JP2016211191A - Water collecting pipe of potential difference-type groundwater removal facility, and method for preventing slime adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water collecting pipe of a potential difference-type groundwater removal facility and a method for preventing slime adhesion capable of maintaining a groundwater removal function without periodical maintenance, reducing maintenance and management costs of a groundwater removal facility, and applicable to diverse groundwater environments.SOLUTION: A water collecting pipe of a groundwater removal facility is buried with an inclination on a slope surface of a natural ground. A water collecting pipe 1 includes a pipe body 2 having a strainer 3 pierced through an outer peripheral wall for collecting groundwater of the natural ground, and an exhaust port provided at an end on a downstream side for draining the groundwater collected through the strainer. A composite metallic member 6 is laid on a groundwater flow channel inside the pipe body 2, the composite metallic member having a first metallic member with a prescribed ionization tendency and a second metallic member connected electrically with the first metallic member. When the composite metallic member comes in contact with the groundwater collected in the pipe body, a potential difference is generated between the first and the second metallic members, the groundwater serving as an electrolyte. Consequently, an electron is discharged that suppresses oxidization of an iron ion contained in the groundwater.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water collecting pipe for a potential difference type groundwater drainage facility and a slime adhesion preventing method, and in particular, is installed on a slope of a natural ground to prevent the occurrence of a landslide, and collects groundwater from the natural ground and discharges it to the surface. The present invention relates to a technique for preventing adhesion of slime in a water pipe using a potential difference generated between different metal members.

  As one of the landslide countermeasure technologies, a strained groundwater catchment pipe is buried in the ground, and the groundwater contained in the ground is discharged to the ground surface through this catchment pipe, thereby reducing the groundwater level and generating landslides. Methods for suppressing are known. Landslide countermeasures using groundwater collection pipes are implemented in many areas. However, it has been confirmed that the drainage function of groundwater is reduced due to clogging of the strainer, and there is concern about the impact on the landslide prevention effect. In addition, it has been confirmed that the substance causing this clogging is a slime produced mainly by iron bacteria (iron bacteria) using iron in groundwater.

  In view of this, an apparatus has been proposed that prevents clogging by suppressing the growth of iron bacteria, which are aerobic bacteria. That is, an apparatus (for example, Patent Document 1) that connects a pipe to a water collection pipe and prevents air from entering the pipe and assembles it, or an open end that is a drain end of the pipe connected to the water collection pipe. An apparatus (for example, Patent Document 2) arranged so as to be immersed under the water surface is known. However, in these apparatuses, a sufficient prevention effect may not be recognized.

  For this reason, until now, the inner wall of the underground water collection pipe was washed with high-pressure water, and the slime, which is a clogging substance adhering to and accumulated in the collection pipe, was removed to restore the lowered groundwater removal function. . However, cleaning with high water pressure requires regular maintenance of the groundwater collection pipe. For this reason, enormous maintenance costs have arisen due to this, and it has become an issue to develop a function maintenance management technology for groundwater catchment pipes that can be rational and reduce costs.

  On the other hand, in order to solve such a problem, the inventor of the present application has devised a method for preventing slime adhesion to a water collecting pipe using a metal material of a magnesium alloy (Patent Document 3). In this method, the electrons generated by the dissolution (ionization) of magnesium act on the dissolved iron (divalent iron ions) in the groundwater to suppress the oxidation of iron ions, thereby preventing the growth of slime in the water collection pipe. It is very easy to prevent. However, since the metal material of the magnesium alloy is relatively expensive, it cannot always be said to be low in cost, and in order to cope with the groundwater environment that varies from region to region, the magnesium alloy is not suitable. It is expected to be difficult only with the method used.

  In addition, as a technology related to these, an iron oxide deposition preventive agent mainly composed of aluminum, which can prevent iron hydroxide and the like from being deposited on equipment such as dark drainage pipes that come into contact with iron-containing acidic water, and the use thereof. A method for preventing clogging of a dark drainage pipe has been proposed (Patent Document 4). However, the facility targeted by this technology is iron-containing acidic water at the test field in the volcanic mudflow area. Its water quality environment is pH 5.89-5.99, SO4 ion 500 mg / l, Ca ion 250 mg / l. Therefore, it is different from the general groundwater environment (pH 6.0 or higher, soft water), and the effect is considered to be limited. Accordingly, there is a need for a slime adhesion prevention measure that can be rationally and cost-effectively and that can be applied to the groundwater environment of various groundwater drainage facilities.

JP 2001-040673 A JP 2001-090094 A Japanese Patent Application No. 2015-068127 JP 2011-245457 A

  Therefore, the present invention can maintain the groundwater drain function without requiring regular maintenance, which has been conventionally required, and can reduce maintenance costs in the groundwater drain facility, and can also be applied to various groundwater environments. An object of the present invention is to provide a water collecting pipe for a potential difference type groundwater drainage facility and a slime adhesion preventing method that can be used.

  In order to achieve the above object, the invention according to claim 1 is a water collecting pipe for a groundwater drainage facility embedded in a slope of a natural ground, and is a strainer for collecting the groundwater of the natural ground. Is provided in the outer peripheral wall, and has a pipe body provided with a discharge port for discharging groundwater collected through the strainer at the downstream end, and has a predetermined ionization tendency inside the pipe body. A first metal member having a first metal component as a main component and a second metal component having a different ionization tendency from the first metal component as a main component and electrically connected to the first metal member A composite metal member having a second metal member formed therein is provided with a flow path for groundwater, and when the composite metal member comes into contact with the groundwater collected in the pipe body, the groundwater A potential difference is generated between the first and second metal members using an electrolyte as an electrolyte, Wherein the releasing of inhibiting electrons oxidation of iron ions contained in the groundwater.

