JP4461275B2 - Earth and sand discharge method and earth and sand discharge work ship - Google Patents

Description

  In the present invention, the suction port opened at the upstream end of the earth and sand discharge pipe faces the water bottom or the vicinity thereof, and the sediment on the bottom of the water is sucked into the earth and sand discharge pipe together with water from the suction port, and the sucked earth and water are sucked into the earth and sand. Sediment discharge method that allows fluid to flow through the discharge pipe to a predetermined discharge location away from the bottom of the water, in particular, the sediment deposited on the bottom of the dam is sucked up by the sediment discharge pipe using siphon action, and has a lower water level than the dam. The present invention relates to a sediment discharge method that is effective in the discharge operation of dam sedimentary sediment that is allowed to flow in a sediment discharge pipe to a river body, and a sediment discharge work ship used for the implementation.

  In the present invention, “sedimentary sediment” refers to light sediments such as sludge and sludge with a relatively small specific gravity deposited on the bottom of a dam, sea, river, etc., and a relatively large specific gravity mixed with sand, pebbles, etc. Any of the heavy earth and sand may be used, or a mixture of these lightweight earth and heavy earth and sand may be used.

  As an important current issue for existing dams used for hydropower generation and irrigation, a large amount of sediment flowing from the upstream side accumulates on the bottom of the dam for many years, reducing its effective depth. As a result, the power generation capacity of the dam is reduced or the amount of stored water is reduced.

Therefore, in order to cope with such a problem, there is a sediment discharge technique in which sediment sediment on the bottom of a dam is sucked up through a sediment discharge pipe using a siphon action and flows in the sediment discharge pipe to a predetermined collection place. Already proposed (see Patent Document 1 below)
JP 11-46515 A

  The technique of the above-mentioned Patent Document 1 is to allow the sediment to flow into the sediment discharge pipe by siphon action, but there is a relatively large frictional resistance (flow resistance) between the flowing sediment and the inner wall surface of the sediment discharge pipe. Therefore, if the water level difference between the dam and the downstream river (that is, the head of the sediment discharge pipe) cannot be secured sufficiently, the sediment cannot smoothly flow in the sediment discharge pipe, which impedes the siphon action. In addition, the earth and sand discharge pipe has a problem in that its inner wall is easily worn and deteriorated and easily breaks, and its replacement frequency increases and maintenance costs increase.

  In addition, water near the bottom of the water generally has a low amount of dissolved oxygen, and the sediment and water deposited on the bottom of the water are often sludge that has problems with odor and turbidity. If earth and sand and water are discharged into a downstream river area as they are, the environment of the river area may deteriorate (deterioration of odor / turbidity, increase in dissolved oxygen amount, etc.).

  The above problems are not limited to sucking and discharging sediment sediment at the bottom of a dam with a siphon-type sediment discharge pipe, but also sediment deposited on the bottom of the sea, rivers, etc. Also occurs when sucking in and discharging.

  The present invention has been proposed in view of the above, and it is an object of the present invention to provide a sediment discharge method capable of easily solving the above-described problems of the prior art at a relatively low cost, and a sediment discharge work ship used therefor. To do.

In order to achieve the above object, the invention of claim 1 is characterized in that the suction port opened at the upstream end of the sediment discharge pipe is made to face the water bottom of the dam or the vicinity thereof, and the sediment sediment on the bottom of the water is put together with water from the suction port. In the sediment discharge method in which the sucked sediment and water are sucked into the discharge pipe through the siphon action, and flow through the sediment discharge pipe to the river water area downstream of the dam and at a lower water level than the dam . dispersed in the water, the first multiphase mixture is allowed diameter 100μ or less fine-bubble countless air, or the gas containing at least oxygen gas fine bubbles and become more multi-phase flow, provided in the sediment discharge pipe near the suction port A part of countless fine bubbles in the multiphase flow is sucked into the earth and sand discharge pipe together with the earth and water from the suction port by the jetting means from the flow jetting means toward the sediment sediment on the bottom of the water. So as to flow and the multiphase flow, and is ejected directly to the sediment discharge pipe from the second multiphase flow jetting means provided near sand discharge pipe to the suction port, innumerable fine bubbles of the mixed phase stream is, suction The mixed phase flow is added from a common mixed phase flow generator to the first and second mixed phase flow jetting means so as to flow in the sediment discharge pipe together with the sediment and water sucked into the sediment discharge pipe from the mouth. characterized in that it is supplied in a pressurized state, also the invention of claim 2, a suction port which opens to the upstream end of the sand discharge pipe to face the bottom of the water or near the dam, water bottom of sediment from the inlet the suction at siphoning sediment discharge tube with water, through which inhaled sediment and water sediment discharge tube, the sediment discharge method so as to flow to the low water river waters than and the dam at the downstream side of the dam , With water , Multiphase flow jetting means in which a multiphase flow consisting of innumerable air microbubbles with a diameter of 100 μm or less dispersed or mixed in the water , or gas microbubbles containing at least oxygen gas is provided in the earth and sand discharge pipe close to the suction port and is ejected directly to the sand discharge pipe from innumerable fine bubbles of the mixed phase stream is a feature that it has to flow the sand discharge pipe with sand and water sucked in soil discharge pipe from the suction port To do.

