How to replace the detachment prevention device

Abstract

To provide a method for replacing detachment prevention devices attached to connection points between fluid pipes, which allows for stable replacement without placing excessive stress on the fluid pipes. [Solution] The method includes at least the following steps: a first support step of attaching a thrust support fitting 20A having a first locking member 21 and a second locking member 22 to the outer surface of a pipe body 2a and supporting the thrust support fitting 20A on a steel sheet pile 10a, which is a first support structure driven into the ground; a second support step of attaching a thrust support fitting 20B having a first locking member 21 and a second locking member 22 to the outer surface of a pipe body 2b and supporting the thrust support fitting 20B on a steel sheet pile 10b, which is a second support structure driven into the ground; and a replacement step of removing an existing detachment prevention fitting 4 attached to the connection part CN1 of pipe bodies 2a and 2b and attaching a newly installed detachment prevention fitting to the connection part CN1.

Description

Technical Field

[0001] The present invention relates to a method for replacing an existing anti-disconnection device attached to a connection portion between fluid pipes connected to each other along a pipeline in a non-stop flow state.

Background Art

[0002] Conventionally, when removing an existing anti-disconnection device attached to a connection portion between fluid pipes constituting a pipeline and replacing it with a new anti-disconnection device, there is a method of replacing the anti-disconnection device while temporarily attaching a member for preventing disconnection between these fluid pipes (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, a structure is such that a member locked to the outer surface of one fluid pipe and a member locked to the outer surface of the other fluid pipe are connected to each other. That is, in order to prevent disconnection in a state supported by the other fluid pipe against the force applied in the disconnection direction of the fluid pipe, the support mode is not stable, an excessive load is generated on the pipe wall of the fluid pipe, and there is a problem that the fluid pipe may be damaged.

[0005] The present invention has been made paying attention to such problems, and an object thereof is to provide a method for replacing an anti-disconnection device that can be stably replaced without causing an excessive load on the fluid pipes when replacing the anti-disconnection device attached to the connection portion connecting the fluid pipes to each other.

Means for Solving the Problems

[0006] To solve the above problems, the method for replacing the detachment prevention device of the present invention is: A method for replacing detachment prevention devices, which are attached to the connections between fluid pipes connected to each other along a pipeline, in a continuous flow state, A first support step involves attaching a locking member to the outer surface of one fluid pipe and supporting the locking member on a first support structure, A second support step involves attaching a locking member to the outer surface of the other fluid pipe to engage with the fluid pipe, and supporting the locking member with a second support structure. The invention is characterized by comprising at least the following steps: removing the existing detachment prevention device attached to the connection between the fluid pipes, and attaching a new detachment prevention device to the connection. This feature allows for the replacement of the detachment prevention devices while stably preventing the fluid pipes from separating, by attaching locking members to the outer surface of each connected fluid pipe and individually supporting these locking members on a support structure.

[0007] The invention is characterized by further comprising a removal step after the replacement step, in which the locking member is removed from one of the fluid pipes and the locking member is removed from the other fluid pipe. This feature ensures safety by preventing the removal of detachment devices from leaving any excess material in the pipeline after replacement.

[0008] The first support structure and the second support structure are characterized by being separate structures. This feature allows the first support structure and the second support structure to support the fluid pipe independently without influencing each other.

[0009] The first support structure and the second support structure are characterized by being an integrated structure. This feature allows for the common and simplified configuration of the first and second support structures.

[0010] The first support structure and the second support structure are characterized by being the natural ground in which the fluid pipe is buried. This feature eliminates the need to prepare any special support structures, as the fluid pipes can be supported by utilizing the soil pressure of the ground beneath which they are buried.

[0011] The aforementioned fluid pipe and the other fluid pipe are characterized in that they form a non-linear pipeline. This feature allows for stable support of the fluid pipe against unbalanced forces acting on a non-linear pipeline.

[0012] The aforementioned fluid pipe and the other fluid pipe are characterized in that they form a straight pipeline. This feature allows for stable support of the fluid pipe against outward forces acting along a straight pipeline. [Brief explanation of the drawing]

[0013] [Figure 1] This is a front view showing an existing detachment prevention fitting attached to the connection portion of an existing fluid pipe, as an embodiment 1 of the present invention. [Figure 2] This is a front view showing the pipes on both sides of the connection point protected by thrust bearings, bracing jigs, supports, and steel plates. [Figure 3] This is a plan view showing the state after thrust bearings, protective jigs, support supports, and steel plates have been installed on the pipe bodies on both sides of the connection point to provide protection. [Figure 4] This is a cross-sectional view AA in Figure 3. [Figure 5] (a) is a cross-sectional view showing the thrust bearing attached to the pipe body as seen from the direction of the pipe axis, and (b) is a cross-sectional view showing the internal structure of the thrust bearing. [Figure 6] (a) is a cross-sectional view of BB in Figure 5(b), and (b) is a cross-sectional view of CC in Figure 5(b). [Figure 7]It is a cross-sectional view showing a state where the movement of the pipe body is restricted by supporting a thrust receiving fitting locked to the pipe body on a steel sheet pile driven into the ground via a holding jig and a support. [Figure 8] (a) is a view showing a state of removing an existing anti-disconnection fitting from a connection part, and (b) is a view showing a state of attaching a new anti-disconnection fitting to the connection part. [Figure 9] It is a front view showing a state where existing anti-disconnection fittings are respectively attached to two connection parts of an existing fluid pipe as Example 2 of the present invention. [Figure 10] It is a plan view showing a state where existing anti-disconnection fittings are respectively attached to two connection parts of an existing fluid pipe as Example 2 of the present invention. [Figure 11] It is a schematic plan view showing the force generated in the support structure when an uneven force acts on the bent pipe part of an existing fluid pipe. [Figure 12] It is a front view showing a state of removing an existing anti-disconnection fitting from the connection part on the downstream side of an existing fluid pipe. [Figure 13] It is a front view showing a state where a new anti-disconnection fitting is attached to the connection part on the downstream side of an existing fluid pipe and the existing anti-disconnection fitting is removed from the connection part on the upstream side. [Figure 14] It is a front view showing a state where a new anti-disconnection fitting is attached to the connection part on the upstream side of an existing fluid pipe. [Figure 15] It is a front view showing a state where the thrust receiving fitting is removed from an existing fluid pipe and the concrete plate is removed. [Figure 16] It is a front view showing a state where thrust receiving fittings as a modified example of the present invention are installed on both sides in the pipe axis direction of an existing anti-disconnection fitting attached to the connection part of an existing fluid pipe. [Figure 17] It is a plan view showing a state where thrust receiving fittings as a modified example of the present invention are installed on both sides in the pipe axis direction of an existing anti-disconnection fitting attached to the connection part of an existing fluid pipe.

