JP3661130B2 - Dewatering method for hydrous sand - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionDehydration reforming method for hydrous soilIn particular, it is included in soil with a high moisture content, such as soft soil and sand generated in shield construction / propulsion construction and caisson construction, and mud-like soil containing bentonite and polymer water-absorbing agent, etc., produced in a mud pressure shield. Suitable for forced drainage of internal water and reformingDewatering method for hydrous sandAbout.
[0002]
[Prior art]
  Conventionally, in order to improve the sludge of construction sludge, generally a solidification method using mainly cement or quicklime is used.
[0003]
  The conventional solidification method for solidifying muddy earth and sand with cement or quick lime has a problem that it is necessary to use a large amount of cement or quick lime for solidification treatment.
[0004]
  Further, the conventional dewatering method for dewatering water from hydrous sand has a problem that the soil quality to be treated is limited. In general, shield construction occupies a part of the road or borrows it to provide a starting base, which limits the number and size of sediment storage hoppers and sediment storage tanks. Cannot be dehydrated.
[0005]
  In shield construction, there are gravel, sand, silt, and clay, but it is rare to excavate for uniform soil quality. In other words, in order to dig up each other layer in shield construction, soil mixed with various soil qualities is stored, and therefore a soil improvement method that can cope with this is required.
[0006]
  For this reason, mud pressure shield construction / propulsion construction and pneumatic caisson construction drainage soil with a high water content and a soft impervious soil with a high moisture content due to a high content of silt and clay. In addition, dewatering and reforming any sludge in which bentonite or polymer water-absorbing agent is mixed with sand or gravel reduces the cost of subsequent reprocessing. Therefore, a dehydration reforming technique that can be reused or effectively used has been desired.
[0007]
  However, recently, improvement of soil quality using electroosmosis has been proposed.
[0008]
  As this prior art, there is JP-A-9-287127.
[0009]
  In this prior art, a pair of holes for an anode and a cathode are formed in the ground, and an anode and a cathode are arranged in the holes, respectively, and a direct current is passed between the electrodes. The groundwater is drained to the outside by a vacuum pump to improve the ground.
[0010]
[Problems to be solved by the invention]
  However, the dehydration by the electroosmosis method in this prior example has a problem that it is necessary to open a hole for attaching an electrode to the ground by boring, and the work is complicated.
[0011]
  In addition, even if the soil moisture content around the electrode is reduced due to electroosmosis, free water may be present in the vicinity of the electrode, and the free water may newly enter the dewatered part or there may be groundwater nearby. There is a problem that there is no limit to the amount of dehydration work.
[0012]
  Also, there are cases where the dehydration work cannot be performed smoothly during the rain or rainy season.
[0013]
  Moreover, in the above-mentioned prior example, there is a problem that the means for easily knowing the moisture content of the soil is not taken, and the soil condition during dehydration cannot be accurately grasped.
[0014]
  In addition, the electrode is composed of a cylindrical body with a slit that is a hole for inflow of groundwater, and the groundwater introduced inside is pumped up, but soil particles enter the inside through the slit and clogging occurs. There is a risk that it will not be possible to raise the drainage smoothly.
[0015]
  Although the present invention is not a technique for improving the ground itself as in the preceding example, there is a common point in using an electroosmotic dehydration method. That is, the present invention uses the excavated hydrous sand.Use a shielding sheet, andElectroosmosisAnd vacuum dehydrationTheCombined useDehydration, processingDoIt is about technology.
[0016]
  The object of the present invention is to provide high moisture content soft earth and sand generated in shield construction and pneumatic caisson construction, high moisture content and soft viscous soil or bentonite and polymer water absorbent generated in a mud pressure shield excavator. Regardless of its nature, such as mud-like earth and sand mixed with etc., the internal water of the earth and sand is quickly discharged to improve the nature of the earth and sand and facilitate the subsequent treatment.Dewatering method for hydrous sandIs to provide.
[0017]
[Means for Solving the Problems]
  The present invention is provided in a soil tank 1 that is partially open and is installed in the ground, in the semi-ground, or on the ground.A plurality of anodes 9 and 9A, and a plurality of cylindrical cathodes having a drainage function that are spaced apart from the anodes 9 and 9A and have a plurality of water passage holes 10a formed on the outer periphery. An electrode for electroosmosis comprising a water pipe 10 is provided, the excavated hydrous sand 6 is put into the earth tank 1, the hydrous earth sand 6 is dehydrated by energizing the electrode, and after dehydration, the dehydrated earth sand is removed from the earth tank 1. In the dewatering method of the hydrous sand to be discharged, a vacuum pump 18 is connected to the outside of the cathode and water collecting pipe 10, and a filter medium 10c for preventing clogging is provided in the cathode and water collecting pipe 10 to block the hydrous sand 6 from the atmosphere. In addition, a shielding sheet 3 that keeps the hydrated earth and sand 6 compacted by the negative pressure in the earth tub 1 by the operation of the vacuum pump 18 is provided above the hydrated earth and sand, and all or any of the plurality of anodes 9 and 9A and the cathode / water collecting pipe 10 Selectively energize one of the electroosmotic and Perform the sky dehydrationThe above object is achieved by the configuration.
