JPS6360392A - Method of constructing pressure conduit tunnel made of precast - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for constructing a precast pressure waterway tunnel used as a headrace for hydroelectric power generation.
These parts, which are precast and divided into small parts in order to introduce prestress to improve strength and eliminate the disadvantages of casting in place, can be efficiently tunneled in narrow tunnels in the ground. It has been devised so that it can be assembled easily.

(Conventional technology) Conventional pressure tunnels are built using a cast-in-place method by incorporating formwork into a tunnel in the ground, which increases the cross-sectional area of the excavation and causes cracks to occur due to earth pressure and internal pressure. There are various problems that are easy to deal with and require long-term curing.

In order to solve such conventional problems, it is possible to mold the bottom plate and the left and right side plates into two or three parts using a precast method, and to assemble them in the mine shaft and to introduce prestress. Most desirable,
Special ingenuity is required to efficiently assemble it in a narrow tunnel.

(Problems to be Solved by the Invention) This invention enables efficient assembly of each member, introduces a predetermined prestress at the same time as the assembly operation, and is devised to reduce the cross-sectional area of the tunnel excavated. It is what was done.

(Means for Solving the Problems) The structure of the present invention for efficiently assembling each member is as follows: A pre-shaped bottom plate 3 and arch-shaped left and right side plates 6 are combined, and this bottom plate 3 and left and right side plates are combined. In the method of constructing a pressure waterway tunnel in which a large number of sets of 6 are joined in the longitudinal direction to form the tunnel 26, the left and right bases 5 of the left and right side plates 6 are joined to the left and right parts 2 of the bottom plate 3, and the left and right side plates 6 are connected along an arch shape. Inner and bottom plate 3
By tensioning the PC steel material 15 disposed in the circumferential direction, the left and right side plates 6 and the bottom plate 3 are connected to each other to form a tunnel unit 26a, and prestress is introduced in the arch-like direction, so that the ground The tunnel unit) 26a is carried into the tunnel 27 of the tunnel unit) 26a.
A precast pressure waterway characterized in that a plurality of prestresses are installed in the longitudinal direction, and prestress is introduced in the longitudinal direction by tensioning the longitudinal prestressing steel material 15 for each of the plurality of pieces, and a tunnel 26 is formed. This is a tunnel manufacturing method.

(Function) When the left and right bases 5 of the left and right side plates 6 are joined to the left and right parts 2 of the bottom plate 3 and the circumferential PC steel members 15 are tensioned, the bottom plate 3 and the left and right side plates 6 are firmly connected with a large compressive force. An arch-shaped tunnel unit 26a is formed, and a prestress along the arch shape is introduced.

Several tunnel units 26a formed in this manner are sequentially carried into the tunnel 27, and by tensioning the PC steel material 15 for each of these plurality, prestress in the longitudinal direction is introduced, and the tunnel 26 is formed. Therefore, mine shaft 2
7, any narrow cross-sectional area that can carry the tunnel unit 26a is sufficient.

In this way, the work of joining the left and right side plates 6 and the bottom plate 3 and the introduction of prestress are easily performed.

(Example) Next, one embodiment of the present invention will be described based on the drawings.

As shown in the front view in Fig. 1, the left side in Fig. 2, the right side in Fig. 3, and the plan view in Fig. 4, the left and right parts 2.2 of the flat bottom l are The bottom plate 3 stands up from the base plate 3 and its upper parts 4, 4 are joined together to form an arch shape, and its base 5° 5 is formed so as to be joined to the left and right parts 2, 2 of the bottom plate 3. The left and right side plates 6, 6 are molded by a precasting method.

The bottom plate 3 and the left and right side plates 6, 6 are both shaped to have short lengths for ease of handling such as transportation.

As is clear from the perspective view shown in FIG.
Sheath tubes 7, 7 and 8, 8 that penetrate along the arch shape
One of the sheathed pipes 7, 7 is arranged near the longitudinal center of the left and right side plates 6, and the other sheathed pipe 8.8 is arranged on the outside in the longitudinal direction, respectively. There is a sheath tube 9 nearby, a sheath tube 10 at the base 5, and both left and right side plates 6.
It runs through the longitudinal direction.

Sheath tubes 11.11 and 12.12 are respectively provided on the left and right portions 2 of the bottom plate 3 at positions where they can communicate with the sheath tubes 7 and 8 of the left and right side plates 6, respectively, with the left and right portions 2 being joined to the base 5. A sheath tube 13 and a sheath tube 14 and 14 are provided, respectively, passing through the left and right parts 2 in the longitudinal direction, and sheath pipes 14 and 14 passing through the bottom part 1 in the left and right direction.

For example, a concave fixing seat 17 is provided with a fixing plate 16 for fixing the PC steel material 15 on the outer corner of the bottom part 1. 1
? , 18. 18 and 19, respectively, and for example, concave fixing plates 20 and 21.21 are also provided on the outer side of the upper part 4.4 of the left and right side plates 6, respectively, and one of the several pieces of the left and right side plates 6 is provided with fixing plates 20 and 21.21, respectively. Concave fixing seats 22 and 23 are provided on the inner side, respectively, and a concave fixing seat 24 is provided on one of several pieces of the bottom plate 3 on the inner side of the left and right parts 2.

