JP7065734B2 - How to build - Google Patents

Description

The present invention relates to a construction method and a precast member for constructing a wave return portion of a diversion wall of a dam.

Patent Document 1 describes a precast concrete member that constitutes a wavy portion of a diversion wall of a dam. The dike wall of the dam consists of a diversion wall body that extends along the toes of the dam and the opposite surface of the overflow water channel is inclined, and a wave return part that overhangs the channel side at the top of the dike wall body. To prepare for. The wavy portion is constructed using a precast concrete member. This precast concrete member integrally has a base portion provided so as to extend upward from the top of the diversion wall main body and an overhanging portion provided so as to project from the base portion toward the waterway side. The precast concrete member has a substantially rectangular parallelepiped shape that constitutes the entire wavy portion. Further, the precast concrete member is lifted by using a crane and a sling wire, and is integrally joined to the top of the main body of the diversion wall to become a wavy portion of the introduction wall.

Japanese Unexamined Patent Publication No. 2010-126977

By the way, in the work of constructing the diversion wall of the dam, it is desired to reduce the weight of the members to be lifted. Generally, there are many places around the dam where the working environment is not good, and it may be difficult to lift a heavy member. That is, in the vicinity of the dam, it may be difficult to carry out the lifting work, and it may be difficult to lift and move a heavy member. Therefore, it is required to improve the efficiency of the construction work of the diversion wall of the dam by reducing the weight of the members to be lifted. Further, since the above-mentioned precast member has a substantially rectangular parallelepiped shape constituting the entire wavy portion, there is room for improvement in terms of weight reduction of the precast member.

It is an object of the present invention to provide a construction method and a precast member capable of reducing the weight of the precast member and efficiently performing the work of constructing the diversion wall of the dam.

The construction method according to one embodiment of the present invention is a construction method in which a wave-returning portion formed on the main body of a diversion wall provided along a waterway of a dam and projecting to the waterway side is constructed by a precast member. The process of installing the precast member on the main body and the waterway of the side wall so that the bottom plate of the precast member projects to the waterway side and the side wall of the precast member stands from the part of the bottom plate that protrudes to the waterway side. It is provided with a step of placing concrete on the opposite side of the bottom plate portion and on the upper side of the bottom plate portion.

In this construction method, the bottom plate portion of the precast member projects toward the waterway side, and the side wall portion of the precast member stands up from the portion of the bottom plate portion that projects toward the waterway side. Then, the wavy portion is constructed by placing concrete on the opposite side of the side wall portion from the water channel and on the upper side of the bottom plate portion. Therefore, since the precast member provided with the bottom plate portion and the side wall portion constitutes a part of the wave return portion, the weight of the precast member constituting the wave return portion of the conduction wall can be reduced. Therefore, even in a place where the working environment around the dam is not good, the weight of the precast member is reduced, so that the work of lifting and moving the precast member can be efficiently performed. Further, the side wall portion of the precast member is erected from the portion of the bottom plate portion that overhangs the waterway side. Therefore, by providing the side wall portion on the water channel side of the precast member, it is possible to eliminate the need for the formwork to be installed on the water channel side. That is, the side wall portion of the precast member can function as a formwork. As a result, since the step of installing the formwork on the waterway side can be omitted, it is possible to eliminate the need for scaffolding or the like for installing the formwork at a high place at the upper end of the diversion wall. Further, since the work of installing the formwork at a high place on the waterway side can be eliminated, the safety of the work can be enhanced.

Further, a reinforcing bar extending from the inside of the main body is projected on the main body, and the reinforcing bar may be embedded in the concrete in the step of placing concrete. In this case, since the reinforcing bar protruding upward from the inside of the main body is embedded in the concrete, the precast member can be more firmly integrated with the main body.

Further, the bottom plate portion is formed with a first through hole that exposes the upper surface of the main body, and in the step of placing concrete, the upper surface of the main body exposed from the first through hole may be filled with concrete. In this case, since the first through hole that exposes the upper surface of the main body is formed in the bottom plate portion of the precast member, the weight of the precast member can be further reduced. Further, by filling the upper surface of the main body exposed from the first through hole with concrete, the precast member can be more firmly integrated into the main body.

Further, the above-mentioned construction method may include a step of installing a formwork on the side opposite to the water channel of the main body before the step of placing concrete. In this case, since the formwork is installed on the side opposite to the water channel of the main body before the concrete is placed, the configuration of the precast member on the opposite side of the water channel can be simplified. Therefore, it contributes to further weight reduction of the precast member.

