JP3663945B2 - Construction method of waste disposal site - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a construction method for a waste disposal site, and more particularly to a construction method suitable for repairing an existing waste disposal site.
[0002]
[Prior art]
As a method of disposing of low-level radioactive waste such as work clothes and gloves used in nuclear power plants, universities and corporate laboratories, medical facilities, etc., a water-blocking wall with a closed cross-section whose tip reaches the impermeable ground There is a method of constructing and excavating the inside of the impermeable wall and burying a sealed container made of reinforced concrete or steel plate containing low-level radioactive waste.
[0003]
However, the construction method of such a waste disposal site has the following technical problems.
[0004]
[Problems to be solved by the invention]
That is, radioactive waste has a very long half-life, and there is a risk that internal fil- ters and steel plates will deteriorate during the period in which radiation is halved, and internal contaminants may diffuse.
[0005]
On the other hand, disposal sites that store this kind of radioactive waste are usually built in impervious rock masses, but the rock mass structure is very complex and must be accurately grasped over a wide range of properties. However, there is a possibility that cracks exist, and if radiation leaks out of the cracks from these cracks, it will have a negative impact on society and the environment.
[0006]
When there is a possibility that such inconvenience may occur, in general, the buried waste will be dug out and transferred to another disposal site. Such a waste disposal site is usually located in a radiation control area, so that there is a problem that it takes a long time to move due to restrictions on access.
[0007]
Such problems are not limited to low-level radioactive waste disposal sites. For example, similar inconveniences may occur in waste disposal sites where hazardous metals such as heavy metals are dumped. When solving the inconvenience, there was a technical problem similar to the disposal site of low-level radioactive waste.
[0008]
The present invention has been made in view of such conventional problems, and the object of the present invention is when there is a disadvantage such as leakage or possibility of leakage of existing contaminants at an existing waste disposal site. An object of the present invention is to provide a construction method for a waste disposal site that can quickly solve the inconvenience.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a pair of water-stopping vertical walls in the ground on the side of an existing waste disposal site constructed in a rock so as to cover the side of the waste disposal site. A horizontal impermeable body with both ends connected to the water-stop vertical wall so as to cover the bottom surface of the waste disposal site in the bedrock ground on the lower surface side of the existing waste disposal site The horizontal impervious body is formed in a form in which a large number of tunnels are connected in the horizontal direction, and the horizontal impervious object is a state in which a plurality of tunnels are connected in the horizontal direction. constructed by excavation capable tunnel boring machine in the plurality of tunnels formed by inserting the guide portion into the preceding tunnel ended and ligated formed sequentially horizontally the prior tunnel as a guide tunnel Was Unishi.
According to the construction method of the waste disposal site constructed in this way, a water blocking vertical wall is constructed in the ground on the side of the existing waste disposal site, and the ground on the lower surface side of the existing waste disposal site Since a horizontal impermeable body with both ends connected to a water-stop vertical wall is constructed so as to cover the bottom surface of the waste disposal site, it is possible to eliminate leakage or possibility of contamination from the existing waste disposal site.
In this case, in the construction method of the present invention, the horizontal impermeable body is constructed by a tunnel boring machine capable of excavation in a state where a plurality of tunnels are connected in the horizontal direction. There is no need to relocate waste containing level radiation waste or hazardous substances to another location.
In addition, since a plurality of tunnels are inserted in the horizontal direction sequentially as guide tunnels by inserting guide portions from the side of the preceding tunnels that have been formed , a large number of tunnels can be surely arranged in the horizontal direction. Can be linked.
The tunnel boring machine includes a pair of tunnel excavating portions connected in a horizontal direction to each other, and a guide portion that is detachably attached to a side of one of the tunnel excavating portions and is inserted into the guide tunnel. And can be configured.
According to this configuration, when excavating a natural mountain with a pair of tunnel excavation parts, the direction is regulated and guided by the guide part inserted and installed in the guide tunnel , so that a large number of tunnels can be formed with high accuracy. be able to.