In addition to the above feature of claim 2 , the invention of claim 3 is characterized in that the multiphase jetting means opens at the bottom of the inner peripheral wall of the sediment discharge pipe, and the opening direction is inclined upward toward the downstream side. characterized in that it is composed of the injection nozzle.

The invention of claim 4 is an earth and sand discharging work ship movable on the water surface of the dam to be used for carrying out the method of claim 2 or 3 , wherein the hull has the suction port. A movable pipe having an upstream end is provided so that the suction port can be moved up and down in water. One end of the movable pipe is connected to the downstream end of the movable pipe, and the other end can communicate with the river water area. The earth and sand discharge pipe is constituted by a transport pipe, and further includes a multiphase flow supply device capable of supplying the multiphase flow to the multiphase flow ejection means.

As described above, according to the present invention, the sediment accumulated on the bottom of the dam is sucked into the sediment discharge pipe by siphon action, flows through the sediment discharge pipe to the downstream river water area, and is discharged into the water area. In addition to being able to efficiently deposit sediment sediment at the bottom of the dam with less energy and cost, it is possible to discharge sediment sediment in small quantities continuously into the downstream river water area, and the discharged sediment is discharged into the river water (natural power). Can be discharged to the downstream side without difficulty. Moreover, since a multiphase flow consisting of water and countless fine bubbles with a diameter of 100 μm or less dispersed and mixed in the water is directly ejected from the multiphase flow ejection means provided in the sediment discharge pipe close to the suction port into the sediment discharge pipe. The sediment sediment on the bottom of the water sucked together with water into the sediment discharge pipe can flow through the sediment discharge pipe in a state where countless fine bubbles with a diameter of 100 μm or less are mixed and dispersed in the water, and the countless fine bubbles By mixing and dispersing effect , especially the size effect of fine bubbles, countless fine bubbles can be placed in a substantially uniform and stable dispersion state in water, effectively reducing the frictional resistance between the flowing sediment and the inner surface of the sediment discharge pipe. on can be reduced, so can reduce the density of the sediment fluid, that Do is possible to flow the sediment smoothly sediment discharge tube. Therefore, since the reduction of the extension and the tube head losses transportation distance it can be achieved transport efficiency of the discharge sand sediment discharge pipe is siphon tube is up, the water level difference between the river waters and dams away from the dam is small rivers siphon tube sediment even to water Rutotomoni be smoothly discharged (sand discharge pipe), premature wear of the sand discharge pipe itself is suppressed improve durability of the tube is achieved, the frequency of pipe replacement due to wear Less can contribute to cost savings. Moreover, since the fine bubbles are air bubbles or gas bubbles containing at least oxygen gas, the aerobic microorganisms in the earth and sand flowing in the earth and sand discharge pipe and the oxygen in the fine bubbles are sufficiently brought into contact with each other. The microorganisms can be activated and this aeration effect improves the odor and turbidity of water containing earth and sand discharged to the discharge site, and the amount of dissolved oxygen increases, which is advantageous for environmental measures. In addition, this aeration effect is effectively demonstrated over a relatively long path from the dam bottom to the downstream river water area, improving the odor and turbidity of the water mixed in the discharged soil and increasing the dissolved oxygen content. Therefore, even if it is discharged as it is to the downstream river area, the influence on the environment of the river area can be minimized.

According aspect of the present invention in particular 1, more becomes mixed flow of water and the innumerable fine bubbles, Ru is ejected toward the bottom of the water sediment from multiphase flow jetting means provided on the sediment discharge pipe near the suction port Therefore, even when the sediment suction capacity of the sediment discharge pipe is relatively small or when the sediment is relatively hard, the sediment sediment is appropriately collapsed and diffused by the fluid pressure of the multiphase flow, and then efficiently sucked into the sediment discharge pipe. it becomes possible, the suction efficiency of up is achieved, yet the multiphase flow is that obtained contribute to simplification of possible combined structure supply means fine-bubble, and the collapse diffusion means sediment.

In particular, according to the invention of claim 3 , since the multi-phase flow jetting means is constituted by an injection nozzle that opens at the bottom of the inner peripheral wall of the sediment discharge pipe and whose opening direction is inclined upward toward the downstream side. And fine bubbles can be efficiently supplied between the bottom of the inner peripheral wall of the earth and sand discharge pipe where the weight mainly acts, and it is effective in reducing the frictional resistance between them, and the downstream side of the injection nozzle opening. the slope, the flow to the downstream side of the sediment is assisted by multiphase flow, Ru can be the flow more smoothly.

In particular, according to the invention of claim 4 , the hull of the earth and sand discharging work ship movable on the surface of the dam is provided with a movable pipe having a suction port at the upstream end so that the suction port can be moved up and down in water. The movable pipe and a transport pipe having one end connected to the downstream end of the movable pipe and the other end communicating with the downstream river water area constitute a sediment discharge pipe. Since it is equipped with a multiphase flow supply device that can be supplied to the jetting means, the sediment discharge work ship can be appropriately moved on the surface of the dam, so that the sediment deposited on the bottom of the dam can be discharged to the river water area downstream. .

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention illustrated in the accompanying drawings.