[0018]
  In this case,The anode is composed of planar anodes 24, 24A, the anodes 24, 24A are provided in the opening of the earth tub 1, the cathode and water collecting pipe 10 is provided in the lower part of the earth tub 1, and the vacuum pump 18 It is connected.
[0019]
  In addition, the soil tank 1 is provided with a neutron density / moisture meter 4 so that the moisture content of the hydrous sand 6 can be measured.
[0020]
  The anodes 9, 9A and the cathode / water collecting pipe 10 are attached to a mounting base 2 that is formed in a lattice shape or a mesh shape and is detachably attached to the earth tub 1, the shielding sheet 3 is attached to the lower surface of the mounting base 2, and The cathode / collector tube 10 is provided with a vacuum tube 10b for drainage connected to a vacuum pump 18 provided outside, and a filter medium for preventing clogging between the vacuum tube 10b and the outer periphery of the cathode / collector tube. 10c is provided.
[0021]
  The anodes 9, 9A and the cathode 10 are arranged with the anodes 9, 9A on the outermost periphery, the cathode 10 on the inside, the anodes 9, 9A on the inside, and the cathode 10 on the inside. Are arranged alternately or in a staggered manner, and all or any one of them is selectively energized.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is not a technique for improving the soil quality of the ground itself. The present invention intends to dehydrate hydrous soil generated during excavation such as shield construction / propulsion construction or pneumatic caisson construction using an electroosmosis method, a vacuum dehydration method, or the like. In this case, electroosmosisWhen using vacuum dehydration, use a shielding sheet, andIngenuity in electrode structure and arrangementEtc.In addition, water in the hydrous sand is quickly extracted and the internal water is discharged.
[0023]
[Example 1]
  1 and 2 show the present invention.Dewatering soil tank used in the first embodiment of the dewatering method for hydrous sandFIG. 1 is a plan view, and FIG. 2 is a longitudinal front view showing an internal structure. FIG. 3 is a plan view showing another arrangement example of the electrodes.
[0024]
  In this first embodimentUseThe dewatering basin includes, for example, a substantially box-shaped basin 1 having an open top, a mounting base 2 for various members housed therein, a shielding sheet 3, dehydrating means using an electroosmosis method, and a vacuum dewatering method. A tip end of a pipe-shaped earth and sand introduction pipe 5 is provided which is provided with a dehydrating and collecting water discharging means and a neutron density / moisture meter 4 and into which the hydrated earth and sand 6 to be treated is introduced into the soil tank opening.
[0025]
  The earth tub 1 is made of an appropriate material in accordance with the installation environment and space suitability conditions, such as steel and reinforced concrete. A dehydration treatment chamber 7 for hydrous sand 6 is formed in the earth tank 1. In the case of steel, electrical insulation is appropriately performed. As this insulating treatment, for example, an insulating resin such as an epoxy resin may be coated.
[0026]
  The mounting base 2 for the various members is formed in a lattice shape or a mesh shape from an insulating and rigid material. This mounting base 2 is detachably attached to the upper part of the earth tub 1. That is, the mounting base 2 is installed in a soil tank 1 by using well-known appropriate attachment means by a cargo handling machine (not shown) such as a crane together with various members attached thereto, Or lifted and removed.
[0027]
  The shielding sheet 3 is formed in a shape that covers the opening of the earth tub 1 with a material that does not allow air to pass, such as vinyl, polyethylene, plastic, or a thin metal plate, and is attached to the top of the mounting base 2. The shielding sheet 3 functions as an insulating member, a waterproof member, a shield between the contained earth and sand 6 inside the earth tub 1 and the atmosphere, and has strength and width to withstand it.
[0028]
  The end portion on the inlet side of the earth and sand injection pipe 5 is connected to a supply facility (not shown) of the hydrous sand 6, and the tip portion on the outlet side is attached to the shielding sheet 3 attached to the mounting base 2. 8 is attached to the dehydration chamber 7.
[0029]
  The dehydrating means by the electroosmosis method includes a plurality of anodes 9, a plurality of cathode / water collecting tubes 10, and a potential variable type DC power supply device 11 installed outside the earth tub 1.