When the tunnel is dug by the tunnel boring machine, concrete or bentonite can be sequentially filled with the progress of excavation in addition to the portion serving as the guide tunnel.
According to this configuration, as the excavation progresses, the portion other than the guide tunnel is sequentially filled with concrete or bentonite, so that the formation efficiency of the horizontal water shield is improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 to 6 show an embodiment of a construction method for a waste disposal site according to the present invention.
[0011]
In the construction method of the waste disposal site shown in the figure, as shown in FIG. 1, the side surface of the existing waste disposal site 10 is covered in the ground 12 on the side of the existing waste disposal site 10. The pair of water-stop vertical walls 14 are constructed to face each other.
[0012]
The existing waste disposal site 10 has already been dumped with low-level radioactive waste and waste containing hazardous metals. The water-stop vertical wall 14 is formed by an underground continuous wall construction method or a grouting wall construction method.
[0013]
When the water-stopping vertical wall 14 is formed, both ends are connected to the water-stopping vertical wall 14 in the ground 12 on the lower surface side of the existing waste disposal site 10 so as to cover the bottom surface of the existing waste disposal site 10. A horizontal impermeable body 16 is constructed.
[0014]
The horizontal impermeable body 16 is obtained by connecting a number of tunnels 18 to each other in the horizontal direction. The tunnel 18 is formed by using a tunnel boring machine 20 described later.
[0015]
FIG. 2 shows an example of a method for forming the tunnel 18. In the example shown in FIG. 2, a start shaft 22 is formed to a predetermined depth on one end side of the existing waste disposal site 10 (an end portion in a direction in which the water blocking vertical wall 14 is not formed).
[0016]
The tunnel boring machine 20 is started almost horizontally from the lower end side of the starting shaft 22, and after reaching the ground via an ascending slope, for example, about 45%, after digging horizontally below the existing waste disposal site 10.
[0017]
The tunnel boring machine 20 that has reached the ground side is transferred to the start shaft 22 side, and is similarly excavated to form a plurality of tunnels 18 interconnected in the horizontal direction.
[0018]
In this case, the reaching shaft 24 can be formed at the position opposite to the starting shaft 22, and when both the starting and the reaching shafts 22, 24 are formed, the tunnel 18 is formed by digging in the horizontal direction and reaching the side. When the direction of the tunnel boring machine 20 is changed in any one of the vertical shafts, the horizontal impermeable body 16 can be formed by operating one machine efficiently.
[0019]
In the example shown in FIG. 2, the starting or reaching shafts 22 and 24 are not individual ones, and may be formed in a groove shape matching the width of the horizontal water shielding body 16 to be constructed, for example.
[0020]
A pair of tunnels 18 positioned at both ends of the horizontal water shield 16 are formed so as to be connected to the water blocking vertical wall 14. As this connecting means, for example, when excavating with the tunnel boring machine 20, excavation is performed by scraping a part of the water-stop vertical wall 14, and concrete or mortar is filled in the excavated tunnel 18. Integrate both.
[0021]
On the other hand, the plurality of tunnels 18 positioned at portions other than the both ends of the horizontal impermeable body 16 are formed so that parts on the outer peripheral side are connected to each other. In the case of the present embodiment, the tunnel boring machine 20 is configured to be able to dig in a state where a plurality of tunnels 18 are connected in the horizontal direction.
[0022]
That is, the boring machine 20 for forming the horizontal impermeable body 16 includes a pair of tunnel excavating portions 26 and 28 and a guide portion 30 as shown in FIGS.
[0023]
Each of the tunnel excavating portions 26 and 28 has cylindrical skin plates 26b and 28b on which cutter disks 26a and 28a that are rotationally driven on the front end side are rotatably provided.
