JP5983995B2 - Waste disposal facility - Google Patents

Description

  The present invention relates to a waste disposal facility for embedding and disposing of a cushioning material-integrated waste body in a disposal tunnel, and a method for embedding the waste body.

  When a waste material integrated with a cushioning material is placed horizontally in a disposal tunnel and disposed of in a landfill, a disposal tunnel with a cross section of the tunnel corresponding to the size of the waste material integrated with a buffer material is required. As a result, there will be a gap between the waste material integrated with the cushioning material placed in the disposal tunnel and the disposal tunnel, but if this gap is left in space, the support that supports the disposal tunnel will deteriorate. In this case, the bias pressure from the natural ground acts, and the soundness of the waste material integrated with the cushioning material is impaired. In order to solve such a problem, the buffer material integrated with the buffer material placed in the disposal tunnel and the gap formed between the disposal tunnel is filled with a pellet-shaped buffer material in which the clay-based water shielding material is compacted ( For example, see Patent Document 1).

JP 2007-319732 A

  By the way, in order to provide a water-tight seal between the waste material integrated with the buffer material and the disposal tunnel, the buffer material in the form of pellets filled between the waste material integrated with the buffer material disposed in the disposal tunnel and the disposal tunnel It is necessary to inject water. This is because the pellet-shaped cushioning material absorbs and swells by irrigating water at an early stage and exhibits an effect of functioning as a water-stopping material.

  However, if the water injection pipe is laid on the wall surface of the disposal tunnel, it becomes an obstacle when carrying in or placing a cushioning material integrated waste.

  The present invention has been made in view of the above, and is provided with a cushioning material-integrated waste body placed in a disposal tunnel without any obstacles when carrying or placing a cushioning material-integrated waste body. It is an object of the present invention to provide a waste disposal facility that enables water injection into a pellet-shaped buffer material filled between disposal tunnels.

  In order to solve the above-described problems and achieve the object, the present invention is to pack a pellet-shaped buffer material between a waste material integrated with a buffer material and placed in a disposal tunnel, and the disposal tunnel. Then, in the waste disposal facility for burying and disposing of the buffer material integrated waste body, the buffer material integrated waste body is mounted when the buffer material integrated waste body is carried into the disposal tunnel. A guide rail for the transport carriage, and when placing the cushioning material-integrated waste that has been carried into the disposal mine shaft, the pedestal rail that serves as a base for the cushioning material-integrated waste material is directed upward from the floor surface of the disposal mine shaft In addition to laying along the axial direction of the disposal tunnel in a protruding manner, water is injected into the pellet-shaped cushioning material filled between the cushioning material-integrated waste body placed on the pedestal rail and the disposal tunnel Water injection hole Characterized in that provided inside the rail.

  Further, the present invention is the above invention, wherein the water injection hole includes a main hole provided along the axial direction of the disposal tunnel, and a plurality of holes branched from the main hole and provided along the inner periphery of the disposal tunnel. It has a branch hole.

  Further, the present invention is the above invention, wherein the plurality of discharge ports serving as the opening ends of the plurality of branch holes are spaced at shorter intervals in the axial direction of the disposal tunnel than the length of the waste material integrated with the cushioning material. It is characterized by opening.

  Moreover, the present invention is characterized in that, in the above-mentioned invention, a water injection means for injecting water having adjusted water pressure from the water injection hole is provided.

  Moreover, the present invention is characterized in that, in the above invention, the water injection means comprises water injection pressure adjusting means for adjusting the water pressure.

  Further, the present invention is characterized in that, in the above invention, a water-impervious plug that suppresses the flow of groundwater in the axial direction of the disposal mineway is installed at an entrance section of the disposal mineway, and further at a key point in the middle of the disposal mineway. And

  Further, the present invention is to fill the buffer material-integrated waste body placed in and disposed in the disposal tunnel and the pellet-shaped buffer material between the disposal tunnel, and then bury the buffer material-integrated waste body In the method of burying and disposing of the waste to be disposed, the step is performed until the pressure equal to the groundwater pressure before excavating the disposal tunnel is formed in the pellet-shaped buffer filled between the buffer material-integrated waste and the disposal tunnel. It is characterized by the fact that the conditioned water is poured.

  Further, the present invention is characterized in that, in the above invention, a water-impervious plug that suppresses the flow of groundwater in the axial direction of the disposal tunnel is installed at an entrance section of the disposal tunnel, and further at a key point in the middle of the disposal tunnel. And

  The waste disposal facility according to the present invention becomes a guide rail of a transport carriage equipped with a buffer material-integrated waste body when the buffer material-integrated waste body is carried into the disposal tunnel, and the buffer material carried into the disposal tunnel In addition to laying pedestal rails that serve as pedestals for cushioning material-integrated waste bodies along the axial direction of the disposal tunnel in a manner that protrudes upward from the floor surface of the disposal tunnel when placing the waste material-integrating waste body, Since the water injection hole is provided inside the pedestal rail for pouring water into the pellet-shaped buffer material filled between the waste material integrated with the buffer material placed on the rail and the disposal tunnel, disposal of the buffer material integrated type It is possible to inject water into the buffer material in the form of a pellet filled between the waste material integrated with the buffer material placed in the disposal tunnel and the obstacle material when the body is carried in or placed.