[0030]
  The anode 9 is composed of a round bar-like long member extending from the top to the bottom of the earth tub 1, and the material is suitably formed of a conductive and mechanical material such as iron, copper, aluminum, or platinum. Has been. Further, each anode 9 is arranged at a required interval between the cathode and the water collecting pipe 10 which are arranged to face each other at a distance, and is fixed to the mounting base 2 via a fixing tool 12 made of an insulating material. Has been.
[0031]
  The cathode / water collecting tube 10 is formed of a cylindrical long member, and is appropriately formed of a material having conductivity and mechanical strength, such as iron, copper, aluminum, or platinum. Each cathode / water collecting tube 10 is provided with a large number of water collecting holes 10a on the peripheral wall. Each cathode / water collecting tube 10 is arranged at a predetermined interval from the anode 9 and is fixed to the mounting base 2 via an insulating fixture 13.
[0032]
  Each of the anodes 9 is connected to an anode terminal of a DC power supply device 11 provided outside the earth tub 1 through an insulating coated electric wire 14. The electric wire 14 is provided with a voltmeter 15 and an ammeter 16. Each of the cathode / water collecting tubes 10 is connected to the cathode terminal of the DC power supply device 11 through an electric wire 14.
[0033]
  Note that the steel members, reinforcing bars, and the chassis of the DC power supply 11 that are constituent members of the earth tub 1 are electrically grounded by a ground 17.
[0034]
  The dewatering / collecting and discharging means by the vacuum dehydration method includes the cathode / water collecting tube 10, a vacuum pump 18, and a water storage tank 19.
[0035]
  Each of the cathode / water collecting tubes 10 is connected to a vacuum pump 18 via a vacuum pulling tube 20 and a vacuum pulling source tube 22 connected to the vacuum pulling tube 20 via a coupling 21.
[0036]
  A drainage pipe 23 is connected to the outlet side of the vacuum pump 18, and the outlet of the drainage pipe 23 is provided adjacent to the water storage tank 19.
[0037]
  One or a plurality of the neutron density / moisture meters 4 are arranged and fixed to the mounting base 2. This neutron density / moisture meter 4 is for measuring the moisture content of the soil.
[0038]
  Next, the soil tank for dehydration of this Example 1Method of dewatering hydrous sandWill be described.
[0039]
  First, the soil tank 1 is installed at a required place such as the ground, underground, semi-ground, or above the ground.
[0040]
  A mounting base 2 having various members attached thereto is suspended and installed in the clay tank 1 by a cargo handling machine such as a crane.
[0041]
  As described above, the mounting base 2 is installed in the earth tub 1, the inside of the earth tub 1 is sealed by the shielding sheet 3, and the earth and sand introduction pipe 5 is set so that the hydrous earth and sand 6 can be introduced into the dehydration treatment chamber 7. The anode 9, the cathode / water collecting tube 10, and the neutron density / moisture meter 4 are set at the use positions. Further, the vacuum pulling tube 20 is connected to the vacuum pulling source tube 22 by the coupling 21, and each cathode / water collecting tube 10 is connected to the vacuum pump 18 so as to be evacuated.
[0042]
  From this state, a predetermined amount of hydrated earth and sand 6 is introduced into the dehydration treatment chamber 7 by means of the earth and sand introduction pipe 5.
[0043]
  Next, the DC power supply 11 is turned on. Further, the vacuum pump 18 is driven almost simultaneously with this or at an appropriate time.
[0044]
  When each anode 9 and each cathode / collector tube 10 are energized via the DC power supply device 11, the water in the earth and sand 6 is extracted by electroosmosis, and the soil water flows as indicated by arrows, and the cathode / collector tube Move towards 10. The energization state is monitored by the voltmeter 15 and the ammeter 16 and controlled appropriately.
[0045]
  That is, in the initial stage of energization, control is performed via the voltmeter 15 and the ammeter 16 so that a large current does not flow.
[0046]
  Further, the amount Q of water flowing into the soil by electroosmosis is obtained by the following equation.
      Q = Ke × ie × A
  Here, Ke: electroosmotic permeability coefficient 5 × 10^-5
          ie: Potential gradient Volt / cm
            A: Penetration area between anode and cathode
[0047]
  From the above equation, it is effective to increase the voltage and reduce the distance between the electrodes in a range that does not hinder the electroosmotic effect.
[0048]
  In this process, by driving the vacuum pump 18 at an appropriate time, the inside of the dehydration processing chamber 7 is passed through the evacuation source tube 22, the evacuation tube 20, the cathode and water collection tube 10, and the many water collection holes 10 a provided therein. Vacuum is drawn and a negative pressure is applied, and the internal water in the earth and sand 6 is dehydrated by the vacuum dehydration method, and at the same time, the soil water is taken into the cathode and water collecting pipe 10 through the water collecting hole 10a. In this case, by maintaining the dehydration chamber 7 in a vacuum state, the atmospheric pressure is caused to act through the shielding sheet 3 and the hydrous sand 6 is consolidated to promote dehydration.