[0024]
The cutter discs 26a and 28a are configured such that excavable ranges partially overlap on the outer periphery, and the excavation cross sections of these discs 26a and 28a are excavated so that the outer periphery of the circular cross section overlaps each other.
[0025]
As shown in FIG. 5, the skin plates 26b and 28b are partially connected on the outer peripheral side. In each skin plate 26b, 28b, a thrust jack (not shown) for advancing the machine 20 is provided.
In addition, on the outer peripheral side of each skin plate 26b, 28b, a gripper (not shown) that protrudes to the natural ground side and takes an excavation reaction force when the machine 20 is advanced is disposed.
[0026]
In the tunnel boring machine 20 of the present embodiment, the soil discharge pipes 26c and 28c and the power lines 26d and 28d provided in the skin plates 26b and 28b are arranged on the rear side of the connecting portion between the skin plates 26b and 28b. And is coupled to a rear carriage 26e provided only on one skin plate 26b side.
[0027]
In addition, on the rear side of the rear carriage 26e, a movable mold 32 is installed to close the connecting portion between the skin plates 26b and 28b, and a pipe 34 for filling concrete or bentonite is provided in the mold 32.
[0028]
On the other hand, the guide portion 30 includes an arc-shaped guide plate 30a and a plurality of guide rollers 30b that are provided on the outer peripheral surface of the guide plate 30a and roll along the inner wall surface of the excavated tunnel 18. 30a is detachably coupled to the side of the skin plate 28b of one tunnel digging portion 28.
[0029]
As will be described later, the guide portion 30 is inserted and installed in the preceding tunnel 18 and regulates the positioning direction of the tunnel excavating portions 26 and 28. When the tunnels 18 of the horizontal water-impervious portion 16 are connected and formed, first, as shown in FIG. 3A, with the guide portion 30 of the tunnel boring machine 20 removed, the two preceding tunnels 18a, 18b is formed.
[0030]
At this time, one tunnel 18a is filled with concrete or bentonite in the tunnel 18a sequentially on the rear side while forming the tunnels 18a and 18b using the movable mold 32 (see FIG. 3 (B)).
[0031]
Then, when the formation of the preceding tunnels 18a, 18b is completed, as shown in FIG. 3C, excavation is performed in a state where the guide portion 30 of the tunnel boring machine 20 is connected to the skin plate 28b.
[0032]
At this time, the guide unit 30 is inserted and installed inside the leading tunnel 18b as a guide tunnel, and forms tunnels 18c and 18d that are mutually connected in the horizontal direction on the side of the tunnel 18b.
[0033]
When the tunnels 18c and 18d are formed, concrete or bentonite is sequentially filled in the tunnels 18b and 18c on the rear side while the tunnels 18c and 18d are formed in a digging manner (see FIG. 3D).
[0034]
Thereafter, the tunnel on the end side not filled with concrete or bentonite is used as a guide tunnel, the guide portion 30 is inserted and installed therein, and the same process is repeated to form a tunnel 18 that forms the horizontal water shield 16. Is formed.
[0035]
When all the tunnels 18 are filled with concrete or bentonite and the construction of the horizontal impermeable body 16 is completed, the concrete or bentonite is similarly filled in the start shaft 22 (the reach shaft 24) to construct a waste disposal site. Is completed.
[0036]
Now, according to the construction method of the waste disposal site constructed as described above, the water blocking vertical wall 14 is constructed in the ground 12 on the side surface of the existing waste disposal site 10, and the lower surface of the existing waste disposal site 10 is constructed. In the ground 12 on the side, the horizontal water shielding body 16 having both ends connected to the water blocking vertical wall 14 is constructed so as to cover the bottom surface of the waste disposal site 10. It will be enclosed by the vertical wall 14 and the horizontal water-impervious body 16, and the leakage of the contaminant from the existing waste disposal site 10 or its possibility can be excluded.
