JP7786711B2 - Control method and workpiece repair method - Google Patents

Description

This disclosure relates to technology for controlling underground and surface water.

Groundwater can sometimes cause pollution and disasters. For example, if hazardous substances leaking from industrial waste disposal sites or radioactive waste disposal sites mix with groundwater, the rivers, lakes, oceans, and surrounding soil into which the groundwater flows can become contaminated with the hazardous substances (see, for example, Non-Patent Document 1). Groundwater infiltration can also loosen the ground, causing landslides and damaging structures such as levees.

"Development of a method for removing iron and heavy metals from mine wastewater using an iron concretion process," Eiichi Yoshida, Koji Yamamoto, Ippei Maruyama, Nagoya University Museum Report, http://www.num.nagoya-u.ac.jp/media/report/docs/037_04.pdf, August 30, 2021.

Installing underground water barriers to block groundwater requires a significant amount of construction time and cost. Technology that effectively controls groundwater using simpler methods is needed.

This disclosure was made in light of these issues, and its purpose is to provide technology for appropriately controlling underground and surface water.

To solve the above-mentioned problems, a control method according to one embodiment of the present disclosure includes the steps of providing an ion supply material containing at least one of a first compound capable of generating cations that constitute poorly soluble salts and a second compound capable of generating anions that constitute poorly soluble salts in an area where water is present underground and/or on the surface of the earth, and changing at least one of the flow rate, flow direction, and retention amount of water by precipitating poorly soluble salts around the ion supply material.

Another aspect of the present disclosure is a reinforcement method. This method includes the steps of providing, in at least one of the underground and the earth's surface, an ion supply material containing at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating anions that constitute a poorly soluble salt, and reinforcing at least one of the underground and the earth's surface by precipitating poorly soluble salt around the ion supply material.

Yet another aspect of the present disclosure is a purification method. This method includes the steps of providing, at least one of underground and on the surface of the earth, an ion supply material containing at least one of a first compound capable of generating cations that constitute poorly soluble salts and a second compound capable of generating anions that constitute poorly soluble salts, and reducing harmful ions present around the ion supply material by forming poorly soluble salts with the cations or anions and precipitating them.

Yet another aspect of the present disclosure is a structure. The structure is present in an area where water is present underground and/or on the earth's surface, and includes an ion supply material containing at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating anions that constitute a poorly soluble salt, and a poorly soluble salt that is present around the ion supply material.

Yet another aspect of the present disclosure is a method for repairing a workpiece. The method includes adding an ion supply material to the vicinity of the sparingly soluble salt of the workpiece.

Yet another aspect of the present disclosure is a method for repairing a workpiece. The method includes the steps of providing a new hole in the workpiece adjacent to the hole, and providing an ion supply material within the new hole.

This disclosure makes it possible to appropriately control underground and surface water.

1 is a diagram showing a schematic configuration of a groundwater control facility according to an embodiment of the structure of the present disclosure; FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. FIG. 10 is a diagram illustrating a schematic configuration of another example of a groundwater control facility according to an embodiment. 1 is a flowchart showing the steps of a groundwater control method according to an embodiment. 1 is a flowchart showing the steps of a method for repairing a groundwater control facility according to an embodiment.

This disclosure describes a technology for controlling the flow rate, flow direction, and retention amount of water present underground or on the surface of the earth. In a control method according to an embodiment of this disclosure, an ion supply material containing at least one of a first compound capable of generating cations that constitute poorly soluble salts and a second compound capable of generating anions that constitute poorly soluble salts is provided in an area where water exists underground or on the surface of the earth. Precipitation of poorly soluble salts around the ion supply material changes at least one of the flow rate, flow direction, and retention amount of water.

Water that can be controlled using the control method of the present disclosure includes all water that exists underground or on the earth's surface, regardless of whether it is seawater or freshwater. The control method of the present disclosure can control water that has seeped into the ground from rivers, ponds, lakes, waterways, seas, canals, etc.; water that has formed in large quantities on the earth's surface due to rainfall, typhoons, tornadoes, river flooding, etc.; water that exists in rivers, ponds, lakes, waterways, seas, canals, etc.; and water that has formed in large quantities on the earth's surface due to rainfall, typhoons, tornadoes, river flooding, etc.

When controlling underground groundwater or seepage water, the ion supply material may be placed underground, such as in soil, ground, bedrock, or the seabed. When controlling river water or seawater on the surface of the earth, the ion supply material may be placed on the surface of the earth or underground in contact with the river water or seawater. As will be described later, ions supplied from the ion supply material diffuse into the surroundings and precipitate sparingly soluble salts, so it is desirable to place the ion supply material in a location where the ions supplied from the ion supply material can diffuse into the surroundings.