FIG. 1 is a conceptual diagram showing a waste disposal facility that is an embodiment of the present invention. FIG. 2 is a conceptual diagram showing main tunnels and disposal tunnels that constitute the buried disposal facility shown in FIG. FIG. 3 is a conceptual perspective view showing the disposal mine shown in FIG. FIG. 4 is a flowchart showing a procedure for burying a waste material integrated with a cushioning material. FIG. 5 is a cross-sectional view showing the disposal tunnel, and is a diagram showing a state at the time of transporting the cushioning material integrated waste. FIG. 6 is a cross-sectional view showing the disposal mine shaft, and is a diagram showing a state at the time of placing the cushioning material integrated waste body. FIG. 7-1 is a cross-sectional view illustrating the disposal tunnel, and is a diagram illustrating a state in which the buffer material in the form of pellets is filled with the buffer material-integrated waste body placed in the disposal tunnel. FIG. 7-2 is a longitudinal sectional view showing the disposal tunnel, and shows a state in which the buffer material in the form of pellets is filled between the waste material integrated with the cushioning material placed in the disposal tunnel. FIG. 8-1 is a cross-sectional view showing a disposal tunnel, and shows a state in which water is poured into a pellet-shaped cushioning material. FIG. 8-2 is a longitudinal sectional view showing the disposal tunnel, and is a view showing a state where water is poured into the pellet-shaped buffer material. FIG. 9 is a conceptual perspective view showing a state in which a grout injection pipe is inserted into the main hole. FIG. 10 is a schematic cross-sectional view showing a water injection path. FIG. 11A is a schematic cross-sectional view illustrating a grout material filling path, and illustrates a state immediately after the start of grout material filling. FIG. 11B is a schematic cross-sectional view illustrating the filling path of the grout material, and is a diagram illustrating a state during the filling of the grout material. FIG. 11C is a schematic cross-sectional view illustrating the grout material filling path, illustrating a state after the grout material is filled. FIG. 12-1 is a schematic cross-sectional view showing a grout material filling path, and shows a state immediately after the start of grout material filling. FIG. 12-2 is a schematic cross-sectional view showing the filling path of the grout material, and shows a state during the filling of the grout material. FIG. 12-3 is a schematic cross-sectional view showing the filling path of the grout material, and shows a state after the grout material is filled. FIG. 13 is a cross-sectional view showing a disposal mine which is another form. FIG. 14 is a diagram illustrating the relationship between the time elapsed since water was poured into the pellet-shaped buffer material and the water permeability coefficient of the pellet-shaped buffer material. FIG. 15 is a diagram illustrating a waste disposal facility in which a disposal tunnel passes through a plurality of spring zones. FIG. 16 is a diagram showing the groundwater pressure distribution in the natural ground in the natural state before excavating the disposal tunnel. FIG. 17 is a diagram showing the groundwater pressure distribution in the natural ground in a state where the disposal mine is excavated and then the amount of spring water is settled. FIG. 18 is a diagram illustrating a groundwater pressure distribution of a natural ground in a state immediately after filling a pellet-shaped buffer material between a disposal mine and a waste body and then injecting water between the disposal mine and the waste body. . FIG. 19 is a flowchart showing a procedure for burying a waste material integrated with a cushioning material. FIG. 20 is a diagram showing the groundwater pressure distribution in the natural ground when the water pressure reaches 300 mH ₂ O in the course of increasing the water injection pressure to the original groundwater pressure before excavating the tunnel in a short time. FIG. 21 is a diagram showing the groundwater distribution in the natural ground when the water injection pressure reaches 500 mH ₂ O corresponding to the original groundwater pressure before excavation of the tunnel. FIG. 22 is a diagram showing a disposal tunnel in which a water shielding plug is installed in the entrance section.

  Hereinafter, embodiments of a waste disposal facility according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  First, a waste body that is buried in a waste disposal facility according to an embodiment of the present invention will be described. The waste that is buried in the waste disposal facility according to the embodiment of the present invention is radioactive waste generated by the use of nuclear power, and more specifically, spent fuel by reprocessing. A high-level radioactive waste (high-level radioactive waste) that remains after separation of useful materials such as uranium and plutonium from waste, including substances produced by nuclear fission (fission products) and the like. High-level radioactive waste is solidified with glass and then stored for 30 to 50 years for cooling and then buried deep underground. Here, high-level radioactive waste solidified with glass is After being sealed in a metal container called an overpack, it is buried as a cylindrical buffer material-integrated waste P (see FIG. 2) surrounded by a buffer material. The cushioning material is a compacted clay-based impermeable material such as bentonite, which reduces the external force applied to the waste when an external force such as an earthquake is applied and the disposal tunnel is deformed, and the intrusion of groundwater To prevent.

  Next, based on FIG. 1, the outline | summary of the embedding disposal facility of the waste body which is embodiment of this invention is demonstrated. FIG. 1 is a conceptual diagram showing an outline of a waste disposal facility that is an embodiment of the present invention.

