JPH09137433A - Flood spillway device in porous water intake equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flood spillway device with low turbidity by a porous water intake equipment of a dam. SOLUTION: A slant gutter pipe 2 is provided to a porous water intake equipment along the surface of a dam body of a dam, a large number of water intakes 6A with gates are provided to the slant gutter pipe 2, at the same time, it is connected to a bottom gutter pipe 4 passing through horizontally the lower part of the dam body, and the lowest stage of water intake 6N among the water intakes is used for a flood spillway device. The highest stage of water intake 6A is larger than twice as large as opening area of the lowest stage of water intake 6N to use it as a second flood spillway device. By the constitution, water discharged by the second flood spillway device can be reduced to low turbidity, and a water purification burden in the case of flooding is not imposed on water utilization side such as public water supplies, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spillway device in a porous intake system installed in a multipurpose dam.

[0002]

2. Description of the Related Art As is well known, most of intake facilities with a gutter in dams are used for multipurpose dams such as intake dams for agriculture. In recent years, this intake facility has been used to prevent water leakage and aging of bank dams. For this reason, and for a dam with a depth of 15 m or more, an intake pipe 2 (which is referred to as a gutter pipe) 2 arranged along the slope of the dam 1 as shown in Fig. 1 is used as the foundation ground under the dam. It is connected to a bottom gutter pipe (also referred to as a water pipe) 4 inserted in a temporary drainage tunnel 3 that penetrates the water pipe, and a high pressure valve (for example, a jet flow gate) 5 is interposed in the water pipe 4 to form a jet flow pipe. -By controlling the flow rate and de-energizing by the gate 5, by appropriately using one of the multiple intake ports 6 arranged in parallel in the oblique pipe 2 at a predetermined interval (for example, 10 m) in the vertical direction. In addition, it is possible to take surface water constantly according to the fluctuation of water level. It became the expression water intake facility. That is,
As a countermeasure against muddy water, sand discharge, and warm water, it has come to be constructed as a porous water intake facility that allows surface water intake. In the figure,
7 is an air pipe, 8 is an operation room, and 9 is a screen for covering the water intake 6.
Reference numerals 10 and 10 denote vertical rectangular tubes for connecting the lowermost intake 6N and the water conduit 4.

Further, for the spillway in such a porous water intake system, the lowermost intake 6N is used. That is, the intakes 6A, 6B on the upper side of the slant pipe 2 have the same opening area, for example, have a diameter of 0.7 mφ, and only the intake 6N at the bottom has a large opening of 1.5 m square. By fully opening the lowest intake 6N, the flood can be safely discharged. This is because the lowermost intake 6N has the largest head of water, so that even if a small intake is formed, a large amount of flood can be discharged economically. When the lowest intake 6N is used for discharge during flood, the water conduit 4
The jet flow gate 5 provided in the above controls the discharge flow rate.

[0004]

DISCLOSURE OF THE INVENTION However, in such a porous water intake facility, if a flood is discharged from the lowermost intake port 6N, it becomes muddy water with high turbidity. In addition to the above, the turbid water was helped by the dam for a long period of time, and the turbid water was discharged for a long period of time. On the water side, especially on the water side for water supply, the purification burden was very dissatisfied. Moreover, if such a spillway method is adopted, it also conflicts with the countermeasures for muddy water, sand discharge and hot water, which are the objectives of the porous water intake facility.

[0005] Therefore, since it is generally said that turbid water in a dam is settled as a layer of 1 m, it is conceivable to use the uppermost intake port for discharge at the time of flood, so the quality of such an idea was analyzed.

First, the intake ports 6A for NO1 and NO6,
The structure of 6N will be described. 2 (A) shows the intake port 6A of NO1 in the sectional view from A of FIG. 1, and FIG. 2 (B) is the sectional view of B of FIG. 1 and shows the intake port 6N of NO6.