  In the accompanying drawings, FIGS. 1 to 8 show a first embodiment of the present invention. FIG. 1 is an overall schematic longitudinal sectional view showing an outline of dredging work, and FIG. 2 is an arrow 2 in FIG. FIG. 3 is an enlarged longitudinal sectional view of the dredger working vessel (enlarged sectional view taken along arrow 3-3 in FIG. 2), FIG. 4 is a plan view taken in the direction of arrow 4 in FIG. 3, and FIG. 6 is a cross-sectional view taken along line 7-7 of FIG. 5, and FIG. 8 is a schematic piping diagram showing a multiphase flow / pressurized water flow supply system. is there. 9 is a diagram corresponding to FIG. 5 showing the second embodiment, FIG. 10 is a diagram corresponding to FIG. 5 showing the third embodiment, FIG. 11 is a view taken along the arrow 11 in FIG. 10, and FIG. 5 is a diagram corresponding to FIG. 5, FIG. 13 is a diagram corresponding to FIG. 6 showing the fourth embodiment, and FIG. 14 is a schematic piping diagram (corresponding to FIG. 8) showing the multiphase flow / pressurized water flow supply system of the fourth embodiment. is there.

  First, in FIGS. 1 and 2, the dredging work system of the present embodiment floats on the stored water surface of the dam D, and the dredging work ship B as a sediment discharge work ship that can move on the water at any time, A movable suction pipe U having an upstream opening end Ue which is provided and can be moved up and down in the water, and a downstream river whose one end is connected to the downstream end of the movable suction pipe U and whose other end is lower than the dam D. The movable suction pipe U and the transport pipe A constitute a siphon pipe S in cooperation with each other, and the siphon pipe S is the earth and sand discharge pipe of the present invention. Configure.

  Thus, the suction port Ue of the movable suction pipe U faces the sediment 1 or the vicinity of the bottom of the dam D, and the siphon action of the siphon pipe S based on the priming action by the water suction pump Pv connected to the siphon pipe S. Is started, the siphon action allows the sediment 1 on the bottom of the dam to be sucked up together with the water, and gradually and continuously flow through the siphon pipe S to the downstream river water area R.

  As clearly shown in FIG. 5, the suction port Ue of the movable suction pipe U is cut obliquely so as to sufficiently secure the opening area, and large foreign matters are not sucked into the movable suction pipe U in the opening surface. A protective mesh f formed in the shape of a hemispherical bowl is applied.

  Also, at the downstream end of the transport pipe A or in the vicinity thereof, a discharge regulating valve Vc composed of an on-off valve capable of interrupting the transport pipe A at any time and temporarily interrupting the siphon action is provided. Then, by closing the release regulating valve Vc, the inside of the transport pipe A can be interrupted at any time at or near its downstream end, so that the siphon action can be temporarily interrupted easily. Accordingly, it is not necessary to operate the water suction pump Pv described later each time the dredging operation is interrupted to introduce priming water into the siphon pipe S, and the convenience of the operation is achieved.

  In addition, a sieve is attached to the downstream opening end Ae of the transport pipe A as necessary, and in the illustrated example, a plurality of mesh-like sieves f1 to f3 that become smaller in order from the upstream side to the downstream side are arranged in series. And detachably attached to each other. Thereby, comparatively large gravel, dust, etc. in the dam D can be collected by the sieves f1 to f3 so as not to flow into the river water area R on the downstream side.

  At least one of the plurality of sieves f1 to f3 can be omitted, and the roughness of the earth and sand flowing into the river water area R can be appropriately selected by the omission. In addition, when large earth and sand are stored in each sieve f1-f3, each sieve f1-f3 is isolate | separated suitably and it is made to take out the earth and sand in it.

  In addition, in the vicinity of the downstream river water area R (the river bank in the illustrated example) facing the downstream opening end A of the transport pipe A, a part of the discharged sediment from the transport pipe A is temporarily stored. Sediment storage area O is installed. By allowing the downstream opening end Ae of the transport pipe A to face the sediment storage area O as needed, at least a part of the sediment 1 of the dam D sucked up by the siphon pipe S is discharged into the river water area R as it is. Therefore, the accumulated sediments can be collected without difficulty, and can be used for construction materials and other purposes.

  Next, a specific configuration of the dredging work system will be described with reference to FIGS. The hull 2 of the dredger B is divided into a number of blocks that are not shown, but can be individually assembled on the site near the dam. The front portion of the hull 2 is formed with a notch-like recess 2a corresponding to the pair of left and right movable suction pipes U, U and open to the front and upper and lower sides to allow them to move up and down. A gate-type gantry 3 is erected at the front end so as to straddle the recess 2a.

  In addition, a control room C through which workers enter and exit is provided on the rear upper surface of the hull 2. Further, on the hull 2, four navigation winches W1 to W4 for allowing the work boat B to freely navigate in the front-rear and left-right directions, and the distal ends of the pair of left and right movable suction pipes U and U are driven up and down. Left and right lifting winches Wa and Wb are provided.

