JP4405414B2 - Landfill treatment method - Google Patents

Description

  The present invention constructs a belly soil layer having a slope on the inner side of a seawall constructed on the bottom of the sea or lake (hereinafter referred to as "the sea"), and a water shielding sheet on the belly soil layer. Further, the present invention relates to a landfill treatment method for landfilling a landfill material such as waste after placing a ballast layer on the water shielding sheet.

  In the landfill, there are industrial land and airports created by putting earth and sand into the sea, as well as a final disposal site where waste is thrown in. When waste is used as landfill material, a revetment will be constructed to prevent harmful substances in the waste from flowing into the open sea. A conventional example of reclaiming the inside of such a revetment and creating a landfill will be described with reference to FIG.

  In order to create a landfill, first, the revetment 10 is constructed on the outer periphery of the landfill area. The revetment 10 is constructed by constructing a foundation mound 11 by introducing rubble after improving the bottom ground 1 and installing a revetment main body 12 on the foundation mound 11. The foundation mound 11 is wider than the revetment main body 12, and both sides are inclined surfaces. If the revetment main body 12 is a caisson as illustrated, the wave-dissipating block 13 may be stacked outside the revetment main body 12.

  A bellowed soil layer 2 that covers the slope of the foundation mound 11 is constructed inside the revetment main body 12. The belly soil layer 2 has a slope that is gentler than the inclined surface of the foundation mound 11. A water-impervious sheet 3 is laid on the bellowed soil layer 2 to prevent the seawater W from circulating inside and outside the revetment 10.

  On the water shielding sheet 3, a ballast layer 4 serving as a weight is placed. The ballast layer 4 is formed in a shape having an inclined surface in close contact with the water-impervious sheet 3 on the bottom side and a stepwise gradient on the upper side. When the bottom surface of the ballast layer 4 and the water-impervious sheet 3 are in close contact with each other, the water-impervious sheet 3 is not damaged, and the seawater W is prevented from flowing inside and outside the revetment 10.

  The ballast layer 4 is formed by, for example, fly ash mortar. Fly ash is coal ash discharged when coal is burned at a coal-fired power plant or the like. The fly ash mortar, which is made by adding cement and water to this fly ash and kneaded, has the property of impervious to water and is excellent in durability. It is small and lightweight.

  Then, waste such as coal ash is input as the landfill material 7 while the seawater W is stored inside the revetment main body 12. Since the ballast layer 4 is placed on the water-impervious sheet 3 laid on the slope of the bellowed soil layer 2 and is slippery, and is formed of a lightweight material such as fly ash mortar, When the landfill material 7 is put on the ballast layer 4, the ballast layer 4 is brought down by the landfill material 7 and subsided. For this reason, the landfill material 7 is thrown away from the ballast layer 4 so that the ballast layer 4 is not brought in and sinks.

  Then, when the landfill material 7 protrudes from the water surface and is deposited up to a predetermined height, as shown by the phantom line in FIG. Even if the landfill material 7 is put on the ballast layer 4, the bottom portion of the ballast layer 4 is supported by the already-filled landfill material 7, so that the ballast layer 4 does not sink and sink. And if the whole inside of the revetment 10 is landfilled with the landfill material 7, water will be drained and a landfill will be completed.

  In addition, Patent Document 1 discloses a water shielding treatment method for a management-type waste landfill revetment using a water shielding sheet.

Japanese Patent Laid-Open No. 2003-7401

  As described above, the landfill material 7 is introduced separately from the ballast layer 4 so that the ballast layer 4 is not brought in and subsided. Therefore, the state where the landfill material 7 is not deposited on the ballast layer 4 may continue for a long time.

  However, the ballast layer 4 is placed on the water-impervious sheet 3 laid on the slope of the bellowed soil layer 2, and is particularly lightweight in the case of fly ash mortar, because it is easy to slip. If the landfill material 7 is not deposited on the ballast layer 4, the revetment 10 is in an unstable state. Moreover, when the landfill material 7 is coal ash discharged from a coal-fired power plant, if the coal-fired power plant is not operating, the landfill material 7 is not discharged, and the revetment 10 is in an unstable state during that time. In the worst case, it will be damaged.

  Then, this invention makes it a subject to provide the landfill processing method which made the inside of a revetment landfill in order to stabilize a revetment early.

  In the landfill treatment method according to the present invention, a bellowed soil layer having a slope is constructed on the inner side of the revetment constructed on the water bottom ground, a water shielding sheet is laid on the slope of the bellows soil layer, and the shielding A landfill treatment method in which a ballast layer is placed on a water sheet, and a landfill material is thrown into the revetment including the ballast layer, and the landfill is placed at a position just before the ballast layer is brought and submerged. By introducing the material, a primary landfill zone is formed along the revetment and at intervals, and then the landfill material is thrown into the landfill area surrounded by the revetment and the primary landfill zone. It is characterized by going.

  According to this landfill processing method, by putting the landfill material into the position on the side where the ballast layer is brought into and subsided, i.e., on the borderline between the position where the ballast is subsided and the position where the ballast is not subsided. A primary landfill zone is formed along and along the revetment. Thereafter, a landfill material is deposited on the ballast layer. The primary landfill strip is in a state of supporting the bottom of the ballast layer, and the ballast layer is pressed against the landfill material without being brought down. In this way, by putting the landfill material into the landfill area surrounded by the revetment and the primary landfill zone, the revetment can be stabilized at an early stage.

  In the landfill treatment method, the landfill material may be coal ash. According to this landfill treatment method, coal ash discharged from a coal-fired power plant that has been reviewed in recent years can be effectively disposed of.