At the intake port 6A of NO1, the branch pipe 1 and the branch pipe 1 are connected.
1 is provided in a branched manner, and the opening of the branch pipe 11 can be fully opened or closed by a sluice valve (also called a gate) 12.
The slant pipe 2 is fixed by a concrete 13 on the slope of the bank 1, and a sluice valve guide 14 and a screen 9 are also fixed to the concrete 13.

At the intake port 6N for NO6, a sluice valve (also called a gate) 15 is provided at the opening of a vertical rectangular tube 11A communicating with the water conduit 4, and the sluice valve 15 is a double-acting hydraulic pressure valve (not shown). It is opened and closed by an operating mechanism such as a cylinder. The vertical rectangular tube 11A is formed of a concrete 16, and a partition plate valve guide 17 and a screen 9 are also fixed to the concrete 16.

[0009] Now, the dam for trial calculation has the highest water level of 306.5.
m, the minimum water level is 279.6 m, and this dam is equipped with a jet flow gate 5 having a valve cross-sectional area of 0.567 m ² , and the intake ports 6A to 6E of NO1 to NO5 are 0.7.
The diameter of mφ is 1.5m for the intake 6N of NO6 at the bottom.
A square opening is provided in the inside of the gutter pipe 2 with a diameter of 1 mφ. In such a water intake facility, using the following flow rate calculation formula,

[0010]

(Equation 1)

Here, Q = flow rate C = flow rate coefficient Av = cross-sectional area of high-pressure valve V = flow rate = Q / Av H = water depth at intake α = f / (2gAv ² ) f = velocity head correction coefficient The flow rate flowing out of the water conduit 4 was calculated.

[0012]

[Table 1]

From Table 1, the following facts were found. That is, when the gate of the intake port 6A for NO1 (including NO2 to NO5) is fully opened (no adjustment such as half-opening is performed) and the opening degree of the jet flow gate 5 is changed from 30% to 100%. It was found that the flow rate of water flowing out of the water conduit 4 was 2.48 m ³ / sec, which was constant even if the opening degree was adjusted. It is considered that the reason is that the water is not flowed into the slant pipe 2 from the water intake port 6A after being narrowed down like an orifice and flowing down. Further, it has been found that the flow rate of water flowing out of the water conduit 4 is extremely lowered as a characteristic of the mortar-shaped dam when the water level is lowered.

By the way, the flow rate of the NO6 intake port 6N is
At the water level of 306.5 m, it is the same when changing the opening of the jet flow gate 5 from 90% to 100%, but at most other openings, the flow rate flowing out of the water conduit 4 can be adjusted. It has become.

Therefore, since the uppermost intake 6A has a constant flow rate even in an emergency, it is not preferable to directly apply the upper intake of the slant pipe 2 to the spillway. Cannot be adopted.

[0016]

Therefore, the present invention has been made to solve the above-mentioned dissatisfaction, and the gist of the present invention is as follows: 1) Arrangement along the bank surface and a predetermined vertical direction. A slant pipe with a large number of gated intakes arranged at intervals is connected to a water conduit in a temporary drainage tunnel penetrating under the dam, and a high-pressure valve is installed in the water conduit. Flow rate is adjustable, and the opening area of the lowermost intake of the intakes is larger than that of other intakes to create a spillway.In a porous intake facility, only the uppermost intake of the outlets A spillway device in a perforated intake facility characterized by forming a second spillway by enlarging the opening area, and 2) A perforated intake system with a large cross-sectional area of the laver pipe according to claim 1. It is in the spillway device in the facility.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the conventional porous water intake equipment described above. However, illustration and description of parts common to the embodiment and the conventional example are omitted. To do.

In this embodiment, the uppermost intake 6A
Is formed into a rectangular cross-section and has a width of 3 m and a height of 1.5 m (opening area of 4.5 m ³ ) to form a so-called second spillway, whereby the flow rate flowing out of the water conduit 4 is calculated by the above formula. When calculated, it becomes as shown in Table 2. Here, since the diameter of the circular pipe 2 is 1.7 mφ and the other specifications are the same as those described above, the illustration thereof is omitted. Of course, the cross-sectional shape of the slant pipe 2 may be square.