Mode for Carrying Out the Invention

[0014] An embodiment for implementing the method for replacing the detachment prevention device according to the present invention will be described below based on an example. [Examples]

[0015] A method for replacing a detachment prevention device according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 8. In the following description, the front side of Figure 1 is the front of the fluid pipe, the back side is the rear, the left side is the leftward direction, and the right side is the rightward direction, with the left side being the upstream side of the flow path and the right side being the downstream side of the flow path.

[0016] As shown in Figure 1, the existing fluid pipe 2 in this embodiment 1 is configured as a flow path (pipeline) by connecting multiple cylindrical pipes in the axial direction. A receiving portion 3a is formed at one end of each pipe, and a spigot portion 3b is formed at the other end. An annular sealing material 5 is provided between the inner circumferential surface of the receiving portion 3a of one of the pipes 2a that are connected to each other, and the outer circumferential surface of the spigot portion 3b of the other pipe 2b that is inserted into the receiving portion 3a, thereby sealing the receiving portion 3a and the spigot portion 3b together.

[0017] Furthermore, a pre-existing anti-detachment fitting 4, which has a split structure, is fitted onto the connection portion CN1 between each pipe body 2a and 2b, thereby preventing the receiving portion 3a and the insertion portion 3b from separating. Each of the split members 4a and 4b constituting the pre-existing anti-detachment fitting 4 has a locking portion 4c formed in the circumferential direction that can engage with a bulge 3f projecting outward from the end of the receiving portion 3a, and a locking claw 4d that can bite into the outer surface of the insertion portion 3b is provided on the inner circumferential surface. By arranging these split members 4a and 4b above and below the receiving portion 3a and the insertion portion 3b and fastening them with bolts and nuts N1, the connection portion CN1 between the receiving portion 3a and the insertion portion 3b is reinforced, and the pipe bodies are prevented from separating due to uneven forces.

[0018] In this embodiment 1, a substantially straight flow path (pipeline) is constructed by connecting straight pipe bodies 2a and 2b in the axial direction. This invention describes a method for removing the existing detachment prevention fittings 4, which prevent these straight pipe bodies 2a and 2b from separating, from the pipe bodies 2a and 2b while the flow is uninterrupted, and replacing them with newly installed detachment prevention fittings 4n.

[0019] In this embodiment, the fluid in the fluid pipe 2 is tap water, but it may also be industrial water, agricultural water, sewage, or other liquids, or even gas or a gas-liquid mixture. The fluid pipe 2 is a ductile cast iron pipe and is formed as a straight pipe with a substantially circular cross-section. In this embodiment, the fluid pipe 2 is arranged in a substantially horizontal direction. The fluid pipe according to the present invention may also be made of other metals such as cast iron or steel, or concrete, polyvinyl chloride, polyethylene, or polyolefin. Furthermore, the inner circumferential surface of the fluid pipe may be covered with an epoxy resin layer, mortar, plating, or a suitable material may be applied to the inner circumferential surface of the fluid pipe by powder coating.

[0020] [How to replace the anti-detachment clip] As shown in Figure 1, the substantially straight flow path consisting of the existing fluid pipe 2 buried underground and the installation location of the detachment prevention fitting 4 to be replaced are identified, and a substantially rectangular excavation area (see Figure 3) in plan view, including the identified installation location of the detachment prevention fitting 4 and its surroundings, is set above the ground level (GL). Next, in order to prevent soil collapse and water intrusion, multiple steel sheet piles 10a and 10b are driven along the left and right sides on both sides in the direction of the pipe axis of the existing fluid pipe 2 in the excavation area, and multiple steel sheet piles 10c are driven on the left and right sides of the front and rear sides. Then, an open excavation hole 9 is formed by excavating the inside of the excavation area using a well-known earth retention method. The depth dimension of the excavation hole 9 from the ground level (GL) to the bottom 9a is set to such an extent that a space is formed between the existing fluid pipe 2 and the bottom of the detachment prevention fitting 4.

[0021] When replacing the existing anti-detachment fittings 4 that have been exposed by the opening excavation, if the existing anti-detachment fittings 4 are removed from the pipe bodies 2a and 2b in a continuous flow state, the fluid pressure inside the pipe will generate a force in the direction of pipe removal between the receiving portion 3a and the insertion portion 3b. Furthermore, since the surrounding area outside the pipe is exposed by removing the ground G due to the opening excavation, it is not possible to obtain a reaction force from the earth pressure of the ground G. Therefore, as shown in Figures 2 to 4, protective measures are taken to prevent the pipe bodies 2a and 2b, which have been exposed by the opening excavation, from moving away from each other in the pipe axis direction.