  As shown in FIG. 1, the waste disposal facility 1 includes a ground facility 2 and an underground facility 3. The ground facility 2 is necessary to receive and inspect radioactive waste (glass solidified) solidified with glass, enclose it in a metal container called an overpack, and then transport it to the deep underground. And other facilities that are necessary for the above ground in connection with construction, operation, and closure. The ground facility 2 of the waste embedding disposal facility 1 according to the embodiment of the present invention includes a facility for surrounding a metal container with a buffer material. The underground facility 3 includes an access tunnel 4 connecting the above-ground and underground facilities, a disposal tunnel 5 for placing the buffer material-integrated waste P, a main tunnel 6 surrounding the disposal tunnel 5, a main tunnel 6 and a main tunnel 6 It is composed of a connecting mine 7 that connects the two. In addition, facilities related to the transport of the buffer-integrated waste body P, facilities related to the construction of a mine shaft, and facilities for maintaining their safety are also constructed underground.

  The access mine shaft 4 connects the ground facility 2 to the underground connecting mine shaft 7 and the main mine shaft 6, and can be arranged flexibly according to the positional relationship with the ground facility 2. The access tunnel 4 is used not only for transporting the waste material P integrated with the buffer material but also for various purposes such as entry and exit of workers, removal of excavated soil, ventilation, drainage, and energy supply. Further, depending on the conveying means, it can be roughly divided into a vertical shaft 41 using an elevator and other lifting equipment and a slope 42 using a vehicle / rail system. For underground workers, the access mineway 4 also serves as an evacuation passage in an emergency. In addition, with the closure of the waste disposal facility 1, the access mine shaft 4 becomes the underground facility 3 that is finally backfilled.

  The disposal tunnel 5 can be divided into a plurality of disposal panels 8 with a certain number of disposal tunnel groups as one section (disposal panel 8) from the viewpoint of underground work such as excavation. Accordingly, the disposal panel 8 can be flexibly arranged according to the characteristics such as when the target rock body is small or inclined. As the arrangement of the disposal panel 8, a distributed arrangement that develops at a horizontal level and a multilayer arrangement that develops in the vertical direction are conceivable. The distributed arrangement is suitable for arrangements based on the characteristics of geological structural elements such as faults, and the multi-layer arrangement is effective when the area required for underground facilities cannot be secured.

  The connecting mine 7 is a mine that connects between the disposal panels 8, and is used for physical distribution associated with work in the underground such as transportation of the buffer material-integrated waste body P from the ground facility 2 and for entering and exiting workers. For each disposal panel 8 in which the buffer material integrated waste body P has been buried, the unnecessary connecting mine shaft 7 can be backfilled.

  Next, the disposal tunnel will be described in more detail with reference to FIGS. 2 is a conceptual diagram showing the main mine and the disposal mine shown in FIG. 1, and FIG. 3 is a conceptual perspective view showing the disposal mine shown in FIG.

  As shown in FIG. 2, the waste disposal / disposal facility 1 according to the embodiment of the present invention is placed in a state where the axial direction of the cushioning material-integrated waste body P formed in a columnar shape is oriented horizontally. The horizontal buffering system is adopted, and the buffer material integrated waste body P, which is carried into the disposal tunnel 5 and fixed, and the disposal tunnel 5 are filled with the pellet-shaped buffer material B (see FIG. 7).

  As shown in FIG. 3, a pedestal rail 51 is laid in the disposal mine shaft 5 of the waste burial disposal facility 1 according to the embodiment of the present invention. The pedestal rail 51 serves as a guide rail for a carriage (for example, a pallet truck fork) on which the buffer material integrated waste body P is mounted when the buffer material integrated waste body P is carried into the disposal tunnel 5. When the cushioning material integrated waste body P carried in is placed, it becomes a base for the cushioning material integrated waste body P. The pedestal rail 51 is laid in such a manner as to protrude upward from the floor surface of the disposal mine shaft 5, and the cross section thereof has an arc shape, and extends in the axial direction of the disposal mine shaft 5.

  Further, in the inside of the pedestal rail 51, a water injection hole 52 for pouring water into a pellet-shaped buffer material B filled between the buffer material-integrated waste body P placed on the pedestal rail 51 and the disposal tunnel 5. Is provided. The water injection hole 52 has a main hole 52 a provided along the axial direction of the disposal tunnel 5 and a plurality of branch holes 52 b branched from the main hole 52 a and provided along the inner periphery of the disposal tunnel 5. ing.

  The discharge ports 52b1 serving as the opening ends of the branch holes 52b are opened at intervals shorter than the length of the cushioning material integrated waste body P in the axial direction of the disposal tunnel 5.

  Next, a procedure for burying the waste material P integrated with a cushioning material will be described with reference to FIG. FIG. 4 is a flowchart showing a procedure for burying a cushioning material integrated waste.

  When the buffer material-integrated waste body P is disposed in the disposal tunnel 5 as shown in FIG. 4, first, the buffer material-integrated waste body P is carried into the disposal tunnel 5. In order to carry in the shock absorber-integrated waste body P, a transport carriage is used. Here, a pallet truck fork F having a roller type tire shown in FIGS. 5 and 6 is used.

