JP7640653B2 - Formwork for manufacturing hexagonal segments - Google Patents

Description

The present invention relates to a formwork for manufacturing hexagonal segments, and in particular to a formwork for manufacturing hexagonal segments having a face-side axial joint surface, a wellhead-side axial joint surface, and a pair of V-shaped circumferential joint surfaces.

The shield method using a shield tunneling machine is widely used as a method for constructing various types of tunnels in urban and plain areas. In the shield method, the face at the tip of the shield tunneling machine is pressed down with mud, muddy water, compressed air, etc. while the ground is excavated with a cutter, and segments are successively installed in the axial and circumferential directions of the tunnel behind the shield tunneling machine to form a lining that covers the inner surface of the tunnel. A shield jack is pressed against the front end of the assembled lining to obtain a reaction force, and the tunnel is constructed underground from the starting shaft to the arrival shaft.

In recent years, in order to improve the efficiency of construction work, a shield construction method using hexagonal segments having a hexagonal planar shape instead of the generally used rectangular planar shape segments that constitute the lining covering the inner periphery of the tunnel has been adopted (see, for example, Patent Document 1 and Patent Document 2). The hexagonal segments have a pair of V-shaped circumferential joint surfaces consisting of a face-side axial joint surface and a wellhead-side axial joint surface that are arranged in parallel, and a face-side oblique joint surface and a wellhead-side oblique joint surface that are arranged in a V shape so as to connect the ends on both sides of these axial joint surfaces (see Figure 1). The hexagonal segments are assembled in sequence, with the face-side axial joint surface and face-side diagonal joint surface of the hexagonal segment that is assembled first to the rear side of the tunnel excavation direction overlapping the portal-side axial joint surface and portal-side diagonal joint surface of the hexagonal segment that is assembled next to the front side of the tunnel excavation direction, while the isosceles trapezoidal portion of each hexagonal segment, which is the forward half of the tunnel excavation direction, is alternately protruding and arranged in a honeycomb pattern in the axial and circumferential directions of the tunnel (see, for example, Patent Document 3, Figure 4).

In addition, in the shield tunneling method using hexagonal segments, a shield jack is pressed against the axial joint surface on the face side of the alternately protruding isosceles trapezoidal parts of the hexagonal segments, and the shield tunneling machine is driven to excavate while taking up the reaction force. In parallel with this, the succeeding hexagonal segment can be assembled in the area between the adjacent isosceles trapezoidal parts against which the shield jack is pressed (see, for example, Patent Document 3, Figure 4). As a result, it is possible to carry out shield construction efficiently by continuously assembling the hexagonal segments while the shield tunneling machine is driving, without interrupting the process of driving the shield tunneling machine for each ring to assemble the segments, as is done in the shield tunneling method using segments with a rectangular planar shape.

Furthermore, in the shield tunneling method using hexagonal segments, the connection between adjacent hexagonal segments is performed using connecting bolts that penetrate between the joint surfaces of the axial joint surface on the face side, the axial joint surface on the wellhead side, the diagonal joint surface on the face side, and the diagonal joint surface on the wellhead side (see, for example, Patent Documents 1, 2, and 3). This makes it possible to prevent the formation of unevenness on the inner surface of the lining body made of hexagonal segments due to bolt boxes for fastening the connecting bolts, which appears on the inner surface of the lining body made of segments having a rectangular planar shape. This also makes it possible to keep the inner surface of the lining body smooth, so there is no need to further construct a secondary lining inside the lining body made of hexagonal segments, preferably with a corrosion protection layer applied to the inner surface, and the shield tunnel constructed by using the inner surface of the lining body made of hexagonal segments as it is as the inner surface of the tunnel can be effectively used, for example, as a sewer pipe for circulating water or a tunnel for a reservoir for temporarily storing rainwater.

Such hexagonal segments are preferably made of concrete, and since the axial joint surface on the face side, the axial joint surface on the wellhead side, and the pair of V-shaped circumferential joint surfaces that are joined to each other in particular must be formed with high precision, a formwork for manufacturing hexagonal segments has been developed for this purpose (see, for example, Patent Document 4).

The formwork for manufacturing hexagonal segments described in Patent Document 4 includes a bottom plate portion, a pair of side plate portions that form both sides of the hexagonal segment and are erected on the bottom plate portion to form a space for pouring concrete, and a pair of end plate portions that form both ends of the hexagonal segment. The pair of end plate portions are arranged so that they can be moved in a direction away from the hexagonal segment that they are formed with the opening and closing means including an end plate slide shaft, a slide roller pin, a lower plate, a guide rail, a base, a guide roller, an opening and closing bolt, etc.

