 17B is a view taken along arrows QQ in FIG. 17A. A rail 9 is installed on the inner surface side (upper surface) of the bottom segment 4a. The rail 9 is formed so as to be continuous with the rail 9 inside the existing segment (ring-shaped structure 10).

The mount 21 is installed on the rail 9. A chill tank (not shown) is provided at the lower part of the gantry 21, and the gantry 21 can move on the bottom segment 4a (on the rail 9). Therefore, as shown in FIG. 17B, the gantry 21 can be moved from the inside of the ring-shaped structure 10 onto the newly installed bottom segment 4a (arrow R in the figure).

A gripping device 21 a is provided at the tip of the gantry 21. The gripping device 21a can be expanded and contracted by a hydraulic jack or the like (not shown). When moving the gantry 21 within the ring-shaped structure 10, the gripping device 21a can be pulled back to prevent interference between the gripping device 21a and the segment 3.

18A is a view showing a state in which the side segment 4b is installed on the installed bottom segment 4a, and FIG. 18B is a view taken along the line SS in FIG. 18A. As shown in FIGS. 18A and 18B, the side segment 4b is installed on the bottom segment 4a by a crane or the like not shown from the ground. At this time, as shown in FIG. 18B, a part of the gripping device 21a is extended (arrow T in the figure), and the side segment 4b is supported by the gripping device 21a. That is, the side segment 4b is positioned by the gripping device 21a.

The water stop member 2a described above is sandwiched between the circumferential end surface of the bottom segment 4a and the circumferential end surface of the side segment 4b. Moreover, the water stop member 2a is newly arrange | positioned at the circumferential direction end surface of the reverse side of the side part segment 4b.

The hole 11 and the recessed part 13 are provided in the width direction (longitudinal direction of an underground structure) end face of the side segment 4b similarly to the bottom segment 4a. Moreover, the water stop member 2b is arrange | positioned at the width direction end surface of the side part segment 4b. The holes 11 and the recesses 13 of the side segments 4b adjacent to each other in the longitudinal direction of the underground structure (left and right direction in FIG. 18A) are formed at positions corresponding to each other.

FIG. 19A is a diagram showing a state where the top segment 4c is further installed on the installed side segment 4b, and FIG. 19B is a view taken along the line U-U in FIG. 19A. As shown in FIGS. 19A and 19B, the top segment 4c is installed on the side segment 4b by a crane or the like not shown from the ground. At this time, as shown in FIG. 19B, the gripping device 21a is extended (arrow V in the figure), and the top segment 4c is supported by the gripping device 21a. That is, the top segment 4c is positioned by the gripping device 21a.

The water-stop member 2a described above is sandwiched between the circumferential end surface of the side segment 4b and the circumferential end surface of the top segment 4c.

The hole 11 and the recessed part 13 are provided in the width direction (longitudinal direction of an underground structure) end surface of the top segment 4c similarly to the bottom segment 4a. Moreover, the water stop member 2b is arrange | positioned at the width direction end surface of the top segment 4c. The hole 11 and the recessed part 13 of the top segments 4c adjacent to each other in the longitudinal direction of the underground structure (the left-right direction in FIG. 19A) are formed at positions corresponding to each other.

Thus, the segment 3 can be formed in a ring shape by arranging the bottom segment 4a, the side segment 4b, and the top segment 4c in the circumferential direction via the water stop member 2a.

Note that the top segments 4c adjacent to each other in the longitudinal direction of the underground structure have different circumferential lengths. For example, by combining the long and short bottom segments 4a and the top segments 4c alternately in the longitudinal direction of the underground structure so that the sum of the circumferential lengths of the bottom segment 4a and the top segment 4c is the same, The position of the connecting portion between the segments 3 can be shifted.