  A pair of left and right movable suction pipes U, U that are arranged in parallel with each other are arranged at the base end of the transport pipe A through a Y-shaped joint pipe J that is fixed to the hull 2 at their base ends, that is, downstream ends. That is, it is connected to the upstream end within the hull 2. The downstream side of the transport pipe A is supported by the float F and extends along the water surface of the dam D to the shore or the dam body, and further extends to the downstream river water region R at a lower water level than the dam D. Out. Note that most of the transfer pipe A is provided with flexibility, so that the transfer pipe A can be easily laid in accordance with the complicated terrain around the dam around which the transfer pipe A is routed.

  Each movable suction pipe U is composed of a straight rigid pipe except for a base end portion Ud composed of a flexible rubber hose, and the rigid pipe portion extends in the longitudinal direction and swings up and down on the hull 2. It is integrally held by a guide frame G made of a rigid frame that is pivotally supported. Further, at the leading end Uu of the guide frame G or the movable suction pipe U, there are terminals of lifting wires L and L that are extended from the left and right lifting winches Wa and Wb and extend downward through the guide sheave of the gantry 3. Each is bound. Therefore, by operating the lifting winches Wa and Wb, the left and right movable suction pipes U and U and the guide frame G are vertically swung through the wires L and L, so that the front side of each movable suction pipe U and U Can be independently driven up and down, and the flexible base end portion Ud can be bent without difficulty when moving up and down.

  The Y-shaped joint pipe J includes a pair of branch pipe portions Ja and Ja which are respectively connected to the downstream ends of the left and right movable suction pipes U and U, and both the branch pipe portions Ja and Ja are connected to the upstream end of the transport pipe a. And a junction pipe portion Jb that communicates with each other. Each branch pipe portion Ja, Ja has an open / close valve Vx that can shut off the corresponding movable suction pipe U from the other movable suction pipe U and the transport pipe A at any time, and the upstream side thereof. An atmosphere release valve Va for individually draining water from the movable suction pipe U is provided in series with each other. Thus, when one of the movable suction pipes U is clogged with dust or the like, the open / close valve Vx of the clogged movable suction pipe U is closed and the front side of the movable suction pipe U is pulled up to the surface of the water to open the air release valve Va. By opening, the atmosphere can be introduced into the pipe and the water in the pipe can be drained accurately. Also during the draining operation, the siphon action can be continuously performed through the other movable suction pipes U without any trouble, so that the work efficiency is improved.

  The hull 2 is pumped and supplied with priming water for starting siphon action on the siphon pipe S from the dam D to the siphon pipe (near the connecting portion between the movable suction pipe U and the transport pipe A in the illustrated example). A water absorption pump Pv is installed. Between the discharge part of the pump Pv and the siphon pipe S, a check valve 4 that allows only one-way flow from the discharge part to the siphon pipe S side is interposed. Further, a water absorption hose 5 communicating with the water of the dam D is connected to the suction side of the water absorption pump Pv, and a check that allows only a one-way flow from the water of the dam D to the pump Pv side in the middle. A valve 6 is interposed.

  In the middle of the siphon pipe S (conveying pipe A in the illustrated example), air mixing means M is provided for adjusting the suction force by the siphon action of the siphon pipe S by mixing air into the pipe. As this air-mixing means M, a conventionally known air-mixing means (for example, an air opening hole formed in the pipe wall is provided in the pipe wall for sucking and mixing air into the transport pipe and adjusting the flow rate of the fluid in the pipe. An opening / closing valve provided with a structure that opens and closes at any time so that the opening degree can be adjusted) is used, and in the illustrated example, it is disposed in the vicinity of the upstream end of the transport pipe A (on the work boat B).

  Thus, by adjusting the mixing ratio of air into the siphon tube S by the air-mixing means M, the suction force adjustment by the siphon action can be arbitrarily performed, so the state of the sediment (such as viscosity, specific gravity, pebbles, etc.) The suction force of the siphon action can be accurately adjusted according to the degree of mixing. Moreover, since the flow rate in the siphon pipe can be adjusted arbitrarily by adjusting the suction force (and therefore the amount of sediment suction), the amount of sediment flowing from the upstream side into the dam D and the river from which dredged soil is released. Depending on the level of the water flow in the water area R (that is, the ability to receive the discharged sediment in the river water area R), the amount of sediment released into the river water area can be adjusted accurately.

  That is, the amount of sediment discharge varies depending on the inner diameter of the siphon tube S, the suction force (strength of water flow), the sludge mixing rate in the sediment in the dam, etc., but flows into the dam A from the upstream side in one year. The total amount of sediment that has accumulated is multiplied by a predetermined magnification (for example, 1.1 to 1.2 times), so that the sediment can be gently discharged from the siphon pipe S to the river water area R on the downstream side over one year. If it is set to a numerical value, it is considered that damage due to inflow of sediment does not occur immediately downstream, midstream, and estuary of dam D.

  In addition, the dredger B is provided with first and second injection nozzles N as a multiphase flow jetting means, which will be described later, provided in the movable suction pipe U for a multiphase flow consisting of water and countless fine bubbles mixed in the water. A multiphase flow supply device X for supplying to N ′ is provided. This multiphase flow supply device X is mounted on the hull 2 and is similar to the multiphase flow generation device 100 that generates a primary multiphase flow that is composed of water and countless fine bubbles mixed in the water and is pressurized to a predetermined pressure. And a pressurized water flow generator 101 that is mounted on the hull 2 and generates a pressurized water flow that is slightly lower in pressure than the primary multiphase flow. The multiphase flow generator 100 is provided in the middle of the first conduit 10 that extends from the pressurized water flow generator 101. The second pipe 20 extending from the pipes merges, and the pressurized water flow and the primary multiphase flow supplied from the respective pipes 10 and 20 are mixed to form a secondary multiphase flow, which is the first and second nozzles N and N. ′ Is supplied.