In other words, the end plate is guided in the direction of movement by the forward/backward guide section formed by the end plate slide shaft and slide roller pin, and by rotating the opening/closing bolt, the guide rail provided on the underside of the lower plate slides along the guide roller attached to the base, thereby moving the lower plate relative to the base and retreating in the direction away from the hexagonal segment (see Figure 5). This prevents cracks or chips from occurring in the hexagonal segment when it is removed from the mold, especially at the corners where the bottom plate and end plate join.

Patent No. 2596666 Japanese Patent Application Publication No. 9-273395 Patent No. 3253870 Patent No. 3481769

However, in the conventional formwork for manufacturing hexagonal segments described above, the forward/backward guide portion that guides the movement direction of the end plate portion is arranged in the area below the bottom plate 52a, as shown in Figure 8, so that the protruding portion 51a toward the bottom plate 52a of the slide shaft 51, which is fixed integrally to the lower part of the end plate portion 50, is sandwiched between the upper and lower slide roller pins 53a, 53b supported by the support bracket 52b of the bottom plate portion 52, and the sandwiched protruding portion 51a of the slide shaft 51 slides between the upper and lower slide roller pins 53a, 53b, thereby guiding the forward/backward direction of the end plate portion 50. For this reason, when the formwork for manufacturing hexagonal segments is used repeatedly, the overhanging portion 51a of the slide shaft 51, which overhangs like a cantilever beam at a considerable length, can easily become eccentric or develop an offset load due to fatigue, and the sliding roller pins 53a, 53b that move in a sliding motion can easily become lateral (meandering) or wobble, which can make it difficult to accurately retract the end plate portion 50 in a specified direction and stably separate it from the formed hexagonal segment.

In recent years, there has been a demand for constructing large shield tunnels with large inner diameters using hexagonal segments, and the area and thickness of each hexagonal segment tends to increase. The number of hexagonal segments used is also increasing, and the number of times that formwork for manufacturing hexagonal segments is being used repeatedly is also increasing. For this reason, there is a need to develop technology that can form high-quality hexagonal segments by precisely retracting the end plate portions in a specified direction when demolded in a more stable state, even when the formwork for manufacturing hexagonal segments is used repeatedly many times.

The present invention aims to provide a formwork for manufacturing hexagonal segments that allows the end plate portion to be retracted in a specified direction with high precision and in a more stable state when demolded, and that can continue to form high-quality hexagonal segments, even when used repeatedly many times.

The present invention relates to a formwork for manufacturing a hexagonal segment for forming, by pouring and hardening concrete, a hexagonal segment having a face-side axial joint surface and a wellhead-side axial joint surface, and a pair of V-shaped circumferential joint surfaces consisting of a face-side oblique joint surface and a wellhead-side oblique joint surface, which are arranged in a V shape so as to connect both end portions of the pair of axial joint surfaces, the formwork comprising: a bottom plate portion having a curved portion along an inner peripheral surface of the hexagonal segment; a face-side side plate portion having a curved portion along the face-side axial joint surface, which are arranged upright on both side edges of the bottom plate portion, and a wellhead-side side plate portion having a curved portion along the wellhead-side axial joint surface, and a V-shaped portion along the V-shaped circumferential joint surface, which are arranged upright on both end edges of the bottom plate portion, the end plate section includes a pair of end plate sections and a base section that supports the bottom plate section, the side plate section and the end plate section as a whole from below, the face side plate section and the mineshaft side side plate section are arranged so that they can be advanced and retreated toward and away from each other via a side plate advancement/retraction mechanism supported by the base section, and the pair of end plate sections are arranged so that they can be advanced and retreated toward and away from the bottom plate section via an end plate advancement/retraction mechanism supported by the base section, the end plate advancement/retraction mechanism including an advancement/retraction guide section consisting of a slide guide shaft that is provided so as to extend linearly in the advancement/retraction direction of the end plate sections and a bearing that is fixed to the end plate sections and is slidable along the slide guide shaft, and an advancement/retraction operation section that advances and retreats the pair of end plate sections,
The slide guide shaft of the advance/retract guide portion is attached with one end fixed to the bottom plate portion and the other end fixed to the base portion, and the bearing slides along the slide guide shaft, whereby the end plate portion advances and retreats in a direction approaching and moving away from the bottom plate portion,
The slide guide shaft of the advance/retract guide portion is a columnar or cylindrical shaft member.
The above object is achieved by providing a form for manufacturing hexagonal segments in which the bearing is a cylindrical rolling bearing .

The hexagonal segment manufacturing formwork of the present invention is preferably such that the advancing/retreating operation part of the end plate advancing/retreating mechanism is provided below the apex of the V-shaped portion of the end plate portion, and the advancing/retreating guide parts of the end plate advancing/retreating mechanism are symmetrically arranged in pairs on both sides of the advancing/retreating operation part, and are each provided below the oblique sides on both sides of the V-shaped portion of the end plate portion.

