JPH08311847A - Baffle pier with blade-like sill type semi-automatic sand flash and intake weir - Google Patents

Abstract

PURPOSE: To enable automatic removal of sediment accumulated on the front of an intake dam bank, reduction and omission of sand basin capacity, and to reduce construction cost in an intake weir used in run-off-river type power generation, and agricultural water and industrial water, pipelines, etc. CONSTITUTION: In a bank back side intake weir, a streamline baffle pier 4 is disposed above an apron 3, and a blade-like sill 1 is fitted to the top thereof to form a slot. Further, a sand removal gate is installed on the sand basin side of an auxiliary dam 2. Further, an intake 6 is provided on the sand basin side, and an entering path is installed on the upper side of the intake 6.

Description

Detailed Description of the Invention

[0001]

The semi-automatic sand removal weir of the present invention is an intake weir used for flow-in type hydroelectric power generation, water intake for agriculture, industrial water, pipelines and the like.

[0002]

2. Description of the Related Art Conventional intake weirs include water intakes on the front side of the dam body, water intakes on the top of the dam (Tirol type), water intakes on the back face of the dam body, lateral water intakes on the back face of the dam body, overwater intake, intakes, and movable gate intakes. , Etc., but there are three typical examples (see FIGS. 10, 11, and 12).
And explain in the bullet points. (B) Water intake on the front side of the embankment (see Fig. 10) has been adopted so far. Sediment is deposited on the front of the dam body of the intake dam by the sediment transport action of the river running water. Therefore, in order to remove the accumulated sediment, a sand discharge gate is provided on the downstream side of the intake, and the gate is opened and closed by human power, an electric motor or the like to discharge the accumulated sediment on the downstream side. Also, since there is usually only one sand discharge gate, over the years, except for the gate part in front of the bank, sediment will be accumulated and the water storage capacity will be reduced. As a result, the sedimentation function in front of the levee body decreases and the inflow of sediment into the intake increases. In addition, since sediment flows from the intake, a sedimentation basin is provided to prevent sediment from entering the headrace channel. It requires a great deal of labor and cost for maintenance. (B) Rubbing cloth undulating weir (movable gate type ~ Fig. 12
In reference), the sediment accumulated on the upstream side in front of the bank is discharged from the inside of the rubberized cloth body at the time of a large flow of the river, and the rubber bag is tumbled to remove the sediment along with the running water. The sediment entering the intake is the same as the intake on the front side of the bank, but the sediment is removed within the entire bank length. Therefore, the water storage capacity will be secured in the upstream part of the front of the dam body, and the inflow of sediment into the settling basin will be reduced. Therefore, it is possible to reduce the capacity of the sand basin. However, mechanical equipment (air compressor,
Ejector, etc.) is required and its maintenance is required. Furthermore, it is more expensive than the fixed intake weir. (C) The intake weir on the side of the back of the dam (see Fig. 11) is used for agricultural water and stream water intake for run-in hydropower generation. This intake weir is considered to be a semi-automatic sand removal intake weir. The mechanism will be described by taking (Fig. 7, Fig. 8, Fig. 9) as an example. When the flow rate is small (Fig. 7), the river running water becomes a jet stream from the top of the dam dam and collides into the surface of the seismic pond. It seems that the jet flows until the beginning of water tapping, but on the water tapping roadbed surface, a bottom flow layer that flows along the roadbed is formed. Therefore, the inflowing sediment flows down together with the underflow layer and collects in the upstream part of the sub dam. Therefore, the sedentary pond acts as a sand basin, and it is possible to omit or reduce the size of the basin. When the flow rate is medium (Fig. 8), jumping occurs due to the depth of the seismic pond and the secondary dam. In that case, the underflow layer becomes a jet flow, but its direction is not fixed, and it becomes swaying jump water, and large waves are transmitted to the downstream. Further, the amount of water taken from the water intake changes with the state of jumping. Moreover, since the inflowing sediment is diffused and mixed by the bottom jet flow, the sedimentation function of the sewer pond decreases. At the time of a large flow rate (Fig. 9), the jumping water is blown away and the normal flow area of the seismic pond disappears and becomes a jet stream. Therefore, the sediment in the sewer pond is washed away downstream. This can be considered as semi-automatic sand removal utilizing the potential energy of running water. However, the depth of the seismic pond is lower than the lower end of the intake, and water intake is impossible.

[0003]

[Problems to be Solved by the Invention] The problems to be solved are described in the items. (A) Eliminate the management of sediment discharge on the front of the intake dam bank. (B) It should be possible to take water even when the river has a large flow rate, and reduce the inflow of sediment into the sand basin. (C) Eliminating mechanical devices and facilitating maintenance. (D) Reducing the capacity (scale) of the sand basin and reducing the cost of construction work including the intake weir and the sand basin. To provide an intake weir that can solve the above-mentioned problems and reduce costs comprehensively.