Figure 1 shows a schematic diagram of a groundwater control facility according to an embodiment of the structure of the present disclosure. If hazardous substances leak from a facility 1, such as an industrial waste disposal site or a radioactive waste disposal site, located in an area where groundwater 2 exists, the leaked hazardous substances may become mixed into the groundwater 2. In this embodiment, in order to reduce the inflow of groundwater 2 contaminated with hazardous substances into rivers, lakes, oceans, areas where contamination should be avoided, etc., groundwater control facility 3 is installed upstream of these areas.

The groundwater control facility 3 includes a borehole 4 provided in an area where groundwater 2 exists, an ion supply material 5 provided inside the borehole 4, and a sparingly soluble salt 6 generated from the ions supplied from the ion supply material 5. The ion supply material 5 includes at least one of a first compound capable of generating cations that constitute the sparingly soluble salt 6 and a second compound capable of generating anions that constitute the sparingly soluble salt 6. The sparingly soluble salt 6 precipitates from the ions supplied from the ion supply material 5 inside and around the borehole 4, thereby blocking at least a portion of the flow path of the groundwater 2 inside and around the borehole 4 and reducing the flow rate of the groundwater 2 to the downstream area.

In the example shown in Figure 1, multiple boreholes 4 are provided at close intervals, and at least a portion of the sparingly soluble salts 6 precipitated between adjacent boreholes 4 combine to form a wall around the groundwater control equipment 3. This further reduces the flow rate of groundwater 2 downstream. Some of the groundwater, whose flow is obstructed by the wall, remains upstream, while some flows around the outside of the wall. Therefore, inside the groundwater control equipment 3, the flow rate of groundwater 2 decreases as sparingly soluble salts 6 form across the multiple boreholes 4, while outside the equipment 3, the flow rate of groundwater 2 increases by the amount of the decrease inside the equipment 3. Furthermore, the amount of groundwater 2 remaining upstream of the groundwater control equipment 3, including the wall, increases, while the amount of groundwater 2 remaining downstream decreases. The groundwater 2 blocked by the groundwater control equipment 3 may be pumped up and transported to a treatment facility for treating hazardous substances, or it may be directed to flow toward a treatment facility.

When the ion supply material 5 contains a first compound, cations that form a sparingly soluble salt are eluted from the first compound; when the ion supply material 5 contains a second compound, anions that form a sparingly soluble salt are eluted from the second compound. When the ion supply material 5 contains both the first compound and the second compound, a sparingly soluble salt is produced from the eluted cations and anions. When the ion supply material 5 contains a first compound, a sparingly soluble salt is produced from the eluted cations and anions contained in the surrounding groundwater, etc. When the ion supply material 5 contains a second compound, a sparingly soluble salt is produced from the eluted anions and cations contained in the surrounding groundwater, etc.

The ions supplied from the ion supply material 5 diffuse into voids and cracks in the bedrock and strata surrounding the borehole 4, forming sparingly soluble salt 6 in the voids and cracks surrounding the borehole 4. This allows the sparingly soluble salt 6 to be blocked not only inside the borehole 4, but also in the voids surrounding the borehole 4. As shown in Figure 1, by providing multiple boreholes 4 and blocking the voids between adjacent boreholes 4 with sparingly soluble salt 6, the surface including the multiple boreholes 4 can essentially function as a watertight wall. This makes it possible to effectively control the flow rate, flow velocity, flow direction, and retention volume of groundwater 2 while significantly reducing construction time and costs compared to installing a watertight wall underground.

Ions supplied from the ion supply material 5 diffuse according to the ion concentration gradient. However, because the concentration of ions originally present around the borehole 4 is typically low, the ions can easily diffuse to the voids and cracks in the bedrock surrounding the borehole 4 without the need for external force. Furthermore, because the ions diffuse dissolved in water, they can easily diffuse into extremely tiny voids and cracks at the atomic and molecular level, even deep underground, regardless of pore water pressure, and form sparingly soluble salts 6 there to block them, more reliably blocking the flow of groundwater 2 inside and around the borehole 4.

The relationship D = VL holds between the width L (cm) of the reaction edge of the sparingly soluble salt 6 formed around the borehole 4, the speed V (cm/s) at which the reaction edge is formed, and the diffusion coefficient D (cm ² /s) of ions in the stratum. For example, if multiple boreholes 4 are provided at 20 cm intervals, ion diffusion and sparingly soluble salt precipitation will progress from each borehole 4, and when the reaction edge width reaches approximately 10 cm, the reaction edges from adjacent boreholes 4 will overlap. If the ion diffusion coefficient D around the borehole 4 is 10 ^{-5 to -6} cm ² /s, it will take approximately several months to a year for the reaction edges from adjacent boreholes 4 to overlap. The spacing and arrangement pattern of the multiple boreholes 4 may be designed according to the ion diffusion coefficient, permeability coefficient, flow rate and velocity of the groundwater 2 around the boreholes 4, the period until the gaps between adjacent boreholes 4 are blocked, and the purpose for which the groundwater control equipment 3 is installed.

