JP2013059724A - Adsorption mat for contaminants and method for treating contaminants contained in dug-up surplus soil - Google Patents

Abstract

An object of the present invention is to provide a pollutant adsorbing mat and a method for treating pollutants contained in excavated residual soil that do not require an extra number of laying and can prevent a decrease in the decrease in the capacity of receiving pollutant diffusion prevention structures or facilities. An adsorbent material layer 11 containing an adsorbent that adsorbs contaminants, an upper sheet 12A disposed above the adsorbent material layer 11, and a lower sheet 12B disposed below the adsorbent material layer 11 are provided. And the upper sheet 12A, the adsorbing material layer 11, and the lower sheet 12B are sewn, so that thickness non-uniformity is suppressed throughout and the thickness of a certain level is maintained.
[Selection] Figure 3

Description

  The present invention relates to a contaminant adsorption mat that adsorbs contaminants and a method for treating contaminants contained in excavated residual soil.

  In a site where civil engineering works such as tunnels, dams, and construction are performed, excavation is generated as excavated soil and excavated ground. Since excavations may contain natural or man-made pollutants, these pollutants diffuse into the surrounding environment when embankment or landfill is carried out using excavations that contain pollutants. Measures to prevent this are required.

  Adsorption layer method is known as one of the countermeasures against construction residual soil containing pollutants. In the adsorption layer construction method, an adsorption layer that is a mixture of a chemical that adsorbs and captures contaminants (hereinafter referred to as "adsorbent") and healthy soil that does not contain contaminants is laid under the contaminated soil layer. It is a construction method that captures pollutants that leach from the contaminated soil layer. The adsorption layer method has a problem that workability is poor because a heavy machine is required to construct the adsorption layer, and it is difficult to uniformly disperse the adsorbent in the adsorption layer.

  In order to solve such problems, in recent years, a method is known in which a pollutant adsorbing mat that adsorbs pollutants in a factory is prepared in advance, and this pollutant adsorbing mat is used in place of an adsorbing layer. For example, Patent Document 1 includes a plurality of bag-shaped portions, a contaminant trapping material filled in the bag-shaped portions, and a collecting unit that integrally bundles the plurality of bag-shaped portions. A pollutant trapping mat (pollutant adsorbing mat) whose main component is charcoal formed by steaming and burning carbonaceous waste material is disclosed. In this mat, by filling the long bag member with the contaminant trapping material, it is possible to suppress the occurrence of the density of the contaminant trapping material inside the bag member and to maintain the shape thereof. In addition, by arranging a plurality of elongated bag members in parallel, the shape of the entire contaminant adsorbing mat is maintained. For this reason, the cross-sectional shape of the contaminant adsorbing mat is an uneven shape in which a portion where the bag member is provided protrudes and the space between the bag members is recessed.

JP 2002-028633 A

  By the way, in order to obtain the contaminant adsorption performance of the contaminant adsorption mat uniformly, it is necessary to make the accumulation thickness of the adsorbent uniform. However, the contaminant adsorbing mat disclosed in Patent Document 1 has an uneven cross-sectional shape. Therefore, in order to make the accumulated thickness of the adsorbent uniform using this contaminant adsorbing mat, it is necessary to lay and lay a plurality of contaminant adsorbing mats. Further, when the number of the pollutant adsorbing mats is an odd number, the accumulated thickness of the adsorbent varies depending on the location. Therefore, in order to make the adsorption performance uniform, it is necessary to laminate an even number of contaminant adsorption mats. Therefore, in the pollutant adsorbing mat described in Patent Document 1, in order to make the adsorbing performance uniform, it may be necessary to lay more pollutant adsorbing mats required for adsorbing contaminants.

  By the way, there is a restriction on the capacity for digging slag due to legal restrictions on the embankment and restrictions on the landfill area. On the other hand, in the pollutant adsorbing mat having unevenness for preventing the adsorbent from being biased as in Patent Document 1, it is necessary to lay an extra number of pollutant adsorbing mats. Is occupied by the contaminant adsorption mat, the placement amount of the excavation shear including the contaminant may be reduced. As a result, there is a problem that the ability to receive excavation of a pollutant diffusion prevention structure or facility is reduced.