Furthermore, in the hexagonal segment manufacturing formwork of the present invention, it is preferable that the slide guide shaft of the advance/retract guide section is a columnar or cylindrical shaft member, and the bearing is a cylindrical rolling bearing.

The mold for manufacturing hexagonal segments of the present invention allows the end plate portion to be retracted in a specified direction with high precision and in a more stable state when demolded, making it possible to continue to form high-quality hexagonal segments, even when used repeatedly many times.

FIG. 2 is a plan view of a mold for manufacturing a hexagonal segment according to a preferred embodiment of the present invention. FIG. 2 is a side view of a mold for manufacturing a hexagonal segment according to a preferred embodiment of the present invention, as viewed from the X direction in FIG. 1 . FIG. 2 is an end view of a hexagonal segment manufacturing form according to a preferred embodiment of the present invention, taken from the Y direction in FIG. 1 . 4 is a cross-sectional view taken along line AA in FIG. 3, illustrating the configuration of the end plate advancing/retracting mechanism. 5 is a cross-sectional view taken along line BB in FIG. 4, illustrating the configuration of the advancing/retracting operation part of the end plate advancing/retracting mechanism. 5 is a cross-sectional view taken along CC in FIG. 4, illustrating the configuration of the advance/retract guide portion of the end plate advance/retract mechanism. 1A to 1D are diagrams illustrating the configuration of a hexagonal segment formed using a formwork for manufacturing a hexagonal segment according to a preferred embodiment of the present invention, in which (a) is a front view, (b) is a side view of (a) viewed from direction D, (c) is a side view of (a) viewed from direction E, and (d) is a circumferential end view of (a) viewed from direction F. 11 is a cross-sectional view illustrating the configuration of a reciprocating guide portion of a conventional end plate reciprocating mechanism.

The hexagonal segment manufacturing formwork 10 according to a preferred embodiment of the present invention shown in Figures 1 to 3 is used as a formwork for forming hexagonal concrete segments 40 (see Figures 7(a) to (d)) that constitute a lining covering the inner surface of a shield tunnel for a reservoir that temporarily stores rainwater, preferably by connecting a plurality of the hexagonal segments 40 in the axial direction (excavation direction) and circumferential direction of the tunnel and assembling them in a honeycomb shape. The shield tunnel for a reservoir is a large circular tunnel with an inner diameter of, for example, about 5000 mm, and each hexagonal segment 40 that forms the lining covering the inner surface of the tunnel is also large, with a width in the tunnel axial direction of about 1000 mm, a length in the tunnel circumferential direction of about 3000 mm, and a thickness of about 300 mm, and a large number of hexagonal segments 40 are used. The hexagonal segment manufacturing formwork 10 of this embodiment has the function of being able to continue to form high-quality hexagonal segments in a precise and stable manner, even when used repeatedly to form a large number of such hexagonal segments 40.

The hexagonal segment manufacturing formwork 10 of this embodiment is a formwork for manufacturing segments to form, by pouring concrete into it and hardening it, a hexagonal segment 40 (see Figures 7(a) to (d)) that has a face-side axial joint surface 41, a wellhead-side axial joint surface 42, and a pair of V-shaped circumferential joint surfaces 45 consisting of a face-side diagonal joint surface 43 and a wellhead-side diagonal joint surface 44 that are arranged in a V shape so as to connect both ends of the pair of axial joint surfaces 41, 42, respectively. As shown in Figures 1 to 3, the hexagonal segment 40 has a curved shape that follows the inner circumferential surface of the hexagonal segment 40. The cut face side plate portion 12 has a curved portion 12a along the cut face side axial joint surface 41 of the hexagonal segment 40, and the cut face side plate portion 13 has a curved portion 13a along the cut face side axial joint surface 42, which are arranged upright on both side edges of the bottom plate portion 11, a pair of end plate portions 14 having V-shaped portions 14a along the V-shaped circumferential joint surface 45, which are arranged upright on both end edges of the bottom plate portion 11, and a base portion 30 that supports the bottom plate portion 11, the side plate portions 12, 13, and the end plate portions 14 as a whole from below. The face side plate 12 and the wellhead side plate 13 are arranged so that they can move toward and away from each other via a side plate advancement mechanism 32 supported by the base 30 (see Figures 2 and 3), and the pair of end plate parts 14 are arranged so that they can move toward and away from the bottom plate part 11 via an end plate advancement mechanism 20 supported by the base 30, as shown in Figures 4 to 6. The end plate advancement mechanism 20 is arranged so that it can move toward and away from the bottom plate part 11 via an end plate advancement mechanism 20 supported by the base 30. The end plate advancement mechanism 20 includes an advancement guide part 23 (see Figure 6) consisting of a slide guide shaft 21 that is fixed at one end to the bottom plate part 11 and the other end to the base 30 and extends linearly in the advancement direction of the end plate part 14, a bearing 22 that is fixed to the end plate part 14 and can slide along the slide guide shaft 21, and an advancement operation part 25 (see Figure 5) that advances and retreats the pair of end plate parts 14.