The sparingly soluble salt may be any salt that has sufficiently low solubility in water at the location where the borehole 4 is to be constructed, is chemically stable, and does not pollute the surrounding natural environment. For example, carbonates such as calcium carbonate, magnesium carbonate, and iron (II) carbonate (siderite, siderite), double salts such as calcium magnesium carbonate (CaMg( _CO3 ) ₂ , dolomite, dolomite), and sulfates such as calcium sulfate may be used. The sparingly soluble salt may be selected appropriately depending on the location where the borehole 4 is to be constructed. For example, calcium carbonate can be converted into calcium bicarbonate, which has a relatively high solubility in water, by chemical reaction with carbon dioxide. Therefore, if the borehole 4 is to be constructed in an environment with a relatively high concentration of carbon dioxide, an ion supply material 5 may be provided in the borehole 4 to supply ions that form sparingly soluble salts other than calcium carbonate. Furthermore, since calcium carbonate can be dissolved by chemical reaction with acid, when the structural material is disposed in an environment with a relatively low pH, an ion supply material 5 may be provided in the borehole 4 to supply ions such as iron (III) ions, whose hydroxides and oxides are sparingly soluble in water. In this way, even if calcium carbonate in or around the borehole 4 is dissolved by acid present around the borehole 4, the acid is neutralized by the calcium carbonate, raising the pH and causing the sparingly soluble hydroxides and oxides to precipitate, which can then block voids in or around the borehole 4. The ions for forming the sparingly soluble hydroxides and oxides may be, for example, iron (III) ions, aluminum ions, copper (II) ions, zinc ions, manganese ions, etc.

When calcium carbonate is precipitated as a sparingly soluble salt, strontium, which is an alkaline earth metal like calcium and has similar chemical properties to calcium, is incorporated into the calcium carbonate. As a result, even if groundwater 2 contains radioactive isotopes of strontium, the calcium carbonate can be precipitated along with the calcium carbonate, thereby removing the radioactive isotopes of strontium from groundwater 2. Furthermore, by immobilizing other radioactive substances by co-precipitating them with sparingly soluble salt 6 or by adsorbing them to sparingly soluble salt 6, not only can the diffusion of contaminated water containing radioactive substances be prevented, but the contaminated water, the ground, or the surface of the earth can also be purified.

When calcium carbonate is precipitated as a sparingly soluble salt, the first compound may be any compound capable of generating calcium ions, having sufficiently high solubility in water at the temperature of the environment in which the ion supply material is disposed, and not polluting the surrounding natural environment. Examples of the first compound include calcium chloride (CaCl ₂ ), calcium nitrate (Ca(NO ₃ ) ₂ ), calcium bicarbonate (Ca(HCO ₃ ) ₂ ), and calcium oxide (CaO).

When calcium carbonate is precipitated as a sparingly soluble salt, the second compound may be, for example, sodium bicarbonate (NaHCO 3 ), potassium bicarbonate (KHCO 3 ), ammonium bicarbonate (NH 4 HCO 3 ), or the like, as long as it can generate at least one of carbonate ions and bicarbonate ions, has sufficiently high solubility in water at the _temperature of the environment in which the ion supply material _{is placed} , and does not pollute the _surrounding natural environment.

By providing the ion supply material 5 underground or on the ground surface, harmful ions contained in the ground or on the ground surface can be precipitated as sparingly soluble salts, thereby purifying the ground or the ground surface. For example, crushed gypsum board is sometimes scattered on the ground to improve the ground. However, when calcium sulfate (CaSO ₄ ) contained in the gypsum dissolves and sulfate ions are released into the soil, they are converted into hydrogen sulfide by sulfate-reducing bacteria, causing corrosion of concrete and the like. Furthermore, when the concentration of sulfate ions increases, sodium sulfate precipitates as a decahydrate salt (Na ₂ SO ₄ ·10H ₂ O: mirabilite) or anhydrous salt (Na ₂ SO ₄ : thenardite). However, the formation of a decahydrate salt generates a large expansion pressure, and the formation of a large amount of decahydrate salt in concrete, bricks, etc. may cause expansion failure. Furthermore, ettringite (3CaO·Al ₂ O ₃ ·3CaSO ₄ ·32H ₂ O), which is formed by the reaction of sulfate with an aluminate phase contained in cement, also has the property of expanding. Therefore, if ettringite forms delayed after cement hardens, it may cause expansion failure. Thus, sulfate ions are harmful ions in that they cause deterioration of structures constructed of concrete, etc. By providing an ion supply material 5 capable of supplying calcium ions in the soil, sulfate ions contained in the soil can be precipitated as calcium sulfate, thereby reducing the sulfate ions contained in the soil and purifying the soil. In this case, the first compound may be calcium chloride (CaCl ₂ ), calcium nitrate (Ca(NO ₃ ) ₂ ), calcium bicarbonate (Ca(HCO ₃ ) ₂ ), etc. Furthermore, according to the technology of this embodiment, the concentration of harmful substances contained in the ground or on the ground surface, such as heavy metal ions and radioactive substances, can be reduced by precipitating, co-precipitating, or adsorbing the harmful substances present in the ground or on the ground surface, thereby purifying the ground or on the ground surface.