  The multi-phase flow generator 100 generates a multi-phase flow in which a very small number of fine air bubbles having a diameter of 100 μm or less are sufficiently dispersed and mixed in water, and pressurizes the mixed phase flow through the second conduit 20. The water is supplied to the first and second nozzles N and N ′, and the water is pumped up from the dam D and used.

  The fine bubbles are so-called “micro bubbles”, and not only the macro-sized bubbles are reduced, but also exhibit various physicochemical properties due to the size effect. For example, normal millimeter-sized bubbles rise quickly in water and grow together by repeating coalescence and absorption, but in the fine bubbles, they rise very slowly as if the moths are still in water, Also, even when a large amount of water is generated in the water, there is almost no coalescence or absorption between the bubbles, the bubbles exhibit excellent uniformity and dispersibility, high gas absorption efficiency into the water, and rapid oxygen dissolution It has the feature that it can be raised.

  A multi-phase flow generator for generating a multi-phase flow in which such fine bubbles are mixed in water in a large amount is conventionally known and has already been industrially mass-produced (for example, JP-A-2000-447, Therefore, the description of the structure of the multiphase flow generator 100 used in this embodiment is also omitted.

  Thus, when the diameter of the fine bubbles in the multiphase flow created by the multiphase flow generator 100 is adjusted to be 100 μm or less, the desired effect of the present invention described later can be achieved by the size effect. In particular, when the diameter of the fine bubbles in the mixed phase flow is adjusted to 50 μm or less, the desired effect of the present invention can be achieved more reliably and sufficiently due to the size effect. It should be noted that the mixing amount of fine bubbles in the primary multiphase flow produced by the multiphase flow generating device 100 and the mixing ratio of the primary multiphase flow to the pressurized water flow are adjusted so as not to interfere with the siphon function of the siphon tube S. Of course.

  The first conduit 10 extending from the pressurized water flow generator 101 is supported along the axis of the outer peripheral portion of each movable suction pipe U and extends to the distal end side of the suction pipe U. On the outer periphery of each movable suction pipe U near the suction port Ue, the secondary mixed phase flow (that is, the mixed flow of the pressurized water flow from the pressurized water flow generator 101 and the primary mixed phase flow from the multiphase flow generator 100) is placed on the bottom of the water. A plurality of (in the illustrated example, a pair of upper, lower, left and right) first injection nozzles N that can be sprayed forward toward the sediment 1 are fixed, and the injection nozzles N and the first conduit 10 are common. The first main on-off valve 15 is connected to a plurality of (four in the illustrated example) branch pipes 11 that are branched on the downstream side and fixed to the movable suction pipe U. In the illustrated example, the opening positions of the upper and lower first injection nozzles N are offset forward and backward in accordance with the inclination of the suction port Ue, and the opening positions of the left and right first injection nozzles N are offset forward and backward. Without being set, the front side of the upper and lower first injection nozzles N (closest to the suction port Ue) is set.

  Further, the second conduit 20 extending from the multiphase flow generating device 100 is supported on the outer peripheral portion of each movable suction pipe U along the axis thereof, extends to the suction pipe U to the vicinity of the tip, and downstream thereof. Is branched into a plurality (four in the illustrated example) of branch pipes 21 and merges with the four branch pipes 11 of the first conduit 10. A common second main on-off valve 25 is provided on the upstream side of the branch portions of the branch pipes 21.

  Thus, the siphon action of the siphon tube S is started and the mixed-phase flow generator 100 and the pressurized water flow generator 101 are operated in a state where the suction port Ue of each movable suction pipe U is brought close to the sediment 1 on the bottom of the dam. Further, when the first and second main on-off valves 15 and 25 are opened, the secondary mixed-phase flow in a pressurized state can be injected from each of the first injection nozzles N, thereby effectively depositing the sediment 1. And can be efficiently sucked into the siphon tube S (movable suction tube U) together with the fine bubbles in the mixed phase flow, and at the suction port Ue of each movable suction tube U. Clogging of foreign matter can be avoided as much as possible.

  A single second injection nozzle N ′ capable of directly injecting the mixed phase flow fed from the mixed phase flow supply device X into each movable suction tube U is provided on the outer periphery of each movable suction tube U near the suction port Ue. Is fixed. The injection nozzle N ′ and the first conduit 10 are connected to each other via a branch pipe 12 branched from the conduit 10 on the upstream side of the first main on-off valve 15. An on-off valve 16 is interposed. Further, the middle of the branch pipe 12 and the second conduit 20 are connected to each other via a branch pipe 22 branched from the conduit 20 on the upstream side of the second main on-off valve 25. A two sub open / close valve 26 is interposed. Accordingly, when the multiphase flow generator 100 and the pressurized water flow generator 101 are operated and the first and second sub-open / close valves 16 and 26 are opened, the secondary multiphase flow in a pressurized state is supplied from the second injection nozzle N ′. Can be directly injected into the movable suction pipe U.

  The second injection nozzle N ′ opens at the bottom of the inner peripheral wall of each movable suction pipe U, and the opening direction is inclined upward toward the downstream side of the movable suction pipe U. And by the inclination to the downstream side of the nozzle opening o, the flow of the earth and sand in the movable suction pipe U to the downstream side is assisted by the secondary mixed phase flow injected from the second injection nozzle N ′, The flow can be made smooth. Incidentally, the opening o of the second injection nozzle N ′ may be single as shown in FIG. 7A, or a plurality of openings o arranged in parallel at intervals in the circumferential direction as shown in FIG. Also good. Although not shown, the opening may be formed long in the circumferential direction. Although not shown, each branch pipe 11, 12 may be provided with a check valve for preventing the backflow of the multiphase flow upstream from the mixing portion between the branch pipes 25 and 26.

  Next, the operation of this embodiment will be described. When hitting the bottom of the dam D, the dredger B is assembled around the dam D and floated on the surface of the dam D. The position of this work ship B is that the anchors fixed to the ends of the wires L ′ fed out from the four navigation winches W1 to W4 on the hull 2 are lowered to appropriate positions (four sides of the ship) at the bottom of the water. The work ship B can be moved to a desired position by appropriately winding and unwinding an arbitrary wire L ′ by W4.

  Next, the front side of the pair of movable suction pipes U is lowered from the work boat B, and the suction port Ue at the tip of the pair is made to face the sediment layer on the bottom of the water. In this state, the water suction pump P connected to the siphon pipe S is operated, and the water sucked by this is pumped into the siphon pipe S as priming water to start the siphon action of the siphon pipe S. Once the siphon action is started, the siphon action continues even if the water absorption pump P is stopped. By the siphon action, the sediment 1 on the bottom of the dam D is sucked up together with water and gradually enters the river water area R. It can discharge continuously, and the position of the work boat B is moved little by little with the earth and sand discharge. As a result, the sediment 1 on the bottom of the dam D can be efficiently drowned with low energy and cost, and the sediment 1 and water can be continuously discharged from the siphon pipe S into the river water area R little by little. By using the original water flow (natural force) of the river, the discharged sediment 1 can be discharged to the downstream side without difficulty, and the influence on the natural environment can be eliminated as much as possible.

  By the way, when the multiphase flow generator 100 and the pressurized water flow generator 101 are operated and the first and second main on-off valves 15 and 25 are opened while the siphon pipe S is in operation, the first injection nozzles N ... The secondary mixed phase flow in the pressure state can be jetted toward the sediment sediment 1 at the bottom of the water, and the sedimentary sediment 1 can be effectively collapsed and diffused by the mixed phase flow. It can be efficiently sucked into the siphon tube S (movable suction tube U) together with the fine bubbles in the portion. In this case, when the first and second sub-open / close valves 16 and 26 are further opened, a secondary mixed phase flow in a pressurized state is supplied from the second injection nozzle N ′ to the inside of the movable suction pipe U downstream from the bottom of the inner peripheral wall thereof. In this way, not only can all the fine bubbles in the multiphase flow be ejected into the movable suction pipe U, but also the flow of earth and sand in the movable suction pipe U to the downstream side. Assisted by the multiphase flow, the flow can be made smooth.

  Thus, the sediment sediment 1 and water in the bottom of the water sucked into the movable suction pipe U can flow in the movable suction pipe U (and hence the siphon pipe S) in a state where countless fine bubbles are mixed and dispersed in the water. Therefore, the frictional resistance between the fluid sediment and the inner surface of the siphon tube S can be effectively reduced by the effect of mixing innumerable fine bubbles, and the density of the sediment fluid can be reduced. Thus, the earth and sand can flow smoothly in the siphon tube S. Therefore, the head loss in the siphon pipe S is reduced, the transport efficiency of the discharged sediment is increased, the transport distance can be secured sufficiently long, and the early wear of the siphon pipe S itself is suppressed and the pipe S The durability of (movable suction pipe U, joint pipe J, transport pipe A) can be improved, and the frequency of pipe replacement due to wear can be reduced to contribute to cost saving.

  Further, in this embodiment, since the fine bubbles are air fine bubbles, the aerobic microorganisms in the earth and sand flowing in the siphon tube S and the oxygen in the fine bubbles can be sufficiently brought into contact with each other. The aeration effect can be enhanced by activating microorganisms, whereby the odor and turbidity of water containing discharged sediment can be improved, and the amount of dissolved oxygen can also be increased efficiently. Moreover, the siphon pipe S extending between the bottom of the dam and the downstream river basin R has a very long flow path in the pipe, and the sediment 1 slowly flows along with a large amount of water in the pipe by the siphon action. Therefore, the aeration effect by the fine bubbles is effectively and sufficiently exhibited throughout the long flow process. Therefore, even if the sediment sediment 1 at the bottom of the dam is discharged directly from the siphon pipe S to the downstream river basin R together with a large amount of water, the odor and turbidity of the water containing the released sediment is effectively improved. Since the amount of dissolved oxygen can be made sufficiently high, it is advantageous in terms of environmental measures for the downstream river water area R.

  FIG. 9 shows a second embodiment of the present invention. In this embodiment, only the configuration of the tip portion of the siphon tube S (movable suction tube U), that is, the suction port Ue and its peripheral portion is different from the previous embodiment, so only the difference will be described. That is, the suction port Ue has a shape cut by a plane orthogonal to the axis of the movable suction pipe U, and the suction port Ue is covered with a protective net f formed in a spherical bowl shape. Further, the upper first injection nozzle N is inclined downward toward the front, and the tip end part enters the protective net f, and approaches the sediment 1 on the lower front side of the suction port Ue to approach the multiphase flow. Can be injected. The other injection nozzles N and N ′ are basically the same as in the previous example except that the opening position of the second injection nozzle N ′ is slightly rearward than that in the previous example.

  10 and 11 show a third embodiment of the present invention. Also in this embodiment, only the configuration of the tip portion of the siphon tube S (movable suction tube U), that is, the suction port Ue and its peripheral portion is different from the previous embodiment, so only the difference will be described. That is, the tip portion of the siphon tube S (movable suction tube U) is inclined slightly forward and downward in front of the suction port Ue, and the suction port Ue is oriented in the inclined direction. In accordance with this inclination, the opening directions of the lower and left and right first injection nozzles N are similarly inclined, and the upper first injection nozzle is omitted. The second injection nozzle N ′ is basically the same as in the second embodiment. The suction port Ue is covered with a protective net f formed in a flat net shape.

  Thus, the second and third embodiments can achieve basically the same effects as the first embodiment.

  12 to 14 show a fourth embodiment of the present invention. In the previous embodiment, the mixed flow (secondary mixed phase flow) obtained by previously mixing the primary mixed phase flow from the mixed phase flow generating device 100 and the pressurized water flow from the pressurized water flow generating device 101 is used as the mixed phase flow ejecting means. In the present embodiment, the primary mixed phase flow from the multiphase flow generation device 100 and the pressurized water flow from the pressurized water flow generation device 101 are not mixed in advance. The present invention is characterized in that the first injection nozzle N as the multiphase flow jetting means and the water jet nozzle Nw as the pressurized water jetting means are jetted separately.

  That is, in this embodiment, near the suction port Ue of the movable suction pipe U, the same number of water injection nozzles Nw are arranged in proximity to and in parallel with the plurality of first injection nozzles N of the first embodiment. . As is apparent from FIG. 14, a multiphase flow supply system from the multiphase flow generating device 100 to the multiphase flow injection nozzle N through the second conduit 20, the second main opening / closing valve 25, and the branch pipe 21, and the pressurized water flow generating device. The supply system of the pressurized water flow from 101 to the water injection nozzle Nw through the first conduit 10, the first main opening / closing valve 15, and the branch pipe 11 is independent of each other. On the other hand, the piping system for supplying the secondary multiphase flow to the second injection nozzle N ′ and other device configurations are basically the same as those in the above embodiment, and each component corresponds to the above embodiment. Reference numerals are attached.

  Thus, in this embodiment, the primary mixed phase flow from the mixed phase flow generating device 100 and the pressurized water flow from the pressurized water flow generating device 101 are used as the first injection nozzle N as the mixed phase flow ejecting means and the pressurized water flow ejecting means. The water injection nozzles Nw can be separately injected, and one of the pressurized water flow or the mixed phase flow can be stopped (that is, only the other) can be stopped if necessary, and the pressurized water flow or the mixed phase flow can also be stopped. Since the setting, adjustment, etc. of the water pressure, flow rate, injection direction, etc. can be performed separately and independently, setting and adjusting operations thereof are relatively easy.

As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various design change can be performed. For example, in the above-described embodiment, the dredger work ship B as the earth and sand discharging work ship is a ship that can travel by itself, but in the present invention, it is a work ship of a type that cannot be driven by itself and is driven from another ship or land. even if there have good.

Moreover, in the said Example, although the multiphase flow supply apparatus X showed what mixed the fine bubble of air with water and produced the mixed phase flow, the fine bubble of gas other than air (for example, gas containing oxygen) was shown. May be mixed with water. To Also multiphase flow, additives that facilitate the separation of water and sediment (mud) (e.g. palm oil) may be added.

Moreover, in the said Example, although what showed the injection | spray part of the multiphase flow in the siphon pipe | tube S as the inner peripheral wall bottom part of the movable suction pipe | tube U near the suction inlet Ue was shown, in this invention, that injection | spray part | part is other than a bottom part. the inner peripheral wall (e.g. top, side) of but it may also be set to.

  Moreover, in the said Example, although the thing which provided the movable suction pipe S by left-right pair and made the downstream ends merge was shown, in this invention, you may comprise the movable suction pipe S from a single pipe | tube.

  In the above embodiment, the primary mixed phase flow from the mixed phase flow generation device 100 and the pressurized water flow from the pressurized water flow generation device 101 are mixed in advance by opening both the first and second auxiliary on-off valves 16 and 26. In the present invention, the mixed flow (secondary multiphase flow) is directly injected into the movable suction pipe U from the second injection nozzle N ′ serving as the multiphase flow injection means. By closing the on-off valve 16 and opening only the second sub-opening / closing valve 26, the primary mixed phase flow from the mixed phase flow generating device 100 is directly mixed with the pressurized water flow from the second injection nozzle N ′ without being mixed in advance with the movable suction pipe U. You may make it inject directly.