Further, in the step of installing the precast member, a plurality of precast members may be installed on the main body, and in the step of placing concrete, concrete may be placed on the plurality of precast members installed on the main body. In this case, after a plurality of precast members are installed on the main body, concrete is cast on the plurality of precast members at once. Therefore, by placing concrete in a batch after installing a plurality of precast members, it is possible to more efficiently construct the wavy portion.

Further, the anchor bolt protrudes from the main body, and a second through hole through which the anchor bolt is inserted is formed in the bottom plate portion. In the process of installing the precast member, the anchor bolt is inserted into the second through hole. It may have a step of arranging a bottom plate portion on the main body and a step of tightening a nut to an anchor bolt. In this case, the precast member can be more firmly installed in the main body by tightening the anchor bolt inserted into the second through hole of the bottom plate portion and the nut to the anchor bolt.

The precast member according to one embodiment of the present invention is a precast member formed on the main body of a diversion wall provided along the waterway of a dam and constituting a wave return portion protruding toward the waterway side, and is on the waterway side. It has a bottom plate part that is placed on the main body so as to overhang, and a side wall part that stands up from the part that overhangs the waterway side of the bottom plate part. It will be cast.

This precast member includes a bottom plate portion that overhangs the waterway side of the dam and a side wall portion that stands up from the portion of the bottom plate portion that overhangs the waterway side, and is on the opposite side of the side wall portion from the waterway and on the upper side of the bottom plate portion. Concrete is poured and a wavy part is constructed. Therefore, since the precast member constitutes a part of the wave return portion, the weight of the precast member can be reduced. Therefore, even in a place where the working environment around the dam is not good, the weight-reduced precast member can be easily lifted, so that the work of constructing the diversion wall can be efficiently performed. Further, since the side wall portion of the precast member is erected from the portion of the bottom plate portion that overhangs the waterway side, the side wall portion can function as a formwork. Therefore, since the formwork to be installed on the waterway side can be eliminated, it is possible to eliminate the need for scaffolding or the like for installing the formwork at a high place at the upper end of the diversion wall. As a result, the construction work of the diversion wall can be efficiently performed, and the safety of the work can be enhanced.

According to the present invention, the weight of the precast member can be reduced, and the work of constructing the diversion wall of the dam can be efficiently performed.

FIG. 1 is a perspective view showing an example of a dam to which a precast member is applied and a method of constructing a wave return portion according to an embodiment. FIG. 2 is a diagram schematically showing a plurality of precast members arranged in the dam of FIG. 1. FIG. 3 is a side view showing a diversion wall of a dam including the precast member of FIG. FIG. 4 is a perspective view showing the upper part of the main body of the diversion wall of FIG. 3 and a plurality of precast members. FIG. 5 is a vertical sectional view showing an example of a structure in which a precast member is joined to the main body of FIG. 6 (a), 6 (b), and 6 (c) are vertical cross-sectional views showing an example of a procedure for constructing a wave return portion according to an embodiment. FIG. 7 is a cross-sectional perspective view showing an example of a formwork installed on the upper part of the main body of the flow guide wall in which the precast member is installed. FIG. 8 is a diagram schematically showing an example of a conventional method for constructing a wave return portion.

Hereinafter, the construction method according to the present invention and the embodiment for carrying out the precast member will be described in detail with reference to the drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate description will be omitted as appropriate. In addition, the drawings may be partially simplified or exaggerated for the sake of easy understanding, and the dimensions, angles, etc. are not limited to those described in the drawings.

As shown in FIG. 1, the dam 1 to which the construction method and the precast member according to the embodiment are applied is, for example, a dam used in an emergency including a heavy rain flood, and has a plurality of crest gates 2. , A waterway 3 constituting an overflow portion of the dam body, a management building 4 for managing the dam 1, and a diversion wall 10 provided along the waterway 3 are provided. Dam 1 is, for example, a dam that is expanded by renovation work to enhance the flood control function.

The crest gate 2 is installed at the top of the dam 1 and is provided, for example, to prevent overflow from the top end of the dam 1 in the event of a flood or the like. In the management building 4, for example, each part of the dam 1 is operated and monitored, and notification of flood prediction and the like is given. The diversion wall 10 is provided on the embankment body of the dam 1 and is a wall body that guides the overflow water from the crest gate 2 to the energy reducing work on the downstream side.

