JP2005095814A - Apparatus and method for dehydrating highly hydrated earth and sand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for dehydrating highly hydrated earth and sand which efficiently dehydrate the highly hydrated earth and sand responding to changing geological materials without reducing an electroosmotic effect. <P>SOLUTION: The apparatus for dehydrating the highly hydrated earth and sand is provided with a soil tank 1 for storing the highly hydrated earth and sand, a water-permeable cathode 3 installed along the inner surface of the soil tank, anodes 6 consisting of a plurality of electrode groups arranged at equal intervals along the soil tank, and to the inner surfaces of the cathode and/or an electrode group 20 of water-permeable bipolar electrodes, a direct current power source 10 applying direct current between the electrodes by connecting the cathode with the anode electrode groups, and a water discharging device 15 collecting, and discharging to the outside of the soil tank, water permeated into the cathode from the highly hydrated earth and sand through the electroosmosis by applying voltage by connecting to the water permeable cathode 3 and/or the inside of the electrode group 20. By using this apparatus, the method is such a one that at least successively lowering voltage is successively applied between the electrodes from the electrode group arranged at the center within the anode electrode groups 6 and the electrode group 20, through a pair of electrode groups adjacent to both sides of them/it to the outermost electrode group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a dewatering device and method for dewatering high water content sediments and the like discharged in connection with construction work and excavation work, particularly high impregnated soil sludge due to silt and viscous soil with high water content. The present invention relates to an apparatus and a method for efficiently dewatering hydrous sand.

  Conventionally, in order to reduce the water content of construction sludge with a high water content and to make it easier to reprocess, solidification methods mainly involving the mixing of solidifying agents such as cement and quicklime, There is a dehydration method that separates sediment and water by a filtration tank. In recent years, as part of the dehydration method, an electroosmosis method has been proposed in which a direct current is applied to the cathode and anode placed opposite to each other in the ground or discharged sludge, and the water collected at the cathode is collected and separated by electroosmosis. ing.

  In the case of the solidification method, if the moisture content becomes high or the scale of construction increases, the amount of solidifying agent required also becomes large, making it difficult to transport and treat a large amount of solidified earth and sand. Problems also increase in terms of workability.

  The dehydration method is applied to underground shield excavation in urban areas that are frequently used in recent years, especially the hydraulic shield method, but the size and number of sedimentation tanks and filtration tanks must be increased as the construction scale increases. If these are installed on the ground surface outside the tunnel, it becomes a big problem in urban areas. In addition, since the geology and moisture content of the underground ground constantly change with the progress of excavation, it is necessary to continuously and sufficiently manage the water pressure necessary to stabilize the face and the amount of bentonite or polymer water-absorbing agent mixed in. However, while the overall construction of the shield construction method becomes complicated and large, the dehydration effect of highly hydrous sand changes according to the earth, sand, gravel, clay, etc. as the geology changes, affecting the operation of related processes.

In the electro-osmosis method, there are cases where the object of dehydration is the ground and high water-containing earth and sand that has been excavated and discharged. In the former, the electrode is directly buried in the ground and energized, while in the latter, the inside is opposed. The storage soil tank provided with the electrodes is filled with discharged highly hydrous soil and energized. When the ground is directly energized, not only does the electrode need to be drilled, but even if the electrode is dewatered, the surrounding free water and groundwater will enter the dewatered part, so the dewatering work will continue indefinitely. In addition, it is difficult to perform smooth work during rainfall or during heavy rain. Also, in the dewatering of highly hydrous soil in the storage soil tank, drying shrinkage occurs locally in the soil as the dewatering progresses, and cracks and voids are likely to occur, and the electrical resistance increases as the void volume increases. And the electroosmotic effect is reduced.
JP-A-9-287127 Japanese Patent Application No. 2002-349801

The tunnel excavation work by the hydraulic shield method described above discharges a large amount of highly hydrous soil, so it is advantageous to apply the electroosmosis method using a storage tank equipped with electrodes for its dehydration treatment,
In order to be able to cope with the geological material and its dimensions that change with the progress of construction, it is necessary to keep the distance between the anode and the cathode large. On the other hand, simply increasing the distance between the electrodes reduces the electroosmotic effect and reduces the amount of dehydration. To prevent this, the theoretical formula of electroosmosis (Q = Ke × ie × A), where Q: amount of water Ke: electroosmotic permeability coefficient 5 × 10
ie: Potential gradient Volt / cm
A: Depending on the permeation area between the anode and the cathode, the applied voltage may theoretically be increased in order to increase the potential gradient. However, in reality, the soil around the anode is rapidly dehydrated and solidified, and as described above, voids are generated. This reduces the electroosmotic effect. The present invention has been proposed in view of these points, and the object of the present invention is to have a high water content capable of efficiently dewatering a highly water-containing earth and sand according to the changing geological material without reducing the electroosmotic effect. It is in providing a sediment dewatering device and a highly water-containing sediment dewatering method.

  In order to solve the above-mentioned problem, a highly water-containing earth and sand dewatering device according to the invention of claim 1 includes an earth tank 1 that is open at the top and is installed underground, semi-underground or above ground to store the highly water-containing earth and sand G, and the earth tank A water-permeable cathode 3 composed of side surface portions 3W, 3W ′, 3B, 3B ′ and a floor surface portion 3d that covers the inner surface of 1, and a plurality of cathodes 3 that are spaced apart from the cathode 3 and arranged approximately equidistantly. Anode groups 6a, 6b, 6c, 6n, 6b ', 6c', 6n 'and / or a plurality of permeable positive / negative bipolar electrode groups 20a, 20b, 20c, 20b', 20c ', a cathode 3 and a plurality of A DC power supply device 10 that is connected to the anode group 6 and / or a plurality of permeable positive / negative bipolar electrode groups 20 and applies a DC voltage between the two electrodes, and a permeable cathode from the highly hydrous soil G by electroosmosis by voltage application 3 and / or the permeable positive / negative bipolar electrode group 20a, 0b, 20c, 20b ', 20c' and collecting the permeated water in, characterized in that it comprises a drainage device 15 for draining out soil bin. The anode 6 includes a central electrode group 6a; 20a and a plurality of pairs of electrode groups 6b, 6b ′; 6c, 6c ′; 6n, 6n ′: 20b, 20b ′; , Each electrode group can be composed of a plurality of electrode bodies or a lattice-like combination of plate-like electrodes. The drainage device can also be or include a submersible pump installed inside the permeable cathode if the scale and size of the permeable cathode increase.

