JP4173932B2 - Bottom sediment discharge method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for discharging sediment at the bottom of a dam reservoir, for example.
[0002]
[Prior art]
There are various types of dams, such as those for power generation, irrigation, and flood control. In this sediment, the sediment in the upstream area of the dam is washed down by the river to the downstream area, and the sediment is deposited in descending order according to the decrease in the slope of the river and the decrease in the flow speed. Large soil particles are also moved away from the river bed (floating) and transported to the vicinity of the dam reservoir in a stream (moving while rolling on the river bed).
[0003]
In other words, when a flood flow accompanied by earth and sand approaches the dam reservoir, the river cross-section increases rapidly, the flow velocity drops, and large gravel particles accumulate near the reservoir entrance. Not only does this sediment cause a decrease in the amount of water stored, but if left untreated, the sediment gradually develops upstream, and during floods, the water level rises in the upstream area, causing flood damage. is there.
[0004]
In addition, the riverbed of the river is scoured in the downstream area of the dam, causing adverse effects on the bridge foundation and bank protection shore, as well as adverse effects on animals and plants due to the outflow of fine particles, and reducing the amount of sand supplied on the coast. Doing so will result in the loss of sandy beaches and destruction of the revetment due to coastal retreat.
[0005]
Therefore, it is necessary to discharge sediment in the dam lake, and there are various conventional methods. One of them uses dredging machines such as grab dredgers, backhoe dredgers, pump dredgers, etc. Grab dredgers are non-navigable types that grab the bottom sediment with grab buckets and are used for primary transport. Uses a ship.
[0006]
A backhoe-type dredger is equipped with a backhoe on a trolley. The hull is anchored with a spud for dredging, and the primary transport of dredged sand is pneumatically fed by an earth ship or pipeline. Pump-type dredgers are used for sucking up earth and sand together with water from the pumping port with a pump in the ship and transporting it primarily through a pipeline, or hanging a submersible sand pump from an assembly boat.
[0007]
As another method, there is a method in which a sand discharge gate is installed in the dam to discharge and discharge the sediment, and another method is disclosed in Japanese Patent Application Laid-Open No. 9-21127 previously proposed by the applicant. There is a siphon type sand removal method as described. In this siphon type, the suction part at one end of the sediment discharge pipe is opened to the bottom of the dam reservoir, the water discharge part at the other end is opened to the river downstream of the dam, and the water and soil in the dam reservoir are removed by siphon action. They are pumped up and flowed downstream of the dam. The suction part is installed in a work base composed of floats, and the work base determines the installation position by winch operation using anchors installed on land.
[0008]
[Problems to be solved by the invention]
The machine-based method not only requires a large amount of energy to drive the machine, but also increases the transportation cost. In addition, the method of installing a gate for sand removal requires a great deal of cost when installed in an existing dam. In this respect, the siphon type can save energy and can reduce the cost, but when gravel is mixed in the sediment, the gravel is sucked in well because of its large particle size. I can't. In addition, the sediment often covers a wide area of the lake bottom, but it is difficult to move the position of the suction portion efficiently.
[0009]
The object of the present invention is to eliminate the inconvenience of the conventional example and to mix the sand with a simple structure when adopting the siphon type sand discharging method in order to reduce the energy and cost required for the sand discharging work. The gravel can be transported smoothly through the sand discharge pipe, and it can handle sediments mixed with gravel, so that the sand can be discharged reliably. It is an object of the present invention to provide a method and apparatus for discharging sediment on the bottom of the water that can be moved easily and can be discharged efficiently.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention opens a suction pipe at one end of a sand pipe with a flexible spiral pipe, and installs a dam reservoir on a movable work table ship at the bottom of the water and a downstream discharge pipe at the other end. In the method of discharging sediment in the bottom of the water that opens to the water channel, pumps up the bottom water and sediment by the siphon action of the sand discharge pipe, and discharges it to the water discharge channel, the suction pipe is attached to the work table ship through the position adjustment means, The position adjusting means includes two guide pipes that are movable in the vertical and horizontal directions by a sliding mechanism such as a combination of guide rails, rollers, or bolts and that are mounted on a work table ship, and a guide rail between these guide pipes , the slide mechanism according to a combination of such rollers or bolts constituted by the mounting angle adjustable and sheath tube Ru is looped is vertically movable axially mounted, insert child suction tube to the sheath tube The one in which the subject matter of the present invention.