20A is a view showing a state in which the tension members 5a are arranged with respect to the segments 3 arranged in a ring shape, and FIG. 20B is a view taken along the line WW in FIG. 20A. A sheath is disposed inside each segment 3 along an arc shape in the circumferential direction. The sheath is arranged so as to be continuous in the circumferential direction of the segments arranged in a ring shape. The tension member 5a is inserted through the sheath. By tensioning the tension member 5a with a jack or the like, prestress can be applied in the circumferential direction of the segments 3 arranged in a ring shape, and the ring-shaped structure 10 can be constructed. Under the present circumstances, the water stop member 2a between each segment is compressed by prestress, and the water stop of the circumferential direction can be ensured reliably.

A predetermined number of ring-shaped structures 10 to which prestress is applied in the circumferential direction are formed by the same procedure.

FIG. 21A is a diagram showing a state in which the tension members 5 are arranged in a predetermined number of ring-shaped structures 10 adjacent in the longitudinal direction in this way. A hole 11 penetrating in the longitudinal direction is formed in a corresponding portion in the circumferential direction of each ring-shaped structure 10. The tension member 5 is inserted into the hole 11 and connected to a jack 17 disposed on the end surface of the segment 3 on the end side. The other end of the tension member 5 is connected to the tension member 5 of the existing ring-shaped structure 10.

Further, a water-stop member 2b is disposed between the ring-shaped structures 10 (including the existing ring-shaped structures 10).

As shown in FIG. 21B, by tensioning the tension member 5 with the jack 17 (arrow X in the figure), prestress can be applied in the longitudinal direction of a predetermined number of ring-shaped structures 10 adjacent in the longitudinal direction. it can. Under the present circumstances, the water stop member 2b between each ring-shaped structure 10 is compressed by prestress, and the water stop of a longitudinal direction can be ensured reliably.

FIG. 22A is a diagram showing an end portion of the gantry 21. As described above, the gripping device 21 a is provided at the end of the gantry 21. Further, the platform 21 is provided with a work scaffold 21b. Here, a part of the gantry 21 can be expanded and contracted outward, and as shown in FIG. 22B, the work scaffold 21b can be extended outward (arrow Y in the figure).

When moving the gantry 21 inside the ring-shaped structure 10, interference between the gantry 21 and the inner surface of the segment 3 can be prevented by shrinking a part of the gantry 21 (working scaffold 21 b). Further, when the gantry 21 is moved to the outside of the ring-shaped structure 10, the work scaffold 21 b of the gantry 21 can be extended outward to the end surface position of the ring-shaped structure 10. By doing so, for example, when the jack 17 is disposed on the end surface of the segment 3 or when the tension member 5 is tensioned, the work scaffold 21b is extended to the end surface of the segment 3, thereby facilitating the work.

It should be noted that the expansion / contraction mechanism at the tip of the gantry 21 may be a slide mechanism as illustrated, but may also be a foldable type.

FIG. 23A is a partial cross-sectional view of adjacent ring-shaped structures 10. For simplicity, only the facing portion between the two ring-shaped structures 10 is illustrated. As described above, the recess 13 is formed on the end surface in the width direction of the segment 3. Since the recessed part 13 is formed in the site | part corresponding to the adjacent ring-shaped structure 10, a space is formed by the recessed parts 13 in the opposing part of adjacent ring-shaped structure 10.

Each inlet 13 is provided with an inlet that communicates with the inner or outer surface of the segment 3. Therefore, as shown in FIG. 23B, the filler 23 can be filled into the space inside the recess 13 from one injection port in a state where the ring-shaped structures 10 are connected to each other in the longitudinal direction of the underground structure.

The filler is, for example, mortar, and can be solidified in a predetermined time after filling the recess 13. In this way, by filling the recess 13 with the filler 23 and solidifying it, the filler 23 functions as a key material, and it is possible to prevent the ring-shaped structures 10 from shifting with respect to the shearing force of the underground structure. .

Here, the segment 3 used in the present invention is larger than the segment used in the shield method when the ring inner diameter is the same. In order to manufacture such a large concrete segment, unlike the conventional segment, it is necessary to manufacture the segment with the end face in the width direction facing up and down due to the size of the formwork support. There is. Therefore, it is difficult for the end surface in the width direction of the segment that becomes the upper surface side during manufacturing to be accurate with the mold.