  In the landfill treatment method, the ballast layer may be fly ash mortar. According to this landfill treatment method, fly ash mortar not only can effectively dispose of coal ash discharged from coal-fired power plants, but also has the characteristics that it is impervious to water and has excellent durability. Since it has, it can be used suitably as a weight of a water shielding sheet.

  According to the present invention, the landfill material is thrown into the position just before the ballast layer is brought and subsidized to form the primary landfill zone, and then landfilled in the landfill area surrounded by the revetment and the primary landfill zone. By introducing the material, the landfill material can be deposited on the ballast layer while the landfill material supports the ballast layer. Therefore, the landfill material is in a state of quickly pressing the ballast layer and the water shielding sheet, and the revetment can be stabilized at an early stage. As a result, even if it takes a long time until the landfill inside the revetment is completely completed, it is possible to prevent the revetment from being damaged and not to perform repair work.

  An embodiment of a landfill processing method according to the present invention will be described with reference to FIG. The same parts as those in the conventional art will be described with the same reference numerals.

  As shown in FIG. 1, this landfill treatment method constructs a belly soil layer 2 on the inner side of a revetment 10 constructed on the outer periphery of a region to be a landfill, and a water shielding sheet 3 on the belly soil layer 2. , The ballast layer 4 is placed on the water-impervious sheet 3, and the landfill material 7 including the ballast layer 4 is introduced. The revetment 10 is composed of a foundation mound 11 constructed on the submerged ground 1 and a revetment main body 12 such as a caisson installed on the foundation mound 11. 13 may be stacked.

  In the landfill processing method of the present embodiment, the position at which the landfill material 7 is first introduced (shown by the one-dot chain line in FIG. 1) is not set to the position just before the ballast layer 4 is brought down, that is, the position where the landfill material 7 is brought down. It is characterized in that it is a position on the border line with the position where it is not brought in and subsided. When the landfill material 7 is put in such a position, the landfill material 7 is deposited in a conical shape and is in a state of supporting the bottom of the ballast layer 4.

  Therefore, even if the landfill material 7 is continuously charged and deposited on the ballast layer 4 as shown by a two-dot chain line, the ballast layer 4 is not brought down. Since the upper side of the ballast layer 4 is formed in a stepped shape, the landfill material 7 does not slide on the ballast layer 4, and a vertical downward load is applied to the ballast layer 4, and the ballast layer 4 presses the water shielding sheet 3. .

  However, when the angle of repose α of the deposited landfill material 7 increases, a large load is applied to the ballast layer 4. The angle of repose varies depending on the landfill material 7 to be employed, that is, the particle size of coal ash and the like. On the other hand, if the coefficient of friction between the ballast layer 4 and the water-impervious sheet 3 is large, the sinking is difficult, and if it is small, the sinking is easy. Therefore, in practice, the position at which the landfill material 7 is introduced is set from the relationship between the angle of repose α and the friction coefficient. Therefore, the position where the landfill material 7 is first introduced may be on the bottom of the ballast layer 4 in some cases.

  In any case, when the landfill material 7 does not bring the ballast layer 4 and sinks it until it protrudes from the water surface, the position at which the landfill material 7 is thrown moves in parallel with the revetment 10. The primary landfill zone 8 is formed along the revetment 10 and having an interval by moving the position where the landfill material 7 is introduced one after another in parallel with the revetment 10.

  Then, as shown by a three-dot chain line in FIG. 1, the landfill material 7 is introduced into the landfill area 9 surrounded by the revetment 10 and the primary landfill zone 8. Although this landfill material 7 is thrown in one after another on the ballast layer 4, since the bottom part is supported by the landfill material 7, it does not carry out sinking.

  Thus, the landfill area where the landfill material 7 protrudes from the water surface approaches the revetment 10. Since the landfill material 7 starts to be introduced from the position just before the ballast layer 4 is brought and subsided, the entire ballast layer 4 is deposited and pressed down early by the landfill material 7 and the revetment 10 is stabilized early.

  Thus, after the revetment 10 is made into the stable state, the inner side of the primary landfill zone 8 is sequentially landfilled. And when the whole area inside the revetment 10 is reclaimed by the landfill material 7, the landfill material 7 is drained, and the landfill work is completed.

  In addition, this invention can be variously changed within the range of the technical matter described in the claim, without being limited to the said embodiment. For example, the landfill material 7 is not limited to waste such as coal ash, but may be earth and sand, and the ballast layer 4 can be implemented in a similar manner other than fly ash mortar. Furthermore, although the term seawater W is used for convenience in the above description, it is needless to say that the present invention can be implemented in lakes and rivers.

It is the schematic which shows one Embodiment of the landfill processing method which concerns on this invention. It is the schematic which shows the conventional landfill processing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Submarine ground 2 ... Soiled soil layer 3 ... Water shielding sheet 4 ... Ballast layer 7 ... Landfill material 8 ... Primary landfill zone 9 ... Landfill zone 10 ... Seawall

Claims (3)

Construct a belly soil layer with a slope on the inside of the revetment built on the bottom of the ground, lay a water shielding sheet on the slope of the belly soil layer, and place a ballast layer on the water shielding sheet And a landfill treatment method in which a landfill material is put inside the revetment including the ballast layer,
By introducing the landfill material at a position just before the ballast layer is brought and subsided, a primary landfill zone is formed along and along the revetment, and then, the revetment and the primary landfill zone are formed. A landfill treatment method characterized by pouring landfill material into a landfill area surrounded by   The landfill processing method according to claim 1, wherein the landfill material is coal ash.   The landfill processing method according to claim 1, wherein the ballast layer is fly ash mortar.

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