  The highly water-containing earth and sand dewatering device according to claim 2 closes the upper opening of the earth tub 1 and holds a plurality of anode groups 6a, 6b, 6c, 6n, 6b ', 6c', 6n 'in a predetermined position. 6-1, and the insulating plate 6-1 has a water-permeable strainer layer 6-3 on the side in contact with the highly hydrous sand in the earth tub, and each surface portion 3W, 3W ′, 3B, 3B ′, The water collecting pipe 4 extending inside 3d, the water collecting pipe 7 communicating with the inside of the strainer layer 6-3 of the insulating plate 6-1, and the water infiltrated into the cathode by the vacuum pump device 15 for drainage, together with the water in the soil tank Water separated into the upper layer of hydrous sand can also be collected.

  In the highly water-containing earth and sand dewatering device according to claim 3, the plurality of permeable positive / negative bipolar electrode groups 20a, 20b, 20c, 20b ′, 20c ′ each have a strainer layer 24 having a water collecting hole 23 on the surface, and a strainer layer 24. The DC power supply 10 is connected to the a terminal connected to the positive electrode side 10-1 and the negative electrode side 10-2 of the DC power supply, respectively. Switches 21a, 21b, 21c, 21b ', 21c' having a b terminal and a c terminal connected to each of the electrode groups 20a, 20b, 20c, 20b ', 20c', and the negative side 10-2 of the DC power source and the cathode And a switch 12 for connecting the three electrodes, and a positive voltage and a negative voltage can be alternately applied to the bipolar electrode groups 20a, 20b, 20c, 20b ′, and 20c ′ in the order of arrangement. That.

  The highly water-containing earth and sand dewatering device according to claim 4 includes a plurality of electrode groups 6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′ and / or a plurality of permeable positive / negative bipolar electrode groups 20a, 20b, 20c, The anode 6 composed of 20b ′, 20c ′ and the cathode 3 composed of the side surface portions 3W, 3W ′, 3B, 3B ′ and the floor surface portion 3d are formed as an electrode block 31, and a plurality of electrode blocks are formed using this electrode block 31 as a unit. The earth tub 1 is formed in a size that can be accommodated, and the electrode block 31 can be inserted into and removed from the earth tub.

  Moreover, in order to solve the said subject, the high water content earth-and-sand dehydration method which concerns on Claim 5 installs the earth tank 1 which opens upper part and stores the high water content earth-and-sand G in the basement, a semi-underground, or the ground. A plurality of anode groups 6a, 6b, 6c, 6n, 6b 'are provided, each having a water permeable cathode 3 composed of side surface portions 3W, 3W', 3B, 3B 'and a floor surface portion 3d. , 6c ′, 6n ′ and / or a plurality of permeable positive / negative bipolar electrode groups 20a, 20b, 20c, 20b ′, 20c ′ are arranged inwardly of the cathode 3 and the DC power supply device 10 is arranged in the cathode 3 And a plurality of anode groups 6 and / or a plurality of permeable bipolar electrode groups 20 and a DC voltage is applied between the two electrodes, and the drainage device 15 is connected to the permeable cathode 3 and / or the permeable bipolar electrode group 20. From high water content sand G by electroosmosis by connecting and applying voltage Aqueous cathode 3 and, or, characterized in that the water penetrated into water-permeable bipolarization electrode group 20 is drained out of the water collecting and Doso.

The high water-containing earth and sand dewatering method according to claim 6 further includes the DC power supply 10 on the positive voltage side with the electrode groups 6a, 6b, 6c, 6n, 6b ', 6c', 6n 'and the open / close switches 8a, 8b, 8c, 8n, 8b ', 8c', and 8n 'are connected to each other, and DC voltage application is performed while the switch 12 is closed and the cathode 3 is connected to the negative voltage side of the DC power supply device 10.
(A) First, the switch 8a connected to the electrode 6a disposed at the center is closed, then the switches 8b and 8b ′ connected to the pair of electrode groups 6b and 6b ′ adjacent to the outside are closed, and the pair of electrodes adjacent to the outside are further closed. By sequentially closing the switches 8c and 8c ′ connected to the groups 6c and 6c ′ to the switches 8n and 8n ′ connected to the outermost pair of electrode groups 6n and 6n ′, the outermost electrode groups on both sides from the central electrode. Up to everything,
(B) First, the switches 8a and 8n ′ of the outermost pair of electrode groups 6n and 6n ′ are passed through the switches 8b and 8b ′ of the pair of electrode groups 6b and 6b ′ adjacent to both sides sequentially from the switch 8a of the center electrode 6a. (C) All switches 8a, 8b, 8c, 8n, 8b ', 8c of all electrode groups 6a, 6b, 6c, 6n, 6b', 6c ', 6n' By closing ', 8n' at the same time,
One of the above is selected according to the dehydration situation.