[0049]
  That is, when the water content in the soil decreases due to electroosmosis, the earth and sand contract and cracks occur. This phenomenon is more likely to occur in soft and viscous soils with a large water content. If cracks occur in the soil, it becomes difficult for current to flow from the anode 9 to the cathode, and the subsequent electroosmotic effect is significantly impaired.
[0050]
  Therefore, by using the vacuum dehydrating action together with the electroosmosis, the above-mentioned crack can be prevented from occurring by always giving the earth and sand a compacting action from above. Thereby, the electroosmosis effect can be continuously provided to earth and sand. Thus, it becomes possible to give a synergistic action and to give an effective dehydration action.
  Further, under the reduced pressure by the vacuum pump 18, an evaporating and drying action due to a drop in the boiling point of water (liquid) is added, and the dewatered soil water is sucked by the vacuum pump 18 in a vaporized state, and this effect is expected to produce a synergistic effect. it can.
[0051]
  The soil water dehydrated from the hydrous sand 6 and taken into the cathode / water collecting pipe 10 through the water passage hole 10a is sucked by the vacuum pump 18 through the vacuum pulling pipe 20 and the vacuum pulling main pipe 22, and this vacuum pump 18 is stored in the water storage tank 19 through the drain pipe 23. The stored water stored in the water storage tank 19 is appropriately processed by a rear muddy water treatment facility (not shown).
[0052]
  Even when the hydrous sand 6 is predominantly sand or gravel, the water in the hydrous sand 6 is effectively dehydrated by the vacuum action via the cathode and water collecting pipe 10. Moreover, fine-grained soil adheres around the cathode and water collecting pipe 10 and clogs and forms impervious soil. Electro-osmotic action is effective for impervious soil. Thus, in the present invention, any kind of soil can be effectively dehydrated.
[0053]
  In addition, since the water | moisture content of the hydrous sand 6 will reduce if dehydration progresses, an electric current value will reduce. Therefore, an energization test using a sample is performed in advance to confirm the progress of dehydration and the current value in the electroosmosis action. Then, the current value is measured by the ammeter 16 during the dehydration treatment of the hydrous sand 6 and the dehydration treatment is performed while grasping the reforming situation.
[0054]
  Further, it is preferable to detect and monitor the water content ratio in real time by the neutron density / moisture meter 4 embedded in the hydrous sand 6 to determine the time to stop the forced dehydration.
[0055]
  When the moisture content of the hydrous sand 6 reaches a set value, the energization to the anode 9 and the cathode / water collecting pipe 10 is stopped. Further, the vacuum pump 18 is stopped, and then the vacuum pulling tube 20 is removed from the vacuum pulling source tube 22.
[0056]
  Subsequently, the mounting base 2 and the members attached to the mounting base 2 are suspended by a cargo handling machine such as a crane and removed from the dehydration processing chamber 7.
[0057]
  Thereafter, the dewatered earth and sand are excavated by a backhoe, a clamshell, and the like, discharged from the dewatering room 7, loaded onto a dump truck and carried out, and one cycle of earth and sand dewatering reforming is completed.
[0058]
  If the above-described dewatering soil tank of the present invention is used, any property of soil can be dewatered and reformed by the synergistic action of electroosmosis and vacuum dewatering.
[0059]
  Further, since it is not necessary to prepare a plurality of dehydration reforming apparatuses corresponding to various types of soil, various types of soil can be treated with a small apparatus.
[0060]
  Furthermore, since the neutron density / moisture meter 4 is installed in the hydrous sand 6 in the dehydration treatment chamber 7, the water content ratio during the dehydration treatment can be detected and processed in real time by this neutron density / moisture meter 4. It is possible to accurately understand and respond to soil quality management of various types of soil.
[0061]
  Note that the anode 9 and the cathode / water collecting pipe 10 may be formed in a taper having a diameter gradually decreasing toward the tip, so that the anode 9 and the water collecting pipe 10 can be easily pulled out from the treated earth and sand.
[0062]
  Further, the anode 9 is not limited to the rod-shaped one shown, and may be a plate-shaped one.
[0063]
  Furthermore, it is preferable that each cathode and water collecting pipe 10 is filled with a filter medium such as fiber, coarse sand, fine-grained gravel, etc. so that fine soil particles do not enter the vacuum pump 18 side. This internal configuration example will be described in another embodiment described later.