[0022] In detail, first, steel plates 11A and 11B are laid on the left side of the upstream pipe 2a and the right side of the downstream pipe 2b at the bottom 9a of the excavation hole 9. Next, the support bodies 12A and 12B, described later, are installed along the steel sheet piles 10a and 10b on the left and right walls so as to surround the outer surfaces of the upstream pipe 2a and the downstream pipe 2b, respectively. Then, the support fixtures 15A and 15B, described later, are installed on the connection part CN1 side of the support bodies 12A and 12B on the upstream pipe 2a and the downstream pipe 2b, respectively. Furthermore, the thrust support fittings 20A and 20B, described later, are installed on the connection part CN1 side of the support fixtures 15A and 15B. In this embodiment, the thrust support fittings 20A and 20B are simply placed on the steel plates 11A and 11B so as to be slidable, but they may also be fixed to the steel plates 11A and 11B via bolts or the like.

[0023] Furthermore, since the steel plates 11A, 11B, support bodies 12A, 12B, contact jigs 15A, 15B, and thrust bearing brackets 20A, 20B used for protective treatment are configured similarly on both the upstream and downstream sides, only the downstream support body 12B, contact jig 15B, and thrust bearing bracket 20B will be described below.

[0024] As shown in Figures 2 to 4, the support 12B is mainly composed of upper and lower H-shaped steel beams 12a, 12a extending in the front-rear direction, front and rear H-shaped steel beams 12b, 12b extending in the vertical direction and positioned between the upper and lower H-shaped steel beams 12a, 12a, and a backing plate 13a and a clamp 13 (see Figure 4) that connect the upper and lower H-shaped steel beams 12a, 12a and the front and rear H-shaped steel beams 12b, 12b, and is assembled to surround the pipe body 2b with the upper and lower H-shaped steel beams 12a, 12a and the front and rear H-shaped steel beams 12b, 12b.

[0025] The mounting jig 15B has a split structure that covers the existing fluid pipe 2 from above and below. More specifically, it mainly consists of semi-cylindrical parts 15a and 15b positioned on the upper and lower parts of the existing fluid pipe 2, bulging parts 15c and 15d projecting outward in the radial direction from one end of each semi-cylindrical part 15a and 15b in the axial direction of the pipe, and bolts and nuts N2 as fastening means for fastening the semi-cylindrical parts 15a and 15b together.

[0026] These semi-cylindrical parts 15a and 15b are positioned above and below the existing fluid pipe 2 and fastened with bolts and nuts N2 to attach them to the outer surface of the existing fluid pipe 2. Furthermore, since the semi-cylindrical parts 15a and 15b are positioned on the outer diameter side of the inner end faces of the bulging parts 15c and 15d, a gap is formed between them and the outer surface of the existing fluid pipe 2 when they are attached to the outer surface of the existing fluid pipe 2 (see Figure 6). The lower semi-cylindrical part 15b has a slit 15e extending in the direction of the pipe axis formed at its lower end, as shown in Figures 4 and 7, allowing the vertical plate 20c of the thrust bearing fitting 20B, which will be described later, to be inserted.

[0027] As shown in Figures 2 to 4, the thrust bearing bracket 20B is a locking member that engages with the outer surface of the fluid pipe 2. It is installed along the outer surface of the straight section of the fluid pipe 2 and has a divided structure consisting of an upper part 20a and a lower part 20b, which are fastened together by bolts and nuts N5, N5.

[0028] More specifically, as shown in Figures 5 and 6, the thrust bearing bracket 20B consists of an upper part 20a and a lower part 20b fitted onto the outer circumferential surface of the fluid pipe 2, first claw members 21, 21 that engage with the outer circumferential surface of the pipe body 2b, second claw members 22, 22 that are separate from the first claw members 21, 21 and engage with the outer circumferential surface of the pipe body 2b, a recess 16 that opens along the inner circumferential surface toward the outer circumferential surface of the pipe body 2b and accommodates the first claw members 21, 21 and the second claw members 22, 22 inside, respectively, and bolts N3, N3 provided on the upper part 20a that press the first claw members 21 and the second claw members 22 toward the outer circumferential surface of the pipe body 2b.

[0029] As shown in Figures 5(b) and 6(a),(b), the recesses 16 are individually formed at four locations in the circumferential direction along the inner surface of the thrust bearing bracket 20B, and the first claw members 21,21 and the second claw members 22,22 are fitted into each recess 16. The number of recesses and claw members is arbitrary and can be any number provided along the circumferential direction of the fluid pipe.

[0030] The first claw members 21, 21 have a first claw portion 21a formed in an arc shape with approximately the same diameter as the outer diameter of the pipe body 2b, which is locked to the outer surface of the pipe body 2b, and a rubber body 18 is interposed between the first claw members 21, 21 and the inner wall of the recess 16 to prevent the first claw members 21, 21 from falling off. The second claw members 22, 22 have a second claw portion 22a formed in an arc shape with approximately the same diameter as the outer diameter of the pipe body 2b, which is locked to the outer surface of the pipe body 2b, and a rubber body 18 is interposed between the second claw members 22, 22 and the inner wall of the recess 16 to prevent the second claw members 22, 22 from falling off.

[0031] As shown in Figure 5(b), the first claw members 21, 21 are provided at substantially opposite positions on the outer surface of the pipe body 2b, with the pipe axis in between, and the second claw members 22, 22 are provided at substantially opposite positions on the outer surface of the pipe body 2b, midway between the first claw members 21, 21 in the circumferential direction, with the pipe axis in between.

[0032] Since the first claw members 21,21 and the second claw members 22,22 are formed in the same shape, simply changing the orientation of the first claw portion 21a and the second claw portion 22a and storing them in the respective recesses 16 prevents the pipe body 2b from moving relative to the thrust bearing fitting 20B in both directions along the pipe axis. Furthermore, by sharing the first claw members 21,21 and the second claw members 22,22, manufacturing effort and costs can be reduced.