[0019]

[Table 2]

As can be seen from Table 2, the top N
Since the opening area of the O1 intake port 6A (second spillway) has a head difference, the lowermost outlet port 6N which is a conventional spillway
Surprisingly, if the jet flow gate 5 is fully opened (100% opening), it will be established as a conventional experience value for the dam if it is set to be about twice as large as the opening area. A safe flood discharge was obtained from the 6N intake at the bottom.

That is, in the present embodiment, the above NO6 is used.
It was possible to make it approximately the same as the flood discharge flow rate by the intake 6N. In other words, if the size of the uppermost intake is determined by the above formula based on the conventional established spillway in any dam, it can be applied to the porous intake facility of that dam.

Therefore, the uppermost NO1 intake 6A
Since it is possible to discharge the water at the time of flooding, when the water intake from the water intake 6A is completed, the emergency situation of overflowing the bank 1 is immediately resolved, and the danger at the time of flood can be avoided. However, when the water is discharged, it becomes a low turbidity discharge, which in turn makes it possible to continuously take water from flood water to flood water, and from flood water to water water, which facilitates water intake operation.
Moreover, the dam water level can be stabilized.

The uppermost water intake 6 of the present embodiment
A has a rectangular cross section to allow surface water intake as much as possible. However, the present invention is not limited to this, and the cross section may be circular, and the opening area thereof is determined according to the cross sectional area of the slant pipe. To be Therefore, if the diameter of the slant pipe cannot be increased due to reasons such as strength, the uppermost intake 6A is also restricted.

Further, the high pressure valve is not limited to the jet flow gate, but a high water pressure slide gate, a cone valve or the like (H
JV, CSV, FCV, HPSG, etc.), in short, as long as it can be applied to the outflow of a water head of 25 m or more.

Of course, according to the present invention, the flood spillway intake 6N at the bottom of the prior art may be left unremoved, and if the muddy water intake is installed elsewhere, it may be omitted. The invention can be immediately applied to the remodeling of an existing porous water intake facility or a new dam with a slight modification of the conventional technology of which safety is established.

[0026]

According to the present invention, the following various effects can be obtained. 1) Since the uppermost intake is configured as a spillway, ordinary water can be taken without trouble by squeezing the high-pressure valve, and the discharge during a flood can be made safe. 2) Since the water discharged during flooding is also surface water intake, it becomes water with low turbidity, and complaints on the water side can be avoided. Especially, when dam water is used for water supply, the burden of purification during flooding is reduced. 3) The operation of irrigation to flood discharge or vice versa becomes continuous, facilitating management and stabilizing the dam water level. 4) Since only the uppermost intake port was configured as a spillway, flood control will be completed immediately after the discharge of the uppermost intake port is completed, which is extremely rational for management. 5) It can also contribute to sand discharge and hot water countermeasures.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a conventional example.

2A is a sectional view taken along line A of FIG. 1, and FIG. 2B is a sectional view taken along line B of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Levee body, 2 ... Inclined pipe, 3 ... Temporary drainage tunnel, 4 ... Water pipe, 5 ... High pressure valve, 6 ... Intake port

Claims (2)

[Claims] 1. An inclined trough pipe, which is arranged along the surface of a dam and has a large number of gated intakes arranged vertically at a predetermined interval, is provided so as to penetrate below the dam. It is connected to a water conduit in a temporary drainage tunnel and a high-pressure valve is installed on the water conduit to enable flow adjustment, and the opening area of the lowermost intake of the intakes is larger than that of other intakes. In the porous water intake equipment, the spillway device in the porous water intake equipment is characterized in that the opening area of only the uppermost water intake of the outlets is enlarged to form a second spillway. 2. A spillway device in a porous water intake facility having a large cross-sectional area of the gutter pipe of claim 1.