[0064]
  FIG. 3 is a bottom view showing another arrangement example of the anode and cathode / collector pipe of the dehydrating means by electroosmosis.
[0065]
  In the electrode arrangement example shown in FIG. 3, a plurality of cathode / water collecting tubes 10 indicated by large circles are arranged at a predetermined interval and are fixed to the lower part of the mounting base 2.
[0066]
  For example, six anodes 9 are arranged in a tortoiseshell shape around each of the cathode water collecting tubes 10 at regular intervals and as indicated by broken lines. Each anode 9 is fixed to the lower part of the mounting base 2.
[0067]
  According to the electrode arrangement example as described above, soil water can be efficiently collected from the anode 9 side to the cathode / water collecting pipe 10 arranged in the center portion by applying a DC voltage. The hydrous sand 6 can be dehydrated and reformed more evenly and promptly.
[0068]
  In the above-described example, six anodes 9 are arranged around the cathode / water collecting tube 10. However, the number is not limited to this, and for example, four rhombus shapes may be arranged.
[0069]
[Example 2]
  4 to 6 show the present invention.MethodSecond embodiment ofSoil tank used forIndicates. FIG. 4 is a plan view showing an arrangement example of the electrodes of the second embodiment, FIG. 5 is a longitudinal sectional view showing the internal structure of the earth tub, and FIG. 6 is a schematic configuration of the internal structure of the cathode and water collecting pipe of this embodiment. .
[0070]
  This second embodiment is characterized by the arrangement of the anode 9A, the cathode / water collecting tube 10 and the structure of the cathode / water collecting tube 10.
[0071]
  That is, in this embodiment, as shown in FIGS. 4 and 5, a plurality of rectangular and plate-like anodes 9 </ b> A are arranged at regular intervals on the inner wall portion of the earth tub 1.
[0072]
  Next, a cylindrical cathode / water collecting tube 10 spaced apart on the inner side is disposed so as to face the anode 9A disposed on the outer side in an inner circumferential shape.
[0073]
  Next, a plate-like anode 9 </ b> A is arranged on the inner circumference so as to be separated from the inside of the cathode / water collecting tube 10.
[0074]
  Next, the cathode / water collecting tube 10 may be arranged inside the anode 9A in an inner peripheral shape. In the illustrated example, the cathodes 10 are arranged in series on each short side of the earth tank 1, the anodes 9 </ b> A are arranged on the inner sides of the cathodes 10 apart from the cathodes 10. The cathode 10 is disposed on the long side, and the anode 9A is disposed in the middle so as to face each other. The anodes 9A and cathode / collector tubes 10 are arranged regularly and alternately on the inner circumference, or the central portion is arranged as shown in the example in the figure, and the number of electrodes and the like is appropriately determined depending on the scale of the earth tub 1 and the like. Is done.
[0075]
  In addition, the structure of the earth tub 1 is substantially the same as that of the first embodiment.
[0076]
  Next, the internal structure of the cathode / water collecting tube 10 will be described with reference to FIG.
[0077]
  The cathode / water collecting tube 10 is formed in an elongated cylindrical shape, and a plurality of water passage holes 10a for introducing soil water into the inside are formed on the outer peripheral surface as shown in FIGS.
[0078]
  As the shape of the cathode / water collecting tube 10, an optimum one of various shapes such as a triangle, a quadrangle, a pentagon, and other polygons is selected and used in addition to a circular cross section.
[0079]
  A hollow vacuum tube 10 b is provided in the central axial direction of the cathode / water collecting tube 10.
[0080]
  A filter medium 10c is filled between the outside of the vacuum tube 10b and the outer periphery of the cathode / water collecting tube 10 where the water passage hole 10a is formed.
[0081]
  As the filter medium 10c, fibers, sand, small gravel, or the like is used to prevent clogging of soil fine particles mixed in the permeated water and to protect the vacuum pump 18.
[0082]
  Above the cathode / water collecting tube 10, an electrode 10 d to which a cathode-side electric wire 14 is connected is provided, and a connecting tube 20 a leading to the vacuum drawing tube 20 is connected to the upper portion of the cathode / water collecting tube 10.
[0083]
  In this embodiment, a large number of cathode and water collecting pipes 10 are provided. For example, every other one is energized and communicated with the vacuum pump 18, and the rest is installed and used as a spare.
[0084]
  That is, the anode 9A and a predetermined cathode / water collecting tube 10 are energized, and the cathode / water collecting tube 10 is vacuumed, and the inside of the cathode / water collecting tube 10 is sucked from the lower end of the vacuum tube 10b to form a vacuum state. Then, the water in the mud in the soil tank 1 is drained as shown by the arrows in FIG. 6 by the electroosmosis action and the vacuum dehydration action.