In addition, in this embodiment, the slide guide shaft 21 of the advance/retreat guide section 23 is preferably a columnar or cylindrical shaft member, and the bearing 22 is preferably a cylindrical rolling bearing (see FIG. 6).

In this embodiment, the hexagonal segment 40 formed using the hexagonal segment manufacturing formwork 10 is a segment preferably made of reinforced concrete having a hexagonal planar shape, with a pair of V-shaped circumferential joint surfaces 45 consisting of a face-side axial joint surface 41 and a wellhead-side axial joint surface 42 arranged in parallel, and a face-side diagonal joint surface 43 and a wellhead-side diagonal joint surface 44 arranged in a V-shape so as to connect the ends on both sides of these axial joint surfaces 41 and 42, as shown in Figures 7(a) to (d). The hexagonal segment 40 has a cross section along the face-side axial joint surface 41 and the wellhead-side axial joint surface 42 that is curved in an arc shape (see Figures 7(b) and (c)). In the hexagonal segment 40, the angle θ between the face-side diagonal joint surface 43 and the wellhead-side diagonal joint surface 44 at each V-shaped circumferential joint surface 45 is 120° (see Figure 7(a)). This allows multiple hexagonal segments 40 to be arranged in a honeycomb pattern in the axial and circumferential directions, with the face-side diagonal joint surface 43 and face-side axial joint surface 41 of the previously installed hexagonal segment 40 overlapping with the wellhead-side diagonal joint surface 44 and wellhead-side axial joint surface 42 of the subsequently installed hexagonal segment 40 without any gaps.

In this embodiment, as shown in Figures 7(a) to (d), the hexagonal segment 40 has an outer seal groove 46a for attaching a sealant formed continuously around the entire circumference at a distance from the outer peripheral surface on the face-side axial joint surface 41, the wellhead-side axial joint surface 42, the face-side oblique joint surface 43, and the wellhead-side oblique joint surface 44, and an inner seal groove 46b for attaching a sealant formed continuously around the entire circumference at a distance from the inner peripheral surface.

Furthermore, in this embodiment, the hexagonal segment 40 has cutouts 46c for attaching caulking material formed continuously around the entire circumference of the axial joint surface 41 on the face side, the axial joint surface 42 on the mouth side, the diagonal joint surface 43 on the face side, and the diagonal joint surface 44 on the mouth side along the edge portion on the inner periphery of the tunnel.

In this embodiment, the hexagonal segment 40 is provided with oblique bolt insertion holes 47a that extend parallel to the face-side oblique joint surface 43 from the side regions on both sides of the face-side axial joint surface 41 toward the center of the mouth-side oblique joint surface 44, as in the tortoise shell-shaped segment (hexagonal segment) described in Patent No. 3253870. At the end of each oblique bolt insertion hole 47a on the face-side axial joint surface 41 side, a fastening recess 47b for fastening the head of a connecting bolt member (not shown) is formed with its opening surface opening to the face-side axial joint surface 41. A positioning recess 47c is provided in the portion of the face-side axial joint surface 41 closer to the face-side oblique joint surface 43 than each fastening recess 47b. At the mouth-side axial joint surface 42 of the hexagonal segment 40, a positioning protrusion 47d is provided at a position corresponding to the positioning recess 47c in the side regions on both sides.

In this embodiment, a pair of face-side diagonal joint surfaces 43 of the hexagonal segments 40 are provided with female screw holes 48a in their central portions. When the wellhead-side diagonal joint surface 44 of the subsequently installed hexagonal segment 40 is superimposed on the face-side diagonal joint surface 43 of the previously installed hexagonal segment 40, the female screw holes 48a are linearly connected to the end openings 47e of the bolt insertion holes 47a provided in the subsequent hexagonal segment 40 on the side opposite the fastening recesses 47b.

Furthermore, in this embodiment, similar to the tortoise shell-shaped segments (hexagonal segments) described in, for example, Patent No. 3253870, the face-side diagonal joint surface 43 and the mouth-side diagonal joint surface 44 of the hexagonal segment 40 are each provided with a positioning guide protrusion 49a and a guide recess 49b for guiding the subsequent hexagonal segment 40 so as to be accurately positioned in the gap between each pair of circumferentially adjacent isosceles trapezoidal portions of the previously installed hexagonal segment 40.

Furthermore, in this embodiment, the hexagonal segment 40 has a gripping hole 49c in the center of its inner surface, which allows the hexagonal segment 40 to be gripped by an erector device (not shown) for assembly, and a pair of lifting insert fittings 49d, which allow the hexagonal segment 40 to be lifted, are provided in the side regions on both sides of the wellhead-side axial joint surface 42.