  Therefore, the present invention has been made in view of the above-described problems of the prior art, and an extra number of laying is not required, and the pollutant diffusion prevention countermeasure structure or facility excavation shear receiving capacity can be reduced. It is an object of the present invention to provide a contaminant adsorption mat that can be prevented and a method for treating contaminants contained in excavated soil.

  The pollutant adsorbing mat according to the present invention includes an adsorbing material layer including an adsorbent that adsorbs the pollutant, a first sheet disposed above the adsorbing material layer, and a second sheet disposed below the adsorbing material layer. And the first sheet, the adsorbing material layer, and the second sheet are sewn, so that thickness non-uniformity is suppressed throughout and the thickness of a certain level is maintained.

  The pollutant adsorbing mat according to the present invention suppresses uneven thickness throughout the first sheet, adsorbing material layer, and second sheet, and maintains a certain thickness or more. ing. Here, the sewing of the first sheet, the adsorbing material layer, and the second sheet serves as a presser that suppresses a partial thickness change between the first sheet and the second sheet. Therefore, the thickness of the adsorbent material layer disposed between the first sheet and the second sheet is maintained, and the bias of the adsorbent contained in the adsorbent material layer is prevented. According to such a pollutant adsorbing mat, the adsorbing performance can be made uniform without stacking, so there is no need to lay an extra number of pollutant adsorbing mats. Therefore, it is possible to prevent a decrease in the ability to receive excavation of a pollutant diffusion prevention structure or facility.

  In the contaminant adsorbing mat according to the present invention, the length of the sewing thread in the thickness direction is the sum of the thicknesses of the first sheet, the adsorbing material layer, and the second sheet, and the total length in the thickness direction of the adsorbing material layer. The first sheet, the adsorbing material layer, and the second sheet may be sewn with the sewing thread rising.

  In this case, since the thickness of the first sheet, the adsorption material layer, and the second sheet is suppressed by the sewing thread, a partial change in thickness between the first sheet and the second sheet is suppressed, and the adsorption material It is possible to prevent the adsorbent contained in the adsorbent material layer from becoming dense due to the biased layer.

  In the contaminant adsorbing mat according to the present invention, the first sheet, the adsorbing material layer, and the second sheet may be sewn at equal intervals toward one direction of the first sheet, the adsorbing material layer, and the second sheet. Good.

  In this case, since sewing is performed at equal intervals, a partial change in thickness between the first sheet and the second sheet is appropriately suppressed. Therefore, it is possible to further prevent the adsorbent contained in the adsorbent material layer from becoming dense due to the biased adsorbent material layer.

  The method for treating pollutants contained in the excavated residual soil according to the present invention is to prevent the contamination of the excavated residual soil placed in the excavated residual soil placement region, and the above-mentioned contamination on the excavated residual soil placement region. It is characterized by laying a material adsorption mat, depositing excavated residual soil containing pollutants on the pollutant adsorbing mat to form embankment, and capturing pollutants discharged from the excavated residual soil in the contaminant adsorbing mat .

  According to the pollutant adsorption mat and the method for treating pollutants contained in the excavated residual soil according to the present invention, an extra number of laying is not required, and the pollutant diffusion prevention countermeasure structure or facility excavation shearing capacity is reduced. Can be prevented.

It is a sectional side view of the excavation residual soil in the processing method of the pollutant contained in the excavation residual soil which concerns on this embodiment. It is a front view of the contaminant adsorption mat which concerns on this embodiment. It is sectional drawing along the III-III line of FIG. It is a figure which shows a part of manufacturing process of the contaminant adsorption mat which concerns on this embodiment. It is a front view which shows the aspect which connected and constructed several contaminant adsorption mats. It is a sectional side view which shows the connection location of a some contaminant adsorbing mat. It is a sectional side view of the excavation residual soil in the processing method of the pollutant contained in the excavation residual soil which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description may be omitted.