The highly water-containing earth and sand dewatering method according to claim 7 has also penetrated into the strainer layer 24 and the strainer layer 24 having the water collecting holes 23 on the surface as the electrode groups 20a, 20b, 20c, 20b ′, 20c ′ of the anode 6, respectively. A water collecting pipe 25 that collects water and sends it to the vacuum pump device 15 is arranged and connected as a switch 21 to the a terminal connected to the positive electrode side 10-1 of the DC power supply device 10 and to the negative electrode side 10-2, respectively. Switches 21a, 21b, 21c, 21b ', 21c' having a b terminal and a c terminal connected to each of the electrode groups 20a, 20b, 20c, 20b ', 20c' and the negative electrode side 10-2 of the DC power supply device 10 The switch 12 is connected between the cathode 3 and the DC voltage is applied while the switch 12 is closed and the cathode 3 is connected to the negative electrode side of the DC power supply 10.
(A) First, the c terminal of the switch 21a connected to the anode electrode 20a disposed at the center is connected to the a terminal side, and the c terminals of the paired electrode groups 20b, 20b ′, 20c, and 20c ′ are a , B are set in the middle of both terminals, and thereafter the c terminal between the switches 21b, 21b ′ of the outer pair of electrode groups 20b, 20b ′ and the switches 21c, 21c ′ of the outermost pair of electrodes 20c, 20c ′. Are sequentially connected to the a terminal,
(B) The c terminal of the switch 21a of the central electrode rod 20a is connected to the a terminal, the c terminals of the switches 21b and 21b ′ of the outer electrode groups 20b and 20b ′ are connected to the b terminal, and the outermost The c terminals of the switches 21c and 21c ′ of the pair of electrode groups 20c and 20c ′ are connected to the a terminal, or (c) the c terminals of the switches of each electrode group of the anode are a terminals depending on the state of dehydration of the earth and sand Switch to the b terminal, and from the state of (b), connect the c terminal of the switch 21a of the electrode group 20a to the b terminal, and connect the c terminals of the other switches 21b, 21b ′ to the a terminal.
One of the above is selected according to the dehydration situation.

  The high water-containing earth and sand dewatering method according to claim 8 is the voltage applied between each of the central anode electrode group 6a; 20a to the adjacent outer electrode group 6b, 6b ′; 20b, 20b ′ and the cathode 3 in order. The DC voltage is applied by lowering the voltage sequentially, and after the DC voltage is applied to the outermost electrode group depending on the dehydration state, the DC voltage is applied by sequentially increasing the voltage to the central electrode group.

  The method of dehydrating a highly hydrous soil according to claim 9 is characterized in that the dehydration of the highly hydrous soil by electroosmosis by applying a voltage between both electrodes is performed by adding an electrolyte to the highly hydrous soil.

  According to the present invention, the cathode for dehydration by the electroosmosis method is provided in a surface shape that covers at least the inner peripheral side surface and the inner floor surface of the highly water-containing earth and sand storage soil tank and has water permeability, and the anodes are connected to each other. Since it is formed of an electrode group arranged at approximately the same distance from the cathode, the effective area for water electroosmosis is remarkably increased, and the permeate water collection effect and the amount of dewatering are greatly improved.

  In addition, since the anode is formed of a plurality of electrode groups that are substantially equidistant from each other and from the cathode, the insulation configuration between the electrode rods of the same polarity is simplified, and the simplified insulation configuration is used for the upper part of the soil tank. A device can be added to collect water from the stored highly hydrous soil to separate, and the amount of dewatering is further improved.

  The cathode and anode have a block structure that can be inserted into and removed from the soil tank, and this electrode block is formed to a size that can accommodate multiple units. The size of the device can be increased or decreased, and the device can be scaled up.

  Electroosmosis dehydration by applying voltage between both electrodes is performed by adding an electrolyte to highly hydrous soil, thus improving dewatering efficiency.

  Several embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view of an embodiment of a high water content earth and sand dewatering device according to the present invention by an electroosmosis method.

  In FIG. 1, a soil tank 1 for storing highly hydrous sand G is provided with a side wall and a floor wall, and is formed in a substantially rectangular box shape having an upper portion as an opening. The material may be any of metal, concrete, resin, etc., but it is desirable to provide ground 2 on the outer wall.

  A substantially rectangular box-shaped cathode 3 composed of side surface parts 3W, 3W ′, 3B, 3B ′ covering the inner peripheral side surface of the wall surface other than the upper opening of the earth tank 1 and a floor surface part 3d covering the inner floor surface is provided in the earth tank 1. Install in. The cathode 3 has an inner peripheral surface made of a water-permeable perforated plate 3-1, and an outer peripheral surface made of a water-impermeable back plate 3-2. A strainer is provided between the perforated plate 3-1 and the back plate 3-2. A layer 3-3 is provided, and a plurality of water collecting pipes 4 having water collecting holes capable of collecting water entering through the perforated plate 3-1 are provided in the strainer layer 3-3 from substantially the center of the cathode floor surface portion 3d to the side surface portion. It extends through 3W, 3W ′, 3B, 3B ′ (for the sake of convenience, only those in the side surface portions 3W, 3W ′ are shown) to the upper outside of the soil tank 1. Desirably, an intake pipe 5 is further provided in the cathode strainer layer 3-3 for supplying air from above the soil tank 1 to at least the center of the floor surface portion 3d through at least the side surface portions 3W and 3W 'of the cathode. The upper edge of the side part of the cathode 3 is closed with a partition plate 3-4.

  The cathode 3 is connected to the negative electrode side of the DC power supply device 10 via a switch 12 and an ammeter 13. However, in the drawing, the cathode 3 is made separately from the side surface portion 3W-3B ′ and the floor surface portion 3d for convenience. In each of the electric wires, the side surface portion 3W, the floor surface portion 3d, and the negative electrode side of the device 10 are connected via an ammeter 13 and a switch 12-1 or 12-2, respectively. If desired, the cathode and the DC power source may be connected via a number of electric wires and switches.

  The anode 6 is composed of a plurality of electrode groups, here, an electrode group 6a located in the approximate center of the longitudinal direction of the rectangular tank 1 or cathode 3, and a pair of electrodes adjacent to the center electrode 6a on both sides in the longitudinal direction. The groups 6b and 6b 'and each pair of electrode groups 6c, 6c', 6n, and 6n 'arranged adjacent to each other on both sides of the groups 6b and 6b', are electrically connected to the upper opening of the box-shaped cathode 3. From the opening to the floor surface portion 3d so that the insulating insulating plates 6-1 are substantially equidistant from each other and the cathode side surface portions 3W, 3W ′, 3B, 3B ′ and the floor surface portion 3d are approximately equidistant from each other. To be extended.