  When the buffer material integrated waste body P is carried into the disposal tunnel 5, the buffer material integrated waste body P is transferred to the pallet truck fork F in the main tunnel 6. As shown in FIG. 5, the pallet truck fork F on which the cushioning material-integrated waste body P is replaced has a cushioning material-integrated waste body up to a height at which the cushioning material-integrated waste body P does not interfere with the pedestal rail 51. P is lifted and the cushioning material integrated waste body P is carried into the disposal mine shaft 5 (step S1). At this time, the pedestal rail 51 becomes a guide rail of the pallet truck fork F, and the pallet truck fork F is guided by the pedestal rail 51 as shown in FIG.

  When the cushioning material-integrated waste body P is loaded to the position where the cushioning material-integrated waste body P is placed, the pallet truck fork F then lowers the cushioning material-integrated waste body P onto the pedestal rail 51. As shown in FIG. 6, the cushioning material integrated waste body P is placed (step S2).

  Next, the pallet truck fork F is carried out to the main tunnel 6 and, as shown in FIG. 7, the buffer material B in the form of pellets is filled between the disposed buffer material-integrated waste P and the disposal tunnel 5. (Step S3). The pellet-shaped buffer material B filled here is a compacted clay-based water-impervious material typified by bentonite, and exhibits water-insulating performance by swelling when poured.

  When the number of buffer material-integrated waste bodies P to be buried and disposed in the disposal tunnel 5 is fixed and filled with the buffer material B in the form of pellets, the inlet of the disposal tunnel 5 is closed (step S4). Next, as shown in FIG. 8, by supplying water from the water injection hole 52, water is injected into the pellet-shaped buffer material B (step S5). When water is poured into the pellet-shaped cushioning material B, the pellet-shaped cushioning material B swells, thereby sealing between the cushioning material-integrated waste body P and the disposal mine shaft 5. Thus, the disposal mine shaft 5 is closed and water is injected, so that the buffer material-integrated waste body P is buried in each disposal mine shaft 5.

  In addition, when there is a very small amount of spring water (bleeding water) on the inner wall of the disposal mine shaft 5, it is absorbed by the pellet-shaped buffer material B after the spring water is filled and exhibits a locally uneven swelling seal state. There are concerns. In order to prevent such a situation, the water outside the disposal mine and the drainage inside the disposal mine are strictly dealt with. However, if there is spring water locally, the mine support material (for example, concrete) The water injection hole 52 may be used for temporary drainage measures by providing an introduction groove or a water guide pipe at the main point and guiding it to the water injection hole 52.

  Further, when water is poured into the pellet-shaped buffer material B filled between the buffer material-integrated waste body P and the disposal mineway 5, the pellet-shaped buffer material B absorbs and swells in a short time, and the buffer material (bentonite). It becomes a highly water-resistant cushioning material in which water and water become homogeneous. Some of the buffer material slightly enters into the branch hole 52b, but it takes several days or more to enter the main hole 52a. Therefore, before that, the grout material injection pipe is inserted into the main hole 52a from the main tunnel 6 to the main hole 52a. And the main hole 52a is filled with a grout material (step S6). Thereby, all the water paths in the axial direction of the disposal mine shaft 5 are sealed with water. As the grout material, a cement-based inorganic material, a bentonite-based material, or the like can be applied, but it is most suitable to inject a slurry made by mixing bentonite with ethanol water or inorganic salt water.

  As described above, when water is poured into the buffer material B in the form of pellets from the main hole 52a, while the grout material is filled into the main hole 52a, the grout material injection tube T is inserted into the main hole 52a as shown in FIG. It is preferable to insert the grouting material injection tube T and the main hole 52a into a core-sheath structure. With this configuration, when water is poured from the main hole 52a into the pellet-shaped buffer material B, an annular path defined between the main hole 52a and the grout material injection pipe T is the water injection path R1 (FIG. 10). When the grout material G is filled in the main hole 52a, the grout material injection tube T becomes the grout material G filling path R2 (see FIG. 10). The sheath tube 52a1 connected to the main hole 52a is provided with a water injection port 52a2 communicating with the water injection path R1, and water is injected from here when water is injected into the pellet-shaped buffer material B. On the other hand, one end and the other end of the grout material injection tube T are open, and one end opening on the front side (inlet side) serves as an injection port T1 for the grout material G. Inject from.

  As shown in FIG. 10, when the injection port T1 is closed and water is injected from the water injection port 52a2, the injected water passes through the water injection path R1 and the branch hole 52b and is discharged from the discharge port 52b1. The discharged water is supplied to the pellet-shaped buffer material B filled between the buffer material-integrated waste body P and the disposal mine shaft 5, and the pellet-shaped buffer material B swells.

  On the other hand, when the grout material G is injected from the injection port T1 of the grout material injection tube T, the injected grout material G moves the inside of the grout material injection tube T from the near side to the back side as shown in FIG. Will invade. When the grout material G reaches the other end opening (discharge port T2) of the grout material injection tube T, the grout material G is discharged from the discharge port T2, as shown in FIG. Then, the grout material G discharged from the discharge port T2 returns from the back side of the main hole 52a to the near side and is filled in the main hole 52a. The grout material G filled from the back side to the front side of the main hole 52a is finally discharged from the water injection port 52a2, as shown in FIG. 11-3. When the grout material G is discharged from the water injection port 52a2, since the grout material G is filled in the main hole 52a, the filling operation of the grout material G is finished.