The height of the diversion wall 10 is required to be equal to or higher than a predetermined height in order to prevent the outflow of water to the outside of the water channel 3, but the higher the height of the diversion wall 10, the higher the cost is expected. Is done. By providing the head of the diversion wall 10 with a wave-returning portion 20 projecting toward the water channel 3, it is possible to suppress the outflow of water to the outside of the water channel 3 even if the height is suppressed, so that the cost is reduced. Contribute to. As an example, the height of the diversion wall 10 is about 30 m.

FIG. 2 is a diagram schematically showing the flow guide wall 10. As shown in FIGS. 1 and 2, in the dam 1 according to the present embodiment, by precasting a part of the wave return portion 20, the wave return portion 20 can be efficiently constructed and the construction period can be shortened. It is possible. The wave return portion 20 includes a plurality of precast members 21 arranged side by side along the direction D1 in which the water channel 3 extends, and a water blocking wall 30 provided at regular intervals along the direction D1.

The dam 1 includes a plurality of regions A (blocks) partitioned by a water blocking wall 30, and for example, a diversion wall 10 is constructed for each of the plurality of regions A. As an example, 15 or more and 30 or less precast members 21 are arranged in the region A. The water stop wall 30 is, for example, a PVC water stop plate. By embedding the water blocking wall 30 in the diversion wall 10 at regular intervals, it is possible to suppress water leakage and inundation even if the diversion wall 10 expands or contracts due to fluctuations in temperature or the like.

FIG. 3 is a side view showing the diversion wall 10. As shown in FIG. 3, the diversion wall 10 is a concrete structure including a main body 11 and a wave return portion 20 provided at the top of the main body 11. In the present specification, the "main body" of the diversion wall refers to a portion other than the wave return portion of the diversion wall. The main body 11 has an inner surface 11a that faces the water channel 3 side and extends in the vertical direction, an outer surface 11b that faces the opposite side of the water channel 3 and inclines toward the water channel 3 side toward the top, and an upper surface 11c that faces vertically upward.

A plurality of reinforcing bars 12 are embedded in the main body 11, and each of the plurality of reinforcing bars 12 protrudes from the upper surface 11c of the main body 11. For example, each of the plurality of reinforcing bars 12 extends from the vicinity of the lower end of the main body 11 along the outer surface 11b. The reinforcing bar 12 projects upward from the portion of the precast member 21 on the opposite side of the water channel 3 from the portion avoiding the precast member 21. A part of the upper side of the reinforcing bar 12 extends diagonally upward from the upper surface 11c. Further, the plurality of reinforcing bars 12 are arranged side by side along the direction D1 (the direction orthogonal to the paper surface of FIG. 3) in which the plurality of precast members 21 are arranged.

The wavy portion 20 is composed of a plurality of precast members 21 and concrete C cast on the precast members 21. The precast member 21 includes a bottom plate portion 22 mounted on the main body 11 so as to project toward the water channel 3, and a side wall portion 23 erected from the portion 22 a of the bottom plate portion 22 projecting toward the water channel 3. That is, the precast member 21 has an L-shape including a bottom plate portion 22 and a side wall portion 23. As described above, since the precast member 21 has a simple shape, it has an advantage that it can be easily manufactured in advance at a factory or the like. For example, the thickness of the bottom plate portion 22 is thicker than the thickness of the side wall portion 23. For example, the concrete C is cast-in-place concrete that is cast after the precast member 21 is installed on the upper surface 11c.

As described above, the precast member 21 constitutes a part of the wave return portion 20. Therefore, the weight of the precast member 21 is reduced as compared with the case where the precast member constitutes the entire corrugated portion. For example, the weight of the precast member 21 is 1 ton or less, and as an example, it is 945 kg or more and 975 kg or less. As described above, the weight reduction of the precast member 21 makes it possible to reliably lift the precast member 21 even with a crane located at a location away from the flow guide wall 10.

FIG. 4 is a perspective view showing the configuration around the precast member 21 before the concrete C is placed and the upper surface 11c of the main body 11. As shown in FIG. 4, the bottom plate portion 22 of the precast member 21 has a rectangular plate shape, for example, a rectangular shape extending long in the direction D2 intersecting the water channel 3. As an example, the direction D2 is a horizontal direction orthogonal to the direction D1.