  The insulating plate 6-1 also includes a water-permeable perforated plate 6-2 on the side facing the highly hydrous soil G in the earth tub 1 and between the insulating plate 6-1 and the perforated plate 6-2. A plurality of water collecting pipes 7 having an opening or a water collecting hole are erected in the strainer layer 6-3 through the insulating plate 6-1 from above the soil tank and sandwiching the strainer layer 6-3. Connect to pump device 15. Thereby, the water separated mainly in the upper part of the highly hydrous sand G stored in the earth tank enters the strainer layer 6-3 and can be collected by the water collecting pipe 7.

  Each electrode group 6a-6n ′ of the anode is connected to the positive electrode side of the DC power supply device 10 by the electric wire 11 via the ammeter 13, the open / close switches 8a, 8b, 8c, 8b ′, 8c ′, 8n ′ and the voltmeter 14. Connected.

  The electrode group 6a-6n 'is formed of a conductive material in any of a cylindrical shape, a prismatic shape, a lattice plate shape, etc., and its inner tip is conical or the like, so that it can be easily inserted into the earth and sand that constitutes a highly water-containing earth and sand. In addition, the structure or surface is such that earth and sand do not easily adhere after dehydration of the highly water-containing earth and sand.

  Both the water collection pipe 4 in the cathode 3 and the water collection pipe 7 of the insulating plate 6-1 holding the anode are connected to a vacuum pump device 15 as a drainage device, and a flow meter 17 capable of measuring the amount of drainage is provided therebetween. A drain pipe 16 is connected to the vacuum pump device 15.

  Intervals x1, x2,... Between the plurality of electrode groups 6a-6n 'of the anode 6. . . xn, x1 ', x2',. . . xn ′ is substantially the same, and the distance xH between each electrode group 6a-6n ′ and each side surface portion 3W, 3W ′, 3B, 3B ′ of the cathode 3 and the floor surface portion 3d is mutually and It is desirable that the distance between the electrode groups is substantially the same.

  In this embodiment, the plurality of electrode groups constituting the anode 6 are described as odd numbers, but this may be an even number. The cathode 3 and the anode 6 are made of an electrically conductive and high mechanical strength material such as iron, copper, aluminum and platinum.

  The insulating plate 6-1 is made of an electrically insulating material having high mechanical strength and durability, such as a natural rubber mixture, a vinyl mixture, an epoxy resin, and a crosslinked polyethylene mixture.

  The operation of the high water content earth and sand dewatering device by the electroosmosis method having the above configuration will be described. The high water content earth and sand G discharged from the upper opening of the cathode 3 installed in the earth tank 1 by the shield method, dredging work or the like is introduced.

  A plurality of anode electrode groups 6a-6n 'are press-fitted into the highly hydrous soil G filled in the cathode 3 at the above-described arrangement and intervals. Desirably, the insulating plate 6-1 holding the electrode groups 6a-6n ′ at the above-described arrangement and interval is fitted into the upper opening of the box-like cathode 3, and the perforated plate 6-2 of the insulating plate is made of the highly hydrous soil G. Contact the top surface. Here, the highly hydrous soil G is in electrical contact with the box-like cathode 3 and the anode 6 composed of a plurality of electrode groups 6a-6n 'with a much wider surface than before.

  First, the switch 8a for connecting the electrode group 6a located at the center among the plurality of anode electrode groups to the positive electrode side of the DC power supply device 10, the side surface portions 3W, 3W ′, 3B, 3B ′ and the floor surface portion 3d of the cathode 3 are provided. The switches 12-1 and 12-2 respectively connected to the negative electrode side of the DC power supply device 10 are closed, and a DC voltage is applied between both electrodes. As a result of the electroosmosis that occurs in the highly hydrous sand due to this voltage application, the water W in the highly hydrous earth and sand is laterally directed from the central electrode group 6a toward the side surfaces 3W-3B ′ and the floor 3d of the cathode. 'And move downward Wd. At this time, movement also occurs in the upward direction Wu toward the perforated plate 6-2 of the upper insulating plate 6-1, as will be described later.

  The water W that has reached the cathode side surfaces 3W-3B 'and the floor surface portion 3d permeates into the strainer layer 3-3 through the perforated plates 3-1 and accumulates. The accumulated permeated water is collected in the water collecting pipe 4 by operating the vacuum pump device 15 and drained through the drain pipe 16.

  Since the air supply pipe 5 for supplying air is provided in the cathode strainer layer 3-3 whose upper opening is closed by the partition plate 3-4, if the air is supplied simultaneously with the water collection, the inside of the strainer is decompressed. The permeated water is drained by the vacuum pump device 15.

  If the soil that constitutes the highly hydrous sand G is, for example, gravel or gravel, the water W is easily separated through the perforated plate 3-1 by the vacuum pump operation and is sucked into the strainer layer 3-3. In such a case, it is effective to perform suction drainage without supplying air and depressurize the inside of the strainer layer.

  Here, only the switch 8a is closed together with the cathode switches 12-1 and 12-2, and the DC voltage is applied only to the cathode 3 and the central anode electrode group 6a, and the other electrode groups 6b, 6c. . . 6n, 6b ', 6c'. . . Although not applied to 6n ', the sludge G in the earth tub 1 is generally at substantially the same potential by voltage application between the entire surface of the box-like cathode 3 and the central anode electrode group 6a. Therefore, the entire surface of the central electrode 6a is charged to +, the surface of the other electrode group 6b-6n 'on the side facing the center electrode group 6a is charged to-, and the surface facing the cathode 3 is charged to +. .