  The waste burial / disposal facility 1 according to the embodiment of the present invention described above is a transport cart (with a cushioning material-integrated waste body P mounted on the disposal shaft 5 when the buffer material-integrated waste body P is carried into the disposal tunnel 5). For example, the pedestal rail 51 that becomes a guide rail of the pallet truck fork F) and becomes a pedestal of the cushioning material-integrated waste body P when the cushioning material-integrated waste body P carried into the disposal mineway 5 is placed is disposed on the disposal mineway 5. Pellets filled between the disposal pit 5 and the waste material P integrated with the cushioning material placed on the pedestal rail 51 and laid along the axial direction of the disposal mine shaft 5 so as to protrude upward from the floor surface Since the water injection hole 52 for injecting water into the buffer material B is provided, the buffer material 1 placed in the disposal tunnel 5 is not obstructed when the buffer material integrated waste body P is carried in or placed. Between the body waste P and the disposal mine 5 The water injection into the filled pellets of buffer material B becomes possible.

  Further, when the waste material P integrated with the buffer material is carried into the disposal mine shaft 5, it becomes a guide rail of the transport cart (for example, the pallet truck fork F) on which the waste material P integrated with the buffer material is mounted. Can move stably in the loading direction.

  Further, since the placed buffer material-integrated waste body P is placed in a state of being separated from the floor surface of the disposal mine shaft 5, it becomes easy to fill the pellet-shaped buffer material B, and water injection is evenly distributed. Done.

  In the waste embedding disposal facility 1 according to the embodiment of the present invention described above, the grout material G is simply injected from the injection port T1 of the grout material injection pipe T. There is room for improvement. Therefore, an improved grout material injection procedure (method) will be described with reference to FIG. FIG. 12 is a schematic cross-sectional view showing a grout material filling path, FIG. 12-1 is a diagram showing a state immediately after the start of grout material filling, and FIG. FIG. 12-3 is a diagram showing a state after the filling of the grout material.

  In the improved grouting material injection procedure (method), before the grouting material G is injected, the inside of the main hole 52a and the branch hole 52b is set to a negative pressure, and the grouting material G is injected while maintaining the state. Specifically, before injecting the grout material G from the injection port T1 of the grout material injection pipe T, a vacuum pump or a vacuum tank (not shown) is connected to the water injection port 52a2. Then, by driving the vacuum pump, the internal air in the main hole 52a and the branch hole 52b is excluded, and the inside of the main hole 52a and the branch hole 52b is set to a negative pressure (vacuum). Next, injection of the grout material G is started from the injection port T1 of the grout material injection tube T in a state where the driving of the vacuum pump is maintained. Then, as shown in FIG. 12A, the grout material G enters the inside of the grout material injection tube T from the near side to the far side. Then, when the grout material G reaches the discharge port T2 of the grout material injection tube T, the grout material G is discharged from the discharge port T2, as shown in FIG. And the grout material G discharged from the discharge port T2 returns to the near side from the back side of the main hole 52a, and is filled into the main hole 52a. At this time, the branch holes 52b in the negative pressure state (vacuum state) are also filled. Eventually, as shown in FIG. 12-3, the grout material G is filled in all of the main holes 52a and the branch holes 52b. According to the grout material injection procedure (method) improved in this way, not only the main hole 52a but also the branch hole 52b can be reliably filled with the grout material G and sealed with water.

  Further, in the waste disposal facility 1 according to the embodiment of the present invention described above, one pedestal rail 51 is provided at the center of the floor surface of the disposal mine channel 5, but as shown in FIG. The pedestal rails 53 may be provided on both sides of the floor surface 5. In this case, a water injection hole 54 having a main hole 54 a and a branch hole 54 b is provided for each pedestal rail 53.

  In the waste disposal / disposal facility 1 according to the embodiment of the present invention described above, the buffer material B in a pellet form is filled between the disposed buffer material-integrated waste body P and the disposal tunnel 5, and then water injection is performed. By pouring water from the holes 52, the pellet-shaped buffer material B swells and forms a stable water shielding layer for a long time between the buffer material-integrated waste body P and the disposal tunnel 5.

  FIG. 14 is a diagram showing the relationship between the time (days) elapsed after pouring water into the pellet-shaped buffer material and the water permeability coefficient of the pellet-shaped buffer material. As shown in FIG. 14, even when water is poured into the dried pellet-shaped buffer material B, the pellet-shaped buffer material B does not immediately exhibit the water-blocking performance, but exhibits the water-blocking performance over several days after water injection. . That is, when water is poured into the dried pellet-shaped cushioning material B, each pellet-shaped cushioning material B absorbs and expands and fills the gaps between the pellet-shaped cushioning materials B, thereby reducing water permeability over several days. And demonstrates water shielding performance. In the example shown in FIG. 14, 5 to 6 days after pouring water into the pellet-shaped buffer material B, the water permeability coefficient becomes 1.0E-11 m / s, and the buffer material's original water shielding performance is exhibited. Sealed by water.

  Thus, since the pellet-shaped buffer material B exhibits the water-insulating performance inherent to the buffer material over several days after water injection, the pellet-shaped buffer material B exhibits 5-6 in the example shown in FIG. (Sun) is concerned about the damage of the sealing material (the buffer material B that has started to swell) due to the groundwater flowing from around the disposal tunnel 5 into the disposal tunnel 5.