For example, the length of the bottom plate portion 22 in the longitudinal direction (direction D2) is 170 cm or more and 220 cm or less, and is 200 cm as an example. The width of the bottom plate portion 22 (the length in the direction D1) is 70 cm or more and 130 cm or less, and is 100 cm as an example. The thickness (height) of the bottom plate portion 22 is 20 cm or more and 30 cm or less, and is 25 cm as an example. However, the values of the length, width and thickness of the bottom plate portion 22 are not limited to the above examples and can be changed as appropriate.

FIG. 5 is a vertical sectional view showing the bottom plate portion 22 and the main body 11. As shown in FIGS. 4 and 5, in the bottom plate portion 22, the first through hole 22b penetrating the bottom plate portion 22 on one side in the longitudinal direction of the bottom plate portion 22 and the anchor bolt 24 are inserted and the bottom plate portion 22 is inserted. It has a second through hole 22c that penetrates the above. The shape of the first through hole 22b is, for example, an octagonal shape, but it can be changed as appropriate. For example, the length of the first through hole 22b extending in the longitudinal direction (direction D2) of the bottom plate portion 22 is 50 cm or more and 100 cm or less, and is 78.5 cm as an example. The width of the first through hole 22b extending in the width direction (direction D1) of the bottom plate portion 22 is 40 cm or more and 85 cm or less, and is 62.5 cm as an example.

The first through hole 22b is a hole for firmly integrating the precast member 21 into the main body 11 by exposing the upper surface 11c of the main body 11 and placing concrete C into the main body 11. As an example, the first through hole 22b is provided at a position opposite to the side wall portion 23 with respect to the center in the longitudinal direction of the bottom plate portion 22. By forming the first through hole 22b, the precast member 21 can be made lighter than the case where the first through hole 22b is not formed.

The bottom plate portion 22 has, for example, a plurality of second through holes 22c, and anchor bolts 24 are inserted into each of the plurality of second through holes 22c. The plurality of second through holes 22c are arranged, for example, at positions surrounding the first through holes 22b, and as an example, are arranged so as to face each of the four corners of the first through holes 22b. Further, for example, a haunch portion 25 is provided between the bottom plate portion 22 and the side wall portion 23. The haunch portion 25 enhances the strength between the bottom plate portion 22 and the side wall portion 23.

The side wall portion 23 has, for example, a rectangular plate shape. The side wall portion 23 is provided so as to stand upward from the end portion in the longitudinal direction of the bottom plate portion 22. For example, the longitudinal end of the bottom plate 22 coincides with the portion 22a of the bottom plate 22 that overhangs the waterway 3 side. The side wall portion 23 has, for example, a rectangular parallelepiped shape.

For example, the length (height) of the side 23a of the side wall portion 23 extending from the bottom plate portion 22 is 70 cm or more and 130 cm or less, and is 100 cm as an example. The length of the side 23b intersecting the side 23a of the side wall portion 23 is 70 cm or more and 130 cm or less, and is 100 cm as an example. The thickness of the side wall portion 23 is, for example, 8 cm or more and 12 cm or less. However, the lengths of the sides 23a and 23b of the side wall portion 23 and the thickness of the side wall portion 23 can be appropriately changed.

The main body 11 has an insertion hole 11d that opens in the upper surface 11c. For example, an insert 13 is embedded in the insertion hole 11d. The insert 13 is, for example, a chemical insert, which is a chemical or grout material. For example, both the insertion hole 11d and the second through hole 22c have a cylindrical hole shape, and the inner diameter of the insertion hole 11d is smaller than the inner diameter of the second through hole 22c. Further, the inner diameter of the insertion hole 11d and the inner diameter of the second through hole 22c are larger than the outer diameter of the anchor bolt 24.

Filler F is filled between the anchor bolt 24 and the second through hole 22c. The filler F is, for example, a grout material. The filler F is hardened, the anchor bolt 24 protrudes upward from the filler F, and the nut 26 is fastened to the portion 24a protruding upward from the anchor bolt 24. For example, the washer 27 is placed on the upper surface F1 of the filler F, and the nut 26 is tightened to the anchor bolt 24 on the upper surface 27a of the washer 27.