In this embodiment, the hexagonal segment 40 having the above-mentioned configuration can be formed by pouring concrete into the hexagonal segment manufacturing formwork 10 shown in Figures 1 to 3 and allowing it to harden. The hexagonal segment manufacturing formwork 10 includes a bottom plate portion 11 having a bottom plate 11a that is a curved portion along the inner circumferential surface of the hexagonal segment 40, a face side side plate portion 12 having a side plate 12a that is a curved portion along the face side axial joint surface 41 of the hexagonal segment 40, and a wellhead side plate portion 13 having a side plate 13a that is a curved portion along the wellhead side axial joint surface 42, and a pair of end plate portions 14 having V-shaped end plates 14a that are V-shaped portions along the V-shaped circumferential joint surface 45, each of which is arranged upright on the edge portions on both sides of the bottom plate 11a of the bottom plate portion 11, and a base portion 30 that supports the bottom plate portion 11, the side plate portions 12, 13, and the end plate portions 14 as a whole from below.

The bottom plate portion 11 is constructed by supporting and fixing the bottom plate 11a, which is a steel plate curved in an arc along the inner peripheral surface of the hexagonal segment 40, from below by a number of steel supports 31 (see FIG. 2) erected from the base portion 30. Similar to the hexagonal segment manufacturing formwork described in Japanese Patent No. 3481769, a number of shaft insertion members 33 (see FIG. 1) constituting the side plate advancement and retreat mechanism 32 are fixed to the steel supports 31 in a state extending in the width direction of the bottom plate 11a. The side plate slide shafts 34 (see FIG. 1) constituting the side plate advancement mechanism 32 are fixed in a state extending in the width direction of the bottom plate 11a at positions corresponding to the shaft insertion members 33 on the face side side plate 12 and the mouth side side plate 13. By inserting and supporting the side plate slide shafts 34 so that they can advance and retreat, the side plate 12a of the face side side plate 12 and the side plate 13a of the mouth side side plate 13 can be moved away from the side edge of the bottom plate 11a or brought into contact with the side edge of the bottom plate 11a.

In addition, as shown in FIG. 6, a fixed rib plate 11b is attached to the end edge of the bottom plate 11a constituting the bottom plate portion 11, where the end plate portion 14 abuts, and extends from the underside in parallel with the end plate 14a and protrudes downward, to which one end of the slide guide shaft 21 of the advance/retract guide portion 23 described later is fixed. The fixed rib plate 11b is firmly attached as one unit to the bottom of the bottom plate 11a via welding or the like, while being reinforced by a reinforcing rib plate 11c fixed to the bottom plate 11a via welding or the like. In addition, a gripping hole insert member 11d is attached in an upright state to the center of the upper surface side of the bottom plate 11a, as shown in FIG. 1 and FIG. 3, in order to form a gripping hole 49c in the center of the inner surface of the hexagonal segment 40.

The face-side side plate 12 and the mouth-side side plate 13 include the face-side side plate 12a and the mouth-side side plate 13a, which have an inner surface curved in an arc shape as a curved portion along the face-side axial joint surface 41 and the mouth-side axial joint surface 42 of the hexagonal segment 40, and the face-side support wall portion 12b and the mouth-side support wall portion 13b, which extend integrally below the face-side side plate 12a and the mouth-side side plate 13a to the lower region of the bottom plate 11a. The face-side side plate 12a and the mouth-side side plate 13a are integrally joined to the upper edge and both end edges of the face-side side plate 12a and the mouth-side side plate 13a so as to protrude vertically outward, and are fixed to the outer surface of the face-side side plate 12a and the mouth-side side plate 13a by welding or the like. At the same time, the radial reinforcing plates 12d and 13d (see FIG. 2) are integrally joined to the outer surface of the face-side side plate 12a and the mouth-side side plate 13a and are fixed to the outer surface of the face-side side plate 12a and the mouth-side side plate 13a by welding or the like. These provide strong reinforcement to the side plate 12a on the face side and the side plate 13a on the mouth side.

In this embodiment, a pair of convex sockets 12e are attached to the inner surface of the side plate 12a of the face-side side plate portion 12 for forming positioning recesses 47c on the face-side axial joint surface 41 of the hexagonal segment 40 (see Figure 1). A pair of concave plugs 13f are attached to the inner surface of the side plate 13a of the mouth-side side plate portion 13 for forming positioning protrusions 47d on the mouth-side axial joint surface 42 of the hexagonal segment 40.

The face-side support wall 12b and the mouth-side support wall 13b are integrally joined with a side plate slide shaft 34 (see FIG. 1) constituting a side plate advancement mechanism 32 similar to the side plate advancement mechanism of the hexagonal segment manufacturing formwork described in the above-mentioned Patent Publication No. 3481769. The side plate slide shaft 34 is inserted and supported by a shaft insertion member 33 (see FIG. 1) fixed to a steel support 31 erected from the base 30 that supports the bottom plate 11a of the bottom plate 11. By operating a known advancement/retraction operation unit 35 (see FIGS. 1 and 3), the face-side side plate 12a integrated with the face-side support wall 12b and the mouth-side side plate 13a integrated with the mouth-side support wall 13b can be moved forward and backward in the direction of approaching and separating from each other.