In such a case, for example, if a metal key material is to be fitted into the recess 13, it may be difficult to fit the key material depending on the position and size accuracy of the opposed recesses 13. However, if the key material is made smaller, the effect of preventing displacement will be reduced.

On the other hand, in this embodiment, after the segments are combined and connected, the filling material 23 serving as the key material is filled into the recess 13 from the outside and solidified. For this reason, even if the accuracy such as the position of the concave portion 13 is somewhat poor, it is possible to reliably prevent the positional deviation.

By repeating the above steps, the ring-shaped structure 10 is connected to a predetermined length, and the excavation part 31 around the ring-shaped structure 10 is backfilled, whereby the underground structure can be constructed. In addition, in order to prevent the ring-shaped structure 10 from being lifted, the ring-shaped structure 10 may be fixed to the ground below the cut portion 31 with an anchor or the like.

As mentioned above, according to this Embodiment, the ring-shaped structure 10 consists of the some segment 3 which has an arch shape, and a member can be made thin by utilizing an arch action. For this reason, the construction period concerning construction of an underground structure can be significantly shortened.

Moreover, the water stop members 2a and 2b are provided on the connecting surfaces of the segments 3, and the segments 3 are connected to each other via the water stop members 2a and 2b in the circumferential direction and the longitudinal direction. Thus, since the water stop members 2a and 2b are disposed on the circumferential surfaces and the longitudinal direction of the segment 3, the water stop members 2a and 2b are compressed when prestress is applied, respectively. Aqueous property can be secured.

Also, since the assembly work of the segment 3 can be performed using the mount 21 that moves on the segment 3, the work is easy. Further, the work scaffold at the tip of the gantry 21 is expanded and contracted, so that the work on the end face in the width direction of the segment 3 is easy.

Moreover, the recessed part 13 is formed in the opposing part of the width direction end surfaces of the segment 3, and after connecting the predetermined number of ring-shaped structures 10 adjacent to a longitudinal direction, the recessed part 13 is filled with the filler 23 from the outside, By solidifying, the shift between the ring-shaped structures 10 can be prevented.

Moreover, when the ring-shaped structure 10 is divided into four in the circumferential direction, the lengths of the bottom segments 4a and the top segments 4c are different from each other with respect to the ring-shaped structures 10 adjacent in the longitudinal direction. The positions of the connecting portions in the circumferential direction between the segments 3 can be shifted.

Note that the ring-shaped structure 10 is not limited to four divisions, and may be divided into a plurality of divisions. Moreover, the number of connections in the longitudinal direction of the ring-shaped structure 10 is not limited to the illustrated example.

Next, the construction method of other underground structures will be explained. FIG. 24A is a side view showing a state in which the segments 3 are connected, for example, on the ground instead of the excavated portion, and FIG. 24B is a plan view. In this embodiment, the assembly work of the ring-shaped structure 10 is performed outside the cut-out portion.

First, on the movable frame 22, the bottom segment 4a, the side segment 4b, and the top segment 4c are placed in a laid state. In a state of being arranged in a ring shape, the tension member 5a is inserted into the circumferential sheath, and prestress is applied in the circumferential direction. In addition, the water stop member 2a is arrange | positioned at the end surface of the circumferential direction of each segment 3. As shown in FIG. That is, the plurality of segments 3 having an arch shape are connected in a ring shape in the circumferential direction via the water stop member 2a, and prestress is applied in the circumferential direction, whereby the ring-shaped structure 10 is constructed. The

FIG. 25A is a diagram showing a process of arranging the segment 3 in the cut-out part 31. The ring-shaped structure 10 is disposed on a gantry 22 a installed below (underground) the excavation part 31. In addition, as shown to FIG. 25A, a support work is arrange | positioned at the predetermined | prescribed space | interval in the excavation part 31, and the ring-shaped structure 10 is suspended with the crane from the clearance gap between support works.