Next, a method of constructing the wave return portion 20 according to the embodiment will be described. In the following, with reference to the part (a) of FIG. 6, the part (b) of FIG. 6, the part (c) of FIG. 6 and FIG. explain. First, as shown in part (a) of FIG. 6, the main body 11 of the diversion wall 10 is constructed (step of constructing the main body of the diversion wall). Specifically, after arranging the formwork M so as to surround the reinforcing bar 12, the concrete C is placed inside the formwork M, and after the concrete C is hardened, the formwork M is moved upward to move the main body 11 upward. To build. The reinforcing bar 12 extends upward from below the main body 11 along the outer surface 11b of the main body 11 and protrudes upward from above the main body 11 (upper surface 11c). The reinforcing bar 12 is arranged before the placement of the concrete C and is buried with the placement of the concrete C.

The insertion hole 11d is formed when the main body 11 is built to a predetermined height or after the main body 11 is built to a predetermined height. The insertion hole 11d is filled with the insert 13 (drug / grout material) and the anchor bolt 24 is inserted, and the anchor bolt 24 is fixed to the insertion hole 11d as the insert 13 is cured.

Further, after the main body 11 is constructed to a predetermined height, the precast member 21 is installed on the upper surface 11c of the main body 11 as shown in the portion (b) of FIG. 6 (step of installing the precast member). At this time, the bottom plate portion 22 is placed on the upper surface 11c, and the precast member 21 is installed so that the side wall portion 23 stands upright from the portion 22a of the bottom plate portion 22 protruding toward the water channel 3.

Installation of the precast member 21 on the main body 11 is performed, for example, by the following procedure. First, the precast member 21 is lifted by a lifting machine such as a crane, and as shown in FIG. 5, the position of the second through hole 22c of the bottom plate portion 22 is aligned with the anchor bolt 24 fixed to the main body 11, and then the anchor. The precast member 21 is arranged so that the second through hole 22c is located on the bolt 24. Then, the anchor bolt 24 is inserted into the second through hole 22c (step of inserting the anchor bolt).

Next, the filler F is injected into the second through hole 22c, and the filler F is solidified between the second through hole 22c and the anchor bolt 24 (step of solidifying the filler). Subsequently, the anchor bolt 24 is inserted through the washer 27, the washer 27 is placed on the upper surface F1 of the filler F, and the nut 26 is strongly tightened to the anchor bolt 24 from above the washer 27 to firmly attach the precast member 21 to the main body 11. Fix (the process of tightening nuts).

As shown in the part (b) of FIG. 6 and FIG. 7, a plurality of precast members 21 are installed on the main body 11. For example, a plurality of precast members 21 are placed on the upper surface 11c by a lifting machine along the direction D1, and each of the plurality of precast members 21 is fixed to the upper surface 11c and installed on the main body 11. As an example, a plurality of precast members 21 are collectively installed in one area A (see FIG. 2).

Next, the formwork M is installed on the opposite side of the main body 11 from the water channel 3. For example, after the main body 11 is constructed, the formwork M used in the construction of the main body 11 is slid upward to install the formwork M, and the formwork M is fixed to the outer surface 11b. Then, the formwork M is also installed at the end of the direction D1 of the main body 11 (the end of the direction D1 of the region A), and the concrete C is placed on the opposite side of the side wall portion 23 from the water channel 3 and above the bottom plate portion 22. The filling space S is formed. In the filling space S, the upper surface 11c of the main body 11 is exposed through the first through hole 22b.

After the installation of the formwork M is completed, concrete C is placed (step of placing concrete) as shown in part (c) of FIG. At this time, concrete C is placed on the plurality of precast members 21 at once. For example, concrete C is placed at a height of 1.23 m on a few precast members 21. Further, the first through hole 22b of the bottom plate portion 22 is filled with the concrete C, and the filling space S is filled with the concrete C. Then, after the concrete C is hardened, the formwork M is removed to complete a series of steps.

Next, the construction method according to the present embodiment and the action and effect of the precast member 21 will be described. In the construction method and the precast member 21 according to the present embodiment, the bottom plate portion 22 of the precast member 21 projects to the waterway 3 side, and the side wall portion 23 of the precast member 21 projects from the portion 22a of the bottom plate portion 22 to the waterway 3 side. Stand up. Then, the corrugated portion 20 is constructed by placing concrete C on the opposite side of the side wall portion 23 from the water channel 3 and on the upper side of the bottom plate portion 22. Therefore, since the precast member 21 including the bottom plate portion 22 and the side wall portion 23 constitutes a part of the wave return portion 20, the weight of the precast member 21 constituting the wave return portion 20 of the conduction wall 10 can be reduced.