As shown in Figs. 1 and 3, the pair of end plate portions 14 arranged on both longitudinal edge portions of the bottom plate portion 11 each include an end plate 14a with an inner surface bent in a V-shape as a V-shaped portion along the V-shaped circumferential joint surface 45 of the hexagonal segment 40, and an end plate support wall portion 14b extending integrally below the end plate 14a to the lower region of the bottom plate 11a. A band-shaped outer peripheral reinforcing plate 14c is integrally joined to the end plate 14a by welding or the like so as to extend vertically outward in the forward and backward direction from the upper edge portion and both edge portions, and a vertical reinforcing plate 14d (see Fig. 3) is integrally joined to the outer surface of the end plate 14a and fixed by welding or the like.

In addition, in this embodiment, on the inner surface of the end plate 14a of the end plate portion 14, a hypotenuse convex socket 14h and a hypotenuse concave plug 14i are attached to each of the face side diagonal joint surface 43 and the wellhead side diagonal joint surface 44 of the hexagonal segment 40 to form a guide convex portion 49a and a guide concave portion 49b for positioning (see Figure 1).

In addition, in this embodiment, as shown in Figures 3 and 4, the end plate support wall portion 14b of the end plate portion 14 is provided with an advance/retract bolt 25a and the like that constitutes the advance/retract operation portion 25 of the end plate advance/retract mechanism 20, which is disposed at the top of the V-shape, and a bearing 22 and the like that constitutes the advance/retract guide portion 23 of the end plate advance/retract mechanism 20 are disposed at the center of each of a pair of oblique sides of the V-shape. That is, in this embodiment, the advance/retract operation portion 25 of the end plate advance/retract mechanism 20 is preferably provided at the lower part of the top of the end plate 14a that forms the V-shaped portion of the end plate portion 14, and the advance/retract guide portion 23 of the end plate advance/retract mechanism 20 is preferably provided in a pair symmetrically on both sides of the advance/retract operation portion 25, and is preferably provided at the lower part of the oblique sides on both sides of the end plate 14a that form the V-shaped portion of the end plate portion 14.

As shown in Figures 4 and 5, the advancing/retracting operation unit 25 of the end plate advancing/retracting mechanism 20 has a similar configuration to the advancing/retracting operation unit of the end plate of the hexagonal segment manufacturing formwork described in the above-mentioned Patent Publication No. 3481769. The advancing/retracting operation unit 25 tightens or loosens the advancing/retracting bolt 25a attached to the end plate support wall 14b of the end plate 14, and moves the guide rail 25b provided on the lower surface of the lower plate 14j of the end plate support wall 14b through the guide roller 25d supported by the pedestal 25c provided on the base 30 by rotating the guide roller 25d, thereby allowing the pair of end plate portions 14 to advance and retreat in the direction of approaching and separating from the bottom plate portion 11 (see the dashed line in Figure 5).

In this embodiment, as shown in Figures 4 and 6, the advance/retract guide portion 23 of the end plate advance/retract mechanism 20 is configured to include a slide guide shaft 21, one end of which is fixed by welding or the like to the fixed rib plate 11b of the bottom plate portion 11 and the other end of which is fixed by welding or the like to a support bracket 36 attached to the base portion 30, and a bearing 22 fixed to the end plate support wall portion 14b of the end plate portion 14.

The slide guide shaft 21 is preferably a columnar or cylindrical metal shaft member, and one end is fixed to the fixed rib plate 11b and the other end is fixed to the support bracket 36, so that it is firmly attached in a state of extending linearly in the advancing/retreating direction along the length of the hexagonal segment 40, which is preferably perpendicular to the V-shaped circumferential joint surface 45 of the hexagonal segment 40 that moves the end plate portion 14 forward and backward. That is, the fixed rib plate 11b is firmly fixed to the bottom plate 11a of the bottom plate portion 11, which is supported and fixed to the base portion 30 via the steel support 31, via welding or the like, as described above, and is also firmly fixed to the support bracket 36 via welding or the like to the base portion 30, so that the slide guide shaft 21, both ends of which are firmly fixed to these members, can be firmly and stably maintained in a state of extending linearly in the advancing/retreating direction.

The bearing 22 is a part that receives the load from a rotating or reciprocating mating part and is supported on a shaft or the like, and is preferably a rolling bearing such as a ball bearing. More specifically, it is preferable to use a linear bushing, which is preferably used in combination with a cylindrical shaft to form a linear motion system capable of infinite linear motion.