  According to a second aspect of the present invention, in the water collecting pipe for the potential difference type groundwater drainage facility according to the first aspect, the composite metal member is disposed on an outer periphery of the metal pipe mainly composed of the first metal component. A metal wire having a metal component as a main component is wound and configured.

  The invention according to claim 3 is the drainage pipe for the potential difference type groundwater drainage facility according to claim 1 or 2, wherein the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body. And the elbow pipe which drains the stored groundwater from the position higher than the upper end part of this discharge port is connected to the discharge port of a pipe body, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, in the water collecting pipe for a potential difference type groundwater drainage facility according to the first or second aspect, the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body. In addition, a lid member for draining the stored groundwater from substantially the same height as the upper end of the discharge port is connected to the discharge port of the pipe body.

  The invention according to claim 5 is a method for preventing the adhesion of slime that induces blockage of a water collecting pipe for groundwater drainage facilities that is buried in a slope of a natural ground, and collects groundwater from the natural ground. A first metal having a predetermined ionization tendency in a pipe body provided with a discharge port for draining groundwater collected through the strainer at a downstream end. A first metal member having a component as a main component and a second metal component having a second metal component having a different ionization tendency as a main component and the second metal component electrically connected to the first metal member. The metal member is inserted and disposed, and is brought into contact with the groundwater collected in the pipe body, and the groundwater is used as an electrolytic solution due to a potential difference generated between the first and second metal members. The generated electrons are converted into iron ions contained in groundwater. By use by inhibiting the oxidation of iron ions, characterized in that for preventing slime adhesion to the interior pipe main body.

  According to a sixth aspect of the present invention, in the potentiometric slime adhesion preventing method according to the fifth aspect, the composite metal member is formed on the outer periphery of a metal tube containing the first metal component as a main component. It is characterized by being configured by winding a metal wire whose main component is.

  The invention according to claim 7 is the potentiometric slime adhesion prevention method according to claim 5 or 6, wherein the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, An elbow pipe for draining the stored groundwater from a position above the upper end of the outlet is connected to the outlet of the pipe body.

  The invention according to claim 8 is the potentiometric slime adhesion prevention method according to claim 5 or 6, wherein the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, A lid member that drains the stored groundwater from substantially the same height as the upper end of the discharge port is connected to the discharge port of the pipe body.

  The invention according to claim 9 is the potentiometric slime adhesion preventing method according to any one of claims 5 to 8, wherein the iron component contained in the ground is eluted and flows into the pipe body of the water collecting pipe. It is characterized by embedding or spreading an iron component elution suppressing material that suppresses the above in the surface of the natural ground.

  This invention is as described above, and according to the invention described in claim 1, is a water collecting pipe for a groundwater drainage facility that is embedded in a slope of a natural mountain, A strainer for collecting water is drilled in the outer peripheral wall, and a pipe body having a discharge port for discharging groundwater collected through the strainer is provided at the downstream end. A first metal member having a first metal component having an ionization tendency as a main component, and a second metal component having a different ionization tendency from the first metal component as a main component; When the composite metal member having the second metal member electrically connected is disposed while securing the flow path of the groundwater, and the composite metal member comes into contact with the groundwater collected in the pipe body In addition, a potential difference is generated between the first and second metal members using the groundwater as an electrolyte. Because it emits electrons that suppress the oxidation of iron ions contained in the groundwater, it has a very simple structure in which a composite metal member made of different metals with different ionization tendency is arranged inside the tube body. It is possible to suppress oxidation of iron ions in groundwater, which causes slime generation. As a result, the groundwater draining function of the water collecting pipe can be maintained without requiring regular maintenance as in the prior art, and the maintenance cost can be reduced. Further, by selecting / changing the type of different metal, the amount of electrons emitted into the groundwater can be adjusted as appropriate, and the present invention can be applied to various groundwater environments having different groundwater properties.

  According to the invention described in claim 2, the composite metal member is formed by winding a metal wire mainly composed of the second metal component around an outer periphery of a metal tube mainly composed of the first metal component. Since it is comprised, a composite metal member can be comprised very simply. Moreover, by making one metal member tubular, the range which contacts with groundwater becomes large, and the contact to the groundwater of a composite metal member and discharge | release of an electron can be maintained over a long period of time.

  According to the third aspect of the present invention, the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, and the stored groundwater is located above the upper end of the outlet. Since the elbow pipe draining from the position is connected to the outlet of the pipe body, the ground metal is impregnated in the ground water in the area where the ground water is stored near the outlet, and the time for the ground water to contact the composite metal member is increased. It can be secured sufficiently. Thereby, generation | occurrence | production of the electromotive force accompanying the electric potential difference between dissimilar metal members and discharge | release of the electron to groundwater can be maintained over a long period of time, and the slime adhesion prevention effect improves. Moreover, since the range in which groundwater contacts with outside air is limited only to the vicinity of the opening of the elbow pipe, oxidation of iron ions contained in the groundwater itself is suppressed, and the slime adhesion preventing effect is further improved.