[0004]

The construction of a baffle pier type semi-automatic sand removal weir with an airfoil sill will be described with reference to an example of (Fig. 1, Fig. 2 and Fig. 3). (A) A streamlined baffle pier 4 is provided on the top of the waterfall 3, and the airfoil sill 1 is attached to the top thereof to form a slot 5 between the waterfall 3 and the airfoil sill 1. (B) Install a sub dam 2 downstream of the water tap 3 to secure the water depth required for water intake. And the slope of the sub dam is θ
= 15 ° to 25 °, and the water spray 3 and the sub dam 2 are rubbed together with a smooth curvature change. In addition, the height of the secondary dam (minimum water depth of the seismic pond) is determined in consideration of the river flow conditions, sedimentation capacity, and sediment thickness. (C) A sand discharging gate 8 is provided on the side of the submerged dam 2 on the sand basin 7. Its function is to remove sedimentary sediment when the flow rate is low,
It is the decrease of the water depth of the seismic pond (suspension of water intake). (D) The intake 6 is provided on the side wall of the sand basin 7. In addition, the lower end of the intake port is determined in consideration of the sediment deposition thickness at a small flow rate and the intake amount. (E) The head between the overflow top 10 and the seismic pond 12 takes into account the flow velocity and sedimentation function of the underflow layer that flows along the floodbed subgrade, and the overflow top at the time of flood and the weir backwater at the upstream. To determine. (F) In order to remove boulders and the like flowing into the sedentary pond 12, an approach passage 14 is installed on the upstream side of the sand basin 7. It features a semi-automatic sand removal weir constructed as described above.

[0005]

Next, the operation of the semi-automatic sand removal weir of the present invention will be described with reference to the examples of FIGS. 4, 5 and 6. (B) When the flow rate of the river is small (Fig. 4), the water flowing down the top of the bank becomes a jet stream and enters the seismic pond. At that time, the earth and sand also flow in, but they are blown to the upper surface of the water tap in the upstream part of the sub dam by the underflow layer that flows along the water tap roadbed, and accumulate there. (B) In the case of medium flow rate (Fig. 5), the water flow falling on the top of the dike causes a jump in the damming pond. The jump jump changes from weak jump to steady jump depending on the Froude number. In addition, the inflowing sediment will be collected in the upstream part of the sub dam through the slots and part of the sediment will be swept down by the flow rectifying action of the airfoil sill and the baffle pier. (C) At high flow rate (Fig. 6), the position of the jump is fixed by the forced jump of the baffle pier with airfoil sill. Then, a strong vortex occurs inside the jump water on the upper surface of the airfoil sill, but due to the rectifying action effect of the airfoil sill, the mixing with the waterfloor subgrade is suppressed. Further, the underflow layer exiting the slot becomes a jet flow due to the hydrodynamic pressure due to the hydraulic jump and the hydrostatic pressure due to the increase in the water level upstream of the airfoil sill, and flows on the sub dam slope surface. Therefore, the inflow sediment and accumulated sediment are blown out of the sewer pond and discharged.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of implementing the present invention and its structure will be described with reference to FIGS. 1, 2 and 3 by way of example. (FIG. 1) is a longitudinal sectional view of the baffle pier type semi-automatic sand removal weir with an airfoil sill (viewed from the line AA of FIG. 2), (FIG. 2) is a plan view,
(FIG. 3) is a perspective view. (A) At the rear side intake weir of the bank, a streamlined baffle pier 4 and an airfoil sill 1 are provided on the upper surface of the waterfall 3 to form a slot 5 between the waterfall 3 and the airfoil sill 1. (B) The change in the cross-sectional area of the slot 5 in the direction of flowing water is gradually reduced from the slot inlet (upstream) toward the slot outlet, changed from reduced to an equal sectional area, or reduced to an equal sectional area to gradually expand. (C) The thickness of the airfoil sill 1 and the size of the baffle pier,
The interval is determined in consideration of the position of the jumping water at a large flow rate, the jumping height (ensuring water intake), and the ability to remove accumulated sediment by jet flow from the outlet of the slot 5. In addition, the sedimentation capacity and sediment removal function at low to medium flow rates will also be considered. (D) The protrusion (sill type) on the upper surface of the wing-shaped sill 1 serves as an auxiliary sill for adjusting the length and height of the jumping water, but it may be omitted if unnecessary. (E) Although the airfoil sill 1 of (FIG. 1) is installed within the water depth of the seismic pond 12, it may be installed above the water level (in the air) depending on the flow condition of the river. (F) The streamlined baffle pier 4 is formed in a streamlined shape so that the sediment flowing into the seismic pond can be smoothly guided to the upstream portion of the sub dam 2. (G) As a building material for the streamlined baffle pier 4 and the airfoil sill 1, reinforced concrete, FRP, and steel materials are used alone or in combination.