[0033] Furthermore, below the arc-shaped portion that fits onto the lower outer surface of the pipe body 2b in the lower part 20b, there is an upright section consisting of a vertical plate 20c perpendicular to the pipe axis, a vertical plate 20d substantially parallel to the pipe axis and perpendicular to the vertical plate 20c, and a bottom plate 20e provided substantially horizontally on the lower surfaces of the vertical plates 20c and 20d.

[0034] As shown in Figure 6(a), when the pipe body 2b attempts to move relative to the thrust bearing 20B in one direction (leftward along the pipe axis), the upper first claw portion 21a of the first claw member 21 tilts clockwise, and the lower first claw portion 21a tilts counterclockwise, and are housed in the recess 16 so as to bite into the outer surface of the pipe body 2b and restrict its movement. On the other hand, as shown in Figure 6(b), when the pipe body 2b attempts to move relative to the thrust bearing 20B in the other direction (rightward along the pipe axis), the upper second claw portion 22a of the second claw member 22 tilts counterclockwise, and the lower second claw portion 21a tilts clockwise, and are housed in the recess 16 so as to bite into the outer surface of the pipe body 2b and restrict its movement. Furthermore, the bolts N3, N3 make it easier for the first claw portion 21a of the first claw member 21 and the second claw portion 22a of the second claw member 22 to bite into the outer surface of the pipe body 2b.

[0035] As shown in Figure 7, the thrust support fitting 20B having the first claw member 21 and the second claw member 22 is fitted onto the outer circumferential surface of the downstream pipe body 2b, and bolts N3, N3 are used to engage the first claw portion 21a of the first claw member 21 and the second claw portion 22a of the second claw member 22 with the outer circumferential surface of the pipe body 2b, thereby securing it, and the fitting is supported by the steel sheet pile 10b, which serves as a second support structure forming the right side of the excavation hole 9, via the support jig 15B and the support body 12B (second support step).

[0036] More specifically, as shown in Figures 4 and 7, the support 12B is installed so that the right sides of the H-shaped steel beams 12a, 12a, 12b, 12b abut against the left side of the steel sheet pile 10b, the contact jig 15B is attached to the outer circumference of the pipe 2b so that a predetermined area on the right side of the bulging parts 15c, 15d (see the shaded area in Figure 4) abuts against the left side of the H-shaped steel beams 12a, 12a, 12b, 12b, and the thrust support fitting 20B is installed so that the right sides of the arc-shaped parts of the upper part 20a and lower part 20b abut against the left end faces of the semi-cylindrical parts 15a, 15b of the contact jig 15B.

[0037] On the other hand, although not shown in detail in the illustrations, the support body 12A, the support jig 15A, and the thrust support fitting 20A are installed on the upstream pipe body 2a in the same way as on the downstream pipe body 2b. The thrust support fitting 20A is fitted onto the outer surface of the upstream pipe body 2a and secured by bolts N3, N3, which bite into the outer surface of the pipe body 2a and lock the first claw portion 21a of the first claw member 21 and the second claw portion 22a of the second claw member 22. At the same time, the steel sheet pile 10a, which serves as the first support structure forming the left side of the excavation hole 9, is supported via the support jig 15A and the support body 12A (first support step).

[0038] After the protective treatment is completed, as shown in Figure 8(a), the existing detachment prevention fittings 4 attached to the connection part CN1 between pipes 2a and 2b are removed from pipes 2a and 2b. When the existing detachment prevention fittings 4 are removed, the pressure inside the pipe causes a detachment effect between the receiving part 3a and the insertion part 3b. In detail, as shown in Figure 3, since pipes 2a and 2b form a substantially straight flow path, a force P1 is generated in the upstream direction on pipe 2a and a force P2 is generated in the downstream direction on pipe 2b, as shown by the thick black arrow in the figure.

[0039] With the protective treatment described above, the thrust bearing fitting 20A, which is locked to the outer surface of the upstream pipe 2a, is supported by the steel sheet pile 10a, which is a first support structure driven into the ground G via the contact jig 15A and the support body 12A, thereby restricting the upstream movement of the upstream pipe 2a. Meanwhile, the thrust bearing fitting 20B, which is locked to the outer surface of the downstream pipe 2b, is supported by the steel sheet pile 10b, which is a second support structure driven into the ground G via the contact jig 15B and the support body 12B, thereby restricting the downstream movement of the pipe 2b.

[0040] In particular, the thrust support fittings 20A and 20B, whose movement in the axial direction relative to the outer surface of the pipe bodies 2a and 2b is restricted, are stably supported by steel sheet piles 10a and 10b driven into the ground G via a support jig 15A and a support 12A. This restricts the movement of the pipe bodies 2a and 2b in the axial direction, thus preventing the pipes from coming out of the receiving end 3a and the insertion end 3b. Furthermore, since the steel sheet piles 10a and 10b are provided along the left and right wall surfaces of the excavation hole 9, which was excavated to expose the buried fluid pipe 2, and are approximately perpendicular to the pipe axis of the pipe bodies 2a and 2b, the pipe bodies 2a and 2b can be stably supported by utilizing the earth pressure of the solid ground G in which the fluid pipe 2 is buried, without the need to prepare any special support structure to support the thrust support fittings 20A and 20B.

[0041] After the removal of the existing detachment prevention fitting 4 is complete, the new detachment prevention fitting 4n is attached to the connection part CN1 between the pipe bodies 2a and 2b, as shown in Figure 8(b) (replacement process). In this way, the upstream and downstream thrust bearing fittings 20A and 20B are individually supported by the upstream steel sheet pile 10a (first support structure) and the downstream steel sheet pile 10b (second support structure), and the pipe bodies 2a and 2b are stably prevented from detaching from each other. With this in place, the existing detachment prevention fitting 4 can be replaced with the new detachment prevention fitting 4n. The new detachment prevention fitting 4n may have the same specifications as the existing detachment prevention fitting 4, or it may have specifications that provide a higher detachment prevention function.