[0037]
In this case, in the construction method of the present invention, the horizontal impermeable body 16 is constructed by the tunnel boring machine 20 capable of excavation in a state where a plurality of tunnels 18 are connected in the horizontal direction, and is therefore dumped in the existing waste disposal site 10. There is no need to relocate low-level radioactive waste or waste containing hazardous substances to another location.
[0038]
Moreover, when the horizontal impermeable body 16 is constructed in this way, it is not necessary to perform work in the management area, and the construction efficiency is greatly improved.
[0039]
Further, in the present embodiment, the multiple tunnels 18 are sequentially connected in the horizontal direction using the preceding tunnel as a guide tunnel, so that the multiple tunnels 18 can be reliably connected in the horizontal direction.
[0040]
Further, in the case of the present embodiment, the tunnel boring machine 20 is detachably mounted on a pair of tunnel excavation portions 26 and 28 that are connected to each other in the horizontal direction and on the side of the tunnel excavation portion 28, and is used as a guide The guide portion 30 is inserted and installed in the tunnel. According to this configuration, the guide is inserted and installed in the guide tunnel when the pair of tunnel excavating portions 26 and 28 excavate the natural ground. Since the digging direction is regulated and guided by the portion 30, a plurality of tunnels 18 can be connected and formed accurately and efficiently.
[0041]
Furthermore, in the case of the present embodiment, when the tunnel 18 is dug by the tunnel boring machine 20, the concrete or bentonite is sequentially filled with the progress of the dug in addition to the portion serving as the guide tunnel. As a result, the formation efficiency of the horizontal impermeable body 16 is improved.
[0042]
【The invention's effect】
As described above in detail in the embodiment, according to the construction method of the waste disposal site according to the present invention, when there is inconvenience such as leakage or possibility of leakage in the existing waste disposal site, The inconvenience can be solved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view of a construction completion state showing a first embodiment of a construction method for a waste disposal site according to the present invention.
FIG. 2 is an explanatory diagram when forming a horizontal impermeable body by a tunnel in the waste disposal site of FIG. 1;
FIG. 3 is an explanatory diagram of a method for interconnecting the tunnels of FIG. 2;
FIG. 4 is an explanatory diagram when a tunnel is dug with a tunnel boring machine used in the construction method of the present invention.
FIG. 5 is a cross-sectional view taken along line A in FIG.
6 is a cross-sectional view taken along line B of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Existing waste disposal site 12 Ground 14 Water blocking vertical wall 16 Horizontal water shield 18, 18a-d Tunnel 20 Tunnel boring machine 22 Starting shaft 24 Reaching shaft 26, 28 Tunnel excavation part 26a, 28a Cutter disk 26b, 28b Skin plate 30 Guide section

Claims (3)

In the ground on the side of the side of the existing waste disposal site built in the bedrock, so as to cover the side of the waste disposal site, and to build a pair of water-stop vertical walls facing each other,
Construction of a waste disposal site that constructs a horizontal impermeable body with both ends connected to the water blocking vertical wall so as to cover the bottom surface of the waste disposal site in the bedrock ground on the lower surface side of the existing waste disposal site Construction method,
The horizontal Saegimizutai is formed a plurality of tunnels in a form linked to the horizontal direction, the horizontal Saegimizutai is constructed by excavation capable tunnel boring machine in a state in which a plurality of connected tunnels in the horizontal direction, the A construction method for a waste disposal site , wherein a plurality of tunnels are formed by inserting guide portions into a preceding tunnel that has been formed and sequentially connecting the preceding tunnels as guide tunnels in the horizontal direction . The tunnel boring machine includes a pair of tunnel excavating portions connected in a horizontal direction to each other and a guide portion that is detachably attached to a side of one of the tunnel excavating portions and is inserted into the guide tunnel. The construction method of the waste disposal site according to claim 1, wherein: The tunnel is filled with concrete or bentonite sequentially as the excavation progresses, in addition to the portion serving as the guide tunnel when the tunnel boring machine performs excavation. Construction method of waste disposal site.

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