  FIG. 1 is a side cross-sectional view of excavated residual soil in a method for treating contaminants contained in excavated residual soil using the contaminant adsorbing mat 10 according to the present embodiment. As shown in FIG. 1, in the method for treating pollutants contained in the excavated residual soil according to the present embodiment, the embankment M is formed on the excavated residual soil placement region Y. The embankment M in the present embodiment is formed by excavation (excavated residual soil) generated by excavation of a tunnel, for example. This excavation may include naturally occurring or artificial contaminants (eg, arsenic, cadmium, lead, VOC, etc.). A pollutant adsorbing mat 10 is laid between the excavated residual soil placement region Y and the embankment M. The number of contaminant adsorbing mats 10 to be laid is determined according to the amount of contaminants assumed to be included in the excavation, and may be two or more or one. May be.

  The contaminant adsorbing mat 10 has a structure in which an adsorbing material layer 11 is sandwiched between fiber substrates such as nonwoven fabrics. The pollutant adsorbing mat 10 can be wound up, and in a stage before being laid and laid in the remaining soil placing area Y, the pollutant adsorbing mat 10 is wound up, and the pollutant adsorbing mat 10 is dug up and the remaining soil placing area. When laying on Y, lay while unwinding the suction sheet. Hereinafter, the contaminant adsorption mat 10 will be described in detail with reference to FIGS. 2 and 3.

  As shown in FIGS. 2 and 3, the contaminant adsorbing mat 10 includes an adsorbing material layer 11, an upper sheet 12 </ b> A (first sheet), a lower sheet 12 </ b> B (second sheet), and a sewing thread 13. The adsorbing material layer 11, the upper sheet 12 </ b> A, and the lower sheet 12 </ b> B are sewn across the entire width of the contaminant adsorbing mat 10 with the sewing thread 13. Further, this sewing is performed at equal intervals in the depth direction of the contaminant adsorbing mat 10. The interval between the adjacent sewing threads 13 is preferably set to an appropriate interval of, for example, about 5 to 30 cm so that the thickness of the adsorbing material layer 11 does not change remarkably. Further, a non-adsorbing portion 14 in which the adsorbing material layer 11 is not formed is formed at the end in the width direction and the depth direction of the contaminant adsorbing mat 10. The thickness of the contaminant adsorbing mat 10 is about 20 to 40 mm throughout.

  The adsorbing material layer 11 is a layer composed of an adsorbing material containing an adsorbent, and adsorbs contaminants contained in moisture penetrating into the contaminant adsorbing mat 10. The adsorbent used here corresponds to a contaminant assumed to be contained in the embankment M, and adsorbs the corresponding contaminant to insolubilize it. As the adsorbing material constituting the adsorbing material layer 11, a mixture of the adsorbent and the non-contaminating soil may be used, or only the adsorbent may be used alone. Further, the adsorbing material layer 11 may include a single adsorbent or may include a plurality of types of adsorbents. The adsorbing material is preferably in the form of particles or fibers having a particle size of about 5 mm or less, but a part thereof may be powdery. The adsorbent material may have a certain degree of viscosity so that the shape of the adsorbent material layer 11 can be maintained. The specific gravity of the adsorbing material is preferably less than 1, and the water content is preferably about 50% or less. The adsorbing material layer 11 is formed to have a uniform thickness over the entire contaminant adsorbing mat 10.

  The upper sheet 12 </ b> A and the lower sheet 12 </ b> B are arranged so as to sandwich the adsorbing material layer 11 so that the adsorbent of the adsorbing material layer 11 does not leak out of the contaminant adsorbing mat 10. The upper sheet 12 </ b> A is disposed above the adsorbent material layer 11, and the lower sheet 12 </ b> B is disposed below the adsorbent material layer 11. As the upper sheet 12A and the lower sheet 12B, a fiber base material such as a nonwoven fabric is used.

  The sewing thread 13 is used to sew the adsorbent material layer 11, the upper sheet 12A, and the lower sheet 12B. As the sewing thread 13, a polyester thread having an extension strength of 20 kg and an extension elongation of 10 to 15% is used. However, the sewing thread 13 is not limited to the above, and it is sufficient that the sewing thread 13 has a sufficient strength to maintain the shape of the contaminant adsorbing mat 10.