Both the first compound and the second compound may be present together in the ion supply material 5. For example, the first compound and the second compound may be present mixedly in the ion supply material 5. Both the first compound and the second compound may be present separately in the ion supply material 5. For example, at least one of the first compound and the second compound may be enclosed in a capsule or the like and contained in the ion supply material 5. The capsule may be made of a material that dissolves in water or the like.

The ion supply material 5 may further include a base material containing at least one of the first compound and the second compound. The base material may be a material that has fluidity that allows it to be poured into the borehole 4 and that hardens after injection through a chemical reaction such as hydration or polymerization, or through heating, cooling, drying, or exposure to light. The base material may be, for example, cement, mortar, concrete, or a thermosetting resin such as an epoxy resin, silicone compound, polyol compound, or phenolic compound, or a thermoplastic resin such as an acrylic resin, or a mixture thereof. The base material may be a material that gradually releases at least one of the cations that constitute the first compound and the anions that constitute the second compound. For example, the base material may be an epoxy resin. The ion supply material 5 in a solidified state may be inserted into the borehole 4.

The ion supply material 5 may include an ion exchange resin onto which the ions to be supplied are adsorbed. In this case, the ion exchange resin can be selected or designed to release ions in an appropriate amount and supply rate depending on the type of ions to be supplied and the composition, amount, and pH of the chemicals dissolved in the groundwater surrounding the borehole 4.

The ion supply material 5 may include capsules that encapsulate and slowly release the ions to be supplied. The ions encapsulated in the capsules may be contained as a first compound or a second compound, or as an ion exchange resin onto which the ions are adsorbed. In this case, too, the material, thickness, shape, etc. of the capsules can be selected or designed to release ions in an appropriate amount and at an appropriate supply rate depending on the type of ions to be supplied and the components, amount, and pH of the chemicals dissolved in the groundwater surrounding the borehole 4.

The ion supply material 5 may contain a sparingly soluble material that serves as a nucleus for precipitating the sparingly soluble salt 6, thereby promoting the precipitation of the sparingly soluble salt 6. The sparingly soluble material may be any material that has sufficiently low solubility in water at the temperature of the borehole 4 in which the ion supply material 5 is provided, is chemically stable, and does not pollute the surrounding natural environment. For example, the sparingly soluble material may be a carbonate such as calcium carbonate, magnesium carbonate, or iron (II) carbonate (siderite, siderite), a double salt such as calcium magnesium carbonate (CaMg( _CO3 ) ₂ , dolomite, dolomite), a sulfate such as calcium sulfate, a metal hydroxide such as iron hydroxide, a metal such as iron, or a mineral such as sand or rock. The sparingly soluble material may be the same as or different from the sparingly soluble salt to be precipitated.

Even if voids or cracks develop in or around the borehole 4 due to external forces such as earthquakes, crustal movements, tidal currents, or typhoons after the poorly soluble salts 6 precipitate and block the voids in or around the borehole 4, if ions supplied from the ion supply material 5 remain, the ions supplied from the ion supply material 5 will diffuse into the voids and cracks in or around the borehole 4, reacting with the counterions to precipitate the poorly soluble salts, thereby blocking the voids and cracks. Thus, the technology of this embodiment can impart a self-repair function to the groundwater control equipment 3, thereby improving the durability of the groundwater control equipment 3. It is desirable to design the ion supply material 5 so that ions supplied from the ion supply material 5 remain even after the voids in or around the borehole 4 are blocked. In addition to the ion supply material 5 designed to supply the ions necessary to block voids in and around the borehole 4 immediately after placement of the borehole 4, the borehole 4 may also be provided with an ion supply material 5 containing ion-containing, easily soluble salts or ion exchange resins in a container such as a capsule that will break and release its contents when an external force is applied that causes damage such as voids or cracks in or around the borehole 4.