[0011]
According to the first aspect of the present invention, when water and sediment in the bottom of the water are pumped up by the siphon action of the sand removal pipe, the air is separated into the central portion of the pipe by the centrifugal separation action caused by the vortex generated inside the sand removal pipe. Since the pebbles gather and move to the peripheral surface in the pipe, the gravel-mixed sediment can be transported smoothly in the pipe, and the sand can be efficiently and easily discharged.
[0012]
In addition, the gravel-clad sediment deposited on the bottom of the dam reservoir can be efficiently discharged downstream, preventing not only the reduction of the water storage volume, but also the scouring of the river bed in the downstream area of the dam. Prevents adverse effects on foundations and bank protection shores, prevents adverse effects on animals and plants due to the outflow of fine particles, and also the loss of sand beaches and destruction of coastal walls due to coastal retreat due to a decrease in the supply of sand on the coast Can also be prevented. Further, by moving the work table ship, the suction pipe can be freely moved to a desired position, and sedimentation over a wide range of the bottom of the water can be easily handled.
[0013]
Furthermore, by holding the suction pipe at the tip of the sand discharge pipe at the optimum gradient with respect to the lake bottom by the position adjusting means, the optimum constant gradient for the sediment that is inclined along the inclined surface of the water bottom, etc. The tip of the suction tube can be opened and suction can be performed efficiently.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing an embodiment of a method for discharging sediment in the bottom of a water and an apparatus therefor according to the present invention, FIG. 2 is a plan view of the same, 1 in the figure shows a sand discharge pipe, one end is formed in a suction pipe 3, The other end is formed in the water discharge pipe 4, the suction pipe 3 is used as the bottom of the water, the water is opened to the bottom of the dam reservoir 5, the water discharge pipe 4 is opened to the water discharge path 6 downstream of the dam, and the middle is the dam body 2 that is a dam body. A pump 7 for releasing air in the pipe is disposed in the sand discharge pipe 1 at the top position of the dam body 2.
[0015]
The sand discharge pipe 1 is composed of a flexible spiral pipe, and a float 8 is attached to an appropriate place in the middle, and is floated on the water of the dam reservoir 5. The pipe diameter is narrower than that laid in the dam reservoir 5, and the discharge channel 6 side. Thicken the material to be laid. Further, as shown in FIG. 4, the inner wall of the sand removal pipe 1 is provided with a spiral strip 9 having a triangular cross section, for example, for generating a vortex in the pipe.
[0016]
Then, the suction pipe 3 at one end of the sand discharge pipe 1 is fixed to a work table ship 10 that is movable in the dam reservoir 5 through a position adjusting means 11. As shown in FIG. 3, the position adjusting means 11 has two guide tubes 12a and 12b mounted on the work table ship 10, and one of the guide tubes 12b is longer than the other guide tube 12a. And at least one of the guide tubes 12b is mounted on the work table ship 10 so as to be movable in the vertical and horizontal directions by a slide mechanism 14 using a combination of, for example, guide rails, rollers, or bolts.
[0017]
Then, the sheath tube 13 is mounted on the two guide tubes 12a and 12b so as to be adjustable in mounting angle and vertically movable by a slide mechanism 14 such as a combination of a guide rail, a roller or a bolt. Therefore, the suction tube 3 is inserted into the sheath tube 13, and the suction tube 3 is fixed to the sheath tube 13 through the straight tube 15 at both end positions of the sheath tube 13.
[0018]
In addition, although not shown, a submersible pump such as a high-pressure turbine pump is installed in the vicinity of the drinking mouth portion of the suction pipe 3, and a screen for preventing inhalation of driftwood and other obstacles is installed.
[0019]
Further, if necessary, an air compressor for stirring the sediment is installed on the work table ship 10 and a cutter for cutting the sediment is attached to the tip of the sand discharge pipe 1. In the figure, 16 indicates a sluice or sub dam installed near the discharge point for power generation in the discharge channel 6.
[0020]
Next, a method for discharging the sediment 17 of the dam reservoir 5 using such an apparatus will be described. The work table ship 10 is moved to the work position, the slide mechanism 14 is operated to adjust the horizontal and vertical positions of the guide tubes 12a and 12b, and the mounting angle of the sheath tube 13 with respect to the guide tubes 12a and 12b is adjusted. The drinking mouth portion of the suction pipe 3 attached to the tip of the sheath pipe 13 is positioned at an optimum angle with respect to the sediment 17.
