JPS60241590A - Branch pipe structure having mantle - Google Patents

Abstract

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

Description

Detailed Description of the Invention The penstock used in pumped storage power plants is a large-diameter pipe with a diameter of 5 m or more, and has a maximum design water pressure of 80 kg1tyd. It is used. Furthermore, in order to reduce the thickness of the steel material, the so-called bedrock burden concept, in which a portion of the water pressure is borne by the concrete surrounding the iron pipe and the bedrock of the ground where the iron pipe is buried, has been widely adopted in Japan. ing.

However, in order to perform rock load design, the displacement of iron pipes due to water pressure must be accurately estimated, so it can be carried out for straight pipes with a constant diameter where deformation is simple. However, as shown in Figure 3, the penstock line has a branch pipe (C) that is connected to the main pipe (α) and has a branch pipe (b) branched out, and this branch pipe (C) is a straight pipe. Although it has a thick plate structure compared to the other parts, the stress analysis is complicated, so it is difficult to directly share the internal pressure with the surrounding rock (C).

That is, there are large variations in the properties of the surrounding rock mass, and the reliability of the strength calculation results is low. Furthermore, if the area around the branch pipe is an infinite rock mass, stress analysis will be extremely complicated, and it will be difficult to define the boundary conditions between the rock mass and the branch pipe.

Furthermore, in order to share the internal pressure of the branch pipe with the surrounding rock (dJ), it is necessary to drill into the branch pipe and inject grout (GL) from the inner surface of the branch pipe into the gap between the branch pipe and the rock. Since the branch pipe is made of high-strength steel, there are metallurgical difficulties in drilling and filling the holes.

The present invention has been proposed to solve these problems, and includes a mantle that covers the intervening pipe on the outside of the branch pipe.
This invention relates to a patented branch pipe structure characterized in that concrete is filled between the mantle and the branch pipe.

As mentioned above in the present invention, a mantle that covers the intermediate pipe is provided on the outside of the branch pipe, and the branch pipe and the mantle pipe are filled with concrete, so that the internal pressure of the branch pipe is shared with the mantle through the concrete. A branch pipe structure that can withstand much higher water pressure (than conventional branch pipes for penstocks) is constructed. Furthermore, filling the space between the mantle and the branch pipe with concrete can be easily carried out by drilling a hole in the mantle made of ordinary steel or a thin plate, and then inserting a jig through the perforated part.

The present invention will be described below with reference to the illustrated embodiments.

(1) is a branch pipe of the penstock, (2) is the main pipe connected to the branch pipe (1), and (31 (3) is a branch pipe branched out from the branch pipe (1).

A spherical stiffening ring (4) and (5) (5i) disposed at the junction of the main pipe (2) and branch pipes (3) (3), covering the branch pipe (1) A mantle (6) is attached to the mantle (6), and a concrete (force) is placed horizontally between the mantle (6) and the branch pipe (1), and the internal pressure of the branch pipe (1) is transferred to the mantle (6) through the concrete (7). ).

Fig. 2 shows an exploded view of the load acting on the branch pipe (1), the filling conc. (
The internal pressure P1 of 1) decreases by P2, and the same branch pipe (11F!
.

Shares the internal pressure of pi-p2. Although F2yF3 is an unknown quantity, it is determined from the condition that continuity is maintained between the branch pipe (11, the filling concrete (7), and the filling concrete) (71 and the mantle (6)).

According to the illustrated embodiment, as described above, the internal pressure of the branch pipe (1) is shared with the mantle (6) via the filling concrete (force), making it possible to manufacture a branch pipe with ultra-high pressure. , without expecting the surrounding rock (8) to share the internal pressure of the branch pipe (1), a simple-shaped spherical mantle (6) and a filled concrete IJ −
) By limiting the internal pressure of the branch pipe (1) to (7), stress analysis becomes easier.

In addition, for grouting between the mantle (6) and the branch pipe (1), a hole is drilled in the mantle (6) made of ordinary steel or wire thin plate, and the perforated part is grouted with concrete (7). By doing so, you can easily achieve your desired purpose.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of a branch pipe structure having a mantle according to the present invention, Fig. 2 is an exploded explanatory view of the load acting on the branch pipe structure, and Fig. 3 is a diagram of a conventional branch pipe structure. FIG. (1)... Branch pipe, (6)... Mantle, (Power... Concrete sub-agent Patent attorney Shige Okamoto 3 other people)

Claims (1)

[Claims] A branch pipe structure having a mantle, characterized in that a mantle is disposed outside the branch pipe to cover the intermediate pipe, and concrete is filled between the mantle and the branch pipe.