[0085]
  When clogging due to fine soil particles or the like in the filter medium 10c of the cathode / collector tube 10 or around the outer peripheral surface is accumulated and the drainage efficiency is lowered, the other cathode / collector tube 10 that has not been used is energized as a spare. By switching between and draining, efficient drainage becomes possible. Thereby, drainage time can be shortened. This change can be easily realized by using a changeover switch.
[0086]
  Of course, all the cathode / water collecting pipes 10 may be driven at a time in accordance with the properties and amount of mud.
[0087]
[Example 3]
  FIG. 7 shows the present invention.MethodThe arrangement | positioning aspect of the anode 9 and the cathode and water collecting pipe 10 of the earthen tank of 3rd Example of this is shown.
[0088]
  In the second embodiment described above, the anode 9A is plate-shaped, but in this example, a round bar-shaped one is used as in the first embodiment.
[0089]
  Further, the anodes 9 are arranged in series at appropriate intervals along the inner wall surface in the earth tub 1, and the cathode and water collecting pipes 10 are arranged in series at appropriate intervals between the anodes 9 inside the series. The anode 9 is disposed between the cathode / collector tubes 10 at the inner position, and the cathode / collector tube 10 is disposed in the same manner on the inner side. Thus, in this embodiment, the anode 9 and the cathode / water collecting tube 10 are arranged in a staggered manner.
[0090]
  According to the experiment, in the anode part, the periphery including the part opposite to the cathode side is also effectively dehydrated. Therefore, when the anode 9 is arranged along the inner wall surface of the earth tub 1, the area of the earth tub 1 is large. A part becomes a part with a large dehydration effect, and the whole improvement of the hydrous sand 6 can be made effective.
[0091]
  Of course, the anode 9 may be a plate-like anode 9A as in the second embodiment.
[0092]
  The internal structure of the cathode / water collecting tube 10 is configured as shown in FIG.
[0093]
[Example 4]
  FIG. 8 shows a fourth embodiment of the present invention.Soil tank used forFIG. 9 is a sectional view showing the internal structure of FIG. 9 and shows the arrangement of the cathode and water collecting tubes at the bottom.
[0094]
  In this embodiment, an anode 24 is provided on the top of the earth tub 1, and this anode 24 is constituted by a flat plate, for example, a copper plate 24, and is cylindrical at the bottom of the earth tub 1 and has a water passage hole 10 a. A plurality of cathode / collector tubes 10 are arranged in a horizontal direction in parallel and spaced apart from each other with a space therebetween, and a dehydration treatment chamber 7 having a large internal space is secured in the earth tank 1. ing.
[0095]
  That is, the anode 24 is attached to the lower part of the shielding sheet 3, for example. The shielding sheet 3 is made of an insulating and strong flat plate member.
[0096]
  When the shielding sheet 3 is attached to the upper part of the soil tank 1 so as to close the opening, the anode 24 can be set at the same time. One end of the electric wire 14 is connected to an appropriate position of the anode 24.
[0097]
  This shielding sheet 3 is detachably attached to the upper part of the earth tub 1 through appropriate means. Further, when attached, the tip of the earth and sand injection pipe 5 is disposed at an appropriate position of the end of the shielding sheet 3 so as to face the dehydration treatment chamber 7 through the attachment member 8 so that the hydrous sand 6 can be filled. Yes.
[0098]
  In addition, you may make it attach the anode 24 on a flat plate to the lower part of the mounting stand 2 shown in the 1st-3rd Example instead of the shielding sheet 3. FIG. In this case, the shielding sheet 3 in the same embodiment is used.
[0099]
  A girder 25 on the rib is erected between the cathode and water collecting pipes 10 which are arranged in parallel at the bottom portion in a substantially horizontal direction with a gap therebetween. Then, a flat protective plate 26 made of, for example, a steel plate is provided on the upper portion thereof, thereby protecting the cathode and water collecting tube 10.
[0100]
  A large number of water passage holes 26 a are formed in the protection plate 26, and the protection plate 26 is provided over almost the entire bottom surface of the soil tank 1. The protective plate 26 is preferably detachable. This is because the lower cathode / water collecting tube 10 can be inspected, cleaned, defective products can be replaced, and the like.
[0101]
  A filter medium 10 c is provided in a space surrounded by the lower surface of the protection plate 26, the girder 25 and the bottom plate 1 a of the earth tub 1.
[0102]
  In other words, the filter medium 10c for preventing the entry of fine soil particles is provided around the cathode / water collecting tube 10. In this case, as shown in FIG. 6, it is not always necessary to provide the filter medium 10c inside the cathode / water collecting tube 10, but a type in which the filter medium 10c is provided may be used.