  Thus, the negatively charged portions of the anode electrode groups 6b-6n ′ on both sides become an apparent cathode, and the water W near the central electrode 6a passes through the −charged portion and the + charged portion of each electrode group on both sides. Then move to the outer electrode group one after another, and move in the direction Ww, Ww ′ from the positive charging portion of the outermost electrode group 6n, 6n ′ to the side surface portions 3W, 3W ′ in the longitudinal direction of the box-like cathode 3. . Similarly, the water W also moves in the direction from the positively charged portion of the central electrode group and both electrode groups to the side portions 3B and 3B 'in the short direction of the box-like cathode 3 and in the direction Wd toward the floor portion 3d. The water that reaches each part of the cathode 3 and permeates the inside thereof is sucked and collected as described above.

  A part of the water W moved from the positively charged central electrode group to the positively charged portion of both side electrode groups moves in the upward direction Wu, and the upward moving water passes through the perforated plate 6-2 of the insulating plate 6 and the strainer. 6-3 penetrates and is sucked through the water collecting pipe 7 and drained.

  The ammeter 13, voltmeter 14 and flow meter 17 confirm the dehydration status of the highly hydrous soil G and confirm the progress of dehydration. In addition to the switches 8a, 12-1 and 12-2 in the closed state at appropriate times The switches 8b and 8b ′ are closed, and a DC voltage is applied to the central electrode group 6a of the anode, the pair of electrode groups 6b and 6b ′ adjacent to both sides thereof, and the respective parts 3W-3d of the cathode 3. This secondary applied voltage is desirably lower than the initial applied voltage, that is, the voltage at the time of applying the primary voltage with only the central electrode group 6a as the anode.

  Next, after confirming the progress of dehydration, as a third voltage application, in addition to the above, the switches 8c and 8c ′ are further closed, and anode electrode groups 6a, 6b and 6a, 6c ′, which are adjacent to the outside, are added. A voltage lower than the secondary applied voltage is preferably applied to 6b ', 6c, 6c' and each cathode part 3W-3d.

  In this manner, as the dehydration progresses, the adjacent pairs of anode electrodes are sequentially increased to the outside, and the voltage is sequentially decreased to apply the DC voltage, and the outermost pairs of anode electrodes 6n and 6n ′ are included. Then, all the electrode groups 6a-6n ′ are used as anodes, and the process is continued until the final next voltage application with the lowest voltage to complete the dehydration of the highly hydrous soil. Further, after applying a DC voltage to the outermost electrode group, the DC voltage is applied by sequentially increasing the voltage depending on the dehydration condition. When the dehydration is completed, the earth and sand in the soil tank 1 is discharged by a soil removal device (not shown).

As a method for applying the DC voltage, in addition to the above, any of the following can be adopted depending on the dehydration situation.
(1) First, the anode electrode group disposed in the center of the earth tub 1 and the switch connected to all the cathodes are closed to apply a DC voltage, and then the switch to the center anode electrode is opened to open the center electrode group. Close the switch to the anode electrode group of both outer pairs and apply a voltage between these anode electrode group and the cathode, and then switch the anode electrode group to which the voltage is applied sequentially to the outer electrode group of the outer pair, A DC voltage is applied sequentially until the outermost pair of electrodes is reached.
(2) A DC voltage is continuously applied to all anode electrode groups and cathodes with all switches closed.

  FIG. 2 shows a second embodiment in which a configuration of a plurality of electrode groups constituting the anode and a switch for connecting these to a DC power supply device is basically changed in the same configuration as that of the first embodiment shown in FIG. The same constituent elements are denoted by the same numbers.

  In FIG. 2, the switch 12 inserted into the electric wire 11 connecting the cathode 3 and the negative electrode side 10-2 of the DC power supply device 10 is the same as that of the first embodiment.

  The electrode group constituting the anode 6 in Example 2 is also composed of a plurality (here, 5) 20a, 20b, 20c, 20b ′, and 20c ′, each having the same mutual spacing and cathode distance as in Example 1. The electrodes are fixedly supported by an insulating insulating plate 6-1 so as to be disposed, but each of the electrode groups is formed in a water-permeable configuration substantially like the cathode 3.

  Each of the electrode groups 20a-20c ′ is composed of a strainer layer 24 having a water collecting hole 23 on the peripheral surface and a water collecting tube 25 extending almost to the center thereof. The electrode group 20a-20c ′ has conductivity as a whole, and the water collecting tube 25 is composed of the cathode 3 The water collecting pipe 4 is connected to the outside of the earth tub 1, and the operation of the vacuum pump device 15 enables water collection by electroosmosis from each electrode group.

  A plurality of switches 21 a, 21 b, 21 c, 21 b ′, 21 c ′ for connecting each of the electrode groups 20 a-20 c ′ to the DC power supply device 10 include an a terminal connected to the positive electrode side 10-1 of the DC power supply device 10, and the device B terminal connected to 10 negative electrode side 10-2, and c terminal connected to each of electrode group 20a-21c '.

  The DC voltage application for dehydrating the highly hydrous soil G is performed in substantially the same manner as in the first embodiment. That is, first, the switch 12 to the cathode 3 is closed, the c terminal of the switch 21a is connected to the a terminal, and a DC voltage is applied to the electrode group 20a and the cathode 3 located in the center in the arrangement direction of the anode electrode group. At this time, the other switches 21b, 21c, 21b ', and 21c' are set at intermediate points, and no voltage is applied to the electrode groups 20b, 20b ', 20c, and 20c' on both sides of the central electrode group. Therefore, as described in the operation of the first embodiment, the surfaces of the electrode groups on both sides are partially charged negatively, and the water in the highly hydrous soil is charged from the central electrode group 20a to the -charged portions of the electrode groups on both sides. The water sequentially moves to the cathode 3 through the water, and the water is not only permeated and collected by the cathode 3 arranged in a plane, but also the permeated water collecting structure by the water collecting hole 23, the strainer layer 24 and the water collecting tube 25 of each anode electrode group. And is effectively dehydrated by the suction action of the vacuum pump device 15.