  A method for manufacturing the contaminant adsorbing mat 10 will be described below. FIG. 4 shows a part of the manufacturing method of the contaminant adsorbing mat 10. FIG. 4A is a view of a state in which the contaminant adsorbing mat 10 is formed as seen from a cross section in the width direction of the contaminant adsorbing mat 10, and FIG. 4B is a diagram in which the contaminant adsorbing mat 10 is formed. It is the figure which looked at the mode which is seen from the section of the depth direction of pollutant adsorption mat 10. FIG. Here, the contaminant adsorption mat 10 is manufactured using the hopper 21, the belt conveyor 22, the height adjusting screw 23, and the height adjusting plate 24.

  The adsorbing material A that has been thrown in from the hopper 21 and dropped onto the belt conveyor 22 is conveyed by the belt 22B that is moved by the rotation of the roller 22A, and falls onto the lower sheet 12B that is installed below the belt conveyor 22. Next, the adsorbing material A is conveyed in the traveling direction together with the lower sheet 12B moving in the traveling direction shown in FIG. Then, when passing through the height adjusting plate 24, the adsorbing material A piled up to a predetermined height or more is removed to form the adsorbing material layer 11 having a flat upper surface. Note that the height at which the height adjusting plate 24 is installed can be adjusted by the height adjusting screw 23. For this reason, the height of the adsorbing material layer 11 can be adjusted by the height adjusting screw 23. Thereafter, the upper sheet 12A is placed on the upper surface of the adsorbing material layer 11 having a flat surface.

  Next, a sewing process is performed on the adsorbing material layer 11, the upper sheet 12A, and the lower sheet 12B formed as described above. As shown in FIG. 3, the adsorbing material layer 11, the upper sheet 12A, and the lower sheet 12B are sewn and fixed to each other. At this time, the pitch of the seam and the pulling force applied to the sewing thread 13 are appropriately adjusted according to the thickness of the contaminant adsorbing mat 10 and the material of the upper sheet 12A and the lower sheet 12B. In practice, the sewing thread 13 is sewn along the upper sheet 12A and the lower sheet 12B. However, in FIG. 3, the sewing thread 13, the upper sheet 12A, the lower sheet 12B, Are described with a gap.

  The length D of the sewing thread 13 in the thickness direction of the contaminant adsorbing mat 10 is the total thickness of the adsorbing material layer 11, the upper sheet 12A, and the lower sheet 12B, and is the total length of the adsorbing material layer 11 in the thickness direction. The upper sheet 12A, the adsorbing material layer 11, and the lower sheet 12B are sewn with the sewing thread rising. The length D is sewn so as to be uniform over the entire contaminant adsorbing mat 10.

  Further, the width and depth of the upper sheet 12A and the lower sheet 12B are formed slightly longer than the width and depth of the adsorbent material layer 11. Only the upper sheet 12A and the lower sheet 12B are sewn at the end portions in the width direction and the depth direction of the upper sheet 12A and the lower sheet 12B, and the upper sheet 12A and the lower sheet 12B are fixed to each other to form the non-adsorption portion 14. Has been.

  Further, when the excavated and remaining soil placement area Y is wider than the surface of the contaminant adsorbing mat 10, a plurality of contaminant adsorbing mats 10 can be connected and used. A method for connecting the contaminant adsorbing mat 10 will be described with reference to FIGS. FIG. 5 shows an example in which four contaminant adsorbing mats 10 of the contaminant adsorbing mats 10A to 10D are connected. When connecting a plurality of contaminant adsorbing mats 10, the non-adsorbing portion 14 is folded, adsorbing material layers 11 of adjacent contaminant adsorbing mats 10 are brought into close contact with each other, and waterproof tape 15 is attached to the connection surface. To do. For example, focusing on the connection surfaces of the contaminant adsorption mats 10A and 10B, as shown in FIG. 6, the non-adsorption portion 14 of the contaminant adsorption mat 10A is folded and the non-adsorption portion 14 of the contaminant adsorption mat 10B is folded. By placing under 10A, the adsorbing material layer 11 of the contaminant adsorbing mat 10A and the adsorbing material layer 11 of the contaminant adsorbing mat 10B are brought into close contact with each other. Then, the waterproof tape 15 is attached above the contact surface between the contaminant adsorbing mat 10A and the contaminant adsorbing mat 10B.