[0103]
  One end of the cathode / water collecting tube 10 is located on one long side of the earth tub 1 and the other end extends toward the other long side facing the other. For example, one end side extends along one long side. It is connected to a hollow connecting tube 27.
[0104]
  The connecting pipe 27 is drawn out of the earth tub 1 and connected to a vacuum pump (not shown) via a coupling 21 to which a vacuum pulling pipe 20 is connected. Further, when a material having good electrical conductivity such as a copper tube is used for the connecting tube 27, each cathode and water collecting tube 10 can be electrically connected by connecting one end of the electric wire 14 to the connecting tube 27.
[0105]
  In addition, the surface of the earth tub 1 is subjected to an insulation treatment by coating an insulating resin such as an epoxy resin. This is to prevent a short circuit between the anode 24 and the cathode / water collecting tube 10. The earth tank 1 is provided with a ground 17.
[0106]
  In use, the anode 24 is set in the opening of the earth tub 1 via the shielding sheet 3 or the mounting frame 2. In addition, the soil tank 1 is filled with the hydrous sand 6 through the earth and sand charging pipe 5. Since the hydrous sand 6 is in contact with the planar anode 24 over a wide area, the electroosmotic dehydration can be effectively performed.
[0107]
  Moreover, since the wide internal space is ensured in the earth tub 1, it can be filled with the hydrous sand 6 in large quantities.
[0108]
  The soil water extracted from the hydrous sand 6 is sucked by moving to the lower cathode / water collecting pipe 10 side as indicated by the arrow and drained to the outside.
[0109]
  The cathode / water collecting pipe 10 is protected by a protective plate 26 against heavy hydrous sand 6, soil water, and dewatered soil.
[0110]
  Moreover, when draining the dewatered earth and sand in the earth tub 1 after dehydration, a clamshell or the like is used.
[0111]
  FIG. 10 is a side view showing another aspect of the anode 24 suitable for use in the fourth embodiment, and FIG. 11 is a bottom view thereof.
[0112]
  In this example, the anode 24A is made of a conductive cabtire cable conductor, a flat braided wire such as copper / bell plating, a copper wire, an aluminum wire, a piano wire, a carbon fiber, etc., and is conductive, flexible and mechanical strength. Are formed in a planar shape with a material having a sword, and attached to the lower surface of the shielding sheet 3 in a lattice shape by sewing or the like. Zigzag or other forms of stitching may be used. An energizing wire 22 is connected to a preferable appropriate position of the anode 24A.
[0113]
  The shielding sheet 3 is formed of an insulating and flexible material such as a natural rubber mixture, a vinyl mixture, an epoxy resin, and a crosslinked polyethylene mixture.
[0114]
【The invention's effect】
  As described above, according to the present invention, with respect to the hydrous soil excavated from the excavation site such as shield construction in the highly hydrous soft ground, discharged into the earth tub, a plurality of anodes and cathodes and collecting pipes are used. Electro-osmosis by energization, vacuum pump for drainage connected to the cathode and drainage pipe, and shielding sheet that keeps the hydrated earth and sand in the soil tank from being sealed and keeps the hydrated earth and sand under the negative pressure accompanying the vacuum pump operation. Provided is a highly efficient hydrous sand dehydration method capable of simultaneously performing vacuum dehydration, and the excavated hydrous sand is dehydrated extremely efficiently by the action of both electroosmosis and vacuum dehydration. Sediment is maintained by keeping it compact after dehydration A very remarkable effect is achieved in that cracking of the metal is prevented and electroosmosis is carried out efficiently.
[0115]
  Also, dehydration can be kept highly efficient by arranging the anode in a planar shape at the upper opening of the earth basin and the cathode and water collecting pipe at the lower part of the earth basin.
[0116]
  By installing a neutron density / moisture meter that measures the moisture content of the earth and sand in the earth tank, it becomes possible to appropriately manage the soil quality of the dehydrated earth and sand.
[0117]
  Attaching each member for electroosmosis consisting of an electrode group and each member for vacuum dehydration that connects the water collection side electrode to a vacuum pump, together with a filter medium for preventing clogging, to be detachably attached to the opening of the earth tub Since it is attached to the base and the shielding sheet is further attached to the lower surface of the mounting base, the attachment and detachment and maintenance of each member become easy and good, and the upper surface of the hydrous sand that has been put into the soil tank together with the removable mounting base To maintain the efficiency of vacuum dehydration.
[0118]
  Furthermore, by appropriately changing the arrangement of the electrode group and the energization pattern, it is possible to perform appropriate dewatering according to the soil quality and dewatering condition of the hydrous sand.