  FIG. 15 is a diagram illustrating a waste disposal facility in which a disposal tunnel passes through a plurality of spring zones. In Japan's geological rock conditions, it is not uncommon for a mine tunnel to penetrate a plurality of spring zones. Therefore, when the mine channel extension of the disposal mine channel 5 is long, as shown in FIG. It may penetrate the bands WA, WB, WC. In such a case, there is a concern about damage to the sealing material (the buffer material B that has started to swell).

  FIG. 16 is a diagram showing the groundwater pressure distribution in the natural ground in the natural state before excavating the disposal tunnel. In the example shown in FIG. 16, it is assumed that the depth of the disposal tunnel to be excavated is 500 m, and the disposal tunnel 5 to be excavated penetrates the three spring water zones WA, WB, and WC. In addition, it is assumed that the groundwater surfaces of the spring zones WA, WB, and WC are on the ground surface (depth 0). As shown in FIG. 16, in the natural state before excavating the disposal mine shaft 5, a spring zone (fault, fault fracture zone, layer of highly permeable volcanic ejecta, etc.) WA, WB, WC The groundwater pressure of is the same everywhere. In other words, the groundwater pressure increases as the depth increases, but if the groundwater pressure is expressed in terms of the water head value (the value corresponding to reading at the water position with a piezo pipe attached to that point), the groundwater at all points The peak price will be equal to the groundwater level near the ground surface.

Since groundwater penetrates underground with a very small flow velocity, the hydrodynamic gradient is not completely zero. Therefore, the distribution of the head value is not completely constant. However, even if there is a difference in groundwater pressure compared to the adjacent spring zone, the macro hydrodynamic gradient of the natural ground deep in the underground (for example, 300 to 1000 m depth) where the waste disposal facility 1 is located Is expected to be less than 1/100. Thereby, for example, the differential pressure of the groundwater pressure in the spring zone 50 m away is about 0.5 mH ₂ O (the pressure difference is about 5 kPa) at the head.

  FIG. 17 is a diagram showing the groundwater pressure distribution in the natural ground in a state where the disposal mine is excavated and then the amount of spring water is settled. As shown in FIG. 17, after excavating the disposal tunnel, the water pressure at the intersection of the spring zone (the wall portion of the disposal tunnel) becomes the same as the atmospheric pressure, so the disposal of the spring zones WA, WB, WC The water pressure (head value) around the tunnel is significantly lower than the original water pressure as time passes after excavation. In FIG. 17, the permeability characteristics of the plurality of spring zones WA, WB, and WC are different. For example, the permeability of the spring zone WB is 10 times the permeability of the adjacent spring zones WA and WB (for example, If the hydraulic conductivity is equivalent to 20 times and the gap volume is 2 times), the water pressure in the spring zone WB is deeper than the water pressure in the spring zone WA or WC (from the wall of the disposal tunnel to the natural ground) And far away).

  After that, after filling the pellet-shaped buffer material B between the disposal tunnel 5 and the buffer material-integrated waste body P placed in the disposal tunnel 5, the drainage action of groundwater springs by a drainage facility (not shown) is stopped. Then, when water is injected between the disposal mine 5 and the buffer material integrated waste body P, immediately after that, groundwater flows into the disposal mine 5 from the spring zones WA, WB, WC. Since the water is filled in the disposal mine shaft 5 within a short time, the water shielding performance is exhibited as time passes (see FIG. 14).

  FIG. 18 is a diagram illustrating a groundwater pressure distribution of a natural ground in a state immediately after filling a pellet-shaped buffer material between a disposal mine and a waste body and then injecting water between the disposal mine and the waste body. . When the inside of the disposal tunnel 5 is filled with water, the water pressure in the spring zone WA or WCC rises and quickly recovers to the original groundwater pressure. On the other hand, the water pressure recovery of the spring zone WB having a large water permeability and a large storage amount is slightly delayed. Thus, the recovery speed of the groundwater pressure in each of the spring zones WA, WB, WC varies depending on the permeability characteristics of the spring zones WA, WB, WC, and the spring pressure of the groundwater between the spring zones. The differential pressure temporarily increases. For example, when a different water pressure recovery phenomenon occurs in each of the spring zones WA, WB, and WC as shown in FIG. 18, a difference occurs in the spring pressure in the anti-wall surface of each of the spring zones WA, WB, and WC. The groundwater flow from the spring zone WA or WC toward the spring zone WB as indicated by an arrow in the figure is generated in the gap portion of the tunnel. The hydrodynamic gradient i in the axial direction of the disposal tunnel 5 on the wall surface of the tunnel leading to this groundwater flow is determined by the separation distances Lab and Lbc of the spring zones WA, WB and WC and the spring immediately before the tunnel closure of the spring zones WA, WB and WC. Corresponding to the values of the water pressures Pa, Pb, Pc, for example, the following conditions are satisfied.