The ring-shaped structure 10 disposed on the gantry 22a can be moved by the crane in the direction of the existing ring-shaped structure 10 (in the direction of arrow Z in the figure) as shown in FIG. 25B. Therefore, the ring-shaped structure 10 arranged on the gantry 22a can be moved in the direction of the already-installed ring-shaped structure 10 and connected in the longitudinal direction. At this time, the water stop member 2 b is disposed between the ring-shaped structures 10 and is tensioned by the tension member 5.

Even in this case, the installation of the water stop member 2b and the tension work of the tension member 5 can be easily performed by using the gantry 21 that can move inside the segment.

As mentioned above, according to this Embodiment, the effect similar to the construction method mentioned above can be acquired.

The underground structure constructed according to the present invention can be applied to any structure that is buried underground and constructed underground, such as underground tunnels, water supply and sewage storage units and underground parking lots. It is.

In addition, as shown in FIG. 26, as the underground structure, the ring-shaped structures 10 may be arranged in a direction perpendicular to the longitudinal direction (for example, in the horizontal direction as illustrated, or in the vertical direction). May be connected to each other. In this case, a connecting portion 25 may be formed between the ring-shaped structures 10, and an opening may be formed in a part of the ring-shaped structure 10 in a space surrounded by the connecting portions 25. Good. By doing in this way, the inside of the adjacent ring-shaped structure 10 can be connected, for example, can also be utilized as a channel | path.

Next, the construction method of the submarine tunnel will be explained. FIG. 27 is a schematic cross-sectional view of the tunnel 51 in the longitudinal direction. The tunnel 51 is configured by connecting a submarine tunnel portion 53 and a land tunnel portion 55.

The submarine tunnel 53 is buried under the seabed 61. The submarine tunnel portion 53 and the land tunnel portion 55 are connected by a connection portion 59. The connection part 59 serves as a ventilation tower, for example. The tunnel 51 of the present invention is configured by connecting at least a submarine tunnel portion 53 with a plurality of precast structures 57. The precast structure 57 is formed by closing the openings on the end faces of the precast structures 1, 1a, and 1b. Note that the precast structure 57 may have a substantially circular shape, or may have a form in which a plurality of circular cross sections are connected.

The precast structure 57 is embedded in the seabed 61. For example, the precast structure 57 is buried with crushed stone. In this case, after excavating the seabed 61 to a predetermined depth, the crushed stone is disposed with a predetermined thickness, and the precast structure 57 is sunk thereon, and then the entire precast structure 57 is buried with the crushed stone. Moreover, you may perform ground improvement with respect to the lower ground which lays a crushed stone as needed.

First, as shown in FIG. 28A, a steel pipe sheet pile cylinder 79 is constructed between a submarine tunnel construction area 53a in which the submarine tunnel section 53 is constructed and a land tunnel construction area 55a in which the land tunnel section 55 is constructed. The steel pipe sheet pile cylinder 79 is formed by connecting a plurality of steel pipe sheet piles. The steel pipe sheet pile cylinder 79 is formed deeper than the connection part 59 (see FIG. 27) between the submarine tunnel part 53 and the land tunnel part 55.

The inner ground surrounded by the steel pipe sheet pile cylinder 79 is excavated, and the bottom plate 83 is constructed to a predetermined depth. The bottom plate 83 is a part where the connecting portion 59 (see FIG. 27) is constructed. That is, the bottom plate 83 is formed at a position deeper than a portion where the submarine tunnel portion 53 and the land tunnel portion 55 are connected.

The production yard 89 is constructed in a predetermined range of the land tunnel construction range 55a on the land side of the steel pipe sheet pile cylinder 79. The production yard 89 is formed by excavating part of the ground in the land tunnel construction range 55a. If the depth of the production yard 89 is lower than the water surface, it is not necessary to cut to the depth for constructing the land tunnel. That is, the production yard 89 may be formed using the entire land tunnel construction range 55a, or may be formed in a range smaller than the land tunnel construction range 55a using only a part of the land tunnel construction range 55a. Also good. The above-described construction of the bottom plate 83 may be performed simultaneously with the construction of the production yard 89.