  According to the fourth aspect of the present invention, the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, and the stored groundwater is substantially the same as the upper end of the outlet. Since the lid member that drains from the height is connected to the outlet of the pipe body, the time for the ground metal to impregnate the ground water in the portion where the ground water near the outlet is stored and the ground water contacts the composite metal member Can be secured sufficiently. Thereby, generation | occurrence | production of the electromotive force accompanying the electric potential difference between dissimilar metal members and discharge | release of the electron to groundwater can be maintained over a long period of time, and the slime adhesion prevention effect improves. Moreover, since a space above the upper end of the discharge port of the pipe body is not required, it is possible to save the space of the entire water collection pipe.

  According to the invention described in claim 5, there is provided a method for preventing the adhesion of slime that induces blockage of a water collecting pipe for groundwater drainage facilities that is embedded in a slope of a natural ground, wherein the groundwater in the natural ground is A first strainer having a predetermined ionization tendency is formed in a pipe body in which a strainer for collecting water is formed in the outer peripheral wall, and a discharge port for draining groundwater collected through the strainer is provided at an end on the downstream side. The first metal member having the metal component as a main component and the second metal component having a different ionization tendency as the main component are electrically connected to the first metal member. A composite metal member having a second metal member is inserted and arranged, brought into contact with groundwater collected in the pipe body, and the potential difference generated between the first and second metal members using the groundwater as an electrolytic solution. The electrons generated by the iron ions contained in the groundwater This prevents the slime from adhering to the inside of the tube body by suppressing the oxidation of iron ions by acting on the metal, so a composite metal member made of different metals with different ionization tendency is inserted and arranged inside the tube body By this extremely simple method, oxidation of iron ions in groundwater that causes slime generation can be suppressed. As a result, the groundwater draining function of the water collecting pipe can be maintained without requiring regular maintenance as in the prior art, and the maintenance cost can be reduced. Further, by selecting / changing the type of different metal, the amount of electrons emitted into the groundwater can be adjusted as appropriate, and the present invention can be applied to various groundwater environments having different groundwater properties.

  According to the invention described in claim 6, the composite metal member has a metal wire mainly composed of the second metal component wound around an outer periphery of the metal tube mainly composed of the first metal component. Since it is comprised, a composite metal member can be comprised very simply. Moreover, by making one metal member tubular, the range which contacts with groundwater becomes large, and the contact to the groundwater of a composite metal member and discharge | release of an electron can be maintained over a long period of time.

  According to the invention described in claim 7, the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, and the stored groundwater is located above the upper end of the outlet. Since the elbow pipe that drains from the position is connected to the outlet of the pipe body, the composite metal member is impregnated in the groundwater in the part where the groundwater is stored near the outlet, and sufficient time is allowed for the groundwater to contact the composite metal member. Can be secured. Thereby, generation | occurrence | production of the electromotive force accompanying the electric potential difference between dissimilar metal members and discharge | release of the electron to groundwater can be maintained over a long period of time, and the slime adhesion prevention effect improves. Moreover, since the range in which groundwater contacts with outside air is limited only to the vicinity of the opening of the elbow pipe, oxidation of iron ions contained in the groundwater itself is suppressed, and the slime adhesion preventing effect is further improved.

  According to the invention described in claim 8, the groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, and the stored groundwater is substantially the same as the upper end of the outlet. Since the lid member that drains from the height is connected to the discharge port of the pipe body, the composite metal member is impregnated in the groundwater in the part where the groundwater is stored near the discharge port, and the time for the groundwater to contact the composite metal member is sufficient. Can be secured. Thereby, generation | occurrence | production of the electromotive force accompanying the electric potential difference between dissimilar metal members and discharge | release of the electron to groundwater can be maintained over a long period of time, and the slime adhesion prevention effect improves. Moreover, since a space above the upper end of the discharge port of the pipe body is not required, it is possible to save the space of the entire water collection pipe.

  According to invention of Claim 9, the iron component elution suppression material which suppresses that the iron component contained in the said natural ground elutes and flows in into the pipe main body of a water collection pipe is embed | buried in the surface of the said natural ground Or since it spreads, the elution itself of iron contained in soil can be eased and the inflow of iron ions into the water collecting pipe can be suppressed. Thereby, it can suppress that the density | concentration of the iron ion in groundwater increases, and the adhesion prevention effect of the slime in a water collection pipe | tube can be improved.

It is a schematic cross section which shows the whole structure of the horizontal boring to which the water collecting pipe for potential difference type groundwater drainage facilities which concerns on embodiment of this invention was applied. It is a photograph which shows the slime adhesion state before the test of the horizontal boring which implemented the confirmation test of the slime adhesion prevention method same as the above. It is explanatory drawing which shows the structural example of the composite metal member arrange | positioned in each water collecting pipe same as the above, (a) is the composite metal member of Example 1 comprised by winding a copper wire around a magnesium pipe, (b) Is a composite metal member of Example 2 configured by winding a copper wire around an aluminum tube, and (c) is a configuration example of a composite metal member of a comparative example configured by winding an aluminum wire around an aluminum tube. It is a photograph which shows the external appearance of the slime adhesion condition to the elbow pipe hole mouth about two weeks after the test start same as the above, (a) is the water collecting pipe which inserted the composite metal member of Example 1, (b) is an Example. 2 is a water collecting pipe into which the composite metal member is inserted, and (c) is an elbow pipe hole of the water collecting pipe into which the composite metal member of the comparative example is inserted. It is a photograph which shows the change condition of the composite metal member inserted in the water collection pipe same as the above, (a) is the composite metal member of Example 1, (b) is the composite metal member of Example 2, (c) is It is the change condition of the composite metal member of a comparative example. It is a photograph which shows the condition of the waste_water | drain stored in the water collection pipe same as the above, (a) is a water collection pipe which inserted the composite metal member of Example 2, (b) is a collection which inserted the composite metal member of a comparative example. This is the situation of the wastewater stored in the water pipe. It is explanatory drawing which shows another structural example of a composite metal member. It is explanatory drawing which shows the example of a connection of the composite metal member arrange | positioned in the adjacent water collecting pipe. It is explanatory drawing which shows the example which applied the connection of FIG. 8 to the six water collection pipes installed in the groundwater drainage facility. It is a photograph which shows the external appearance of the cover member connected to a drain pipe outlet same as the above, (a) is the cover member R, (b) is the external appearance of the cover member R 'as the modification. (A) is the front view and side sectional view which show the state where lid member R same as the above was connected to the discharge port, and (b) the front view showing the state where lid member R 'same as the above was connected to the discharge port It is a figure and side sectional drawing.