[0042] After the installation of the newly installed anti-detachment fitting 4n is complete, the support 12A, contact jig 15A, and thrust bearing fitting 20A used for protective treatment are removed from the pipe body 2a, and the support 12B, contact jig 15B, and thrust bearing fitting 20B used for protective treatment are removed from the pipe body 2b, thereby completing the replacement process for the anti-detachment fitting 4 (removal process). Finally, the steel plates 11A and 11B are removed, and the excavated hole 9 is backfilled to complete the work.

[0043] [Effects / Effects] As described above, the method for replacing a detachment prevention device as an embodiment of the present invention is a method for replacing an existing detachment prevention fitting 4 attached to a connection part CN1 between pipe bodies 2a and 2b connected to each other along a flow path (pipeline) in a continuous flow state, wherein a thrust receiving fitting 20A having first claw members 21, 21 and second claw members 22, 22 that engage with the pipe body 2a is attached to the outer surface of one pipe body 2a, and the thrust receiving fitting 20A is supported by a steel sheet pile 10a which serves as a first support structure driven into the ground G. The method comprises at least a first support step, a second support step of attaching a thrust support fitting 20B having first claw members 21, 21 and second claw members 22, 22 that engage with the pipe body 2b to the outer surface of the other pipe body 2b, and supporting the thrust support fitting 20B with the steel sheet pile 10b, which serves as a second support structure driven into the ground G, and the ground G, and a replacement step of removing the existing detachment prevention fitting 4 attached to the connection part CN1 between the pipe bodies 2a, 2b and attaching a newly installed detachment prevention fitting 4n to the connection part CN1.

[0044] According to this, thrust bearings 20A and 20B are attached to the outer surfaces of the mutually connected pipe bodies 2a and 2b, and these thrust bearings 20A and 20B are individually supported by the support structures, which are steel sheet piles 10a and 10b (left and right walls of the ground G). In this way, the pipe bodies 2a and 2b are stably prevented from separating from each other, and the separation prevention fitting 4 can be replaced with a newly installed separation prevention fitting 4n.

[0045] Furthermore, by including a removal step after the replacement step in which the thrust bearing fitting 20A is removed from one pipe body 2a and the thrust bearing fitting 20B is removed from the other pipe body 2b, no excess material is left in the pipeline after the replacement with the newly installed detachment prevention fitting 4n, thereby ensuring safety.

[0046] Furthermore, since the steel sheet pile 10a, which serves as the first support structure, and the steel sheet pile 10b, which serves as the second support structure, are separate structures, the steel sheet pile 10a and the steel sheet pile 10b can independently support the pipe bodies 2a and 2b without influencing each other.

[0047] Furthermore, since the steel sheet pile 10a as the first support structure and the steel sheet pile 10b as the second support structure are driven into the ground G in which the pipes 2a and 2b are buried, there is no need to prepare any special support structures, and the pipes 2a and 2b can be supported by utilizing the earth pressure of the ground G in which the pipes 2a and 2b are buried.

[0048] Furthermore, since one pipe body 2a and the other pipe body 2b form a straight conduit, the pipe bodies 2a and 2b can be stably supported against the detachment forces P1 and P2 acting along the straight conduit. [Examples]

[0049] A method for replacing a detachment prevention device according to Embodiment 2 of the present invention will be described with reference to Figures 9 to 15. In the following description, the front side of Figure 9 is the front of the fluid pipe, the back side is the rear, the left side is the leftward direction, and the right side is the rightward direction, with the left side being the upstream side of the flow path and the right side being the downstream side of the flow path. In Embodiment 2, the same reference numerals are used for the same components and parts as in Embodiment 1, and detailed explanations are omitted. The description will mainly focus on components and parts that differ from Embodiment 1.

[0050] In this embodiment 2, the predetermined location of the existing fluid pipe 102 is configured such that pipe bodies 102a, 102b, and 102c, which are circular pipes having a receiving portion 3a and an insertion portion 3b, are connected in a substantially horizontal direction along the pipe axis, as shown in Figures 9 and 10. As shown in Figure 10, pipe bodies 102a and 102c are straight pipes, and pipe body 102b is a curved pipe having a bend in plan view. In this embodiment 2, the other straight pipe body 102c is arranged diagonally in plan view to the other straight pipe body 102a, and these pipe bodies 102a and 102c are connected via the curved pipe body 102b, thereby forming a non-linear flow path (pipeline). In addition, existing detachment prevention fittings 104A and 104B are attached to the connection portion CN2 with pipe bodies 102a and 102b and the connection portion CN3 with pipe bodies 102b and 102c.

[0051] In a flow path (pipeline), a curved section (irregularly shaped section) is subjected to an unbalanced force, that is, a force that attempts to move the section in a direction intersecting the pipeline, resulting from the unbalanced action of water pressure within the pipe. In the case of the fluid pipe 102 of this embodiment 2, an unbalanced force P3 acts on the pipe body 102b constituting the curved section in the direction of the thick black arrow (left-front direction). If the existing detachment prevention fittings 104A and 104B are removed while the flow is uninterrupted, as shown in Figure 11, an unbalanced force acts on the pipe body 102b. On the outer curved side of pipe body 102b, a force pa acts on the other pipe bodies 102a and 102c in the direction of detachment, and on the inner curved side of pipe body 102b, a force pb (see thin black arrow in the figure) acts on the other pipe bodies 102a and 102c in the direction of insertion, which may cause the pipe to detach. This second embodiment describes a method for replacing the two existing detachment prevention fittings 104A and 104B by applying protective measures to prevent the pipe bodies 102a and 102c from moving.

[0052] In this embodiment 2, the non-linear flow path consisting of the existing fluid pipe 102 buried underground and the installation locations of the detachment prevention fittings 104A and 104B to be replaced are identified and excavation holes are formed. However, illustrations of the ground G and excavation holes, as well as explanations of the excavation process, are omitted. Furthermore, after excavating the opening to expose the existing detachment prevention fittings 104A and 104B attached to the connection parts CN2 and CN3 of the existing fluid pipe 102, the illustration of the existing fluid pipe 102 before the installation of the thrust receiving fittings 120A and 120B as locking members and the concrete plate 110 as a support structure as protective measures is omitted. Also, the detachment prevention fittings 104A and 104B are configured in the same way as the detachment prevention fitting 4 in the above embodiment, and the thrust receiving fittings 120A and 120B are configured in the same way as the thrust receiving fittings 20A and 20B in the above embodiment, so detailed explanations of each are omitted.

[0053] When replacing existing detachment prevention fittings 104A and 104B, as shown in Figures 9 and 10, first, a concrete slab 110, which serves as a support structure with a roughly rectangular shape in plan view, is laid below the existing fluid pipe 102. While reinforced concrete is preferred for the concrete slab 110, a concrete slab without reinforcement, or a steel plate or resin plate, may also be used.

[0054] Next, the thrust support fitting 120A is fitted onto the outer surface of the upstream pipe 102a and secured by bolts N3, N3, which cause the first claw portion 21a of the first claw member 21 (not shown) and the second claw portion 22a of the second claw member 22 to bite into the outer surface of the pipe 102a. Then, the bottom plate 120e is fixed and supported to the concrete slab 110, which serves as the first support structure, using a plurality of adhesive anchor bolts N10 (first support step).

[0055] Furthermore, the thrust support fitting 120B is fitted onto the outer surface of the downstream pipe body 102c and secured by bolts N3, N3, which cause the first claw portion 21a of the first claw member 21 (not shown) and the second claw portion 22a of the second claw member 22 to bite into the outer surface of the pipe body 102a. Then, the bottom plate 120e is fixed and supported to the concrete plate 110, which serves as a second support structure, using multiple adhesive anchor bolts N10 (second support step).

[0056] With the protective treatment described above, the thrust support fitting 120A, which is locked to the outer surface of the upstream pipe 102a, is supported by the concrete plate 110, which is the first support structure, thereby restricting the movement of the upstream pipe 102a. Meanwhile, the thrust support fitting 120B, which is locked to the outer surface of the downstream pipe 2b, is supported by the steel sheet pile 10b, which is the second support structure, thereby restricting the movement of the pipe 102b in the downstream direction. To explain the internal stress acting on the concrete plate 110 that supports the thrust support fittings 120A and 120B, the concrete plate 110 is divided into three regions, as shown in Figure 11: a first region E1 along the fluid pipe 102, a second region E2 on the outer curve side (left front side) of the curved section of the fluid pipe 102, and a third region E3 on the inner curve side (right rear side) of the curved section of the fluid pipe 102.

[0057] When an unbalanced force P3 acts, forces pa, pa act in the direction that opens the receiving portion 3a and the insertion portion 3b in the second region E2 side of the connection portion CN2, CN3, and forces pb, pb act in the direction that closes the receiving portion 3a and the insertion portion 3b in the third region E3 side of the connection portion CN2, CN3. Due to this unbalanced force P3, an internal stress Qa is generated in the second region E2 on the outer curved side of the concrete slab 110 in the direction that tears the concrete, as indicated by the thick white arrow, while an internal stress Qb is generated in the third region E3 on the inner curved side, as indicated by the thick white arrow, in the direction that compresses the concrete.

[0058] Thus, the concrete slab 110, as a support structure, is integrally and continuously provided on both sides of the fluid pipe 102 in the axial direction, with an outer second region E2 and an inner third region E3 extending outwards. This allows the internal stresses Qa and Qb caused by the unbalanced force P3 to be distributed and supported over a wide area. In this way, the concrete slab 110 can firmly support the pipe bodies 102a and 102c, making it less likely for the pipes to detach due to the unbalanced force P3 when the existing detachment prevention fittings 104A and 104B are removed.

[0059] Next, as shown in Figure 12, the existing detachment prevention fitting 104B attached to the connection part CN3 between pipe bodies 102b and 102c is removed, and then, as shown in Figure 13, the new detachment prevention fitting 114B is attached to the connection part CN3 (replacement process).

[0060] Next, as shown in Figure 13, the existing detachment prevention fitting 104A attached to the connection part CN2 between pipe bodies 102a and 102b is removed, and then, as shown in Figure 14, the new detachment prevention fitting 114A is attached to the connection part CN2 (replacement process).

[0061] Once the installation of the newly installed anti-detachment fittings 114A and 114B is complete, the replacement process for the anti-detachment fittings 104A and 104B is completed by removing the thrust support fitting 120A from the pipe body 102a and the thrust support fitting 120B from the pipe body 102c, as shown in Figure 15 (removal process). Finally, the steel plates 11A and 11B are removed and the excavated hole 9 is backfilled to complete the work.

[0062] [Effects / Effects] As described above, the method for replacing the detachment prevention device as Embodiment 2 of the present invention is a method for replacing existing detachment prevention fittings 104A and 104B attached to connection parts CN2 and CN3 between pipe bodies 102a and 102c connected to each other along a flow path (pipeline) in a continuous flow state, wherein a thrust receiving fitting 120A having first claw members 21, 21 and second claw members 22, 22 that engage with the pipe body 102a is attached to the outer surface of one pipe body 102a, and the thrust receiving fitting 120A is supported by a concrete plate 110 as a first support structure. The method comprises at least the following steps: a first support step; a second support step in which a thrust support fitting 120B having first claw members 21, 21 and second claw members 22, 22 that engage with the pipe 2b is attached to the outer surface of the other pipe 102c, and the thrust support fitting 120B is supported by a concrete plate 110 which serves as a second support structure; and a replacement step in which existing detachment prevention fittings 104A, 104B attached to the connection parts CN2, CN3 between the pipes 102a, 102c are removed, and new detachment prevention fittings 114A, 114B are attached to the connection parts CN2, CN3.

[0063] According to this, thrust bearings 120A and 120B are attached to the outer surfaces of the mutually connected pipes 102a and 102c, and these thrust bearings 120A and 120B are supported by a concrete plate 110, which is a common support structure. In this way, the existing detachment prevention fittings 104A and 104B can be replaced with new detachment prevention fittings 114A and 114B while the pipes 102a and 102c are stably prevented from separating from each other.

[0064] Furthermore, since the first support structure and the second support structure are a single concrete slab 110, the configuration of the first and second support structures can be standardized and simplified. In addition, since the thrust bearings 120A and 120B attached to each pipe 102a and 102c can be fixed to the common concrete slab 110, the load on each thrust bearing 120A and 120B can be distributed over a wide area, simplifying the structure, and the relative positional relationship between the thrust bearings 120A and 120B can be maintained, making pipe detachment less likely.

[0065] Furthermore, since one pipe body 102a and the other pipe body 102c form a non-linear conduit, the pipe bodies 102a and 102c can be stably supported against the unbalanced force P3 acting on the non-linear conduit.

[0066] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0067] [Differentiation] Next, modifications of the present invention will be described with reference to Figures 16 and 17. In Embodiment 1, thrust bearings 20A and 20B as locking members are supported on steel sheet piles 10a and 10b via supports 12A and 12B and jigs 15A and 15B, and in Embodiment 2, thrust bearings 120A and 120B as locking members are supported on a concrete plate 110. However, the present invention is not limited thereto, and thrust bearings 220A and 220B, each having a locking part (not shown) such as a locking claw that can be locked onto the outer surface of the pipe bodies 2a and 2b, may be supported by locking them onto a pile 225 driven into the bottom 9a of the excavation hole 9.

[0068] Specifically, the thrust bearing brackets 220A and 220B have a split structure that covers the existing fluid pipe 2 from above and below, and mainly consist of semi-cylindrical parts 221 and 222 positioned on the upper and lower parts of the existing fluid pipe 2, a locking plate 223a projecting outward from one end edge of the upper semi-cylindrical part 221 and a locking plate 223b projecting outward from the other end edge of the lower semi-cylindrical part 222, and bolts and nuts N20 as fastening means for fastening the semi-cylindrical parts 221 and 222 together.

[0069] Inside the semi-cylindrical portions 221 and 222, there are locking parts (not shown) such as locking claws that can engage with the outer surfaces of the pipe bodies 2a and 2b. By fastening the upper and lower semi-cylindrical portions 221 and 222 together with multiple bolts and nuts N20, the locking parts (not shown) are engaged with the outer surfaces of the pipe bodies 2a and 2b, thereby restricting the movement of the semi-cylindrical portions 221 and 222 relative to the pipe bodies 2a and 2b in the pipe axis direction.

[0070] The locking plate 223a of the upstream thrust bearing fitting 220A is provided along the front end edge of the upper semi-cylindrical portion 221, and the locking plate 223b is provided along the rear end edge of the lower semi-cylindrical portion 222. The locking plates 223a and 223b of the downstream thrust bearing fitting 220B are reversed in orientation compared to the locking plates 223a and 223b on the upstream side. In addition, each locking plate 223a and 223b has a locking groove 224 that is roughly L-shaped in plan view, into which a pile 225 driven into the bottom 9a can be inserted.

[0071] In the above-described embodiment 1, multiple steel sheet piles 10a, 10b, and 10c are driven to prevent the existing fluid pipe 2 from floating up. On the other hand, when excavating by open digging without retaining walls, as in this modified example, if the bearing capacity due to the earth pressure of the ground G is insufficient, the existing fluid pipe 2 may float upward. When this floating occurs, there is a possibility that the pile 225 will come out of the bottom 9a. As a countermeasure against the pile 225 coming out of the bottom 9a, the locking plates 223a and 223b are assembled to the semi-cylindrical parts 221 and 222 so that they are reversed in the vertical direction relative to the existing fluid pipe 2, thereby preventing the pile 225 from coming out of the bottom 9a due to floating up. Alternatively, the locking plates 223a and 223b may be assembled to the semi-cylindrical parts 221 and 222 so that they are reversed in the front-to-back direction relative to the existing fluid pipe 2.

[0072] Thus, thrust bearing brackets 220A and 220B can be attached by locking locking parts (not shown) to the outer surfaces of the pipe bodies 2a and 2b, and the piles 225 driven into the bottom 9a of the excavated hole 9 can be locked into the locking grooves 224 of the respective locking plates 223a and 223b, thereby supporting the pipe bodies 2a and 2b in the ground G via the piles 225, which are supporting structures driven into the ground G. This allows the pipe bodies 2a and 2b to be stably supported against detachment forces P1 and P2 acting along the straight pipeline.

[0073] In this modified example, the pile 225 is shown as being driven into the bottom 9a, but the present invention is not limited to this, and the pile 225 may be driven into the left and right walls or the front and rear walls of the excavation hole 9. Furthermore, it may be supported by multiple support structures as long as it is secured to at least one of the support structures among the bottom 9a, the left and right walls of the excavation hole 9, or the front and rear walls.