  Next, with reference to FIG. 7, the processing method of the pollutant contained in the excavated residual soil according to the present embodiment will be described. First, in the processing method of the pollutant contained in the excavated residual soil according to the present embodiment, the contaminant adsorbing mat 10 is laid on the partitioned excavated residual soil placement region Y. Next, the embankment M is formed on the pollutant adsorbing mat 10 by raising earth and sand such as excavation scraps generated by civil engineering work such as a tunnel. At this time, as shown in FIG. 7, it is assumed that the excavation ladle contains a naturally occurring or artificial pollutant P.

  Then, the covering soil C is laid around the embankment M. The covering soil C is made of bentonite mixed soil or concrete. By covering the embankment M with the cover soil C, the inflow of rainwater to the embankment M is prevented.

  When the embankment is raised and the embankment M is formed in this way, the water Wp flows down from the embankment M toward the remaining soil placement area Y as time passes. This moisture Wp contains the pollutant P contained in the embankment M. In other words, the pollutant P is discharged from the excavation through the moisture Wp. At this time, if the moisture Wp that has flowed down is dug up and reaches the remaining soil placement region Y, the contaminant P contained in the moisture Wp will be dug up and leached into and out of the remaining soil placement region Y.

  In this regard, in the method for processing contaminants contained in the excavated residual soil according to the present embodiment, the contaminant adsorbing mat 10 is interposed between the excavated residual soil placement region Y and the embankment M. For this reason, the pollutant P contained in the moisture Wp flowing down from the embankment M can be adsorbed and captured by the adsorbent material layer 11 of the contaminant adsorbing mat 10. For this reason, the water W passing through the pollutant adsorbing mat 10 and digging up and flowing into the residual soil placement area Y is the one in which the pollutant P is removed. Therefore, the leaching and outflow of the pollutant P with respect to the inside and outside of the excavated residual soil placement region Y can be prevented.

  Contaminant adsorbing mat 10 according to the present embodiment has an upper sheet 12A, an adsorbing material layer 11, and a lower sheet 12B sewn, thereby suppressing thickness non-uniformity over the entire thickness and having a certain thickness or more. Is maintained. Here, the sewing of the first sheet, the adsorbing material layer, and the second sheet serves as a presser that suppresses a partial thickness change between the upper sheet 12A and the lower sheet 12B. Therefore, the thickness of the adsorbent material layer 11 disposed between the upper sheet 12A and the lower sheet 12B is maintained, and the bias of the adsorbent contained in the adsorbent material layer 11 is prevented. According to such a contaminant adsorbing mat 10, the adsorption performance can be made uniform without stacking, and therefore it is not necessary to lay an extra number of contaminant adsorbing mats 10. Therefore, it is possible to prevent a decrease in the amount of excavation load, and as a result, it is possible to prevent a decrease in the capability of accepting excavation of a pollutant diffusion prevention structure or facility.

  In the pollutant adsorbing mat 10 according to the present embodiment, the length of the sewing thread in the thickness direction is the total thickness of the upper sheet 12A, the adsorbing material layer 11, and the lower sheet 12B. The upper sheet 12A, the adsorbing material layer 11, and the lower sheet 12B are sewn with the sewing thread rising over the entire length in the thickness direction. In this case, the partial change in thickness between the upper sheet 12A and the lower sheet 12B is suppressed by the sewing thread 13, and the adsorbent contained in the adsorbent material layer 11 becomes dense due to the adsorbent material layer 11 being biased. Can be prevented.