  Hereinafter, the case where the water collecting pipe for a potential difference type groundwater drainage facility according to an embodiment of the present invention is applied to horizontal boring which is a groundwater drainage facility will be described as an example.

  FIG. 1 is a schematic cross-sectional view showing the overall configuration of horizontal boring, which is a groundwater drainage facility. In FIG. 1, reference numeral 1 denotes a water collecting pipe. The water collecting pipe 1 is embedded below the ground water surface of the natural ground A in an inclined state with its open end facing downward. The water collecting pipe 1 has a pipe main body 2 made of a hollow cylindrical pipe, the upper end of which is closed, so that earth and sand do not enter from the upper end, and the opened lower end protrudes from the earth wall B of the natural ground A. Has been. In the length direction of the tube body 2, a plurality of strainers 3, which are holes penetrating the tube wall of the tube body 2, are formed at predetermined intervals. Therefore, since the pipe body 2 to which the strainer 3 is applied is buried in the natural ground A in a downward inclined posture from the upper end to the lower end, water is collected from the natural ground A into the pipe main body 2 via the strainer 3. The underground water 4 is led from the earth wall B to a lower discharge port opened.

  An elbow pipe E is connected to the discharge port of the pipe body 2. As shown in the figure, one end of the elbow pipe E is connected to the discharge port of the tube main body 2, and the other end is a hole that opens outward at a position above the upper end of the discharge port. . Therefore, the groundwater led to the discharge port of the pipe body 2 is temporarily stored in the vicinity of the discharge port of the pipe body 2 without being immediately drained, and when the height reaches the lower end of the hole of the elbow pipe E, It is discharged as 5.

  On the other hand, a composite metal member 6 configured by connecting two kinds of metal members having different ionization tendencies to each other is disposed inside the tube body 2 while securing a flow path of groundwater flowing through the tube body 2. Yes. Specifically, the composite metal member 6 includes a metal tube (first metal member) mainly composed of a first metal component having a predetermined ionization tendency, and an ionization tendency different from that of the first metal component. A metal wire having a second metal component as a main component (second metal member), and one end of the metal wire is wound around the outer peripheral surface of the upstream end of the metal tube a plurality of times Has been.

  As a method of fixing the composite metal member 6 to the tube main body 2, for example, a metal tube wound with a metal wire is fixed directly to the bottom of the tube main body 2 by heat welding or removably fixed via a support member. Although any method can be employed, it is sufficient that a sufficient flow path for guiding the groundwater to the discharge port side of the pipe body 2 is ensured regardless of which method is used.

  According to the water collecting pipe 1 configured as described above, the groundwater 4 collected inside through the strainer 3 is in contact with the composite metal member 6 disposed inside the pipe main body 2 while being discharged from the lower end. Guided to the side. The composite metal member 6 is configured by connecting two kinds of metal members (metal tube and metal wire) having different ionization tendencies as described above, but in this way, metals having different ionization tendencies are made into an appropriate electrolyte solution. When immersed, a potential difference is generated between the metal members, and a current flows from a metal having a small ionization tendency (plus) to a metal having a high ionization tendency (minus). Electrochemically, a metal (anode) having a high ionization tendency generates electrons, and the generated electrons flow into a metal (cathode) having a low ionization tendency. At this time, a voltage (electromotive force) is generated between the two metals. The electromotive force increases as the difference in ionization tendency between the two metal components increases, and the value varies depending on the temperature of the solution and the ion concentration of the electrolyte. Further, the magnitude of the electromotive force is proportional to the magnitude of the current, and serves as an index of the amount of generated electrons.

On the other hand, iron bacteria (iron bacteria) living in groundwater oxidize divalent iron ions, which are also dissolved in groundwater, to trivalent iron ions, and use the oxidation energy generated at that time. It is known to survive and proliferate. The trivalent iron ions become reddish brown iron hydroxide (Fe (OH) ₃ ) and settle together with the organic matter produced by the iron bacteria and settle inside the water collecting pipe, causing slime that causes the water collecting pipe to become clogged. Form. At this time, in the groundwater, electrons emitted from a metal (anode) having a large ionization tendency react with divalent iron ions to prevent oxidation to trivalent iron ions.