[0007]

The effect of the semi-automatic sand removal weir of the present invention (Figs. 4, 5, and 6) is shown in the flow diagram conceptual diagram (Figs. 7, 8, and 9) of the side dike backside weir. Description will be made in comparison. (Foreword) About 80% of the energy consumed in Japan depends on oil, coal, etc. imported from abroad.
Hydropower is a purely domestic, renewable energy and clean energy with a low environmental load. Therefore, it is necessary to actively promote small and medium-scale hydropower development, but the economy is inferior and development is delayed compared to other power sources. In run-of-river hydropower generation, the largest component of the cost of power generation is civil engineering costs (intake weir, sand basin, headrace, etc.). Therefore, the cost reduction of civil engineering works will greatly contribute to the improvement of economic efficiency. The effects of the present invention are described in the bullet points. (B) At the time of small river flow (Fig. 4), the damping pond functions as a sand basin. The water that overflows the top of the bank is accelerated by the head and flows into the sewer pond. The water flow becomes an underflow layer that flows along the watering subgrade at a velocity faster than the surface of the seismic pond. When the underflow layer flows down with the inflowing sediment and passes through the slot outlet, it is decelerated by the diffusion of water veins. Therefore, the sediment will collect at the connection between the secondary dam and the waterfall. This mechanism is similar to that of the lateral weir (Fig. 7) on the back side of the bank. (B) At a medium flow rate (FIG. 5), the baffle pier with an airfoil sill of the present invention functions to rectify the swaying bottom layer jet flow (see FIG. 8) and to suppress fluctuations in the jumping position. The levee body overflow water at the side intake side weir (see Fig. 8) is
The increase in river flow increases kinetic energy and causes a jump in the seismic pond. At that time, the inflowing jet intermittently flows along the channel floor or along the surface of the jumping water, and temporally fluctuates. For this reason, the sedimentation function is reduced by sowing the sediment that accumulates when the flow rate is small. Therefore, by providing the airfoil sill of the present invention, the swaying bottom layer jet flow is rectified to ensure the sedimentation function of the dampening pond. Furthermore, due to the jet flow effect from the slot outlet, the sand with a small particle size can be swept away from the damping pond. This can be thought of as automatic sand removal utilizing the potential energy of the water stream. (C) When the river has a large flow rate (see FIG. 6), the baffle pier with airfoil sill of the present invention secures a water intake amount and, at the same time, removes sediment from the damping pond. At the backwater intake side weir (see FIG. 9), the jumping water in the seismic pond is blown away, and the water flow becomes a jet stream. Therefore, the sediment will be washed out of the sewer pond. However, the depth of the seismic pond will decrease and it will not be possible to take water. When the baffle pier with airfoil sill of the present invention is provided, forced jumping occurs. Therefore, the position of the jump water is fixed, and at the same time, the depth of the seismic pond is secured,
Can take water. Moreover, the scavenging action of the jet exiting from the slot outlet makes it possible to remove the sediment deposited at a small flow rate. (D) Due to the above action, the sand basin can be omitted depending on the reduction of the capacity of the sand basin and the flow condition of the river. Due to the above effects, the present invention is effective in reducing the cost of small and medium flow-in type hydroelectric power generation.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a semi-automatic sand removal weir having a baffle pier with an airfoil sill of the present invention (AA in FIG. 2).
It is a line arrow).

FIG. 2 is a plan view showing an example of a baffle pier type semi-automatic sand drainage weir with an airfoil sill.

FIG. 3 is a perspective view showing a main part of the present invention.

FIG. 4

[Figure 5]

FIG. 6 shows a baffle pier type semi-automatic sand removal weir with airfoil sill of the present invention when a small amount of water is discharged from a river.

[Fig. 4] At medium flow rate

[Fig. 5] At large flow rate

FIG. 6 is a vertical sectional view conceptually showing a flow state in the depressurization pond.

[Figure 7]

FIG. 8

[Fig. 9] At a small river discharge at the weir on the back side of the dam

[Figure 7] Medium flow rate

[Fig. 8] At large flow rate

FIG. 9 is a vertical sectional view conceptually showing a flow state in the depressurization pond.

FIG. 10 is a vertical cross-sectional view of a general intake side weir on the front side of a dam body.

FIG. 11 is a vertical cross-sectional view of a general dam on the rear side of a dam body.

FIG. 12 is a vertical cross-sectional view of a general rubber upholstery undulating water weir (movable gate type).

[Explanation of symbols]

Reference symbols (Fig. 1, Fig. 2, Fig. 3) 1 Airfoil sill 2 Secondary dam 3 Water hammer 4
Streamlined baffle pier 5 Slot 6 Intake 7 Sand set 8
Sand discharge gate 9 Overflow water (shooting flow) 10 Overflow top 11 Upstream water level 12 Suppression pond 13 Downstream water level (normal current) 14 Approach path

Claims (1)

[Claims] 1. A streamlined baffle pier 4 is provided on the upper surface of a water hammer 3 in a water intake weir on the back side of a dam body. Attaching the airfoil sill 1 to the top of it, the water spatter 3 and the airfoil sill 1
A slot 5 (hole) is formed between and. The structure of the semi-automatic sand removal weir characterized by the above.