The production yard 89 is formed up to the steel pipe sheet pile cylinder 79. On the side of the production yard 89, a mountain stop is provided. That is, the pile is joined to the steel pipe sheet pile cylinder 79. Further, a part of the steel pipe sheet pile cylinder 79 is cut out to form a passage of the precast structure 57. That is, the production yard 89 communicates with the sea. In addition, since the gate 85 is formed in the surface facing the sea of the steel pipe sheet pile cylinder 79, it is prevented that seawater flows into the production yard 89 on the land side of the gate 85.

In the production yard 89 that functions as a dry dog, the precast structure 57 is assembled. For example, a ballast is provided inside the precast structure 57. Further, both end portions of the precast structure 57 are closed.

When the assembly of the precast structure 57 is completed, the gate 85 is opened and seawater is introduced into the production yard 89 as shown in FIG. 28A. The material of the gate 85 is, for example, iron or concrete (precast), and the gate 85 is opened and closed by a method of pulling up with a large heavy machine or a method of a temporary sluice gate.

As shown in FIG. 28B, the precast structure 57 that has surfaced on the sea surface is towed to the sea side by the tow ship (arrow N in the figure). That is, the precast structure 57 is towed and moved from the production yard 89 to the sea of the installation site. As shown in the figure, the gate 85 may not be moved up and down, but may be double open.

The precast structure 57 towed to the sea is towed to the settling site. At this time, as described above, the seabed 61 where the precast structure 57 is set is excavated in advance to a predetermined depth, and crushed stone is laid as described above. The bottom where the seabed 61 is excavated and crushed stone is laid is defined as the seabed 61a. That is, the precast structure 57 is set on the seabed 61a.

After towing the precast structure 57 to the settling location, water is introduced into the ballast to set the precast structure 57. As described above, the precast structure 57 can be deposited on the seabed 61a at a desired location. At this time, a part of the connecting portion 59 (see FIG. 27) is constructed on the bottom plate 83 by, for example, caisson or the like, excluding the passage portion of the precast structure 57 (upper portion of the steel pipe sheet pile cylinder 79), for example. Also good.

Repeat the manufacturing, towing and laying of the precast structure 57 described above. After the plurality of precast structures 57 are deposited, adjacent precast structures 57 are connected to each other. In addition, any structure may be sufficient for the connection of the precast structures 57, as long as normal segments can be connected. Moreover, after all the precast structures 57 have passed through the portion of the steel pipe sheet pile cylinder 79, the connecting portion 59 (see FIG. 27) is completed to the ground. Thus, the precast structure 57 can be used as a buried box.

Here, the connection structure of the conventional box-shaped submerged box is provided with a flexible mechanism for absorbing surrounding deformation. On the other hand, a flexible mechanism is not necessary for the connecting portion between the precast structures 57 of the present invention. This is because the precast structure 57 of the present invention is composed of a large number of segments 3, and displacement can be allowed little by little at the connecting portions between the individual annular members. For example, when the precast structure 57 of the present invention is configured by connecting 80 to 100 annular members in the longitudinal direction, if the flexible mechanism in the conventional connection structure allows deformation of about 100 mm, In the invention, it suffices that the deformation can be allowed by being dispersed by about 1 mm at the connecting portions of the annular members. For this reason, a flexible mechanism becomes unnecessary in the connection part between submerged boxes.

As a result, since the submerged tunnel using the precast structure 57 of the present invention has substantially constant rigidity in the longitudinal direction, a large rigidity change part is not formed at the connection part as in the conventional case, and stress is reduced. Concentration is also unlikely to occur.

In addition, in order to connect the precast structures 57 to each other, a sealing member is sandwiched between the precast structures 57, and hydraulic bonding is performed. In the hydraulic pressure bonding, first, the precast structure 57 having the sealing member attached to the end face is attached to the other precast structure 57 and drawn by a drawing jack (not shown). At this time, the sealing member is compressed by the force of the pulling jack to obtain a water stop effect. Next, when the water surrounded by the end face of the precast structure 57 and the seal member is drained, an external water pressure and a differential pressure are generated on the opposite end face of the precast structure 57, and the seal member further increases the amount of compression, thereby ensuring safety. High water stopping effect is obtained.