  That is, in the water collection pipe 1, the composite metal member 6 having different metal members having different ionization tendencies arranged inside the pipe main body 2 is in contact with the ground water 4 collected in the pipe main body 2. Thus, a potential difference is generated between the metal members using the groundwater 4 as an electrolytic solution, and electrons are emitted from the metal member (anode) having a large ionization tendency. And the emitted electron reacts with the bivalent iron ion contained in groundwater, and the production | generation of the trivalent iron ion which is a causative substance of slime is suppressed by suppressing the oxidation. Further, by suppressing the oxidation of divalent iron ions, the oxidation energy generated during the oxidation is reduced, and the growth of iron bacteria that survive using this energy is also suppressed. Thereby, the adhesion of slime to the inside of the tube body 2 is prevented. Further, in the water collecting pipe 1, by promoting dissimilar metals having different ionization tendencies and immersing them in the ground water, the ionization of the anode metal (electric corrosion) and the anticorrosion effect of the cathode metal are expected.

  In addition, by connecting the elbow pipe E to the discharge port of the pipe body 2 as shown in the figure, the composite metal member 6 is impregnated in the groundwater in the portion where the groundwater near the discharge port is stored, and the groundwater is mixed with the composite metal member 6. Sufficient time for contact can be secured. For this reason, generation | occurrence | production of the electromotive force accompanying the electric potential difference between two types of metal members and discharge | release of the electron to groundwater can be maintained over a long time, and the adhesion prevention effect of slime improves. Moreover, since the range in which groundwater contacts with outside air is limited only to the vicinity of the opening of the elbow pipe E, the oxidation of divalent iron ions contained in the groundwater itself is suppressed, and the slime adhesion preventing effect is further enhanced. be able to.

  Next, a potential difference type slime adhesion preventing method for a water collecting pipe according to an embodiment of the present invention will be described. Here, a case where the slime adhesion preventing method is applied to an existing water collection pipe installed in a groundwater drainage facility such as horizontal boring will be described as an example.

(Composite metal member insertion process)
First, a composite metal member constituted by connecting two types of metal members having different ionization tendencies to each other is inserted and arranged from the outlet side inside a pipe body of an existing water collection pipe installed in a groundwater drainage facility. The composite metal member is arranged along the bottom of the pipe body so as to be surely brought into contact with the groundwater flowing from the upper end when it is arranged inside the pipe body of the water collecting pipe. As a composite metal member, as described above, a metal tube mainly composed of a metal component having a predetermined ionization tendency is wound around a metal tube mainly composed of a metal component having an ionization tendency different from the component, The thing which connected both can be used.

  Then, the composite metal member is impregnated in the ground water to generate an electromotive force between the metal members having different ionization tendency, and electrons are emitted from the metal (anode) having a large ionization tendency into the ground water. The emitted electrons react with divalent iron ions dissolved in the groundwater, and the divalent iron ions are oxidized to suppress the action of trying to become trivalent iron ions. This reduces the oxidation energy generated in groundwater, suppresses the growth of iron bacteria, suppresses the formation of trivalent iron ions that cause slime, and prevents the slime from adhering to the tube body. To do.

  In order to continuously generate an electromotive force between two types of metal members, an elbow pipe is connected to the outlet of the pipe body, groundwater is temporarily stored, and a composite metal member is impregnated in the storage portion. To do. As a result, sufficient time for the groundwater to contact the composite metal member can be secured, and the generation of electromotive force due to the potential difference between the two types of metal members and the emission of electrons into the groundwater can be sustained for a long time. be able to. Moreover, the range in which groundwater contacts with outside air is limited only to the vicinity of the opening of the elbow pipe E, and oxidation of divalent iron ions contained in the groundwater itself is suppressed. Therefore, the slime adhesion preventing effect can be further enhanced.

(Spreading process of iron elution inhibitor)
Further, as an additional factor for promoting the slime adhesion preventing effect, in addition to the composite metal member insertion step, a metal material (eg, a magnesium metal material or a calcium-containing material) containing a typical element belonging to Group 2 of the periodic table as a main component It is also effective to embed or disperse) in the topsoil of the natural ground where the water collection pipe is buried as an iron elution inhibitor.

  In other words, these substances, which are more easily ionized than iron, react and neutralize the causative substances sulfate, nitrate, and chloride contained in acid rain. It has the effect of mitigating and suppressing the inflow of iron ions into the water collection pipe. In addition, since calcium-containing materials are easily soluble in water, a high immediate effect can be expected in the effect of preventing the elution of iron by acid rain. On the other hand, since the dissolution speed of the magnesium metal material is relatively gentle, the elution effect of iron can be maintained for a long time. Thus, if the inflow of iron ions into the water collection pipe is suppressed, the concentration of iron ions in the groundwater can be suppressed, and the effect of preventing the adhesion of slime into the water collection pipe can be further improved. .

  In addition, this inventor implemented the above-mentioned potentiometric slime adhesion prevention method in the actual landslide site, and performed the confirmation test about the effect. Hereinafter, the test results will be described. The confirmation test was conducted by horizontal boring in Niigata Prefecture, a groundwater drainage facility for landslides in the mudstone area.

  In order to examine how different types of metals that make up the composite metal member should be selected when conducting the test, the waste water discharged from the water collection pipes installed in the actual horizontal boring is used. The magnitude of the generated electromotive force was measured. The measurement results are shown in Table 1.

  According to Table 1, in this measurement, when the anode is magnesium and the cathode is copper, the electromotive force is maximum (1.6 V), and when the anode is aluminum and the cathode is iron, the electromotive force is minimum (0. 15V). In addition, the electromotive force when other metals are combined is as shown in Table 1.