[Brief description of the drawings]
FIG. 1 shows the present invention.MethodIn the first embodiment ofUseThe top view of a soil tank is shown.
FIG. 2 is a schematic explanatory view showing the internal structure and overall configuration of the earth tub of the embodiment.
FIG. 3 Example same as aboveInThe other example of arrangement | positioning of an electrode is shown.
FIG. 4 is an explanatory diagram of an arrangement state of electrodes in a second embodiment of the present invention.
FIG. 5 shows a second embodiment of the present invention.Used forIt is a schematic explanatory drawing which shows the internal structure and whole structure of a clay tank.
FIG. 6 shows an example of the internal structure of a cathode / water collecting tube used in each embodiment of the present invention.
FIG. 7 is a plan view of a clay tank showing an example of electrode arrangement in a third embodiment of the present invention.
FIG. 8 is a longitudinal sectional view showing the internal structure of a clay tank in a fourth embodiment of the present invention.
FIG. 9 is an explanatory plan view showing an arrangement state of the cathode / water collecting tubes in the embodiment.
FIG. 10 is a side view showing another example of the anode used in the fourth embodiment of the present invention.
FIG. 11 shows a bottom view of the above.
[Explanation of symbols]
1 soil tank
1a Bottom plate
2 Mounting rack
3 Shielding sheet
4 Neutron density and moisture meter
5 Sediment input pipe
6 earth and sand
7 treatment room
8 Mounting members
9 Anode
10 Cathode and water collecting tube
10a Water collecting hole
10b Vacuum tube
10c Filter media
10d terminal board
11 DC power supply
12 Fixture
13 Fixing tool
14 Electric wire
15 Voltmeter
16 Ammeter
17 Earth
18 Vacuum pump
19 Water tank
20 Vacuum tube
21 coupling
22 Vacuum source tube
23 Drain pipe
24, 24A anode
25 Girder
26 Protection plate
26a Water flow hole
27 Filter media

Claims (5)

A plurality of anodes (9, 9A) and a plurality of anodes (9, 9A) are disposed apart from the anodes (9, 9A) in a partially open earth basin (1) installed in the ground, semi-ground, or on the ground. And an electroosmotic electrode comprising a plurality of cylindrical cathode / water collecting pipes (10) having a drainage function in which a large number of water passage holes (10a) are formed in the outer peripheral portion, and excavated hydrous sand (6) was placed in the soil tank (1) inside, dehydrated hydrous soil (6) by supplying an electric current to the electrode, in the dehydration method of the water-containing sediment discharging process the dehydration after dehydration sediment from Doso (1) ,
A vacuum pump (18) is connected to the outside of the cathode / water collecting pipe (10), and a filter medium (10c) for preventing clogging is provided on the cathode / water collecting pipe (10) to block the hydrous sand (6) from the atmosphere. In addition, a shielding sheet (3) for keeping the hydrous sand (6) compacted by the negative pressure in the earth tank (1) by the operation of the vacuum pump (18) is provided above the hydrous sand, and the plurality of anodes (9, 9A) and A method for dewatering a hydrous soil, characterized by selectively energizing all or any of the cathode and water collecting pipe (10) to perform electroosmosis and vacuum dewatering . The anode is a planar anode (24, 24A), the anode (24, 24A) is provided in the opening of the earth tub (1), and the cathode and water collecting pipe (10) is an earth tub (1). The dehydrated treatment method for hydrous soil according to claim 1, wherein the dehydrated treatment method is provided at a lower portion of the soil and connected to the vacuum pump (18). Before SL neutron density-moisture meter in the soil tank (1) (4) is provided, the dehydration processing method of the water-containing sediment according to claim 1, characterized in that the water content ratio of the water-containing soil (6) was measurable . The anode (9, 9A) and cathode and water collecting pipe (10), mounted in a grid or mounting frame detachably attached in a mesh shape to be formed by soil tank (1) (2), shielding sheet (3 ) attached to the lower surface of the frame (2) attached to, vacuum tubes for drainage connected to a vacuum pump provided outside (18) the (10b) provided on said cathode and water collecting pipe one or (10), this The method for dewatering hydrous soil according to claim 1 , wherein a filter medium (10c) for preventing clogging is provided between the vacuum tube (10b) and the outer periphery of the cathode / water collecting tube. Before SL anode (9, 9A) and cathode (10) is arranged an anode (9, 9A) to the outermost peripheral portion, arranged cathode (10) on the inside, an anode (9, 9A) on the inside arrangement, and the cathode (10) on the inside, and arranged alternately or zigzag form, dehydration of water-containing sediment of claim 1, wherein the selectively energizable installed in either entirely or Processing method .

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