Therefore, even in a place where the working environment around the dam 1 is not good, the weight of the precast member 21 is reduced, so that the work of lifting and moving the precast member 21 can be efficiently performed. Further, the side wall portion 23 of the precast member 21 is erected from the portion 22a of the bottom plate portion 22 overhanging the waterway 3 side. Therefore, by providing the side wall portion 23 on the water channel 3 side of the precast member 21, the formwork to be installed on the water channel 3 side can be eliminated.

As shown in FIG. 8, in the conventional method of constructing the wave return portion 100, it is necessary to install the formwork N on the waterway side and pour concrete, so that the scaffolding X for installing the formwork N is used. It was necessary to construct the formwork support Y on the waterway side. Since these operations need to be performed near the upper end of the main body of the diversion wall having a height of about 30 m, it is difficult and there is a problem in terms of work safety because the work is performed at a high place.

On the other hand, as shown in FIG. 6 and the like, in the present embodiment, the side wall portion 23 is provided on the water channel 3 side of the precast member 21, so that the side wall portion 23 functions as a formwork and is therefore installed on the water channel 3 side. The formwork to be used can be eliminated. As a result, since the step of installing the formwork can be omitted, the scaffolding X and the formwork support Y for installing the formwork N at a high place at the upper end of the flow guide wall 10 can be eliminated. Further, since the work of installing the formwork N at a high place on the waterway 3 side can be eliminated, the safety of the work can be enhanced.

Further, a reinforcing bar 12 extending from the inside of the main body 11 projects on the main body 11, and in the step of placing concrete, the reinforcing bar 12 is embedded in the concrete C. Therefore, since the reinforcing bar 12 projecting upward from the inside of the main body 11 is embedded in the concrete C, the precast member 21 can be more firmly integrated with the main body 11.

Further, the bottom plate portion 22 is formed with a first through hole 22b that exposes the upper surface 11c of the main body 11. In the step of placing concrete, concrete is formed in the upper surface 11c of the main body 11 exposed from the first through hole 22b. Fill with C. Therefore, since the first through hole 22b that exposes the upper surface 11c of the main body 11 is formed in the bottom plate portion 22 of the precast member 21, the weight of the precast member 21 can be further reduced. Further, by filling the upper surface 11c of the main body 11 exposed from the first through hole 22b with concrete C, the precast member 21 can be more firmly integrated into the main body 11.

Further, the above-mentioned construction method includes a step of installing the formwork M on the opposite side of the main body 11 from the water channel 3 before the step of placing concrete. Therefore, since the formwork M is installed on the side of the main body 11 opposite to the water channel 3 before the concrete C is placed, the configuration of the precast member 21 on the opposite side of the water channel 3 can be simplified. Therefore, it contributes to further weight reduction of the precast member 21.

Further, as shown in FIGS. 6 and 7, in the process of installing the precast members, a plurality of precast members 21 are installed on the main body 11, and in the process of placing concrete, concrete C is placed on the plurality of precast members 21. To be placed. Therefore, after the plurality of precast members 21 are installed on the main body 11, the concrete C is cast on the plurality of precast members 21 at once. Therefore, by placing the concrete C in a batch after installing the plurality of precast members 21, the construction work of the wave return portion 20 can be performed more efficiently.

Further, as shown in FIG. 5, an anchor bolt 24 protrudes from the main body 11, and a second through hole 22c through which the anchor bolt 24 is inserted is formed in the bottom plate portion 22, and a precast member is installed. The step includes a step of inserting the anchor bolt 24 into the second through hole 22c and arranging the bottom plate portion 22 on the main body 11, and a step of tightening the nut 26 to the anchor bolt 24. Therefore, the precast member 21 can be more firmly installed in the main body 11 by tightening the anchor bolt 24 inserted into the second through hole 22c of the bottom plate portion 22 and the nut 26 to the anchor bolt 24. The precast member 21 is firmly fixed to the main body 11 via anchor bolts 24 and the like. As a result, it is possible to suppress the occurrence of construction problems such as the precast member 21 being displaced due to the pressure of the concrete C when the concrete C is placed.

Although the construction method and the embodiment of the precast member according to the present invention have been described above, the present invention is not limited to the above-described embodiment, and the present invention is modified to the extent that the gist described in each claim is not changed. Or it may be applied to other things. That is, the contents and order of each step of the construction method, and the shape, size, weight, number, and arrangement mode of each part of the precast member can be variously modified without changing the gist of each claim.