  This measurement result is an index for judging how large the electromotive force generated between different metals is for the wastewater discharged from the groundwater drainage facility. That is, from this measurement result, even the drainage of an unknown groundwater drainage facility can be roughly estimated if it is an electromotive force between different metals listed in Table 1. In addition, by changing the combination of different metals, it is possible to select a slime adhesion prevention condition suitable for the properties of groundwater. From the above measurement results, in this test, a composite metal member was configured using a metal member containing aluminum, copper, and magnesium as active ingredients, and the test was performed.

  FIG. 2 shows the state of slime adhesion to the horizontal boring before the test. This horizontal boring is a facility where a large amount of iron bacteria slime adheres to the water collection pipe in less than one year after the establishment of the facility, and it can be seen that a large amount of slime adheres to the water collection pipe. The total length of each drainage pipe installed in this horizontal boring is about 60m from the lower end outlet to the upper end, but before the start of the test, the section about 20m deep from the outlet of the water collection pipe, the drainage pipe protection wall, etc. Was cleaned with a brush or the like.

  The confirmation test was carried out with three water collecting pipes indicated by circles in FIG. Of these, a copper wire as a second metal member is wrapped around the end of a 2.0 m long magnesium alloy tube (magnesium tube) as the first metal member, as the first example, around the central water collecting pipe. Then, a composite metal member having a total length of about 10 m was inserted by connecting three of them together with the extension of the copper wire. Moreover, the copper wire which is a 2nd metal member is attached to the end part of the aluminum alloy pipe | tube (aluminum tube) of length 2.0m which is a 1st metal member as Example 2 in the right end water collecting pipe. A composite metal member having a total length of about 10 m was inserted by winding and connecting three of them together with an extension of the copper wire. Further, the water collecting pipe at the left end is a composite metal member composed of the same kind of metal member, and an aluminum wire is wound around an aluminum alloy pipe (aluminum pipe) having a length of 2.0 m, and three of these are connected to form a copper wire. A total length of about 10 m was inserted together with the extension, and this was used as a comparative example.

  In addition, in each water collecting pipe, slime is likely to be generated near the opening of the elbow pipe where the ground water comes into contact with the outside air. A short cut magnesium tube was inserted into the section up to the mouth. Similarly, in the water collection pipe (Example 2 and Comparative Example) into which the aluminum pipe was inserted, an aluminum wire formed in a spiral shape was inserted into a section from the discharge port of the water collection pipe to the hole of the elbow pipe. The structural example of the composite metal member of these Examples 1 and 2 and a comparative example is shown to Fig.3 (a)-(c).

  The magnesium tube used in this test is approximately 3% aluminum and approximately 1% zinc, which is marked as “AZ31” in the ASTM standard (American Society of Testing and Materials). %, A magnesium alloy tube comprising about 96% magnesium was used. Moreover, the aluminum tube used the thing with an aluminum component of almost 100%, and the surface was grind | polished with sandpaper and the oxide film currently formed on the surface of the pipe | tube was fully removed.

Table 2 shows the properties of the drainage from each water collection pipe before the start of the test. In order to simplify the notation here, the composite metal member of Example 1 is (magnesium tube + copper wire), the composite metal member of Example 2 (aluminum tube + copper wire), and the composite metal member of Comparative Example is (Aluminum tube + aluminum wire). As shown in Table 2, the drainage from each water collection pipe has a pH of 6.4 to 6.6, and is neutral and soft water. Moreover, total iron (T-Fe) is 13.0-20.0 mg / l, and it is the water quality which a slime adheres to a water collection pipe very easily. The amount of slime attached to the water collection pipe increases when total iron (T-Fe) is 1 mg / l or more. Table 2 shows the amounts of iron ions (Fe), sulfate ions (SO ₄ ²⁻ ), and calcium ions (Ca ²⁺ ) contained in the groundwater of each water collecting pipe.

  FIG. 4 shows the internal state of each elbow tube hole opening about two weeks after the start of the test. In FIG. 4, (a) is a water collecting pipe of Example 1 in which (magnesium pipe + copper wire) is inserted, (b) is a water collecting pipe of Example 2 in which (aluminum pipe + copper wire) is inserted, (c) is It is an internal condition of each elbow pipe hole about the water collection pipe of the comparative example which inserted (aluminum pipe + aluminum wire).

  As shown to Fig.4 (a), in Example 1 which wound the copper wire around the magnesium tube and was inserted, adhesion of slime was recognized and the generation amount was also remarkable. However, since a large amount of slime was temporarily observed in the water collection pipe port where the magnesium pipe was inserted, it seems that more time-consuming testing / survey is necessary. On the other hand, as shown in FIG. 4B, in Example 2 in which a copper wire was wound around an aluminum tube and inserted, almost no slime was observed. Further, as shown in FIG. 4 (c), in the comparative example in which the aluminum wire was wound and inserted into the aluminum tube, a large amount of slime was generated so that the spiral aluminum wire could not be seen at all when placed in the hole of the elbow tube. .

  FIG. 5 shows a change state of each composite metal material inserted into the water collecting pipe. In Example 1 (magnesium tube + copper wire) shown in FIG. 5 (a), the entire magnesium tube is covered with black-green deposits to cause significant corrosion, and the tube surface has deposits and pinholes close to metallic iron. There were several places. Moreover, although the connection part with the magnesium pipe was discolored black in the copper wire, the straight line part was coated with a metallic luster material in some places.