A pH adjuster may be installed inside the borehole 4 to increase the pH of the groundwater. If the groundwater 2 contains iron ions, as the pH of the groundwater 2 is increased by the pH adjuster, the iron ions precipitate or colloidize in the form of α-, β-, γ-, or δ-iron oxyhydroxide, iron (III) oxide, iron (III) hydroxide, etc., and are adsorbed onto the surface of the pH adjuster. This reduces the concentration of iron ions in the groundwater 2 and the flow rate of the groundwater 2. Iron oxides are known to co-precipitate heavy metal compounds when they precipitate or colloidize. Therefore, the concentrations of not only iron ions in the groundwater 2 but also heavy metal ions such as lead (Pb), cadmium (Cd), and arsenic (As), and light metal ions such as aluminum (Al), can be reduced. Furthermore, it is known that alpha nuclides such as uranium form complexes and dissolve in water under acidic conditions, but precipitate under alkaline conditions. Therefore, as the pH of the groundwater 2 is increased by the pH adjuster, the concentration of alpha nuclides such as uranium can be reduced. Similarly, the concentration of other harmful substances that dissolve in water under acidic conditions but precipitate under alkaline conditions can also be reduced. The pH adjuster may include at least one of calcium carbonate, calcium bicarbonate, calcium oxide, and calcium hydroxide. The pH adjuster may include concrete, cement, cement clinker, alite, belite, aluminate, ferrite, etc. The pH adjuster may be any compound whose aqueous solution is alkaline, such as sodium carbonate, sodium bicarbonate, sodium hydroxide, calcium acetate, or sodium acetate. The pH adjuster may be the same compound as the ion supply material 5, or a different compound. The pH adjuster may be provided inside a borehole 4 that has an ion supply material 5 provided therein, or inside a borehole 4 that does not have an ion supply material 5 provided therein. Multiple boreholes 4 may be provided, with some boreholes 4 having an ion supply material 5 provided therein and others having a pH adjuster provided therein. When a compound that causes the aqueous solution to be alkaline is used as the ion supply material 5, the ion supply material 5 may also serve as a pH adjuster.

The borehole 4 may be drilled deep enough to penetrate the permeable ground and reach the less permeable ground. Note that if there are existing boreholes or underground structures in the area where the groundwater 2 exists, and the ion supply material 5 is to be provided inside the borehole 4 or at the contact point between the underground structure and the ground, it is not necessary to drill a new borehole.

Figure 2 shows a schematic diagram of another example of a groundwater control facility according to an embodiment. Groundwater control facility 3 is installed upstream of the downstream area of groundwater 2 to reduce the inflow of groundwater 2 contaminated with hazardous substances leaked from facility 1 located in the area where groundwater 2 exists into the downstream area. In this example, multiple boreholes 4 are installed at wider intervals than in the example shown in Figure 1, and the sparingly soluble salts 6 are not integrated. Again, the flow rate of groundwater 2 decreases inside the groundwater control facility 3 and increases outside. Furthermore, the amount of groundwater 2 stored increases upstream of the groundwater control facility 3 and decreases downstream. This reduces the contamination of rivers, soil, and other areas downstream of the groundwater.

Figure 3 shows a schematic diagram of another example of the configuration of a groundwater control system according to an embodiment. When the foundation ground of the embankment body 11 constituting the embankment 10, such as a river embankment, is highly permeable, rainwater or river water may seep into the foundation ground, potentially causing leaks or piping problems. By providing groundwater control system 3 in the foundation ground, the infiltration of rainwater or river water into the foundation ground can be suppressed. Inside the groundwater control system 3, the flow rate of groundwater 2, which has infiltrated with rainwater or river water, decreases, while outside the groundwater control system 3, the flow rate of groundwater 2 increases. Furthermore, the amount of groundwater 2 retained on the river side of the groundwater control system 3 increases, while the amount of groundwater 2 retained on the land side decreases. Furthermore, by providing an ion supply material 12 on the surface of the embankment body 11 and precipitating sparingly soluble salt 13 on the surface of the embankment body 11, the infiltration of rainwater or river water into the embankment body 11 can be suppressed. This improves the strength and durability of the embankment 10.

Figure 4 shows a schematic diagram of another example of the configuration of a groundwater control system according to an embodiment. When a contamination source 7 containing harmful substances is present in an area where groundwater 2 exists, groundwater control system 3 is installed upstream of the contamination source 7 to reduce the inflow of groundwater 2 into the contamination source 7. The groundwater control system 3 changes the flow direction of groundwater 2 to bypass the contamination source 7. The flow rate of groundwater 2 decreases inside the groundwater control system 3 and increases outside the groundwater control system 3. Furthermore, the amount of groundwater 2 stored increases upstream of the groundwater control system 3 and decreases downstream. This reduces the contamination of groundwater 2. Similarly, when a weak area with loose ground, such as an embankment, exists in the area where groundwater 2 exists, groundwater control system 3 is installed upstream of the weak area to reduce the inflow of groundwater 2 into the weak area. This reduces the risk of groundwater 2 seeping through and collapsing the weak area, causing a landslide.

Figure 5 shows a schematic diagram of another example of a groundwater control system according to an embodiment. When a pollution source 7 containing hazardous substances, such as industrial waste, is disposed of in an area where groundwater 2 exists, groundwater control system 3 is installed around the pollution source 7 to reduce the inflow of groundwater 2 into the pollution source 7 and the outflow of groundwater 2 from the pollution source 7. The groundwater control system 3 changes the flow direction of groundwater 2 to bypass the pollution source 7. The flow rate of groundwater 2 decreases inside the groundwater control system 3, while the flow rate of groundwater 2 increases outside the system. Furthermore, the amount of groundwater 2 remaining from the pollution source 7 increases inside the area surrounded by the groundwater control system 3, while the amount of groundwater 2 remaining from the pollution source 7 decreases downstream of the groundwater control system 3. This prevents the inflow of contaminated groundwater 2 into downstream areas and prevents the pollution source 7 from collapsing due to the infiltration of groundwater 2, resulting in landslides.