For example, in the above-described embodiment, the precast member 21 including the bottom plate portion 22 and the side wall portion 23 erected on the waterway 3 side has been described. However, it may be a precast member including a bottom plate portion, a first side wall portion erected on the water channel 3 side, and a second side wall portion erected on the opposite side of the water channel 3. In this case, it is possible to omit the formwork M installed on the opposite side of the water channel 3.

Further, in the above-described embodiment, the precast member 21 provided with the bottom plate portion 22 having the first through hole 22b and the second through hole 22c has been described. However, it may be a precast member that does not have at least one of the first through hole 22b and the second through hole 22c. In this way, the shape of the precast member can be changed as appropriate.

Further, in the above-described embodiment, an example of fixing the precast member 21 to the main body 11 by using the filler F, the anchor bolt 24, the nut 26, and the washer 27 has been described. However, the method of fixing the precast member 21 to the main body 11 can be appropriately changed.

Further, in the above-described embodiment, an example of constructing the diversion wall 10 of the dam 1 to be expanded by the repair work in order to enhance the flood control function has been described. However, the construction method and the precast member according to the present invention can be applied to dams having a flood control function or dams to be expanded by repair work, and can be applied to various dams.

1 ... dam, 2 ... crest gate, 3 ... waterway, 4 ... administration building, 10 ... diversion wall, 11 ... main body, 11a ... inner surface, 11b ... outer surface, 11c ... top surface, 11d ... insertion hole, 12 ... reinforcing bar, 13 ... Insert, 20 ... Wave return part, 21 ... Precast member, 22 ... Bottom plate part, 22a ... Part, 22b ... First through hole, 22c ... Second through hole, 23 ... Side wall part, 23a, 23b ... Side, 24 ... Anchor bolt, 24a ... part, 25 ... haunch part, 26 ... nut, 27 ... washer, 27a ... top surface, 30 ... water blocking wall, A ... area, C ... concrete, D1, D2 ... direction, F ... filler, F1 ... top surface, M ... formwork, S ... filling space.

Claims (5)

It is a construction method in which a wave return portion formed on the main body of a diversion wall provided along the waterway of a dam and projecting to the waterway side is constructed by a precast member.
A step of installing the precast member on the main body so that the bottom plate portion of the precast member projects toward the waterway side and the side wall portion of the precast member stands up from the portion of the bottom plate portion that projects toward the waterway side. When,
The process of installing the formwork on the opposite side of the main body from the water channel,
A step of placing concrete on the side of the side wall portion opposite to the water channel and on the upper side of the bottom plate portion.
Equipped with
Reinforcing bars extending upward from the inside project along the opposite surface of the main body on the main body between the formwork and the precast member.
In the step of placing the concrete, the reinforcing bar is embedded in the concrete.
How to build. A first through hole that exposes the upper surface of the main body is formed in the bottom plate portion.
In the step of placing the concrete, the upper surface of the main body exposed from the first through hole is filled with concrete.
The construction method according to claim 1 . It is a construction method in which a wave return portion formed on the main body of a diversion wall provided along the waterway of a dam and projecting to the waterway side is constructed by a precast member.
A step of installing the precast member on the main body so that the bottom plate portion of the precast member projects toward the waterway side and the side wall portion of the precast member stands up from the portion of the bottom plate portion that projects toward the waterway side. When,
A step of placing concrete on the side of the side wall portion opposite to the water channel and on the upper side of the bottom plate portion.
Equipped with
A first through hole that exposes the upper surface of the main body is formed in the bottom plate portion.
Waterstops are provided on the diversion wall at regular intervals.
In the step of placing the concrete, the upper surface of the main body exposed from the first through hole is filled with concrete, and the waterstop extending upward from the first through hole is embedded in the concrete.
How to build. A step of installing a formwork on the opposite side of the main body from the water channel is provided.
Reinforcing bars extending upward from the inside project along the opposite surface of the main body on the main body between the formwork and the precast member.
In the step of placing the concrete, the reinforcing bar is embedded in the concrete.
The construction method according to claim 3. Anchor bolts protrude from the main body, and a second through hole through which the anchor bolts are inserted is formed in the bottom plate portion.
The process of installing the precast member is
A step of inserting the anchor bolt into the second through hole and arranging the bottom plate portion on the main body.
The process of tightening the nut to the anchor bolt and
Have,
The construction method according to any one of claims 1 to 4 .

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