JPS6226363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an undulating weir made of a flexible membrane such as rubber-coated cloth, and more particularly to an undulating weir made of a flexible membrane provided with vibration prevention means.

(Prior art and its problems) In the flexible membrane undulating weir, a flexible membrane envelope (bag-like body) forming the weir body is attached to at least the river bed in the direction across the river, and the inside of the envelope is Expansion is achieved by sending fluid, such as air or water, as an expansion medium from an inlet/exhaust (water) pipe communicating with the bottom of the envelope (see, for example, Japanese Patent Publication Nos. 11702-1970 and 2371-1971).

In this type of undulating weir, when the overflow water depth h increases as shown in FIG. 1, the weir body, which is expanded and erected by the fluid 5 as an expansion medium fed into the envelope 1, vibrates. One of the causes of vibration is that the overflow water 15 generates negative pressure in the downstream part 16 of the inner weir, and the amount of negative pressure changes due to fluctuations in the overflow water, causing the enveloping weir body to vibrate. It is considered that The overflow water depth (h) when this vibration starts to occur varies depending on the expansion medium, but generally h/H0.2 for air expansion type and h/H for water expansion type.
It is 0.5. In addition, H is the river bed 2 of the weir body formed by the envelope 1
The height is from .

Conventionally, as a means for preventing vibrations in this type of undulating weir, a plurality of elongated and highly flexible spoilers 3 with a substantially trapezoidal cross section are mounted on the top of the envelope 1 in order to divide the overflow water 15 as shown in FIG. If flowing water is arranged in parallel in the transverse direction (for example, see Utility Model Publication No. 51-37724), or if a water conveyance pipe 7 is installed from the upstream side to the downstream side of the weir as shown in Figure 3, the float 9 will be There is one in which it floats on the upstream side and pressure water is injected from the water conduit into the negative pressure section 16 on the downstream side of the inner weir of overflow water (for example, see Japanese Patent Publication No. 57-404).

In the former case, a very large block must be attached to the cover, and furthermore, the rubber block protrudes above the riverbed when it is toppled, obstructing the flow of river water. In addition, the latter causes problems with the reliability of the device, such as the check valve 8 and the float 9 not operating, and the water pipe becoming clogged.

In Figures 1, 2, and 3, 6 is the inlet/exhaust (water) pipe, 1
0 is a guide, 11 is a connecting body such as a rod-shaped body or a link, 12 is a guide, 13 is a stopper, and 14 is upstream water.

(Structure of the Invention) In view of the above, the present invention has been developed to solve these problems. That is, the present invention provides an undulating weir in which a fluid is injected into the inside of a flexible membrane envelope to cause it to expand and erect, and the fluid is discharged from the inside of the envelope to cause it to contract and fall down. This is characterized in that a passage is provided to allow atmospheric air to flow into the negative pressure section on the downstream side of the inner weir, thereby preventing vibration of the weir. The present invention will be described in detail below with reference to illustrative FIGS. 4 and 5.

As shown in FIG. 4, a groove 20 is provided in the concrete side wall 17 on the downstream side of the weir, and a pipe 21 is installed in the groove 20. Both ends of the pipe are open, and the upper end is located at an arbitrary position on the side wall 17 where overflow water does not splash on the pipe.
The lower end reaches the negative pressure section 16 on the downstream side of the overflow water inner weir.

Alternatively, as shown in FIG. 5, a part of the groove 20 provided in the side wall 17 is covered with a plate 22, and the opening at the upper end is located at an arbitrary position on the side wall 17 where overflow water does not splash, and the opening at the lower end is It may also reach the negative pressure section 16.

This structure creates air passages,
Atmospheric air flows into the negative pressure section 16 and removes the negative pressure, thereby preventing vibrations. However, these air passages
The weir should not protrude from the side wall 17 toward the river side so as not to prevent the weir from collapsing.

(Effects of the Invention) As described above, the present invention provides an air passage on the side wall of the weir, which prevents river water from being obstructed when the weir collapses, unlike the conventional method, and improves the reliability of devices such as check valves and floats. It has the advantage of being able to prevent vibrations without causing any problems.

[Brief explanation of the drawing]

Figures 1 to 5 are views of the flexible membrane undulating weir cut in the direction of river flow, with Figure 1 explaining the generation of vibration, and Figures 2 and 3 showing conventional vibration prevention means. 4 and 5 respectively illustrate the present invention. 1... For example, a covering (bag-like body) made of rubberized cloth, 2
...River bed, 3... Spoiler, 5... Air or water or air and water, 6... Inlet/exhaust (water) pipe, 7
... Water pipe, 8 ... Check valve, 9 ... Float, 1
0...Guide, 11...Connecting body such as a rod or a link, 12...Guide, 13...Bung, 14...
Upstream water, 15... Overflow water, 16... Negative pressure section, 17
... side wall, 18 ... automatic collapse water level, 19 ... end of weir body, 20 ... groove provided in side wall, 21 ... pipe,
22...board.

Claims (1)

[Scope of Claims] 1. In an undulating weir in which fluid is injected into the inside of a flexible membrane envelope to cause it to expand and erect, and fluid can be discharged from the inside of the envelope to cause it to contract and fall down, a side wall of the weir is provided with a 1. An undulating weir made of a flexible membrane, characterized in that an air passage is provided to allow air to flow into a negative pressure section on the downstream side of an inner weir for overflowing water, thereby preventing vibration of the weir. 2. The flexible membrane undulation weir according to claim 1, wherein an air passage is provided in the side wall by providing a groove in the side wall and installing a pipe therein. 3. The flexible membrane undulating weir according to claim 1, wherein an air passage is provided in the side wall by providing a groove in the side wall and covering a portion of the groove with a plate.