Figure 6 shows a schematic diagram of another example of the configuration of a groundwater control facility according to an embodiment. When a pollution source 7 containing hazardous substances, such as industrial waste, is disposed of in an area where groundwater 2 exists, groundwater control facility 3 is installed along a flow path to direct the groundwater 2 away from the pollution source 7. The groundwater control facility 3 changes the flow direction of the groundwater 2 to bypass the pollution source 7. The flow rate of groundwater 2 decreases inside the groundwater control facility 3, while the flow rate increases outside the facility. Furthermore, the amount of groundwater 2 remaining around the pollution source 7, located inside the facility and surrounded by the groundwater control facility 3, decreases, and the amount of groundwater 2 remaining downstream of the facility 3 also decreases. This prevents contaminated groundwater 2 from flowing into downstream areas and prevents the pollution source 7 from collapsing due to the infiltration of groundwater 2, resulting in landslides.

Figure 7 shows a schematic diagram of another example of the configuration of a groundwater control facility according to an embodiment. When an underground structure 8 under construction exists in an area where groundwater 2 exists, groundwater control facility 3 is provided upstream of the underground structure 8 to reduce the inflow of groundwater 2 into the underground structure 8. The flow rate of groundwater 2 decreases inside the groundwater control facility 3, while it increases outside. Furthermore, the amount of groundwater 2 remaining increases upstream of the groundwater control facility 3, while it decreases downstream. This prevents groundwater 2 from interfering with the construction of the underground structure 8.

Figure 8 shows a schematic configuration of another example of a groundwater control facility according to an embodiment. When a dam 9 is present in an area where groundwater 2 exists, groundwater control facility 3 is provided along a flow path for directing groundwater 2 into dam 9. The groundwater control facility 3 changes the flow direction of groundwater 2 toward dam 9. The flow rate of groundwater 2 decreases inside the groundwater control facility 3, while it increases outside. Furthermore, the amount of groundwater 2 stored increases around the dam 9 located between the groundwater control facilities 3, while the amount of groundwater 2 stored decreases on the opposite side of the dam 9 across from the groundwater control facility 3. This allows groundwater 2 to be guided toward the periphery of the dam 9.

Figure 9 shows a schematic diagram of another example of the configuration of a groundwater control facility according to an embodiment. Groundwater control facility 3 is installed in advance in ground that is expected to liquefy in the event of an earthquake or other event. As sparingly soluble salt 6 precipitates and increases in volume, it compresses the surrounding gravel, and the gaps between the gravel are blocked by sparingly soluble salt 6, expelling groundwater that had accumulated in the gaps between the gravel and reducing the amount of accumulated water. This strengthens the ground.

Figure 10 shows a schematic diagram of another example of the configuration of a groundwater control facility according to an embodiment. Groundwater control facility 3 is installed in advance in loose ground that is prone to collapse. In this case, too, the sparingly soluble salts 6 precipitate and increase in volume, compressing the surrounding gravel. Furthermore, the sparingly soluble salts 6 block the gaps in the gravel, expelling groundwater that had accumulated in the gaps, reducing the amount of accumulated water. This strengthens the ground, thereby reducing the occurrence of landslides.

Figure 11 shows a schematic diagram of another example of the configuration of a groundwater control facility according to an embodiment. Before constructing an underground structure 8, a groundwater control facility 3 is installed in advance in ground with a high water content. As sparingly soluble salts 6 precipitate and increase in volume, the surrounding gravel is compressed, and the gaps between the gravel are blocked by the sparingly soluble salts 6, expelling groundwater that had accumulated in the gaps between the gravel and reducing the amount of accumulation. This allows the underground structure 8 to be constructed on reinforced ground, thereby improving the strength and durability of the underground structure 8.

Figure 12 is a flowchart showing the steps of a control method according to an embodiment. A borehole 4 is provided in an area where water exists underground and/or on the surface (S10). An ion supply material 5 is provided inside the borehole 4 (S12). A poorly soluble salt 6 is precipitated from ions supplied from the ion supply material 5 inside and around the borehole 4 (S14). The poorly soluble salt 6 blocks voids inside and around the borehole 4, changing the flow rate, flow velocity, flow direction, and retention amount of water present underground and/or on the surface.