A secondary lining may be placed on the inner surface of the precast structure 57 and the inner surface of the connecting portion. Thus, the connection between the precast structures 57 is completed. The subcast tunnel 57 is completed by sinking the precast structure 57 over the entire length of the submarine tunnel 53 to complete the joining and backfilling the precast structure 57.

Thus, since the precast structure 57 is connected and configured, an arch-shaped cross section can be easily formed. Therefore, the resistance to external pressure is improved as compared with a box-type submerged box formed by spot casting in a dry dog as in the prior art. For this reason, thickness can be made thin.

Also, the land tunnel construction range 55a is used as the production yard 89 for assembling the precast structure 57. For this reason, the precast structure 57 can be assembled at a place close to the set place. Further, the production yard 89 formed by the excavation can be used as it is for the construction of the land tunnel portion 55 thereafter. Therefore, there is no waste and the tunnel 51 can be constructed efficiently.

Next, the construction method of the land tunnel 55 will be described. The land-based tunnel portion 55 can be constructed by the above-described open-cut method, but can also be constructed as follows.

First, almost the entire construction area of the land tunnel part 55 is excavated, and a production yard is newly constructed at, for example, the endmost part (the side far from the seabed tunnel part 53 and close to the ground surface). The newly constructed production yard is formed at a position lower than the sea level. A gate is provided at the sea side end of the production yard. The gate prevents seawater from flowing into the production yard. That is, seawater is introduced into the land tunnel construction area 55a outside the gate (sea side).

In the production yard that functions as a dry dog by the gate, the precast structure 57 is assembled. When the assembly of the precast structure 57 is completed, the gate is opened and seawater is introduced into the production yard in the same manner as described above. The precast structure 57 that has surfaced on the water surface is towed to the sea by a towed ship. That is, the precast structure 57 is towed from the production yard to the settling site.

After the precast structure 57 has moved over the water to the settling site in the land tunnel construction area 55a, water is introduced into the ballast to set the precast structure 57. As described above, the precast structure 57 can be deposited at a desired place. The precast structure 57 installed at the end of the land tunnel portion 55 is connected to the connection portion 59 between the submarine tunnel portion 53 and the land tunnel portion 55.

Repeat the manufacturing, towing and laying of the precast structure 57 described above. After the plurality of precast structures 57 are deposited, adjacent precast structures 57 are connected to each other. The connection between the precast structures 57 is the same as the construction of the submarine tunnel portion 53.

After the pre-casting structure 57 is completely set, secondary lining is placed on the inner surface and the inner surface of the connecting portion. Thus, the connection between the precast structures 57 is completed. The precast structure 57 is deposited over the entire length of the land tunnel portion 55 to complete the joining, and the precast structure 57 is backfilled to complete the land tunnel portion 55.

As described above, in the present invention, the land tunnel portion 55 can also be constructed by setting the precast structure 57. That is, the land tunnel part 55 using the segment 3 can be easily constructed even for the relatively shallow land tunnel part 55 where the shield method cannot be used.

The embodiment of the present invention has been described above with reference to the accompanying drawings, but the technical scope of the present invention is not affected by the above-described embodiment. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

For example, it goes without saying that the embodiments described above can be combined with each other.

1, 1a, 1b, 57 ......... Precast structure 2a, 2b ......... Water stop member 3 ......... Segment 3a ......... Lower segment 3b ......... Upper segment 4a ......... Bottom segment 4b ......... Side Section segment 4c ......... Top segment 5, 5a ... ... Tension member 7 ... ... Connecting projection 8 ... ... Guide projection 8a ... ... Hole 8b ... ... Connecting member 9 ... ... Rails 9a, 9b, 9c, 9d ............ Water stop member 10 ......... Ring-shaped structure 11, 12 ......... Hole 13 ......... Recess 14 ......... Rebar 16 ......... Foam 16a ......... Pipe 17 ......... Jack 18 ......... Anchor plate 18a ......... Coupler sleeve 18b ......... Coupler joint 21 ......... Base 21a ......... Grip device 21b ......... Working scaffold 22, 22a ......... Base 23 ......... Filler 24 ... ... Hole 25 ......... Connecting part 27, 27a, 27b ......... Tensioning member 31 ......... Cut-off part 33 ......... Bearing 35 ......... Rail 37 ......... Winch 39 ......... Fluidized soil 41 ... …… Stand 43 ……… Underground structure 45 ……… Coating film 47 ……… Waterproof sheet 51 ……… Tunnel 53 ……… Submarine tunnel 53a ……… Submarine tunnel construction area 55 ……… Onshore tunnel 55a ......... Tunnel construction area 59 ......... Connection 61, 61a ......... Submarine 79 ......... Steel sheet pile 83 ......... Bottom plate 85 ......... Gate 89 ......... Production yard