Left and right side plates precast in this way 6.6
and the bottom plate 3, as illustrated in FIGS. 7 and 8, the upper part 4
．． 4 to each other, the base 5 to the left and right parts 2 of the bottom plate 3, and the PC steel material 15 in the circumferential direction to the sheath pipe 7 and the sheath pipe 11.
The upper end of this PC steel material is fixed to the fixing plate 16 of the fixing seat 20 by inserting the PC steel material 15 in the circumferential direction through the sheath pipe 8 and the sheath pipe 12 respectively.
Fix the upper end of this PCM material 15 to the fixing plates 16 of the fixing seats 18 and 19 of the bottom plate 3 by tensioning these PC steel materials 15 from the side of the bottom part 1 using the tensioning device 25.
Once the PC steel material 15 in the circumferential direction of the book is fixed, the left and right side plates 6.
6 are joined to each other at 4.4 above, and the left and right side plates 6, 6 and the bottom plate 3 are joined to each other at the base 5 and the left and right parts 2 to form one arch-shaped tunnel unit 26a, Prestress is applied to the tunnel unit 26 along this arch shape.
introduced into a. A large number of tunnel units 26a are joined to each other in the front-rear direction, and the tunnel units 26a are joined to each other by tensioning the PC steel material 15 inserted into the sheath pipe 9, 10, 13, and a tunnel 26 of a desired length is created.
, and a longitudinal prestress is introduced into this tunnel 26.

Next, the tunnel construction procedure will be explained.

A tunnel 27 is excavated in the ground, and outside the tunnel 27, as shown in FIG. 1 is inserted into the bottom plate guide G2, the base portions 5 of the left and right side plates 6 will be in positions where they join the left and right portions 2 of the bottom plate 3.

The PC steel members 15 are inserted in the circumferential direction into the sheath tubes 7 and 11 and the sheath tubes 8 and 12, respectively, and the upper ends of these PC steel members 15 are fixed to the fixing seats 20 and 21, and the bottom plate is attached as shown in FIG. When the lower ends of these PC steel materials 15 are pulled out from the fixing seats 18 on the left and right portions 2 of 3, and the tension device 25 in contact with the bottom plate 3 is used to tension the PC steel materials 15 from the lower end side, prestress is created in the circumferential direction. is introduced, and the left and right side plates 6, 6
and the bottom plate 3 are firmly connected to each other with a large compressive force to form an arch-shaped tunnel unit 26a.

Next, for example, five of these tunnel units 26a,
The PC steel material 15 inserted into the sheath pipes 9, 10, and 13 is temporarily tightened, and the five integrated pieces are carried into the tunnel 27 using, for example, a cart 28 with jacks 36, as shown in FIG. , release the temporary tightening and lift the inner upper part of the tunnel unit 26a using a lifting machine 29 such as a forklift as shown in FIG. The mobile device 29 moves and lifts the tunnel unit 26a,
The tunnel unit 26a on the trolley 28 is lifted by the jack 36 and moved to the moving machine 29.
The tunnel unit 26a is pushed out toward the tunnel 26a and lifted again by the lifting and moving machine 29, and the tunnel unit 26a is installed in the tunnel 27 in this way. For example, for every five pieces that have been installed in this way, the PCfJ material 15 is inserted into the sheath pipe 9.10° 13 in the longitudinal direction, and these PC steel materials 15 are tensioned.

The procedure for this tensioning work will be explained by exemplifying the sheath pipe 9 and the fixing seat 22 shown in an enlarged scale in FIG. 13.
Connect the unstressed longitudinal PCN material (on the right side in the figure) to the threaded portion 15a (on the left side in the figure) via the coupler 30, and as shown in FIG. One tunnel unit 26a without a hole is joined to the outermost side of the five tunnel units 26a to form a short PC steel member 15.
are connected to the PCM material 15 on the right side of the figure via a coupler 30, and the tension device 25 is used to tighten these PC steel materials 15.
15 is tightened and the anchor nut 31 is screwed into the threaded portion 15a to fix the PC steel material 15, the extension and addition of the five tunnel units 26a is completed and prestress is introduced in the longitudinal direction.

When the fixing is completed, the outermost short PC steel T-pieces are removed, and the five tunnel knits 6a are carried into the tunnel 27 using the jacked cart 28 again in the above-mentioned order, and installed using the forklift 29. A tension force is applied to the five tunnel units 26a that were added and one tunnel unit 26a, and these five new tunnel units 26a are combined, and in this way, for example, five tunnel units 26a are added. Become.

After forming the tunnel 26 of a predetermined length, the sheath tube 9.
10. Inject grout into the grout holes 32, 33.13 in the bottom plate 3 and left and right side plates 6, respectively, as shown in FIG.
34 is used to fill the gap between the shaft 27 and the tunnel 26 with grout from inside the tunnel 26.