[0021]
The side of the water discharge pipe 4 is closed, and a submersible pump provided near the drinking mouth of the suction pipe 3 is operated to supply water into the sand discharge pipe 1 to fill the pipe with water. Alternatively, the pump 7 is operated to release air from the sand discharge pipe 1. After the air in the pipe is removed in this way, if the side of the water discharge pipe 4 is opened, the water of the dam reservoir 5 and the sediment 17 are sucked up from the suction pipe 3 by the siphon action and pass through the sand discharge pipe 1 from the water discharge pipe 4. It is discharged into the discharge channel 6. At this time, since the water discharge pipe 4 has a large diameter, a large drainage capacity can be obtained.
[0022]
In the case of sediments 17 with a large amount of fine particles, this is often solidified due to past droughts, etc., and sediments with large particle sizes such as gravel are often mixed. May decrease extremely. In response to this, the fixed earth and sand are cut by a cutter attached to the tip of the suction pipe 3, or the air compressor is blown and stirred by operating the air compressor to exert the air lift effect, thereby discharging the earth and sand. To reduce the frictional resistance in the pipe.
[0023]
Further, since the ridge 9 is provided in a spiral shape on the inner wall of the sand discharge pipe 1, a rotating flow is generated in the water and the earth and sand in the pipe, and the air is caused to enter the central portion of the sand discharge pipe 1 by the centrifugal separation action. Gravels with a large particle size are distributed in the periphery of the pipe and can be transported smoothly in the pipe even with gravel-filled earth and sand.
[0024]
As the work proceeds, the drinking mouth at the tip of the suction pipe 3 is moved vertically and horizontally by the slide mechanism 14, and the work table ship 10 is freely moved to discharge the sediment 17 on the lake bottom in sequence. As the work table ship 10 moves, the sand removal pipe 1 also moves. However, since the sand discharge pipe 1 is formed of a flexible spiral pipe, the work table ship 10 smoothly follows the movement.
[0025]
Moreover, driftwood and other obstacles that have settled on the bottom of the lake are removed by a screen provided in the suction pipe 3 and are not sucked into the sand discharge pipe 1.
[0026]
【The invention's effect】
As described above, the sediment discharge method and apparatus for a dam reservoir according to the present invention is a sand discharge pipe when a siphon type sand discharge method is employed in order to reduce the energy and cost required for the sand discharge operation. Since the projecting shape of the inner wall is spiral, the gravel mixed in the sediment can be moved to the inner periphery of the pipe by the centrifugal action in the pipe, making it possible to transport the inside of the sand discharge pipe smoothly, Corresponding to sedimentation, sand can be discharged reliably. Moreover, since the sand discharge pipe is moved by the work table ship, the suction part can be easily moved with respect to the sediment over a wide area of the bottom of the water, and sand can be discharged efficiently.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a method and apparatus for discharging sediment in a dam reservoir according to the present invention.
FIG. 2 is a plan view showing an embodiment of a sediment discharging method and apparatus for a dam reservoir according to the present invention.
FIG. 3 is a front view of an essential part showing an embodiment of a sediment discharge method and apparatus for a dam reservoir according to the present invention.
FIG. 4 is a longitudinal front view of a sand discharge pipe of a main part showing an embodiment of a sediment discharge device for a dam reservoir of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sand discharge pipe 2 ... Dam body 3 ... Suction pipe 4 ... Drain pipe 5 ... Dam reservoir 6 ... Drain channel 7 ... Pump 8 ... Float 9 ... Projection 10 ... Worktable ship
11 ... Position adjusting means 12a, 12b ... Guide tube
13 ... Saya tube 14 ... Slide mechanism
15 ... Straight pipe 16 ... Sluice or secondary dam
17 ... sedimentation

Claims (1)

A dam reservoir installed on a movable work table ship, a suction pipe at one end of a sand pipe with a flexible spiral pipe is opened to the bottom of the water, a water outlet pipe at the other end is opened to a downstream water channel, and a siphon of a sand pipe In this method, the suction pipe is attached to the work table ship through the position adjusting means, and the position adjusting means includes a guide rail, a roller. or by a slide mechanism with a combination of bolts vertical, and two guide tubes mounted freely workbench ship moved in the horizontal direction, the guide rails between the guide tube, by a slide mechanism according to a combination of such rollers or bolts constituted by the mounting angle adjustable and sheath tube Ru is looped is vertically movable pivotally, underwater method of sediment discharge, which comprises inserting a suction tube into the sheath tube

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