Claims (12)

1. A ring-shaped precast structure in which a plurality of segments having an arch shape are connected,
   The segments are connected in the circumferential direction and the longitudinal direction,
   A precast structure, wherein prestress is applied in a circumferential direction and a longitudinal direction of the connected segments.
2. The precast structure according to claim 1, wherein the segments are connected to each other in the circumferential direction and the longitudinal direction via a water stop member.
3. The precast structure according to claim 1, wherein a hollow portion of concrete is provided inside the segment.
4. The precast structure according to claim 3, wherein a foam is embedded in the hollow portion.
5. The precast structure according to claim 3, wherein a pipe is embedded in the hollow portion.
6. The outer peripheral surface of the segment is provided with a first protrusion as a positioning guide in the longitudinal connection between the segments,
   The first protrusions of the segments adjacent in the longitudinal direction are connected by a connecting member,
   2. A precast structure according to claim 1, wherein prestress is applied over the entire length of the connected segments in the longitudinal direction.
7. The outer peripheral surface of the segment is provided with a second protrusion for connecting the segments in the circumferential direction,
   The precast structure according to claim 1, wherein the second protrusions are tensioned by a tension member in a state where the positions of the second protrusions of the segments adjacent in the circumferential direction are matched. body.
8. 2. The precast structure according to claim 1, wherein the end faces of the segments facing each other in the longitudinal direction are provided with concave portions at mutually corresponding portions, and the concave portions are filled with a filler and solidified.
9. A construction method for an underground structure,
   Installing a segment having an arch shape in the excavation part from the ground;
   Using a gantry that moves on the segments, connecting a plurality of segments to each other via a water stop member in the circumferential direction, applying prestress in the circumferential direction, and building a ring-shaped structure;
   Connecting a predetermined number of the ring-shaped structures adjacent to each other in the longitudinal direction perpendicular to the circumferential direction via a water stop member, and applying prestress in the longitudinal direction;
   The construction method of an underground structure characterized by comprising.
10. A construction method for an underground structure,
    Connecting a plurality of segments having an arch shape in the circumferential direction via a water stop member, applying prestress in the circumferential direction, and building a ring-shaped structure;
    Installing the ring-shaped structure from the ground to the excavation part;
    A predetermined number of the ring-shaped structures adjacent to each other in the longitudinal direction perpendicular to the circumferential direction are connected via a water-stopping member using a platform that moves in an existing ring-shaped structure, and prestressed in the longitudinal direction. A step of providing
    The construction method of an underground structure characterized by comprising.
11. The gantry is movable inside the ring-shaped structure, and a part of the gantry can be expanded and contracted outward.
    When moving the gantry inside the ring-shaped structure, shrinking a part of the gantry, preventing interference between the gantry and the inner surface of the segment,
    When the gantry is moved to the outside of the ring-shaped structure, a part of the gantry can be extended outward to an end face position of the ring-shaped structure. The construction method of the underground structure of Claim 9 or Claim 10.
12. The ring-shaped structure is divided into four in the circumferential direction, and is configured by connecting a bottom segment, a pair of side segments, and a top segment,
    11. The underground structure according to claim 9, wherein in the ring-shaped structures adjacent to each other in a longitudinal direction perpendicular to a circumferential direction, the bottom segments and the top segments are different in length. Construction method.

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