  On the other hand, in Example 2 (aluminum tube + copper wire) shown in FIG. 5 (b), the adhesion of slime to the tube surface could hardly be confirmed. Moreover, the connection part with the aluminum pipe was discolored black like the Example 1 copper wire, and the metallic luster was confirmed by the linear part. Furthermore, the stored drainage of the water collection pipe was dark black-green (see FIG. 6 (a)). In addition, in the comparative example (aluminum tube + aluminum wire) shown in FIG. 5 (c), the adhesion of reddish brown slime to the tube surface was slight, but when releasing the water seal of the hole mouth, Slime-like stored drainage flowed out (see FIG. 6B).

  As a result of measuring the metallic luster attached to the copper wire with a field emission scanning electron microscope (FE-SEM), this metallic luster is an iron-based deposit excluding the underlying copper and dirt components. It was confirmed that. The main component constitution was as shown in Table 3.

  The test results in each water collecting pipe are summarized as shown in Table 4 above.

  Divalent iron ions are easily oxidized in the presence of oxygen and change to reddish brown iron hydroxide, but the hue changes from light green to grayish green to black brown to reddish brown as oxidation progresses. It is known to do. That is, in this test, the wastewater stored in the water collection pipe of the comparative example was reddish brown, whereas the wastewater stored in the water collection pipe of Examples 1 and 2 was dark black-green or black. Since it was gray, it was shown that the oxidation action of iron ions was inhibited in these water collecting pipes, and the oxidation of iron ions did not proceed. In particular, in the water collecting pipe in which (aluminum pipe + copper wire) of Example 2 was inserted, in addition to the hue of drainage, there was almost no adhesion of slime to the elbow pipe opening or the pipe surface. It was shown that the adhesion preventing effect was demonstrated.

  On the other hand, in the water collecting pipe in which (magnesium pipe + copper wire) of Example 1 was inserted, although a certain slime adhesion preventing effect was recognized, the corrosion deterioration of the magnesium pipe was remarkable, and this time from the viewpoint of the sustained prevention effect. It was not suitable for use at the test site. About this point, it is thought that corrosion deterioration can be relieved by using the connection metal with a magnesium pipe as aluminum or zinc instead of copper and reducing electromotive force. Alternatively, it is considered suitable for use in an electrochemically mild groundwater environment with a relatively small amount of iron ions and other electrolytic mass.

  As described above, according to the water collecting pipe for the potential difference type groundwater drainage facility and the slime adhesion preventing method according to the present invention, the composite metal member having different kinds of metals having different ionization tendency is inserted and arranged in the water collecting pipe and collected in the pipe. By contacting the groundwater with water, and using this groundwater as an electrolyte, a potential difference is generated between the two metal members, and electrons are released from the metal with a high ionization tendency into the groundwater, thereby preventing the slime from adhering inside the water collection pipe. It can be easily and reasonably prevented. For this reason, the regular maintenance like the conventional one becomes unnecessary, and the maintenance management cost in the groundwater drainage facility can be reduced. In addition, by preliminarily determining the characteristics and electromotive force of the drainage discharged from the water collection pipe of the groundwater drainage facility, and selecting a suitable combination of dissimilar metal members according to the characteristics of the drainage, it can be used for various groundwater environments. The invention can be applied.

  In addition, as a connection method of the dissimilar metal member which comprises a composite metal member, the 2nd metal member (copper which becomes a cathode) to the 1st metal member (magnesium tube or aluminum tube) which becomes an anode as demonstrated in FIG. 7), the first metal member and the second metal member are both made of metal pipes, and these are alternately arranged to form a metal wire of the same material as the second metal member. You may make it connect with. Alternatively, these metal tubes may be directly joined.

  Moreover, as shown in FIG. 8, it is also effective to mutually connect the composite metal members arranged in each water collection pipe with respect to the water collection pipes adjacent in the groundwater drainage facility. That is, among the water collecting pipes adjacent to each other in the groundwater drainage facility, the second metal member → the first water pipe is formed inside one of the water collecting pipes (hereinafter referred to as the first water collecting pipe) from the front end side toward the rear end side. A composite metal member connected in the order of metal member → second metal member → first metal member... Is inserted. Further, inside the water collecting pipe (hereinafter referred to as the second water collecting pipe) adjacent to the first water collecting pipe, the above is an aspect in which the connection order of the metal members is reversed, that is, from the front end side to the rear end side. The composite metal members connected in the order of the first metal member → the second metal member → the first metal member → the second metal member are inserted. Then, a metal wire such as a coated copper wire or aluminum wire is passed through the hole body of the elbow pipe E connected to the discharge port of each water collecting pipe into the pipe body, and the composite metal disposed in each water collecting pipe. Connect the members to each other.

  And as shown in FIG. 9, the composite metal member in an adjacent water collection pipe is connected similarly to the above about all the water collection pipes (here 6 pieces) installed in the groundwater drainage facility. In this way, by electrically connecting the composite metal members arranged in the adjacent water collection pipes, not only the composite metal member inserted in the same water collection pipe but also inserted in the adjacent water collection pipes. A potential difference also occurs between the composite metal members. At this time, since the groundwater contained in the soil between adjacent water collecting pipes is naturally conductive, electrons are exchanged through the strainer provided in the pipe main body of each water collecting pipe. Thereby, not only the groundwater collected in the water collection pipe but also the groundwater contained in the soil has an effect of inhibiting oxidation of iron ions, and the elution of iron ions into the water collection pipe can be suppressed.