Figure 13 is a flowchart showing the steps of a method for repairing groundwater control equipment according to an embodiment. After the installation of the groundwater control equipment 3, an investigation of the groundwater flow rate, flow velocity, flow direction, and retention volume reveals that the groundwater control by the groundwater control equipment 3 is insufficient, or that voids or cracks have occurred in the sparingly soluble salt 6 of the groundwater control equipment 3. If this reveals, the groundwater control equipment 3 is repaired. An ion supply material 5 is added to the borehole 4 (S20). A new borehole 4 is then drilled near the existing borehole 4 (S22), and an ion supply material 5 is then drilled inside the new borehole 4 (S24). Sparingly soluble salt 6 precipitates from ions supplied by the newly drilled ion supply material 5 (S26). The sparingly soluble salt 6 blocks the voids inside and around the borehole 4, changing the groundwater flow rate, flow velocity, flow direction, retention volume, etc. Either S20, S22, or S24 may be performed, or all of them may be performed.

The present disclosure has been described above based on examples. These examples are merely illustrative, and those skilled in the art will understand that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present disclosure.

In the embodiment, a sparingly soluble salt is precipitated around the sparingly soluble material, but sparingly soluble compounds other than salt may also be precipitated. In this case, the ion supply material may contain a compound that is readily soluble in water but reacts chemically with other compounds present in the environment in which the ion supply material is placed to produce a sparingly soluble precipitate. For example, an ion supply material for a structure to be constructed underground near a volcano may contain a compound that generates zinc ions, which reacts with hydrogen sulfide present in the surrounding area to precipitate zinc sulfide.

An overview of one aspect of this disclosure is as follows:

The control method disclosed herein includes the steps of providing an ion supply material containing at least one of a first compound capable of generating cations that constitute sparingly soluble salts and a second compound capable of generating anions that constitute sparingly soluble salts in an area where water exists underground or on the earth's surface, and changing at least one of the flow rate, flow direction, and retention amount of water by precipitating sparingly soluble salts around the ion supply material. This allows for appropriate control of water underground or on the earth's surface, thereby preventing disasters, pollution, and other problems. Furthermore, since this method allows for a simpler method of controlling water underground or on the earth's surface, it is possible to reduce construction time and costs. The ion supply material may be provided underground, such as in soil, ground, bedrock, or the seabed where groundwater exists, or on the earth's surface or in contact with river water, seawater, or the like.

The control method further includes the step of providing a hole in the above-mentioned region, and the step of providing an ion supply material includes providing the ion supply material inside the hole, and at least one of the flow rate, flow direction, and retention amount of water inside and around the hole may be changed by precipitating sparingly soluble salts inside and around the hole. This allows for appropriate control of water present underground or on the surface, and prevents the occurrence of disasters, pollution, and the like. Note that in this disclosure, "hole" includes one with a bottom. Furthermore, "providing" an ion supply material includes "filling," "injecting," "putting in," "inserting," "encapsulating," and the like, depending on the form of the ion supply material.

The ion supply material may be provided upstream of an area where water inflow should be reduced. The ion supply material may be provided downstream of an area where water outflow should be reduced. The ion supply material may be provided along a flow path that guides water. This allows for appropriate control of water underground and on the surface, preventing disasters and pollution.

Ion supply materials may be present at multiple locations in the above-mentioned region, and at least one of the flow rate, flow direction, and retention volume of water may be changed by the precipitation of sparingly soluble salts between adjacent ion supply materials. This allows for appropriate control of water underground and on the surface, preventing the occurrence of disasters and pollution.

At least a portion of the poorly soluble salt precipitated between adjacent ion supply materials may merge to form a wall. This can further change at least one of the flow rate, flow direction, and retention amount of water present underground or on the surface.

Multiple holes may be provided, and the spacing between the holes may be determined based on the diffusion coefficient of at least one of cations and anions at the locations where the holes are provided. This allows for appropriate control of water present underground and on the surface, while also reducing construction time and costs.

The spacing between the multiple holes may be determined based on the relationship D = VL between the width L (cm) of the reaction edge of the sparingly soluble salt formed around the hole, the speed V (cm/s) at which the reaction edge is formed, and the diffusion coefficient D (cm ² /s). This makes it possible to appropriately control water present underground and on the surface, and also reduces construction time and costs.

The sparingly soluble salt may be calcium carbonate. This reduces material costs while improving the durability of equipment for controlling water present underground or on the surface.

When calcium carbonate precipitates, it may also absorb strontium contained in the water. This can reduce the amount of radioactive strontium isotopes contained in water underground and on the surface of the earth.

The ion supply material may include a base material and at least one of a first compound and a second compound mixed into the base material. This can reduce construction time and costs.

The base material may contain epoxy resin. This allows ions to be gradually released from the first compound and second compound mixed into the base material, thereby more reliably sealing off voids inside and around the borehole 4.

A pH adjuster may be placed inside the hole to increase the pH of the water. This can reduce the iron ions and heavy metal ions contained in water underground and on the surface.

The reinforcement method disclosed herein comprises the steps of providing, in at least one of the underground and the surface, an ion supply material containing at least one of a first compound capable of generating cations that constitute sparingly soluble salts and a second compound capable of generating anions that constitute sparingly soluble salts, and reinforcing at least one of the underground and the surface by precipitating sparingly soluble salts around the ion supply material. This allows for appropriate reinforcement of the underground and the surface, preventing the occurrence of disasters and other problems. It also reduces construction time and costs.