In this embodiment, the bearing 22 is firmly fixed as one unit to the end plate support wall 14b by, for example, fixing the outer cylinder 22a to the support plate 14f of the support stand 14e provided on the end plate support wall 14b of the end plate 14, with the slide guide shaft 21, which is a cylindrical shaft with both ends fixed, inserted inside the outer cylinder 22a. As a result, the end plate 14 is guided by the slide guide shaft 21 via the bearing 22, and can move precisely and smoothly along the length of the hexagonal segment 40, preferably in a direction perpendicular to the V-shaped circumferential joint surface 45 of the hexagonal segment 40 that is formed.

In this embodiment, a slide roller 38 supported by a roller support bracket 37 is attached to the base 30 directly below the end plate 14 adjacent to the support bracket 36 (see FIG. 6). A slide rail 14g provided on the lower end surface of the end plate support wall 14b of the end plate 14 abuts against the slide roller 38, allowing the end plate 14 to slide along the slide roller 38. This allows the end plate 14 to be moved more stably and smoothly along the length of the hexagonal segment 40, preferably in a direction perpendicular to the V-shaped circumferential joint surface 45 of the hexagonal segment 40 to be formed.

To form a hexagonal segment 40 using the hexagonal segment manufacturing formwork 10 of this embodiment having the above-mentioned configuration, the end plate 14a of the end plate portion 14 and the side plates 12a, 13a of the side plate portions 12, 13 are advanced and retreated by the end plate advancement mechanism 20 and the side plate advancement mechanism 32 described above, and these are brought into contact with both end edges and both side edges of the bottom plate 11a of the bottom plate portion 11 in an upright state, thereby forming a casting space for pouring concrete above the bottom plate 11a. In addition, reinforcing steel bars are appropriately arranged in the formed casting space, and as shown in FIG. 1, a sheath tube 26 for forming a diagonal bolt insertion hole 47a in the hexagonal segment 40, a female screw anchor 27 for forming a female screw hole 48a, and a lifting insert metal fitting 49d for lifting the hexagonal segment 40 are installed, for example, by supporting the reinforcing steel bars or block members. After that, concrete is poured into the casting space above the bottom plate 11a, and the outer periphery of the poured concrete is finished with a trowel so that it conforms to the arc-shaped curved surface.

After the poured concrete has hardened and a prescribed curing period has elapsed, the end plate 14a of the end plate portion 14 and the side plates 12a, 13a of the side plate portions 12, 13 are advanced and retreated by the end plate advancement mechanism 20 and side plate advancement mechanism 32 described above, and are removed by retreating them away from the hardened concrete. This makes it possible to easily remove the formed hexagonal segment 40 from the hexagonal segment manufacturing formwork 10.

The hexagonal segment manufacturing formwork 10 of this embodiment, which has the above-mentioned configuration, makes it possible to continue forming high-quality hexagonal segments by allowing the end plate portion to be retracted in a specified direction with high precision and in a more stable state when demolded, even when used repeatedly many times.

In other words, according to this embodiment, the end plate advancement/retraction guide section 23 of the end plate advancement/retraction mechanism 20, which moves the pair of end plate sections 14 toward and away from the bottom plate section 11, is composed of a slide guide shaft 21 that is fixed at one end to the bottom plate section 11 and at the other end to the base section 30 and extends linearly in the advancement/retraction direction of the end plate sections 14, and a bearing 22 that is fixed to the end plate sections 14 and is slidably mounted along the slide guide shaft 21.

As a result, according to this embodiment, by guiding the advance/retract guide unit 23 during demolding, the advance/retract operation unit 25 can move each end plate 14 linearly and precisely in the advance/retract direction along the length of the hexagonal segment 40 being formed, preferably perpendicular to the V-shaped circumferential joint surface 45 of the hexagonal segment 40. This makes it possible to effectively prevent cracks and chips from occurring at the joint corners between the bottom plate 11a of the bottom plate 11 and the end plate 14a of the end plate 14 during demolding. In particular, even if positioning guide protrusions 49a and guide recesses 49b are formed on the face side diagonal joint surface 43 and the wellhead side diagonal joint surface 44 of the V-shaped circumferential joint surface 45 of the hexagonal segment 40, it is possible to effectively prevent cracks and chips from occurring at these uneven parts during demolding.