  In the contaminant adsorbing mat 10 according to the present embodiment, the upper sheet 12A, the adsorbing material layer 11, and the lower sheet 12B are sewn at equal intervals toward one direction of the upper sheet 12A, the adsorbing material layer, and the lower sheet 12B. ing. Since the sewing is performed at equal intervals, a partial thickness change between the upper sheet 12A and the lower sheet 12B is appropriately suppressed. Therefore, it is possible to further prevent the adsorbent contained in the adsorbent material layer 11 from becoming dense due to the adsorbent material layer 11 being biased.

  In the processing method of the pollutant contained in the excavated residual soil according to the present embodiment, the above-mentioned contaminant adsorbing mat 10 is laid on the excavated residual soil placement area Y, and the excavated material containing the pollutant is generated on the contaminant adsorbing mat 10. The remaining soil is deposited to form the embankment M, and the pollutants discharged from the remaining soil are trapped in the contaminant adsorption mat to prevent the contaminants from spreading in the remaining soil. Therefore, it is possible to prevent a decrease in the ability to receive excavation of a pollutant diffusion prevention structure or facility.

  Moreover, in the processing method of the contaminant contained in the excavated residual soil according to the present embodiment, the plurality of contaminant adsorbing mats 10 are connected, and the waterproof tape 15 is adhered on the connection surface. In this way, by connecting and using a plurality of contaminant adsorption mats 10, the contamination contained in the excavated residual soil even when the excavated residual soil placement region Y is wider than the surface area of the contaminant adsorbing mat 10. The substance can be processed. Further, by adhering adjacent adsorbing material layers 11 to each other and attaching waterproof tape 15 to the connection surface, the contaminant adsorbing mat 10 can be laid so that the adsorbing material is dispersed without any gap. For this reason, it is possible to appropriately prevent the pollutant from diffusing into the excavated residual soil placement region Y.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the adsorbing material layer 11, the upper sheet 12A, and the lower sheet 12B are sewn across the entire width of the contaminant adsorbing mat 10 with the sewing thread 13, but the adsorbing material layer 11, upper portion The sheet 12 </ b> A and the lower sheet 12 </ b> B may be sewn over the entire depth direction of the contaminant adsorbing mat 10 with the sewing thread 13. Further, the adsorbing material layer 11, the upper sheet 12 </ b> A, and the lower sheet 12 </ b> B may be sewn across the entire width direction and depth direction of the contaminant adsorbing mat 10 with the sewing thread 13.

10, 10A, 10B, 10C, 10D ... Pollutant adsorption mat 11 ... Adsorption material layer 12A ... Upper sheet 12B ... Lower sheet 13 ... Sewing thread 14 ... Non-adsorption part 15 ... Waterproof tape 21 ... Hopper 22 ... Belt 22A ... Roller 23 ... Height adjustment screw 24 ... Height adjustment plate M ... Filling C ... Covering soil Y ... Digging and remaining soil placement area

Claims (4)

An adsorbent material layer containing an adsorbent that adsorbs contaminants;
A first sheet disposed above the adsorbent material layer;
A second sheet disposed below the adsorbent material layer;
With
A contaminant adsorbing mat that maintains non-uniform thickness and maintains a certain thickness or more by sewing the first sheet, the adsorbing material layer, and the second sheet. The length of the sewing thread in the thickness direction is the sum of the thicknesses of the first sheet, the adsorption material layer, and the second sheet,
2. The contaminant adsorbing mat according to claim 1, wherein the first sheet, the adsorbing material layer, and the second sheet are sewn in a state where a sewing thread rises over the entire length in the thickness direction of the adsorbing material layer. . The said 1st sheet | seat, the said adsorption material layer, and the said 2nd sheet are sewn at equal intervals toward the one direction of the said 1st sheet | seat, the said adsorption material layer, and the said 2nd sheet | seat. The contaminant adsorbing mat described in 1. In order to prevent the diffusion of pollutants in the excavated residual soil placed in the excavated residual soil placement area,
The pollutant adsorbing mat according to claim 1 or 2 is laid on the excavated residual soil placement region,
On the pollutant adsorbing mat, the excavated residual soil containing the pollutant is deposited to form an embankment, and the pollutant discharged from the excavated residual soil is captured in the pollutant adsorbing mat. Methods for treating contained contaminants.

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