[Dynamic gradient of groundwater flow from spring zone WA to spring zone WB] (Example 1)
Separation distance Lab = 10m
Spring water pressure Pa = 300mH ₂ O, Pb = 100mH ₂ O
i = (300-100) / 10 = 20

[Dynamic gradient of groundwater flow from spring zone WC to spring zone WA] (Example 2)
Separation distance Lbc = 100m
Spring pressure _{Pb~~100mH 2 O, Pc = 200mH 2} O
i = (200-100) / 100 = 1

  The above trial calculation example is an example. Actually, since various flow fields are generated according to the hydraulic characteristics of the spring zones WA, WB, WC, a plurality of spring zones WA, WB, WC As for the flow of groundwater that permeates the vicinity of the wall surface of the disposal mineway 5 in the axial direction of the disposal mineway 5, the groundwater flows under various conditions. For example, in the trial calculation examples 1 and 2, as in the trial calculation example 1, when the dynamic water gradient becomes large or the pressure difference becomes large, there is a concern that the sealing performance is impaired. Specifically, a piping phenomenon occurs in which a flow path through which groundwater flows predominantly along the wall surface of the tunnel occurs, and thereafter, the groundwater flowing through the water channel flows and scours and loses the buffer material B. There is concern.

  Such a phenomenon is temporary, and if a material having a water-impervious seal characteristic as shown in FIG. 14 is used as a filler for a gap along the wall surface of a tunnel, such a dynamic water can be used within a few days. Since the groundwater flow phenomenon with a large gradient is eliminated, the concern is resolved if the seepage flow with a large hydrodynamic gradient for several days after the disposal tunnel 5 is filled with groundwater can be suppressed.

Embodiment 2
The waste embedding disposal facility according to the second embodiment of the present invention eliminates the above-mentioned concerns, and the waste embedding disposal facility 1 according to the above-described embodiment of the present invention includes water injection means. It is a thing. The water injection means is for injecting water from the above-described water injection hole, and includes water injection pressure adjusting means. The water injection means is constituted by, for example, a discharge pump 9 (see FIGS. 20 and 21) whose discharge pressure can be adjusted, and adjusts the water injection pressure by adjusting the discharge pressure. Specifically, the pressure is adjusted so as to gradually increase from a pressure that is substantially the same as the atmospheric pressure, and finally, the pressure is adjusted to be approximately the same as the groundwater pressure before the disposal tunnel is excavated.

  Next, the procedure for burying the waste material P with the cushioning material integrated type will be described with reference to FIG. FIG. 19 is a flowchart showing a procedure for burying a waste material integrated with a cushioning material. Here, it is assumed that the depth of the disposal tunnel 5 to be excavated is 500 m, and the disposal tunnel 5 to be excavated penetrates the three spring zones WA, WB, WC. It is also assumed that the groundwater surfaces of the spring zones WA, WB, WC are on the ground surface (depth 0).

  In the case where the buffer material-integrated waste body P is disposed in the disposal tunnel 5, as shown in FIG. 19, first, the waste body-integrated waste body P is carried into the disposal tunnel 5 (step S11). A transport cart is used to carry in the buffer material-integrated waste body P. Here, as an example, a pallet truck fork equipped with a roller-type tire is used.

  When the buffer material-integrated waste body P is carried into the disposal tunnel 5, the buffer material-integrated waste body P is replaced with a pallet truck fork in the main tunnel 6. The pallet truck fork on which the cushioning material-integrated waste body P has been replaced lifts the cushioning material-integrated waste body P to a height at which the cushioning material-integrated waste body P does not interfere with the pedestal rail 51. The body-shaped waste body P is carried into the disposal tunnel 5.

  When the buffer material-integrated waste body P is carried to the position where the buffer material-integrated waste body P is placed, the pallet truck fork then lowers the buffer material-integrated waste body on the pedestal rail 51 to The material-integrated waste body P is placed (step S12).

  Next, the pallet truck fork is carried out to the main tunnel 6, and the buffer material B in a pellet form is filled between the fixed buffer material integrated waste P and the disposal tunnel 5 (step S13). The pellet-shaped buffer material B filled here is a compacted clay-based water-impervious material typified by bentonite, and exhibits water-insulating performance by swelling when poured.

  When the number of buffer material-integrated waste bodies P to be buried and disposed in the disposal tunnel 5 is placed and filled with the buffer material B in the form of pellets, the entrance of the disposal tunnel 5 is closed (step S14). Next, water is injected into the pellet-shaped buffer material B by absorbing water from the water injection hole 52 (step S15).

  By adjusting the discharge pressure of the discharge pump 9, the pressure of the water injected into the pellet-shaped buffer material B is adjusted in a short time (or promptly) from the pressure at which the water injection pressure is substantially the same as the atmospheric pressure. The pressure is adjusted so as to increase gradually (step S16). And when the water injection pressure becomes equal to the groundwater pressure before excavating the disposal mine shaft 5, that state is maintained (step S17).

FIG. 20 is a diagram showing the groundwater pressure distribution in the natural ground when the water pressure reaches 300 mH ₂ O in the course of increasing the water injection pressure to the original groundwater pressure before excavation in a short time, FIG. 21 is a diagram illustrating the groundwater pressure distribution in the natural ground when the water injection pressure reaches 500 mH ₂ O corresponding to the original groundwater pressure before excavation of the tunnel.