The purification method disclosed herein comprises the steps of providing, at least either underground or on the surface of the earth, an ion supply material containing at least one of a first compound capable of generating cations that constitute sparingly soluble salts and a second compound capable of generating anions that constitute sparingly soluble salts, and reducing harmful ions present around the ion supply material by forming sparingly soluble salts with cations or anions and precipitating them. This allows for the proper purification of the underground and the surface of the earth, preventing disasters and pollution, and reducing construction time and costs.

The harmful ions may be sulfate ions, which can prevent corrosion of concrete and other materials and improve durability.

The structure disclosed herein is present in an area where water exists underground or on the surface of the earth, and includes an ion supply material containing at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating anions that constitute a poorly soluble salt, and poorly soluble salt present around the ion supply material. This allows for appropriate control of water present underground or on the surface of the earth, thereby preventing the occurrence of disasters, pollution, and the like. Furthermore, because water present underground or on the surface of the earth can be controlled using a simpler method, construction time and costs can be reduced.

The ion supply material may be present inside pores in the above-mentioned area. This allows for appropriate control of water underground or on the surface, preventing disasters and pollution. Furthermore, since water underground or on the surface can be controlled using a simpler method, construction time and costs can be reduced.

The disclosed method for repairing a workpiece includes adding an ion supply material near the sparingly soluble salt. This improves the durability of equipment for controlling water present underground or on the surface, enabling appropriate control of water present underground or on the surface over the long term.

The disclosed method for repairing a workpiece includes the steps of creating a new hole near the existing hole and providing an ion supply material inside the new hole. This improves the durability of equipment for controlling water present underground or on the surface, enabling appropriate control of water present underground or on the surface over the long term.

1 Facility, 2 Groundwater, 3 Groundwater control facility, 4 Borehole, 5 Ion supply material, 6 Sparingly soluble salt, 7 Contamination source, 8 Underground structure, 9 Dam, 10 Levee, 11 Levee body, 12 Ion supply material, 13 Sparingly soluble salt.

Claims (14)

providing an ion supplying material containing at least one of a first compound capable of generating cations constituting a poorly soluble salt and a second compound capable of generating an anion constituting the poorly soluble salt in a region where water exists in at least one of the underground and the surface of the earth;
A step in which the hardly soluble salt is precipitated around the ion supply material, thereby changing the flow direction of the water;
Equipped with
The ion supplying material is provided along the flow path through which the water is to be guided.
Control method. providing holes in the region;
providing the ion supply material includes providing the ion supply material within the hole;
The control method according to claim 1 , wherein the precipitation of the hardly soluble salt inside and around the hole changes at least one of the flow rate, flow direction, and retention amount of the water inside and around the hole. 3. The control method according to claim 1, wherein the ion supplying material is provided upstream of a region where the inflow of water is to be reduced. 4. The control method according to claim 1, wherein the ion supplying material is provided downstream of a region where the outflow of water is to be reduced. A control method described in any one of claims 1 to 4, wherein the ion supply material is present at multiple locations in the region, and at least one of the flow rate, flow direction, and retention volume of the water is changed by the precipitation of the sparingly soluble salt between adjacent ion supply materials. 6. The control method according to claim 5 , wherein at least a portion of the hardly soluble salt precipitated between adjacent ion supply materials is integrated to form a wall. A plurality of the holes are provided,
The control method according to claim 2 , wherein the intervals between the plurality of holes are determined based on the diffusion coefficient of at least one of the cations and the anions at locations where the plurality of holes are provided. The control method according to claim 7, wherein the spacing between the plurality of holes is determined based on the relationship D= VL between the width L (cm) of the reaction edge of the hardly soluble salt formed around the hole, the speed V (cm/s) at which the reaction edge is formed, and the diffusion coefficient D (cm ² /s). the poorly soluble salt is calcium carbonate,
9. The control method according to claim 1, wherein strontium contained in the water is taken up when calcium carbonate precipitates. The control method according to claim 1 , wherein the ion supply material includes a base material and at least one of the first compound and the second compound mixed in the base material. 9. The control method according to claim 2 , 7, or 8 , wherein a pH adjuster for increasing the pH of the groundwater is provided inside the hole. In order to repair a workpiece, the workpiece is present in an area where water exists underground and/or on the surface of the earth, and the workpiece includes an ion supply material containing at least one of a first compound capable of generating cations constituting a poorly soluble salt and a second compound capable of generating anions constituting the poorly soluble salt, and the poorly soluble salt is present around the ion supply material, the method includes adding the ion supply material to the vicinity of the poorly soluble salt.
How to repair a workpiece . The method for repairing a workpiece according to claim 12 , wherein the ion source material is present within holes present in the region. providing a new hole adjacent to the hole;
providing the ion supply material inside the new hole;
The method of claim 13 , comprising: