Demolition and removal method

Abstract

To provide a demolition and removal method that can divide desired portions with high accuracy and can perform demolition and removal efficiently.SOLUTION: A demolition and removal method comprises the steps of: forming a plurality of notches C2 extending along a surface C1 of concrete C and in a wall thickness direction D3 on the surface C1; forming explosive loading holes H between the plurality of notches C2 in plan view or between extensions of the plurality of notches C2 in plan view; loading an explosive into the explosive loading holes H; blasting the explosive to form a dividing portion Z connecting the plurality of notches C2 to each other; and removing the concrete C located in an area defined by the dividing portion Z and the plurality of notches C2 in plan view.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a method for dismantling and removing concrete. [Background technology]

[0002] Patent Document 1 describes a demolition method for demolishing a columnar concrete structure. In this demolition method, a plurality of dividing planes are set that extend in the longitudinal direction of the concrete structure and intersect with each other, and a plurality of holes are formed that extend along the dividing planes. Linear explosives including electric detonators and detonating cords are placed in the holes. The linear explosives are then detonated to form through cracks along the dividing planes, thereby dividing the concrete structure, and the divided concrete structure is then removed.

[0003] Patent Document 2 describes a method for demolishing reinforced concrete. The reinforced concrete has concrete in which main reinforcing bars, secondary reinforcing bars, and stirrups are embedded. A plurality of slits are drilled in the concrete, aligned in the horizontal direction. The portion of the concrete surrounded by the plurality of slits is demolished.

[0004] Patent Document 3 describes a method for blasting a concrete structure. In this method, a plurality of detonation holes in which explosives are loaded and a plurality of voids in which no explosives are loaded are formed in the concrete structure. In this method, the number, position, depth and arrangement of the detonation holes and voids are adjusted to control cracks that occur when the explosives loaded in the detonation holes are detonated.

[0005] Patent Document 4 describes a method for demolishing a gatepost structure. The demolishing of a gatepost structure includes a preparation step before blasting the gatepost structure with explosives, and a step of blasting the gatepost structure to overturn it. In the preparation step, charge holes are drilled in the gatepost structure and explosives are loaded into the charge holes. In the blasting step, the gatepost structure is blasted with explosives to form a concave groove in the side of the gatepost structure, causing it to overturn. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5795232 [Patent Document 2] Japanese Patent Publication No. 158569 / 1983 [Patent Document 3] Patent No. 6761734 [Patent Document 4] Patent No. 6893401 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, when dismantling and removing wall-shaped concrete, a controlled demolition method is sometimes used. In the controlled demolition method, explosives are loaded into drilled holes, and the concrete is crushed by the shock waves and gas pressure of the explosion. However, if reinforcing bars are embedded in the concrete or there are steel plates such as liners, secondary crushing such as cleaning up the reinforcing bars may be required, or the desired crushing capacity may not be achieved. Since the controlled demolition method cannot divide the desired parts with high precision, there is room for improvement in terms of the efficiency of dismantling and removal.

[0008] An object of the present disclosure is to provide a dismantling and removal method that can divide desired portions with high precision and can perform dismantling and removal efficiently. [Means for solving the problem]

[0009] The demolition and removal method according to the present disclosure is (1) a method for dismantling and removing wall-shaped concrete. The demolition and removal method includes the steps of forming a plurality of notches on the surface of the concrete, the notches extending along the surface and in the wall thickness direction, forming explosive loading holes between the plurality of notches in a plan view or between extensions of the plurality of notches in a plan view, loading explosives into the explosive loading holes, detonating the explosives to form dividing sections connecting the plurality of notches to each other, and removing the concrete located in the dividing sections and in the area defined by the plurality of notches in a plan view.

[0010] In this demolition and removal method, by forming a plurality of cuts extending along the surface of the concrete and in the wall thickness direction, even if there are embedded reinforcing bars and steel plates such as liners, the reinforcing bars and the steel plates can be cut. An explosive loading hole is formed between the plurality of cuts in a plan view, or between the extension lines of the plurality of cuts in a plan view, and a dividing section can be formed between the plurality of cuts by detonating an explosive loaded in the explosive loading hole. Then, the concrete located in the dividing section in a plan view and the area defined by the plurality of cuts is removed. Since the reinforcing bars, etc. are cut before the concrete is removed, the reinforcing bars, etc. can be removed together with the removal of the concrete. Therefore, secondary crushing such as cleaning up the reinforcing bars can be eliminated. A desired crushing capacity can be achieved by forming a plurality of cuts in advance, forming an explosive loading hole between the plurality of cuts, and detonating the explosive loaded in the explosive loading hole. By detonating explosives, the concrete can be removed from the area defined by the dividing section and multiple cuts in a plan view, so that the desired locations can be divided with high precision and the concrete can be dismantled and removed efficiently.

[0011] (2) In the above (1), the multiple cuts may include a pair of first cuts formed on the surface and a second cut connecting the pair of first cuts to each other on the surface. The step of forming the multiple cuts may include a step of forming a pair of first cuts before the step of forming the explosive charging hole, and a step of forming a second cut connecting the pair of first cuts to each other after forming the dividing portion. In this case, the second cut connecting the pair of first cuts to each other is formed, so that the desired portion of the concrete can be divided with higher accuracy. Since the second cut is formed on the surface after the dividing portion is formed by blasting the explosive, the second cut is not formed at the time of blasting the explosive, so that the concrete can be prevented from flying out due to the blasting of the explosive. Therefore, the safety of the concrete demolition and removal work can be improved.

[0012] (3) In the above (1), the multiple cuts may include a pair of first cuts formed on the surface and a second cut connecting the pair of first cuts to each other on the surface. The step of forming the multiple cuts may include a step of forming the pair of first cuts before the step of forming the explosive loading hole, and a step of forming a second cut connecting the pair of first cuts to each other before the explosive is detonated. In this case, the second cut can be formed before the explosive loading hole is formed and the explosive is detonated.

[0013] (4) In any of the above (1) to (3), the step of forming the multiple cuts may cut the reinforcing bars embedded in the concrete at the same time as forming the cuts. In this case, the reinforcing bars embedded in the concrete are cut when the multiple cuts are formed, so that the reinforcing bars embedded in the concrete can be removed at the same time as the concrete is removed. This eliminates the need for secondary crushing for the disposal of the reinforcing bars, thereby further improving the efficiency of demolition and removal.

[0014] (5) In any of the above (1) to (4), in the step of forming the multiple cuts, the steel plate provided on the surface of the concrete may be cut while the cuts are being formed. In this case, even if there is a steel plate such as a liner on the surface of the concrete, this steel plate is cut when the multiple cuts are formed. Therefore, the steel plate can be removed together with the concrete. Therefore, since the steel plate can be removed together with the concrete, the efficiency of demolition and removal can be further improved.

[0015] (6) In any of the above (1) to (5), the step of forming an explosive loading hole may include a step of forming a first explosive loading hole and a step of forming a second explosive loading hole located at a position farther from the surface than the first explosive loading hole. In the step of loading an explosive into the explosive loading hole, an explosive may be loaded into the first explosive loading hole, and in the step of forming the dividing section, the dividing section may be formed by blasting the explosive loaded into the first explosive loading hole. The dismantling and removal method may include a step of loading an explosive into the second explosive loading hole after forming the dividing section, and blasting the explosive loaded into the second explosive loading hole to form the second dividing section. The step of removing the concrete may be performed after forming the second dividing section. In this case, in the step of forming the explosive loading hole, the first explosive loading hole is formed at a position close to the surface, and the second explosive loading hole is formed at a position farther from the surface than the first explosive loading hole. Then, explosives are loaded into the first explosive loading hole and blasted to form a dividing section, and explosives are loaded into the second explosive loading hole and blasted to form a second dividing section. Thus, by blasting in multiple stages from the surface, the entire concrete can be decomposed simply and efficiently. Therefore, the subsequent removal of the concrete can be performed efficiently, and the entire concrete can be removed smoothly.

[0016] (7) In the above (6), the concrete may be annular in plan view, and the surface of the concrete may be the inner surface of the annular concrete in plan view. In this case, the dividing section and the second dividing section can be formed in order from the inner surface of the concrete to the surface closest to the concrete, so that the concrete can be efficiently decomposed in order from the inner surface. Furthermore, when the dividing section is formed on the inner surface, the outer portion of the annular concrete is restrained, so that the scattering of concrete due to blasting can be directed toward the inside of the concrete.

[0017] (8) In any of the above (1) to (7), the demolition and removal method may include a first concrete and a second concrete located vertically below the first concrete. After the step of removing the first concrete is performed, demolition and removal of the second concrete may be started. In this case, the above-mentioned demolition and removal can be performed in order starting from the first concrete located vertically above. Therefore, even a large concrete structure including the first concrete and the second concrete can be efficiently demolition and removal. Effect of the Invention

[0018] According to the present disclosure, desired portions can be cut with high precision and dismantling and removal can be performed efficiently. [Brief description of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view showing an exemplary nuclear reactor to which a dismantling and removal method according to an embodiment is applied; [Diagram 2] 1 is a perspective view showing a wall-shaped concrete structure to which a dismantling and removal method according to an embodiment is applied; [Diagram 3] 1 is a flowchart illustrating an example of steps of a dismantling and removal method according to an embodiment. [Figure 4] 1A is a perspective view showing one step of a dismantling and removal method according to an embodiment, and FIG. 1B is a plan view showing one step of a dismantling and removal method according to an embodiment. [Diagram 5]1A is a perspective view showing one step of a dismantling and removal method according to an embodiment, and FIG. 1B is a plan view showing one step of a dismantling and removal method according to an embodiment. [Figure 6] 1A is a plan view showing one step of a dismantling and removal method according to a modified example, and FIG. 1B is a plan view showing one step of a dismantling and removal method according to a modified example. [Figure 7] FIG. 2 is a diagram showing an example of an explosive used in the demolition and removal method according to the embodiment. [Figure 8] 1(a) and 1(b) are perspective views showing one step of a dismantling and removal method according to an embodiment. [Figure 9] FIG. 2 is a perspective view showing one step of the dismantling and removal method according to the embodiment. [Figure 10] 10 is a flowchart showing an example of steps of a dismantling and removal method according to a second embodiment. [Figure 11] FIG. 11 is a perspective view showing one step of a dismantling and removal method according to a second embodiment. [Figure 12] FIG. 11 is a perspective view showing one step of a dismantling and removal method according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the dismantling and removal method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

[0021] (First embodiment) 1 shows an example of a nuclear reactor N made of concrete C to which a dismantling and removal method according to an embodiment is applied. The nuclear reactor N is, for example, a research reactor, and includes a biological shield 2, which includes concrete C and reinforcing bars.

[0022] The reactor N is, for example, a vertically long cylindrical body having a vertical hole N1 in which the pressure vessel 3 is disposed. As an example, the reactor N is a pressurized water reactor (PWR). Inside the pressure vessel 3, a plurality of fuel assemblies are provided, each of which is made up of a bundle of fuel rods that generate thermal energy by causing a nuclear fission reaction, and the heat generation is controlled by controlling the nuclear fission reaction with a control rod inserted between the plurality of fuel assemblies.

[0023] For example, a steel plate F (see FIG. 4) may be applied along the inner surface of a vertical hole N1 of a nuclear reactor N. As an example, the vertical hole N1 has a cylindrical shape. In this embodiment, for example, the steel plate F is cut to dismantle the concrete C in the high-dose region in the primary shielding wall of the nuclear reactor N. The activation levels inside the nuclear reactor N are classified into, for example, waste for intermediate depth disposal (L1), waste for pit disposal (L2), waste for trench disposal (L3), clearance (CL), and non-radioactive waste (NR). The activation levels are L1, which is the highest, L2, which is the second highest, L3, which is the third highest, CL, which is the fourth highest, and NR, which is the lowest.

[0024] The disposal methods for L1 waste, L2 waste, L3 waste, CL waste, and NR waste are different. CL and NR do not need to be treated as radioactive waste, but L3 requires trench disposal in shallow ground, L2 requires pit disposal, and L1 requires intermediate depth disposal.

[0025] The disposal costs for L1 intermediate depth disposal tend to be higher than those for L2 pit disposal, which in turn tend to be higher than those for L3 trench disposal. As such, the higher the activation level of the waste, such as concrete C, the higher the disposal costs, so it is necessary to selectively remove only the parts with high activation levels.

[0026] For example, concrete C includes a high activation region A1 that has a certain amount of radiation or more and constitutes a surface C1 of concrete C, and a low activation region A2 that has an amount of activation less than a certain amount and is located on the opposite side of the surface C1 of the high activation region A1. Furthermore, in this embodiment, the high activation region A1 includes a first region A11 and a second region A12 that has a lower activation level than the first region A11, and the low activation region A2 includes a third region A21 and a fourth region A22 that has a lower activation level than the third region A21. As an example, the first region A11 corresponds to concrete C with L1, the second region A12 corresponds to concrete C with L2, the third region A21 corresponds to concrete C with L3, and the fourth region A22 corresponds to concrete C with CL.

[0027] The distribution of activation levels of the concrete C, such as the above-mentioned first region A11, second region A12, third region A21, and fourth region A22, is, for example, known in advance. The method for knowing the distribution of activation levels may be a method of calculating the activation levels of each part of the concrete C by activation calculation, or a core analysis in which a part of the concrete C is extracted and analyzed.

[0028] In this embodiment, for example, concrete C is dismantled and removed in a state in which the distribution of activation levels of concrete C is known in advance. As described above, the disposal costs of intermediate depth disposal at L1 tend to be higher than the disposal costs of pit disposal at L2, which in turn tend to be higher than the disposal costs of trench disposal at L3.

[0029] If concrete C of L2 or L3 gets mixed with concrete C of L1 when concrete C is dismantled and removed, there is a problem in that disposal costs become high because the disposal cost of L1 is charged for the mixed concrete C. In contrast, with the dismantling and removal method according to this embodiment, concrete C of L1, concrete C of L2, and concrete C of L3 can be clearly separated and dismantled and removed, so disposal costs can be reduced.

[0030] Fig. 2 is a perspective view showing a schematic diagram of a wall-shaped concrete C to which the method for dismantling and removing according to the present embodiment is applied. As shown in Fig. 1 and Fig. 2, in the method for dismantling and removing concrete C according to the present embodiment, concrete C is divided into a plurality of blocks B whose sizes can be changed, and dismantling and removing each block B, thereby making it possible to prevent concrete C of L1 from being mixed with concrete C of L2 or L3. In other words, in the method for dismantling concrete C according to the present embodiment, dismantling according to the level of radioactivity of concrete C is possible.

[0031] For example, block B indicates an area into which concrete C in a high-dose region in the primary shielding wall of reactor N is divided. As an example, block B is an area into which concrete C is divided vertically and horizontally. Block B has a surface C1 extending in a first direction D1 and a second direction D2 intersecting with the first direction D1, and has a thickness in a wall thickness direction D3 intersecting with both the first direction D1 and the second direction D2. For example, the first direction D1 is a vertical direction, and the second direction D2 is a horizontal direction. The second direction D2 may be a circumferential direction of the vertical hole N1 of reactor N.

[0032] Next, a method for dismantling and removing concrete C according to this embodiment will be described. Fig. 3 is a flow chart showing an example of steps of the method for dismantling and removing according to this embodiment. As shown in Fig. 4(a) and Fig. 4(b), concrete C to be dismantled and removed has, for example, a first reinforcing bar T1 extending in a first direction D1, a second reinforcing bar T2 extending in a second direction D2, and a steel plate F provided on a surface C1 of the concrete C.

[0033] First, a plurality of cuts C2 are formed in the concrete C (a process of forming a plurality of cuts, step S1). The plurality of cuts C2 include a first cut C21 extending in a first direction D1 and a second cut C22 extending in a second direction D2 (see FIG. 8(b)). In step S1, a pair of first cuts C21 extending in the first direction D1 and the wall thickness direction D3 are formed on the surface C1 of the concrete C (a process of forming a pair of first cuts). The pair of first cuts C21 are formed so as to be aligned along the second direction D2. In step S1, the first cuts C21 are formed, and the steel plate F and the second reinforcing bar T2 embedded in the concrete C are cut.

[0034] For example, the first cut C21 is formed by bringing a cutter that cuts the concrete C into contact with the surface C1. The cutter that cuts the concrete C is, for example, a disc cutter. In this case, the first cut C21 is formed by bringing the blade of the rotating disc cutter into contact with the surface C1.

[0035] In this case, a cut having a length in the wall thickness direction D3 according to the diameter of the blade of the disc cutter can be easily formed. However, the cutting machine for cutting the concrete C may be one other than a disc cutter, for example, a wire saw. In this way, the type of cutting machine for cutting the concrete C is not particularly limited.

[0036] For example, the length X1 of the first cut C21 in the wall thickness direction D3 is 200 mm or more and 400 mm or less. However, the length X1 is a value determined according to, for example, the diameter of the blade of the disc cutter, and is not particularly limited. However, it is preferable that the length X1 is a length that can cut the steel plate F and the second reinforcing bar T2.

[0037] For example, the distance X2 between the pair of first cuts C21 is 500 mm or more and 1500 mm or less. The length X3 of the first cut C21 in the first direction D1 is 1500 mm or more and 2000 mm or less. However, the values ​​of the distance X2 and the length X3 can be set arbitrarily depending on the size of the block B to be dismantled and removed, and are not particularly limited.

[0038] After the first cuts C21 are formed, as shown in FIG. 5(a) and FIG. 5(b), an explosive loading hole H is drilled (step of forming an explosive loading hole, step S2). The explosive loading hole is a hole into which an explosive G (see FIG. 7) is loaded. The explosive loading hole H is formed, for example, by an electric drill. The explosive loading hole H is formed between the multiple first cuts C21 in a plan view, or between the extension lines E1 of the multiple first cuts C21 in a plan view. FIG. 5(a) and FIG. 5(b) show an example in which the explosive loading hole H is formed between a pair of extension lines E1 aligned along the second direction D2.

[0039] The explosive loading hole H extends along the first direction D1. For example, the length of the explosive loading hole H in the first direction D1 is the same as the length X3 of the first cut C21 in the first direction D1. In this case, the length of the explosive loading hole H in the first direction D1 is 1500 mm or more and 2000 mm or less. In this embodiment, "same" includes not only the case where they are strictly the same, but also the case where they are not strictly the same but have the same effect as when they are the same (for example, when they are approximately the same).

[0040] The cross section of the explosive loading hole H when cut along a plane perpendicular to the first direction D1 is, for example, circular. As an example, the width X4 (for example, diameter) of the explosive loading hole H is 20 mm or more and 35 mm or less. However, the value of the width X4 can be appropriately changed depending on the amount of explosive G to be loaded into the explosive loading hole H, and is not particularly limited.

[0041] For example, the explosive loading hole H is formed on the back side (opposite side to the surface C1) of a virtual line segment E2 that connects the ends of a pair of first cuts C21 opposite to the surface C1. When an explosive G is loaded into the explosive loading hole H and the explosive G is detonated, a division portion Z (see FIG. 8(a)) is formed from the explosive loading hole H toward each first cut C21. Therefore, when the explosive loading hole H is located on the back side of the virtual line segment E2, a larger block B can be dismantled by detonating the explosive G. However, the explosive loading hole H may be formed on the virtual line segment E2.

[0042] In step S2, for example, a plurality of explosive loading holes H are formed. The plurality of explosive loading holes H are formed, for example, so as to be aligned along the second direction D2. The distance X5 between two explosive loading holes H aligned along the second direction D2 is longer than the distance X6 in the second direction D2 from the first cut C21 to the explosive loading holes H. For example, the distance X5 is 300 mm or more and 700 mm or less, and the distance X6 is 200 mm or more and 300 mm or less.

[0043] 5(a) and 5(b) show an example in which two explosive loading holes H are formed. However, as shown in FIG. 6(a), three or more explosive loading holes H may be formed aligned along the imaginary line segment E2. Also, as shown in FIG. 6(b), one explosive loading hole H may be formed on the imaginary line segment E2. In this way, the number of explosive loading holes H is not particularly limited. However, when there are multiple explosive loading holes H, the division section Z can be formed with higher accuracy than when there is only one explosive loading hole H.

[0044] After the explosive loading hole H is formed, the explosive G is loaded into the explosive loading hole H (a process of loading explosive G, step S3). Fig. 7 shows an example of the explosive G loaded into the explosive loading hole H. The explosive G loaded into the explosive loading hole H includes, for example, a detonation cord G1 and an electric detonator G2 that detonates the detonation cord G1.

[0045] In the detonation cord G1, for example, the core charge is covered with paper tape or thread, and the paper tape or thread is waterproofed with asphalt or synthetic resin to form the detonation cord G1. The core charge of the detonation cord G1 is, for example, pentaerythritol tetranitrate. The electric detonator G2 is attached to the detonation cord G1 (for example, by vinyl tape).

[0046] For example, a detonation cord G1 is loaded into the explosive loading hole H. The loaded detonation cord G1 extends along a first direction D1 in the explosive loading hole H. The amount of the detonation cord G1 loaded into one explosive loading hole H is, for example, 30 g or more and 40 g or less. However, the amount of the detonation cord G1 can be changed as appropriate.

[0047] When blasting is performed using the detonating cord G1 loaded in the explosive loading hole H, the amount of explosive required to demolish and remove the concrete C can be reduced to about 1 / 10 compared to the conventional blasting method. Therefore, the amount of debris scattered around due to blasting can be reduced, and safety can be improved. Blasting using the detonating cord G1 loaded in the explosive loading hole H is also called micro-blasting. When micro-blasting is performed, noise and vibration loads can be reduced compared to the conventional blasting method.

[0048] After the detonation cord G1 is loaded into the explosive loading hole H, the explosive G is detonated by detonating the detonation cord G1 with the electric detonator G2 attached to the detonation cord G1 (step S4). By detonating the explosive G, as shown in FIG. 8(a), a separation section Z that connects the multiple first cuts C21 to each other is formed (a process of forming a separation section).

[0049] When the detonation cord G1 loaded in the explosive loading hole H is detonated, a division portion Z is formed on the back surface of the concrete C. The division portion Z is formed in an area including the rear side of the multiple first cuts C21 and the explosive loading hole H, and is a crack portion extending in both the first direction D1 and the second direction D2 inside the concrete C. For example, the length of the division portion Z in the first direction D1 is the same as the length X3 in the first direction D1 of the first cuts C21 and the length in the first direction D1 of the explosive loading hole H.

[0050] After the explosive G is detonated, as shown in Fig. 8(b), a second cut C22 that connects the pair of first cuts C21 is formed to cut the concrete C (step S5). The second cut C22 may be formed at the same time as the first cut C21 is formed (in step S1), or may be formed before the explosive G is detonated. The second cut C22 is formed so as to extend in both the second direction D2 and the wall thickness direction D3 on the surface C1.

[0051] The second incisions C22 are formed, and the steel plate F and the first reinforcing bars T1 (see FIG. 5(b) and the like) embedded in the concrete C are cut. For example, the second incisions C22 are formed by applying a cutting machine such as a disc cutter to the surface C1, in the same manner as when the first incisions C21 are formed.

[0052] After the cuts C2 are formed, the concrete C located in the region defined by the dividing portion Z and the plurality of cuts C2 in plan view is removed (step of removing the concrete) as shown in Fig. 8(b) and Fig. 9. For example, the concrete C located in the region defined by the dividing portion Z, the pair of first cuts C21, and the second cut C22 is removed.

[0053] As a result, the concrete C that extends in the first direction D1 and the second direction D2 and has a thickness in the wall thickness direction D3 can be dismantled and removed for each block B. This dismantling and removal is performed, for example, sequentially from the vertically upper part to the vertically lower part of the concrete C. Then, after all of the concrete C has been removed, the series of steps of the dismantling and removal method is completed.

[0054] Next, the effects of the dismantling and removal method according to this embodiment will be described in more detail. In the dismantling and removal method according to this embodiment, by forming a plurality of cuts C2 extending along the surface C1 of the concrete C and extending in the wall thickness direction D3, it is possible to cut into the first reinforcing bar T1, the second reinforcing bar T2, and the steel plate F such as a liner even if the first reinforcing bar T1, the second reinforcing bar T2, and the steel plate F are embedded.

[0055] An explosive loading hole H is formed between the multiple cuts C2 in a plan view, or between extension lines E1 of the multiple cuts C2 in a plan view, and an explosive G loaded in the explosive loading hole H is detonated to form a dividing section Z between the multiple cuts C2. In this embodiment, the concrete C is divided and the dividing section Z can be formed instantly. Therefore, the concrete C can be divided much faster than when the back surface of the concrete C is cut by a wire saw or the like.

[0056] Then, the concrete C located in the area defined by the dividing portion Z and the multiple cuts C2 in the plan view is removed. Because the first reinforcing bar T1, the second reinforcing bar T2, and the steel plate F are cut before the concrete C is removed, the first reinforcing bar T1, the second reinforcing bar T2, and the steel plate F can be removed together with the concrete C.

[0057] Therefore, secondary crushing such as cleaning up rebars can be eliminated. A desired crushing capacity can be achieved by forming a plurality of cuts C2 in advance, forming explosive loading holes H between the plurality of cuts C2, and detonating the explosive G loaded into the explosive loading holes H. Since the concrete C in the area defined by the dividing portion Z and the plurality of cuts C2 in a plan view can be removed by detonating the explosive G, the desired portion can be divided with high accuracy and the concrete C can be efficiently demolished and removed.

[0058] In this embodiment, the multiple cuts C2 include a pair of first cuts C21 formed on the surface C1 and a second cut C22 connecting the pair of first cuts C21 to each other on the surface C1. The step of forming the multiple cuts C2 includes a step of forming the pair of first cuts before a step of forming the explosive loading hole H, and a step of forming the second cut C22 connecting the pair of first cuts C21 to each other after forming the separation portion Z.

[0059] In this case, by forming the second cut C22 that connects the pair of first cuts C21 to each other, the desired portion of the concrete C can be divided with even higher accuracy. By forming the second cut C22 after blasting the explosive G to form the dividing portion Z, the second cut C22 is not formed when the explosive G is blasted, so that it is possible to prevent the concrete C from flying out due to the blasting of the explosive G. Therefore, it is possible to improve the safety of the work of dismantling and removing the concrete C.

[0060] As described above, the step of forming the multiple cuts C2 may include a step of forming the second cuts C22 that connect the pair of first cuts C21 to each other before detonating the explosive G. In this case, the second cuts C22 can be formed before forming the explosive loading hole H and detonating the explosive G.

[0061] In this embodiment, in the step of forming the multiple notches C2, the first reinforcing bars T1 and the second reinforcing bars T2 embedded in the concrete C are cut while the multiple notches C2 are formed. In this case, the first reinforcing bars T1 and the second reinforcing bars T2 embedded in the concrete C are cut when the multiple notches C2 are formed, so that the first reinforcing bars T1 and the second reinforcing bars T2 embedded in the concrete C can be removed together with the removal of the concrete C. This makes it possible to eliminate the need for secondary crushing for cleaning up the reinforcing bars, thereby further improving the efficiency of demolition and removal.

[0062] In this embodiment, in the step of forming the multiple incisions C2, the steel plate F provided on the surface C1 of the concrete C is cut while the incisions C2 are formed. In this case, even if a steel plate F such as a liner is present on the surface C1 of the concrete C, the steel plate F is cut when the multiple incisions C2 are formed. Therefore, the steel plate F can be removed together with the concrete C. Therefore, since the steel plate F can be removed together with the concrete C, the efficiency of demolition and removal can be further improved.

[0063] Second embodiment Next, a dismantling and removal method according to the second embodiment will be described. Some of the steps of the dismantling and removal method according to the second embodiment are the same as some of the steps of the dismantling and removal method described above. Therefore, in the following description, descriptions that overlap with the above description will be omitted as appropriate. Figure 10 is a flow chart showing some of the steps of the dismantling and removal method according to the second embodiment.

[0064] For example, as shown in Fig. 11, the concrete C is annular in plan view. For example, a first concrete C and a second concrete C positioned vertically below the first concrete C are included, and after a step of removing the first concrete C is performed, dismantling and removal of the second concrete C is started.

[0065] First, steps S1 to S4 shown in FIG. 3 are executed. That is, a plurality of cuts C2 are formed in the concrete C, an explosive loading hole H (first explosive loading hole) is drilled, and an explosive G is loaded into the explosive loading hole H and detonated. The explosive loading hole H may be formed by a rock drill. After the explosive G is detonated to form the division portion Z, the second cut C22 may be formed as described above, or the second cut C22 may not be formed. Then, the concrete C may be removed as shown in FIG. 9, or the concrete C may not be removed.

[0066] Then, the process proceeds to the steps of the flowchart shown in FIG. 10. First, the second explosive loading hole J is formed by drilling (step of forming the second explosive loading hole, step S11). As shown in FIG. 5(a) and FIG. 11, the second explosive loading hole J may be formed when the explosive loading hole H is formed, or may be formed after the explosive loading hole H is formed. The second explosive loading hole J is located at a position farther from the surface C1 than the first explosive loading hole H. The second explosive loading hole J is formed radially outward of the concrete C in a plan view than the first explosive loading hole H. For example, a plurality of second explosive loading holes J are formed so as to be aligned along the circumferential direction of the concrete C in a plan view.

[0067] After the second explosive loading holes J are formed, explosives G are loaded into the second explosive loading holes J (step of loading explosives, step S12). At this time, explosives G are loaded into a plurality of second explosive loading holes J. Then, as shown in FIG. 12, the explosives G loaded into the second explosive loading holes J are detonated to form second division sections W (step of forming second division sections). By forming the second division sections W, the concrete C is in a state in which many cracks are formed, and can be easily dismantled and removed. At this time, the concrete C is disassembled and dismantled and removed by heavy machinery (step of removing concrete, step S14). The heavy machinery includes, for example, a nibbler or a breaker, and various types of heavy machinery can be used.

[0068] Next, the effects obtained from the dismantling and removal method according to the second embodiment will be described. In the second embodiment, the step of forming an explosive loading hole includes a step of forming a first explosive loading hole H, and a step of forming a second explosive loading hole J located at a position farther from the surface C1 than the first explosive loading hole H. In the step of loading an explosive into the explosive loading hole, an explosive G is loaded into the first explosive loading hole H, and in the step of forming a dividing section, the explosive G loaded into the first explosive loading hole H is detonated to form a dividing section Z.

[0069] This dismantling and removal method includes a step of forming a dividing portion Z, loading an explosive G into the second explosive loading hole J, and blasting the explosive G loaded into the second explosive loading hole J to form a second dividing portion W. The step of removing the concrete is performed after forming the second dividing portion W. Thus, in the step of forming the explosive loading hole, the first explosive loading hole H is formed at a position close to the surface C1, and the second explosive loading hole J is formed at a position farther from the surface C1 than the first explosive loading hole H. Then, the first explosive loading hole H is loaded with explosive G and blasted to form a dividing portion Z, and the second explosive loading hole J is loaded with explosive G and blasted to form the second dividing portion W. Thus, by performing blasting in multiple stages from the surface C1, the entire concrete C can be easily and efficiently decomposed. Therefore, the subsequent removal of the concrete C can be efficiently performed, and the entire concrete C can be smoothly removed.

[0070] In the second embodiment, the concrete C is annular in plan view, and the surface C1 of the concrete C is the inner surface of the annular concrete C in plan view. Therefore, the dividing portion Z and the second dividing portion W can be formed in order from the inner surface of the concrete C, so that the concrete C can be efficiently decomposed in order from the inner surface.

[0071] As described above, the demolition and removal method may include a first concrete C and a second concrete C located vertically below the first concrete C, and may start demolition and removal of the second concrete C after the step of removing the concrete of the first concrete C is performed. In this case, the above-mentioned demolition and removal can be performed in order starting from the first concrete C located vertically above. Therefore, even a large concrete structure such as a concrete structure including a first concrete C and a second concrete C can be efficiently demolition and removal.

[0072] Various embodiments of the dismantling and removal method according to the present disclosure have been described above. However, the dismantling and removal method according to the present disclosure is not limited to the above-described embodiments, and may be modified within the scope of the gist described in the claims. In other words, the content and order of the steps of the dismantling and removal method according to the present disclosure can be appropriately changed within the scope of the gist described above.

[0073] For example, in the first embodiment described above, an example has been described in which a steel plate F is provided on the surface C1 of the concrete C, and the incisions C2 are formed and the steel plate F is cut. However, there are cases in which the steel plate F is not provided on the surface C1 of the concrete C. In this case, the process of forming the incisions C2 and cutting the steel plate F can be omitted.

[0074] In the first embodiment described above, an example in which the concrete C is dismantled and removed as a block B has been described. However, the concrete C does not have to be dismantled and removed as a block B, and can be dismantled and removed in any shape. In the embodiment described above, an example in which the concrete C in a high-dose area in the primary shielding wall of the reactor N is dismantled and removed has been described. That is, an example in which the concrete C in the reactor N, which is a pressurized water reactor (PWR), is dismantled and removed has been described. Since the PWR has many highly activated parts, the dismantling and removal method according to the embodiment described above may be particularly effective. However, the target to which the dismantling and removal method according to the present disclosure is applied is not limited to PWRs and is not particularly limited. For example, the dismantling and removal method according to the present disclosure may be applied to a boiling water reactor (BWR), or may be applied to a structure other than a reactor.

[0075] In the above-described second embodiment, an example in which the concrete C is dismantled and removed after the second dividing portion W is formed has been described. However, for example, a third explosive loading hole may be formed, and after the second dividing portion W is formed, an explosive may be loaded into the third explosive loading hole, and the explosive loaded into the third explosive loading hole may be detonated to form the third dividing portion. Furthermore, a fourth explosive loading hole and a fourth dividing portion may be formed. In this way, the number of explosive loading holes and the number of dividing portions can be appropriately changed according to the thickness of the concrete, etc.

[0076] In the above, the first and second embodiments of the dismantling and removal method according to the present disclosure have been described. However, the dismantling and removal method according to the present disclosure may be a method in which a part of the first embodiment and a part of the second embodiment are combined. In this manner, the first and second embodiments can be appropriately combined. [Explanation of symbols]

[0077] 2...biological shield, 3...pressure vessel, A1...high activation area, A2...low activation area, A11...first area, A12...second area, A21...third area, A22...fourth area, B...block, C...concrete, C1...surface, C2...notch, C21...first notch, C22...second notch, D1...first direction, D2...second direction, D3...wall thickness direction, E1 ...extension line, E2...imaginary line segment, F...steel plate, G...explosive, G1...detonating cord, G2...electric detonator, H...explosive loading hole (first explosive loading hole), J...second explosive loading hole, L2...concrete, N...reactor, N1...vertical hole, T1...first rebar, T2...second rebar, X1...length, X2...distance, X3...length, X4...width, X5,X6...distance, W...second separation section, Z...separation section.

Claims

1. A method for dismantling and removing wall-shaped concrete, comprising: forming a plurality of cuts in a surface of the concrete, the cuts extending along the surface and in a wall thickness direction; forming explosive loading holes between the plurality of cuts in a plan view or between extensions of the plurality of cuts in a plan view; loading an explosive into the explosive loading hole; blasting the explosive to form a disconnection portion connecting a plurality of the cuts to each other; removing the concrete located in an area defined by the dividing portion and the plurality of cuts in a plan view; Equipped with Disassembly and removal method.

2. the plurality of cuts include a pair of first cuts formed on the surface and a second cut connecting the pair of first cuts to each other on the surface; The step of forming the plurality of cuts includes: forming a pair of the first cuts before the step of forming the explosive loading hole; forming the second cuts connecting the pair of first cuts to each other after forming the dividing portion; Including, The dismantling and removal method according to claim 1.

3. the plurality of cuts include a pair of first cuts formed on the surface and a second cut connecting the pair of first cuts to each other on the surface; The step of forming the plurality of cuts includes: forming a pair of the first cuts before the step of forming the explosive loading hole; forming the second notches connecting the pair of first notches to each other before detonating the explosive; Including, The dismantling and removal method according to claim 1.

4. In the step of forming the plurality of cuts, the cuts are formed and a reinforcing bar embedded in the concrete is cut. The dismantling and removal method according to any one of claims 1 to 3.

5. In the step of forming the plurality of cuts, the cuts are formed and a steel plate provided on the surface of the concrete is cut. The dismantling and removal method according to any one of claims 1 to 3.

6. The step of forming the explosive loading hole includes a step of forming a first explosive loading hole, and a step of forming a second explosive loading hole located at a position farther from the surface than the first explosive loading hole, In the step of loading an explosive into the explosive loading hole, an explosive is loaded into the first explosive loading hole, In the step of forming the dividing portion, the explosive loaded in the first explosive loading hole is detonated to form the dividing portion, and forming a second division portion by loading an explosive into the second explosive loading hole after forming the division portion, and detonating the explosive loaded into the second explosive loading hole, The step of removing the concrete is performed after forming the second dividing portion. The dismantling and removal method according to claim 1.

7. The concrete is annular in plan view, The surface of the concrete is an inner surface of the concrete that is annular in a plan view. The dismantling and removal method according to claim 6.

8. The method includes the steps of: providing a first concrete; and providing a second concrete located vertically below the first concrete. After the step of removing the first concrete is performed, dismantling and removal of the second concrete is started. The dismantling and removal method according to claim 6 or 7.

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