Whole schematic longitudinal cross-sectional view which shows the outline | summary of the dredging work which shows 1st Example of this invention The top view of the said Example (2 arrow directional view of FIG. 1) Enlarged longitudinal sectional view of the dredger work vessel (enlarged sectional view taken along arrow 3-3 in FIG. 2) 4 is a plan view in the direction of arrow 4 in FIG. Side view showing the tip of the movable suction pipe 6 arrow view of FIG. Sectional view along line 7-7 in FIG. Schematic piping diagram showing the multiphase flow / pressurized water flow supply system of the first embodiment FIG. 5 correspondence diagram showing the second embodiment FIG. 5 corresponding diagram showing the third embodiment. 11 arrow view of FIG. FIG. 5 correspondence diagram showing the fourth embodiment. FIG. 6 corresponding diagram showing the fourth embodiment. Schematic piping diagram showing the multiphase flow / pressurized water flow supply system of the fourth embodiment (corresponding to FIG. 8)

A Transport pipe B Dredging ship (Sediment discharge work ship)
D Dam N 1st injection nozzle (multi-phase flow ejection means)
N 'second injection nozzle (multiphase flow injection means)
Nw water jet nozzle (pressurized water jet)
o Opening R River water area (discharge location)
S Siphon pipe (sediment discharge pipe)
U Movable suction pipe Ue Suction port X Multiphase flow supply device 1 Sediment sediment 2 Hull 100 Multiphase flow generator 101 Pressurized water flow generator

Claims (4)

The suction port (Ue) opened at the upstream end of the sediment discharge pipe (S) faces the bottom of the dam (D) or in the vicinity thereof, and the sediment (1) on the bottom of the water is put together with water from the suction port (Ue). The suction pipe (S) is sucked by siphon action, and the sucked sediment (1) and water are passed through the sediment discharge pipe (S), downstream of the dam (D) and at a lower water level than the dam (D). In the earth and sand discharge method to flow to the river water area (R) of
And water, dispersed in the water, mixed and allowed diameter 100μ or less fine-bubble countless air, or a gas containing at least oxygen gas fine bubbles and become more multi-phase flow, inlet (Ue) near soil discharge pipe ( The first multiphase flow ejection means (N) provided in S) is ejected toward the sediment sediment (1) at the bottom of the water, and a part of the countless fine bubbles in the multiphase flow is The water is sucked into the sediment discharge pipe (S) from the suction port (Ue) and flows through the sediment discharge pipe (S) .
Further, the mixed phase flow is directly jetted into the sediment discharge pipe (S) from the second mixed phase flow ejection means (N ′) provided in the sediment discharge pipe (S) close to the suction port (Ue), and the mixed phase flow. Innumerable fine bubbles inside flow along the earth and sand discharge pipe (S) together with the earth and sand (1) sucked into the earth and sand discharge pipe (S) from the suction port (Ue),
The first, wherein said that the multiphase flow is supplied under pressure from a common multi-phase flow generating device (100) for the second multiphase jetting unit (N '), sediment discharge how . The suction port (Ue) opened at the upstream end of the sediment discharge pipe (S) faces the bottom of the dam (D) or in the vicinity thereof, and the sediment (1) on the bottom of the water is put together with water from the suction port (Ue). The suction pipe (S) is sucked by siphon action, and the sucked sediment (1) and water are passed through the sediment discharge pipe (S), downstream of the dam (D) and at a lower water level than the dam (D). In the earth and sand discharge method to flow to the river water area (R) of
And water, dispersed in the water, mixed and allowed diameter 100μ or less fine-bubble countless air, or a gas containing at least oxygen gas fine bubbles and become more multi-phase flow, sediment discharge tube close to the suction port (Ue) ( The infinite number of fine bubbles in the mixed-phase flow are directly ejected from the mixed-phase flow ejection means (N ′) provided in S) into the sediment discharge pipe (S), and the sediment discharge pipe (S) from the suction port (Ue). A method for discharging soil and sand, characterized in that the soil and sand (1) and water sucked into the fluid flow in the sediment and sand discharge pipe (S). The multi-phase flow ejection means (N ′) is composed of an injection nozzle that opens (o) at the bottom of the inner peripheral wall of the earth and sand discharge pipe (S) and whose opening direction is inclined upward toward the downstream side. The sediment discharge method according to claim 2 , characterized in that it is characterized in that A soil discharge work ship movable on the water surface of the dam (D) to be used for carrying out the method according to claim 2 or 3 ,
The hull (2) is provided with a movable suction pipe (U) having the suction port (Ue) at the upstream end so that the suction port (Ue) can be moved up and down in water. ) And a transport pipe (A) having one end connected to the downstream end of the movable suction pipe (U) and the other end communicating with the river water area (R), the earth and sand discharge pipe (S) is configured,
A sediment discharge work ship further comprising a multiphase flow supply device (X) capable of supplying the multiphase flow to the multiphase flow ejection means (N ').

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