In addition, according to this embodiment, the forward and backward guide section 23 consisting of the slide guide shaft 21 and the bearing 22 is fixed at both ends of the slide guide shaft 21, which is preferably a columnar or cylindrical shaft member, to the fixed rib plate 11b of the bottom plate section 11 and the support bracket 36 of the base section 30, respectively, and is firmly attached by extending linearly with high precision in the forward and backward direction of the end plate section 14, and the bearing 22, which is preferably a near bush, which is a rolling bearing, is firmly attached to the support stand 14e provided on the end plate support wall section 14b of the end plate section 14, and is stably attached along the slide guide shaft 21. Since it can slide in a fixed state, unlike the conventional advance/retract guide section (see Figure 8) that slides the cantilevered protruding portion of a slide shaft between the upper and lower slide roller pins, repeated use of the formwork can cause eccentricity or offset load due to fatigue, which can lead to lateral wobble (wandering) and rattling. By advancing and retracting the end plate section 14 in a stable and precise manner over a long period of time, it is possible to repeatedly form high-quality hexagonal segments many times.

Furthermore, according to this embodiment, the advance/retract operation unit 25 of the end plate advance/retract mechanism 20 is provided below the apex of the V-shaped portion formed by the end plate 14a, and the advance/retract guide units 23 are symmetrically arranged in pairs on both sides of the advance/retract operation unit 25, and are each provided below the hypotenuses on both sides of the V-shaped portion formed by the end plate 14a. This makes it possible to retreat the end plate 14a, which is the V-shaped portion, in a more balanced manner, and by advancing and retreating the end plate portion 14 in a more precise and stable state, it becomes possible to continue forming hexagonal segments of good quality.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, the advancing/retracting operation unit of the end plate advancing/retracting mechanism does not necessarily have to be provided below the top of the V-shaped portion of the end plate, and the advancing/retracting guide units of the end plate advancing/retracting mechanism do not necessarily have to be provided in a pair symmetrically arranged.

10: Formwork for manufacturing hexagonal segments 11: Bottom plate portion 11a: Bottom plate (curved portion)
11b Fixed rib plate 12 Face side side plate portion 12a Side plate (curved portion)
12b Face side support wall portion 13 Portal side side plate portion 13a Side plate (curved portion)
13b Well mouth side support wall part 14 End plate part 14a End plate (V-shaped part)
[0033] 14b End plate support wall portion 14e Support stand 20 End plate advance/retract mechanism 21 Slide guide shaft 22 Bearing 22a Outer cylinder portion 23 Advance/retract guide portion 25 Advance/retract operation portion 25a Advance/retract bolt 30 Base portion 32 Side plate advance/retract mechanism 33 Shaft insertion member 34 Side plate slide shaft 35 Advance/retract operation portion 36 Support bracket 40 Hexagonal segment 41 Face side axial joint surface 42 Wellhead side axial joint surface 43 Face side oblique joint surface 44 Wellhead side oblique joint surface 45 V-shaped circumferential joint surface

Claims (2)

A form for manufacturing a hexagonal segment for forming, by pouring and hardening concrete, a hexagonal segment having a face-side axial joint surface and a wellhead-side axial joint surface, and a pair of V-shaped circumferential joint surfaces consisting of a face-side oblique joint surface and a wellhead-side oblique joint surface arranged in a V shape so as to connect both ends of the pair of axial joint surfaces,
the hexagonal segment; a face-side side plate portion having a curved portion along the face-side axial joint surface, and a wellhead-side side plate portion having a curved portion along the wellhead-side axial joint surface, the face-side side plate portion being arranged upright on both side edges of the bottom plate portion; a pair of end plate portions having V-shaped portions along the V-shaped circumferential joint surface, the end plate portions being arranged upright on both end edges of the bottom plate portion; and a base portion supporting the bottom plate portion, side plate portions, and end plate portions from below as a whole;
The face side side plate portion and the wellhead side side plate portion are arranged so as to be movable toward and away from each other via a side plate advancing/retracting mechanism supported by the base portion, and the pair of end plate portions are arranged so as to be movable toward and away from the bottom plate portion via an end plate advancing/retracting mechanism supported by the base portion,
the end plate advancing/retreating mechanism includes an advancing/retreating guide section including a slide guide shaft extending linearly in the advancing/retreating direction of the end plate section, and a bearing fixed to the end plate section and slidably provided along the slide guide shaft, and an advancing/retreating operation section for advancing and retracting the pair of end plate sections,
the slide guide shaft of the advance/retreat guide portion is attached in a state in which one end is fixed to the bottom plate portion and the other end is fixed to the base portion,
When the bearing slides along the slide guide shaft, the end plate portion advances and retreats in a direction approaching and separating from the bottom plate portion,
The slide guide shaft of the advance/retract guide portion is a columnar or cylindrical shaft member.
The formwork for manufacturing hexagonal segments is such that the bearings are cylindrical rolling bearings . The formwork for manufacturing hexagonal segments according to claim 1, wherein the advancing/retreating operation part of the end plate advancing/retreating mechanism is provided below the apex of the V-shaped part of the end plate, and the advancing/retreating guide parts of the end plate advancing/retreating mechanism are symmetrically arranged in pairs on both sides of the advancing/retreating operation part, and are respectively provided below the oblique sides on both sides of the V-shaped part of the end plate.