[0074] [Other variations] Furthermore, in the above-described embodiments 1 and 2 and their modifications, examples of thrust bearings 20A, 20B, 120A, 120B, 220A, and 220B having multiple first claw members 21 and second claw members 22 were shown as examples of locking members. However, the present invention is not limited thereto, and may also be a thrust bearing having a single locking part. Moreover, as long as it has a locking part, it may be, for example, a thrust ring, and the structure of the locking member of the thrust bearing or the like can be arbitrarily changed.

[0075] Furthermore, in the above-described embodiments 1 and 2 and their variations, the present invention illustrates a configuration in which either a first support step of supporting the upstream thrust bearings 20A, 120A, and 220A on the first support structure, or a second support step of supporting the downstream thrust bearings 20B, 120B, and 220B on the second support structure, is performed before the other step. However, the present invention is not limited thereto, and either the first support step or the second support step may be performed first. Also, the first support step and the second support step may be performed almost simultaneously and in parallel.

[0076] Furthermore, while the above-described embodiment 1 and its modified form illustrate a configuration in which there is one connection point CN1 between the pipes, and embodiment 2 illustrates a configuration in which there are two connection points CN2 and CN3 between the pipes, the present invention is not limited thereto, and the number of connection points between the pipes can be arbitrary, and there may be one or three or more connection points between the pipes.

[0077] Furthermore, while the first embodiment illustrates a configuration in which the backing jigs 15A, 15B and the support bodies 12A, 12B are positioned between the thrust support fittings 20A, 20B and the steel sheet piles 10a, 10b, the present invention is not limited thereto. The locking members may be directly supported by the support structure, or they may be indirectly supported via intervening members such as the backing jigs 15A, 15B and the support bodies 12A, 12B. Other members besides the backing jigs 15A, 15B and the support bodies 12A, 12B may also be intervened. In addition, the thrust support fittings 20A, 20B may be directly supported on the left and right walls of the excavation hole 9 without the steel sheet piles 10a, 10b.

[0078] Furthermore, in the above-described embodiments 1 and 2 and their modifications, examples of support structures were given in which steel sheet piles 10a and 10b driven into the ground G, concrete slabs 110, and piles 225 driven into the ground G were applied. However, the present invention is not limited thereto, and the support structure may be a structure other than those described above.

[0079] Furthermore, while the above-described embodiments 1 and 2 and their modifications illustrate a configuration in which the existing detachment prevention fittings are replaced with new detachment prevention fittings and then the locking members, which are thrust receiving fittings 20A, 20B, 120A, 120B, 220A, and 220B, are removed, the present invention is not limited thereto. After replacing the existing detachment prevention fittings, the excavated hole 9 may be backfilled without removing the locking members.

[0080] Furthermore, in the above-described embodiment 2, an unbalanced force P3 acting on the curved section of the flow path (pipeline) causes a pipe detachment effect at the connection sections CN2 and CN3. Therefore, when replacing the existing detachment prevention device, the protective treatment described in the above embodiment is exemplified. However, the present invention is not limited to this. For example, since unbalanced forces also act on irregularly shaped pipe sections other than curved sections in the flow path (pipeline), such as T-junctions, drop-off sections, pipe ends, and gate valve sections, it is preferable to apply the protective treatment described in the above embodiment when replacing the existing detachment prevention device provided at the connection sections of these irregularly shaped pipe sections. [Explanation of Symbols]

[0081] 2. Fluid pipes (existing fluid pipes) 2a, 2b Body 3a Socket part 3b Socket 4. Detachment prevention fitting (existing detachment prevention device) 4n Detachment prevention fitting (new detachment prevention device) 9. Excavation hole 10a Steel sheet pile (first support structure) 10b Steel sheet pile (second support structure) 11A, 11B Steel Plate 12A,12B Support 15A, 15B Fixing jig 20A, 20B Thrust bearing bracket (locking member) 20a Upper part 20b Lower part 21 1st claw member 21a 1st claw part 22 Second claw member 22a 2nd claw part 102 Fluid pipes (existing fluid pipes) 102A, 102B Thrust bearing bracket (locking member) 102a~102c Body 104A, 104B Detachment prevention fittings (existing detachment prevention devices) 110 Concrete slab (first support structure, second support structure) 114A, 114B Detachment prevention fitting (new detachment prevention device) 120A, 120B Thrust bearing bracket (locking member) 220A, 220B Thrust bearing bracket (locking member) 225 Piles (First support structure, Second support structure) CN1~CN3 Connection Section

Claims

1. A method for replacing detachment prevention devices, which are attached to the connections between fluid pipes connected to each other along a pipeline, in a continuous flow state, A first support step involves attaching a locking member to the outer surface of one fluid pipe and supporting the locking member on a first support structure, A second support step involves attaching a locking member to the outer surface of the other fluid pipe to engage with the fluid pipe, and supporting the locking member with a second support structure. A method for replacing a detachment prevention device, characterized by comprising at least a replacement step of removing the existing detachment prevention device attached to the connection between the fluid pipes and attaching a new detachment prevention device to the connection.

2. The method for replacing a detachment prevention device according to claim 1, further comprising a removal step of removing the locking member from one fluid pipe and removing the locking member from the other fluid pipe after the replacement step.

3. The method for replacing a detachment prevention device according to claim 1, characterized in that the first support structure and the second support structure are separate structures.

4. The method for replacing a detachment prevention device according to claim 1, characterized in that the first support structure and the second support structure are an integrated structure.

5. The method for replacing a detachment prevention device according to claim 1, characterized in that the first support structure and the second support structure are the ground in which the fluid pipe is buried.

6. The method for replacing a detachment prevention device according to any one of claims 1 to 5, characterized in that one fluid pipe and the other fluid pipe constitute a non-linear pipeline.

7. The method for replacing a detachment prevention device according to any one of claims 1 to 5, characterized in that one fluid pipe and the other fluid pipe constitute a straight pipeline.

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