As shown in FIG. 20, when the pressure on the tunnel wall surface of each spring zone WA, WB, WC rises to 300 mH ₂₀ (pressure value of about 30 MPa), the injected water flows backward and the spring zone WA, Invade WB and WC. Thereby, the pressure of the spring zones WA, WB, WC in which the groundwater pressure has decreased is recovered. If rapid water injection is not performed, as shown in FIG. 18, the difference in the recovery speed of groundwater pressure (head value) at a position away from the wall surface of the disposal mine shaft 5 is remarkable. The problem is that the water pressure difference increases. As a result, if water is rapidly poured, the water pressure distribution between the spring zones recovers in a very short time, thereby eliminating the water pressure difference between the spring zones.

As shown in FIG. 21, when the water injection pressure is increased to 500 mH ₂ O which is substantially the same as the original groundwater pressure before excavation in a short time, the water head value around the disposal tunnel is equal to the original groundwater pressure Pi. Recover to value. After that, the difference in groundwater pressure between the spring zones is almost zero, and the groundwater flow in the mine shaft direction no longer occurs.

  Moreover, in the temporary situation until the water pressure in the spring water zones WA, WB, WC becomes substantially the same as the underground water pressure Pi before excavating the disposal tunnel, the disposal tunnels from the spring zones WA, WB, WC Since groundwater does not flow into 5, the flow of groundwater in the axial direction of the disposal mine channel 5 is less likely to occur. As a result, the concern that the gap sealing performance is impaired can be solved.

  FIG. 22 is a diagram showing a disposal tunnel in which a water shielding plug is installed in the entrance section. As shown in FIG. 22, the waste disposal facility 1 equipped with a discharge pump (water injection means) 6 capable of adjusting the water injection pressure may have a water blocking plug 10 installed in the entrance section of the disposal tunnel. preferable. Thus, if the water shielding plug 10 is installed, the flow of groundwater in the axial direction of the disposal tunnel is suppressed.

  In the description of the waste disposal facility 1 described above, the distribution of the groundwater pressure (head) in the main tunnel 6 is omitted. Thereby, in the entrance section of the disposal mine shaft 5, there is a concentric groundwater head contour C centered on the main mine shaft 6 (see FIG. 22).

  Therefore, in addition to the effect of suppressing the flow of groundwater toward the main tunnel 6, the water-impervious plug 10 described above does not flow the injected water to the main tunnel 6, and the spring zones WA, WB, The effect supplied to WC is also demonstrated. It should be noted that the number of the water shielding plugs 10 is not limited to one at the entrance section, and it is also effective to install a plurality of the water shielding plugs 10 in the middle of the disposal tunnel 5.

  The waste disposal facility 1 according to the above-described embodiment of the present invention adjusts the pressure of water to be injected, so that the difference in groundwater pressure between spring zones becomes almost zero. No axial groundwater flow occurs. As a result, the concern that the gap seal performance is impaired is eliminated.

DESCRIPTION OF SYMBOLS 1 Burial disposal facility 2 Ground facility 3 Underground facility 4 Access tunnel 5 Disposal tunnel 51 Base rail 52 Water injection hole 52a Main hole 52a1 Sheath pipe 52a2 Water injection port 52b Branch hole 52b1 Discharge port 53 Base rail 54 Water injection hole 54a Main hole 54b Branch hole 6 Main tunnel 7 Connection tunnel 8 Disposal panel 9 Discharge pump 10 Water blocking plug P Waste material integrated with buffer material B Pelletized buffer material F Pallet truck fork
G Grout material R1 Injection route R2 Filling route T Grout injection tube T1 Inlet T2 Discharge port WA, WB, WC Spring zone C Contour line

Claims (6)

Embedding of waste that is carried into the disposal tunnel and filled with the cushioning material-integrated waste that has been placed and the disposal tunnel, and then the buffering material-integrated waste is buried At the disposal facility,
When the buffer material-integrated waste body is carried into the disposal tunnel, it becomes a guide rail of a transport carriage equipped with the buffer material-integrated waste body, and the buffer material-integrated waste body carried into the disposal tunnel is fixed. A pedestal rail serving as a pedestal for the cushioning material-integrated waste body when projecting from the floor surface of the disposal mineway along the axial direction of the disposal mineway, and on the pedestal rail The waste body is characterized in that a water injection hole is provided in the pedestal rail for pouring water into a pellet-shaped buffer material filled between the stationary buffer material-integrated waste body and the disposal tunnel. Burial disposal facility.   The water injection hole has a main hole provided along the axial direction of the disposal tunnel, and a plurality of branch holes branched from the main hole and provided along the inner periphery of the disposal tunnel. The waste disposal facility according to claim 1.   The plurality of discharge ports serving as opening ends of the plurality of branch holes are opened at intervals shorter than the length of the cushioning material integrated waste body in the axial direction of the disposal tunnel. The waste disposal facility described in 1.   The waste disposal facility according to any one of claims 1 to 3, further comprising a water injection means for injecting water with adjusted water pressure from the water injection hole.   5. The waste disposal facility according to claim 4, wherein the water injection means includes water injection pressure adjusting means for adjusting water pressure.   6. A water-impervious plug that suppresses the flow of groundwater in the axial direction of the disposal tunnel is installed at an entrance section of the disposal tunnel, and further at a key point in the middle of the disposal tunnel. Waste disposal facility.

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