The left and right side plates 6, 6 mentioned above are formed into an arch shape by joining the upper parts 4, 4 of the left and right parts to each other, and FIG. 14 shows a front view, and FIG. 15 shows a side view. As illustrated in the figure, the present invention can be applied even if the left and right side plates (■) are integrally molded without being divided, and the sheath tube T arranged in the arched direction of the left and right side plates (■) is , it has a simple shape that communicates with the sheath tubes 11.11 of the left and right parts 2.

The PC steel material 15 may be an unbonded PC steel material instead of being inserted into the sheath tube as described above.

Respective anchorage seats 17, 18. ... is filled with mortar to smooth out the recesses.

(Effects of the Invention) The method for constructing a precast pressure waterway tunnel according to the present invention is configured as described above, and the left and right side plates 6
and the bottom plate 3 are first connected to each other to form a tunnel unit 26a, and the tunnel units 26a are sequentially carried into the tunnel 27 and the tunnel knits 26a are joined in the front-rear direction to construct the tunnel 26. Therefore, in the tunnel 27, the loading and tonnage unit 2
6a mutually joining and tensioning the longitudinal prestressing steel members 15, which are performed without protruding from inside the arch shape of the tunnel unit 26a, and the tunnel 27 is used to transport the tunnel unit 26a. It is only necessary to excavate as narrow a cross-sectional area as necessary for the tunnel 27, and the cost of excavating the tunnel 27 is reduced.

The tunnel units 26a carried into the tunnel 27 tension the PC@ material 15 in the longitudinal direction, so that a large compressive force acts on these tunnel units 26a and they are firmly connected to each other and are sufficiently A large prestress is introduced.

The invention of a method for lifting the inner upper part of the tunnel unit 26a with a lifting moving machine 29 and carrying it into the tunnel 27 is as follows:
The tunnel unit 26a can be stably supported, and the lifting work is carried out with the lifting machine 29 housed within the arch shape of the tunnel unit 26a.
It is sufficient that the excavation cross section of No. 7 is slightly larger than the arch-shaped surface of the tunnel unit 26a.
This has become even more advantageous in reducing drilling costs.

[Brief explanation of the drawing]

The figures show embodiments of the present invention, and FIGS. 1 and 14 are front views of tunnel units in the respective embodiments, and FIGS. 2, 3, and 4 are left and right side views, respectively. , a plan view, FIG. 5 is a perspective view of the tunnel, FIG. 6 is a vertical sectional view of FIG. 5, FIGS. 7, 8, 9, 10, 11.
12 is an explanatory view of the tunnel assembly process, FIG. 13 is an enlarged sectional view of the main part in FIG. 11, and FIG. 15 is a right side view of FIG. 14. 2...Left and right parts, 3...Bottom plate, 4...Top, 5...
・Base, 6...Left and right side plates, 15...PCI+ material, 2
6...Tunnel, 26a...Tunnel unit, 2
7... Mine shaft, 29... Lifting moving machine.

Claims (4)

[Claims] (1) In a pressure waterway tunnel construction method in which a pre-shaped bottom plate and arch-shaped left and right side plates are combined, and multiple sets of the bottom plate and left and right side plates are joined in the longitudinal direction to form a tunnel, the left and right sides of the left and right side plates are The base of the is joined to the left and right parts of the bottom plate, and the circumferential P is arranged in the left and right side plates and in the bottom plate along an arch shape.
By tensioning the C steel material, the left and right side plates and the bottom plate are connected to each other to form a tunnel unit, and prestress is introduced in the arch-shaped direction, and the tunnel unit is carried into the underground tunnel and the tunnel unit is formed. A precast pressure waterway tunnel characterized in that prestress is introduced in the longitudinal direction and a tunnel is formed by installing a large number of units in the longitudinal direction and tensioning the longitudinal prestressing steel material for each of the plurality of tunnel units. How to build. (2) The precast pressure waterway tunnel according to claim 1, wherein the left and right side plates are each divided into left and right side plates. (3) The method for constructing a precast pressure waterway tunnel according to claim 1, wherein the left and right side plates are formed so that the left and right sides are not divided. (4) In a pressure waterway tunnel construction method in which a pre-shaped bottom plate and arch-shaped left and right side plates are combined, and a tunnel is constructed by joining the bottom plate and a large number of the left and right side plates in the longitudinal direction, the left and right sides of the left and right side plates are The base is joined to the left and right parts of the bottom plate, and the circumferential P is arranged along the arch shape inside the left and right side plates and inside the bottom plate.
By tensioning the C steel material, the left and right side plates and the bottom plate are connected to each other to form a tunnel unit. At the same time, prestress is introduced in the arch-shaped direction, and a lifting machine that lifts the inner upper part of the tunnel unit moves the ground. A tunnel is formed by carrying in and installing at a predetermined position in the tunnel, and by tensioning the longitudinal prestressing steel for each of the plurality of tunnel units, a prestress is introduced in the longitudinal direction, and a tunnel is formed. How to build a precast pressure waterway tunnel.