  Thereafter, switching to the anode electrode group and control of the applied voltage are performed in the same order as in the first embodiment, and the dehydration process is performed by sequentially applying the voltage from the central electrode group to the outermost electrode group.

The switch operation described below may be performed according to the dehydration situation. That is:
First, while closing the switch 12 to the cathode 3, the c terminal of the switch 21a is connected to the a terminal and a positive voltage is applied to the central anode electrode group 20a, while the c terminals of the switches 21b and 21b ′ are connected to the b terminal. And a negative voltage is applied to the outer electrode pairs 20b and 20b ′, and the terminals c of the switches 21c and 21c ′ are connected to the terminal a to connect the outermost electrode groups 20c and 20c ′. In this case, by applying a positive voltage, the dehydration effect by the water collection configuration of the series of anode electrodes described above can be more actively promoted. Therefore, in this case, the plurality of electrode groups 20a, 20b, 20c, 20b ′, and 20c ′ function as an electrode group that is bipolarized.

  In particular, when the earth tub 1 is large and it is necessary to increase the number of anode electrodes, DC voltage application by switching the switches using the a terminals, b terminals, and intermediate points of the switches 21a-21c 'described above is concentrated. Effective for water effect. Further, for the plurality of anode groups, the electrode groups 20a, 20b, 20c, 20b ′ for positively and negatively forming the positive electrode groups 6a, 6b-6n, 6b′-6n ′ of Example 1 with the water permeability of this example. , 20c ′, a reliable dehydration effect can be achieved in a wide range of applications using various voltage application methods according to the various dehydration conditions described above.

  FIG. 3 shows a third embodiment in which the configuration of the box-like cathode of the first embodiment or the second embodiment and a plurality of anode electrode groups are blocked.

  In FIG. 3, the electrode configuration of Example 1 or Example 2 including a box-shaped cathode 3, a water collecting tube 4, an anode 6 composed of a plurality of electrode groups, and an electric wire 11 connecting both electrodes to a DC power supply device 10 is created as a block 31. To do. The earth basin 32 is formed in a size that can accommodate a plurality of blocks (here, 3 blocks are shown) with the electrode block 31 as a unit. A switch or DC power supply device 10 for applying a DC voltage to the electrode and a vacuum pump device 15 for sucking or collecting water permeating into the electrode are blocked in the same manner as in the first or second embodiment. It arrange | positions for every 31 or arrange | positions uniformly with respect to all the blocks 31, and performs the above-mentioned operation | movement for every block. According to the third embodiment, the dewatering apparatus including the earth tub can be enlarged to greatly increase the dewatering capacity.

  In this embodiment, one DC power supply device 10 is provided. However, by providing a DC power supply device 10 for each block 31 and setting an application voltage and an application time for each block 31, dehydration and treatment of soil having different soil properties. The amount of soil can be set freely and the dewatering efficiency is improved. In this case, it is desirable to provide an electrical insulator (not shown) between the blocks 31 to electrically insulate the blocks 31 from each other.

  The sludge dewatering treatment of the present invention using the dewatering apparatus of Example 1 to Example 3 has a plurality of anode electrode groups or a plurality of water permeable bipolar electrode groups having a cathode surface that is enlarged in the form of a water permeable cathode as a box shape. The method is characterized in that electroosmosis is generated by confronting the electrodes, and further, there is a characteristic method in the procedure of applying a DC voltage to a plurality of anode electrodes and cathodes. An example of further improving the effect of the earth and sand dewatering method will be described as Example 4.

  Here, first, (1) calorium chloride, (2) an electrolyte such as a sulfuric acid band, and (3) carbon are added to the highly hydrous sand generated by the shield method or dredging work for tunnel excavation, and thereafter, Example 1 or Electroosmosis by applying a DC voltage as described in Example 2 is caused to dehydrate the highly hydrous soil.

FIG. 4 compares the above three types of electrolytes (1) to (3) and shows the relationship between the amount of electrolyte added and the efficiency of dehydration when added to a highly hydrous soil and dehydrated, with no electrolyte added. The dehydration efficiency (vertical axis) of 100 is taken as 100. The amount to be added is determined by prior experiments according to the soil quality and water content of the sludge. For example, when adding the most efficient caloric chloride to the sludge of the lower Yurakucho layer, it should be about 900 g / m ^3. desirable. Here, there is a dehydration effect in the order of strong ionization tendency among electrolytes, and the order is K, Ca, Na, Mg, Al, but it is desirable to employ a compound that is not harmful in terms of environment.

  Calium chloride has a dehydration efficiency of 170-200%, which is not only the best among the three types, but also has a high level of safety as it is widely used as a food additive, reagent, etc. It is considered an optimal electrolyte. Carbon has a dehydration efficiency of 120-150%, but the soil after dehydration is suitable for use as a soil for planting and backfilling as a foundation for wooden buildings.

  In any of the first to third embodiments described above, the cathode 3 is described as covering both the inner peripheral surface and the inner floor surface of the soil tank 1, but the present invention is not limited to this. Alternatively, it may be provided so as to cover only the inner peripheral surface or only the inner floor surface. In either case, the cathode spreads in a plane and faces the anode group, and water can permeate into the permeable cathode with high efficiency electroosmosis. A configuration in which the cathode is provided along is advantageous.

  Thus, the highly water-containing earth and sand dewatering device according to the present invention, as described in claim 1, is installed in the underground, semi-underground or above ground with the upper part opened, and the soil tank 1 for storing the highly water-containing earth and sand G, A water-permeable cathode 3 composed of a side surface covering the inner surface of the tank 1 and a floor, and a plurality of anode groups 6 and / or a plurality of anode groups 6 which are installed inwardly and separated from the cathode 3, and / or a plurality of anode groups A permeable positive / negative bipolar electrode group 20, a cathode 3 and a plurality of anode groups 6 and / or a direct current power supply device 10 connected to a plurality of permeable positive / negative bipolar electrode groups 20 to apply a DC voltage between the two electrodes; Since the water permeable cathode 3 and / or the water permeable bipolar electrode group 20 from the highly water-containing earth and sand G by electroosmosis by applying voltage is collected and drainage device 15 for draining outside the soil tank, The permeation area during electroosmosis increases, and the dehydration efficiency is greatly improved.