  In addition, the elbow pipe connected to the discharge port of the pipe body is not limited to the shape shown in FIG. 1, but may be one that temporarily stores groundwater near the discharge port and drains it when a certain amount of water has accumulated. Any shape may be used. For example, the discharge port lid member R shown in FIG. 10 (a) has a main body S that is circular in front view and has an outer diameter that fits into the discharge port of the tube main body. A small circular drainage hole T is formed near the upper end of the front height direction. In addition, a partition U is provided on the back surface of the drain hole T and is partitioned so that a flow path from the discharge port of the pipe body to the drain hole T does not directly communicate (see also FIG. 11A). Further, the discharge port lid member R ′ shown in FIG. 10 (b) has a shape similar to the lid member R in FIG. 10 (a), and is a small pipe for discharging groundwater instead of drilling a drain hole in the front of the main body. V can be integrally formed on the upper portion of the main body S ′, and groundwater can be drained therefrom (see also FIG. 11B).

  In either case, the groundwater is not immediately drained from the outlet, but is temporarily stored near the outlet, and drained when the groundwater reaches almost the same height as the upper end of the outlet. As a result, as in the case of connecting the elbow pipe described above, it is possible to secure time for the groundwater to come into contact with the composite metal member, and to generate the electromotive force accompanying the potential difference between the two types of metal members and to the groundwater. The release of electrons lasts for a long time, improving the slime adhesion prevention effect.

  Moreover, when compared with the above-mentioned elbow pipe, the amount of water stored in the water collection pipe is reduced, but since a space in the height direction is not required, the space of the whole water collection pipe can be saved. In particular, in groundwater drainage facilities installed in snowy areas such as mountainous areas, snow and avalanches may damage the vicinity of the discharge port including the elbow pipe, but these lid members may cause such damage. It is almost none and is effective as an incidental facility according to the present invention.

DESCRIPTION OF SYMBOLS 1 Water collecting pipe 2 Pipe main body 3 Strainer 4 Groundwater 5 Drainage 6 Composite metal member A Ground mountain B Earth wall E Elbow pipe R, R 'Lid member

Claims (9)

It is a water collection pipe for groundwater drainage facilities that is buried on the slope of a natural mountain,
A strainer that collects groundwater of the natural ground is drilled in the outer peripheral wall, and includes a pipe main body provided with an outlet for draining groundwater collected through the strainer at an end on the downstream side,
Inside the tube main body, a first metal member mainly composed of a first metal component having a predetermined ionization tendency and a second metal component having a different ionization tendency from the first metal component are principal components. And a composite metal member having a second metal member electrically connected to the first metal member is disposed while securing a flow path of groundwater,
When the composite metal member comes into contact with the groundwater collected in the pipe body, the ground metal is used as an electrolytic solution to cause a potential difference between the first and second metal members, and iron ions contained in the groundwater Drainage pipe for potential difference type groundwater drainage facility, which emits electrons that suppress oxidation of water.   2. The potential difference formula according to claim 1, wherein the composite metal member is configured by winding a metal wire mainly composed of the second metal component around an outer periphery of a metal tube mainly composed of the first metal component. Water collection pipe for groundwater drainage facilities.   An elbow pipe for temporarily storing the groundwater collected through the strainer near the outlet of the pipe body and draining the stored groundwater from a position above the upper end of the outlet is provided on the pipe body. The water collecting pipe for a potential difference type groundwater drainage facility according to claim 1 or 2, which is connected to a discharge port.   A lid member for temporarily storing the groundwater collected through the strainer near the outlet of the pipe body and draining the stored groundwater from substantially the same height as the upper end of the outlet is provided in the pipe body. The drainage pipe for potential difference type groundwater drainage facilities according to claim 1 or 2, which is connected to the discharge port. A method for preventing the adhesion of slime that induces blockage of a water collecting pipe for groundwater drainage facilities that is buried in a slope of a natural mountain,
A strainer that collects groundwater of the natural ground is drilled in the outer peripheral wall, and a discharge port for draining the groundwater collected through the strainer is provided inside the pipe body provided at the end on the downstream side. A first metal member having a first metal component having an ionization tendency as a main component, and a second metal component having a different ionization tendency from the first metal component as a main component; Inserting and arranging a composite metal member having a second metal member electrically connected, and contacting the groundwater collected in the pipe body;
By suppressing the oxidation of iron ions by causing electrons generated due to the potential difference generated between the first and second metal members to act on the iron ions contained in the ground water using the ground water as an electrolyte solution, A potentiometric slime adhesion prevention method characterized by preventing slime adhesion inside the main body.   6. The potential difference formula according to claim 5, wherein the composite metal member is formed by winding a metal wire mainly composed of the second metal component around an outer periphery of a metal tube mainly composed of the first metal component. Slime adhesion prevention method.   The groundwater collected through the strainer is temporarily stored near the outlet of the pipe body, and an elbow pipe for draining the stored groundwater from a position above the upper end of the outlet is provided on the pipe body. The potentiometric slime adhesion prevention method according to claim 5 or 6, wherein the method is connected to a discharge port.   The pipe body is provided with a lid member for temporarily storing the groundwater collected through the strainer near the outlet of the pipe body and draining the stored groundwater from substantially the same height as the upper end of the outlet. The potentiometric slime adhesion prevention method according to claim 5 or 6, wherein the method is connected to a discharge port of the liquid.   9. The iron component elution suppressing material for suppressing the iron component contained in the natural ground from being eluted and flowing into the pipe body of the water collecting pipe is embedded or dispersed on the surface of the natural ground. The method of preventing potential difference slime adhesion described in 1.