  Moreover, the high water content earth and sand dewatering method which concerns on this invention installs the earth tub 1 which opens an upper part and stores high water content earth and sand underground, a semi-underground, or the ground as described in Claim 5, A water-permeable cathode 3 composed of a side surface portion and a floor surface portion that covers the inner surface is provided, and a plurality of anode groups 6 and / or a plurality of water-permeable positive / negative bipolar electrode groups 20 that are arranged at approximately equal distances are provided inside the cathode 3. The DC power supply device 10 is connected to the cathode 3 and the plurality of anode groups 6 and / or the bipolar electrode groups and a DC voltage is applied between the two electrodes, and the drainage device 15 is connected to the permeable cathode 3. And / or the water permeable bipolar electrode group 20 to collect water permeated into the permeable cathode 3 and / or the permeable bipolar electrode group 20 from the highly hydrous soil G by electroosmosis by applying voltage. Since the water is drained outside, the electroosmotic area between the Yin and Yang electrodes increases. , Dewatering efficiency is greatly improved.

  Further, the high water-containing earth and sand dewatering method according to the present invention, as described in claim 6-9, sequentially opens and closes each switch from the center of the plurality of electrode groups to the outermost one of both sides, or at least sequentially. Since voltage application is performed by lowering the applied voltage, the electroosmosis area between the electrodes is further increased, and the electroosmosis is performed by adding an electrolyte to the highly hydrous soil, so that the dehydration efficiency is further improved.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the structure of the 1st Example of the high water content earth and sand dehydration apparatus which concerns on this invention. The longitudinal cross-sectional view which shows the structure of 2nd Example of the high water content earth-and-sand dehydration apparatus which concerns on this invention. The longitudinal cross-sectional view which shows the structure of 3rd Example of the high water content earth-and-sand dehydration apparatus which concerns on this invention. The relationship figure of the electrolyte addition amount and the dewatering efficiency in one Example of the highly water-containing earth and sand dewatering method concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Earth tank 3 Cathode 3W, 3W ', 3B, 3B' Side surface part 3d Floor surface part 3-1 Perforated board 3-2 Back board 3-3 Strainer layer 4 Water collecting pipe 5 Supply pipe 6 Anode 6a, 6b, 6c, 6n , 6b ', 6c', 6n 'Anode group 6-1 Insulating plate 6-2 Perforated plate 6-3 Strainer layer 7 Water collecting pipe 8a, 8b, 8c, 8n, 8b', 8c ', 8n' Switch 10 DC power supply Device 11 Electric wire 12 Switch 15 Vacuum pump device 20a, 20b, 20c, 20b ', 20c' Permeable positive / negative bipolar electrode group 21a, 21b, 21c, 21b ', 21c' Switch 23 Water collecting hole 24 Strainer layer 25 Water collecting pipe 31 Electrode block 32 Earth tank

Claims (9)

An earth tank (1) that is open at the top and is installed underground, semi-underground or above ground to store highly hydrous soil (G);
A water-permeable cathode (3) composed of side surfaces (3W, 3W ′, 3B, 3B ′) and a floor surface portion (3d) covering the inner surface of the earth tub (1);
A plurality of anode groups (6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′) and / or a plurality of water permeation units installed inwardly and spaced apart from the cathode (3) Sex positive / negative bipolar electrode group (20a, 20b, 20c, 20b ′, 20c ′),
A DC power supply device (10) connected to the cathode (3) and the plurality of anode groups (6) and / or the plurality of water permeable positive / negative bipolar electrode groups (20) to apply a DC voltage between the two electrodes;
Water that permeated into the permeable cathode (3) and / or the permeable positive / negative bipolar electrode group (20a, 20b, 20c, 20b ′, 20c ′) from the highly hydrous soil (G) by electroosmosis by applying voltage is collected. A highly water-containing earth and sand dewatering device comprising a drainage device (15) for draining water outside the soil tank.   An insulating plate (6-1) for closing the upper opening of the earth tub (1) and holding a plurality of anode groups (6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′) in a predetermined position; The insulating plate (6-1) has a permeable strainer layer (6-3) on the side in contact with the highly hydrous sand in the earth tub, and each surface portion (3W, 3W ′, 3B, 3B ′) of the cathode (3). 3d), a water collecting pipe (4) extending to the inside, a water collecting pipe (7) leading to the inside of the strainer layer (6-3) of the insulating plate (6-1), a vacuum pump device (15) for drainage, The high water-containing earth and sand dewatering device according to claim 1, wherein water separated into the upper layer of the high water-containing earth and sand in the soil tank can be collected together with the water that has penetrated into the cathode.   A plurality of permeable positive / negative bipolar electrode groups (20a, 20b, 20c, 20b ′, 20c ′) penetrate into the strainer layer (24) and the strainer layer (24) each having a water collecting hole (23) on the surface. The water collecting pipe (25) that collects the collected water and sends it to the vacuum pump device (15), and the DC power supply device (10) is connected to the positive terminal (10-1) of the direct current power supply and the negative terminal side A switch (21a, 21b,) having a b terminal connected to (10-2) and a c terminal connected to each of the plurality of water permeable positive / negative bipolar electrode groups (20a, 20b, 20c, 20b ′, 20c ′) 21c, 21b ′, 21c ′) and a switch (12) for connecting between the negative electrode side (10-2) of the DC power source and the cathode (3), and a plurality of bipolar electrode groups are alternately arranged in the order of their arrangement. The ability to apply voltage and negative voltage High water sediment dewatering apparatus according to claim 1, wherein.   A plurality of anode groups (6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′) and / or a plurality of water permeable positive / negative bipolar electrode groups (20a, 20b, 20c, 20b ′, 20c ′) The anode (6) and the cathode (3) composed of the side surface portions (3W, 3W ′, 3B, 3B ′) and the floor surface portion (3d) are formed as an electrode block (31), and a plurality of the electrode blocks (31) are used as a unit. 4. A highly hydrous soil dewatering according to claim 2, wherein the earth basin (1) is formed to a size capable of accommodating a plurality of electrode blocks, and the electrode block (31) can be inserted into and removed from the earth basin. apparatus. An earth tank (1) that opens the upper part and stores the highly hydrous sand (G) is installed underground, semi-underground or above ground.
A water-permeable cathode (3) comprising a side surface portion (3W, 3W ′, 3B, 3B ′) and a floor surface portion (3d) covering the inner surface of the earth tub (1) is provided,
A plurality of anode groups (6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′) and / or a plurality of permeable positive / negative bipolar electrode groups (20a, 20b, 20c, 20b) arranged at approximately equal distances, respectively. ', 20c') spaced apart inward of the cathode (3),
A DC power supply (10) is connected to the cathode (3) and the plurality of anode groups (6) and / or the plurality of water permeable positive / negative bipolar electrode groups (20) to apply a DC voltage between the two electrodes,
The drainage device (15) is connected to the permeable cathode (3) and / or the permeable positive / negative bipolar electrode group (20), and the permeable cathode (3) Alternatively, a highly water-containing earth and sand dewatering method characterized in that water that has permeated into the permeable positive / negative bipolar electrode group (20) is collected and drained out of the soil tank. On the positive voltage side of the DC power supply device (10), each of the electrode groups (6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′) of the anode (6) and the open / close switches (8a, 8b, 8c, 8n) , 8b ′, 8c ′, 8n ′) and DC voltage application is performed while the switch (12) is closed and the cathode (3) is connected to the negative voltage side of the DC power supply device (10). a) First, the switch (8a) connected to the anode electrode group (6a) disposed in the center is closed, and then the switch (8b, 8b ′) connected to the pair of electrode groups (6b, 6b ′) adjacent to the outside is closed. Further, the switch (8n, 8n ′) connected to the outermost pair of electrode groups (6n, 6n ′) from the switch (8c, 8c ′) connected to the pair of electrode groups (6c, 6c ′) adjacent to the outside. To the outermost electrode group on both sides of the center electrode group. Made to the whole of,
(B) First, the outermost pair of electrode groups through the switch (8b, 8b ′) of the pair of electrode groups (6b, 6b ′) adjacent to both sides sequentially from the switch (8a) of the central anode electrode group (6a). (6n, 6n ′) is performed by sequentially closing and opening the switches (8n, 8n ′), or (c) all anode electrode groups (6a, 6b, 6c, 6n, 6b ′, 6c ′, 6n ′). ) By simultaneously closing all the switches (8a, 8b, 8c, 8n, 8b ′, 8c ′, 8n ′).
6. The method of dewatering a highly hydrous soil according to claim 5, wherein any one of the above is selected according to the dewatering situation. As a group of electrodes (20a, 20b, 20c, 20b ′, 20c ′) of the anode (6), a strainer layer (24) having water collecting holes (23) on the surface and water that has permeated into the strainer layer (24). A terminal connected to the positive electrode side (10-1) of the DC power supply device (10) as a switch (21) in which a water collecting pipe (25) that collects water and sends it to the vacuum pump device (15) is arranged. And switches (21a, 21b, 21c, 21b ′, b terminals connected to the negative electrode side (10-2) and c terminals connected to each of the electrode groups (20a, 20b, 20c, 20b ′, 20c ′), 21c ′) and a switch (12) connecting between the negative electrode side (10-2) of the DC power supply device (10) and the cathode (3) are arranged, and DC voltage application is performed by closing the switch (12) and applying the cathode ( 3) The negative power of the DC power supply (10) While connected to the side,
(A) First, the c terminal of the switch (21a) connected to the anode electrode group (20a) disposed at the center is connected to the a terminal side, and the pair of electrode groups (20b, 20b ′, 20c, 20c) on the other sides. The c terminal of ') is set in the middle of both terminals a and b, and thereafter the outermost electrode group (20c, 20c) from the switch (21b, 21b') of the outer electrode group (20b, 20b '). ') By sequentially connecting the c terminals up to the switches (21c, 21c') to the a terminal.
(B) The c terminal of the switch (21a) of the central anode electrode group (20a) is connected to the a terminal, and the c terminal of the switch (21b, 21b ′) of the outer pair of electrode groups (20b, 20b ′). Is connected to the b terminal, and the c terminal of the switch (21c, 21c ′) of the outermost pair of electrodes (20c, 20c ′) is connected to the a terminal, or (c) from the state of (b) The c terminal of the switch (21a) of the central electrode group (20a) is connected to the b terminal, and the c terminal of the switch (21b, 21b ′) of the outer pair of electrode groups (20b, 20b ′) is connected to the a terminal. Do,
6. The method of dewatering a highly hydrous soil according to claim 5, wherein any one of the above is selected according to the dewatering situation.   From the central anode electrode group (6a; 20a) to the outermost pair of electrode groups (6n, 6n ′; 20c, 20c ′) sequentially through the adjacent outer pair of electrode groups (6b, 6b ′; 20b20b ′) The voltage applied between each of the cathodes and the cathode (3) is sequentially lowered to apply a DC voltage, and depending on the dehydration condition, after application to the outermost electrode group, the applied voltage is gradually increased to increase the central electrode group. The high water-containing earth and sand dewatering method according to claim 6 or 7, characterized by applying up to (6a; 20a).   The method of dehydrating a highly hydrous soil according to any one of claims 5 to 8, wherein the dehydration of the highly hydrous soil by electroosmosis by applying voltage between both electrodes is performed by adding an electrolyte or the like to the highly hydrous soil.

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