Piping installation method, precast block arrangement method and arrangement structure

Abstract

This design facilitates the construction of thrust block arrangements that reduce the impact of thrust forces acting on pipe joints. [Solution] A piping construction method including a joint, comprising: an excavation step (S11) of excavating the ground at the location where the piping will be buried; and a placement step (S12) of placing the piping including the joint and a precast block that contacts the joint from the outside to receive the thrust force received by the joint from the fluid present in the piping.

Description

Technical Field

[0001] The present invention relates to a pipe construction method, a precast block placement method, and a placement structure.

Background Art

[0002] For example, in the bent portions or T-joint portions of water supply pipes, a thrust force acts that tries to move the pipe to the back side of the bent portion or T-joint portion due to the internal water pressure. Especially during an earthquake, joint detachment of the pipe occurs at the thrust action portion, and water leakage damage frequently occurs. The thrust resistance in design calculations is calculated by the frictional resistance between the pipe bottom surface and the surrounding ground and the passive earth pressure on the back of the pipe. As a countermeasure method for thrust, a method of forming and fixing a thrust block by pouring concrete after assembling a formwork around the bent portion of the pipe is known as the prior art. By installing a thrust block with a large self-weight, the frictional resistance between the block bottom surface and the surrounding ground increases, and furthermore, the pressure receiving area of the passive earth pressure increases, thereby improving the thrust resistance.

[0003] For example, Patent Document 1 discloses a thrust block production kit that can produce a plurality of types of thrust blocks by combining panels specified in association with the hydrostatic pressure applied to the water distribution pipe of a pipeline where a thrust block is installed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, although the thrust block fabrication kit disclosed in Patent Document 1 is convenient, it requires the use of formwork to surround the joint piping and pour concrete into it, which necessitates on-site construction. This necessitates formwork assembly and curing periods, resulting in a longer construction period and increased construction costs.

[0006] One aspect of the present invention aims to facilitate the construction of a thrust block arrangement structure that is less susceptible to the effects of thrust forces acting on pipe joints. [Means for solving the problem]

[0007] To solve the above problems, a pipe installation method according to one aspect of the present invention is a pipe installation method including a joint, comprising: an excavation step of excavating the ground at a location where the pipe will be buried; and a placement step of placing the pipe including the joint and a precast block that contacts and receives the thrust force received by the joint from the fluid present in the pipe from the outside of the joint at the excavated location.

[0008] Furthermore, an arrangement structure according to one aspect of the present invention is an arrangement structure in the ground of a pipe including a joint and a precast block, wherein the precast block is positioned to receive the thrust force received by the joint from the fluid flowing inside the pipe by contacting the joint from the outside.

[0009] Furthermore, a precast block placement method according to one aspect of the present invention includes an excavation step of excavating the ground in which a pipe including a joint is buried until the joint is exposed, and a placement step of placing a precast block that will receive the thrust force received by the joint from the fluid present in the pipe, in contact with the outside of the joint. [Effects of the Invention]

[0010] According to one aspect of the present invention, a thrust block arrangement structure that is less susceptible to the effects of thrust forces acting on pipe joints can be easily constructed. [Brief explanation of the drawing]

[0011] [Figure 1] A flowchart showing the flow of the piping installation method S1 according to Embodiment 1 of the present invention. [Figure 2] This is a schematic diagram illustrating the thrust pressure from the fluid present inside the pipe. [Figure 3] This is a schematic plan view showing the position of the precast blocks to be placed in the T-pipe joint. [Figure 4] Figure 3 is a schematic cross-sectional view of the arrangement of precast blocks. [Figure 5] This is a schematic plan view showing other arrangement examples of precast blocks. [Figure 6] This is a flowchart showing the flow of the precast block arrangement method S2 according to Embodiment 2 of the present invention. [Figure 7] This is a flowchart showing the flow of the piping construction method S3 according to Embodiment 3. [Figure 8] This is a flowchart showing the flow of the precast block arrangement method S4 according to Embodiment 3. [Modes for carrying out the invention]

[0012] [Embodiment 1] The following describes in detail a piping construction method according to one embodiment of the present invention, with reference to the drawings. This piping construction method is a method for burying pipes, including fittings, in the ground. The pipes assumed in this embodiment are pipes through which fluids pass, such as water supply pipes. The size of the pipes is not particularly limited, but the thrust force described later becomes a problem for relatively large-diameter pipes. The pipes include fittings such as bending joints for changing their direction, i.e., bending, and T-joints for branching.

[0013] Piping systems that include bends and branches are generally constructed by cutting straight pipes to predetermined lengths and joining these lengths with joints. At joints in bends and branches, thrust pressure from the fluid inside acts from the inside of the pipe outwards. For example, as shown in Figure 2, suppose two pipes D1 and D2 are connected by a bend joint D3 with a bend angle θ. If the internal pressure of the fluid inside the pipe is P and the cross-sectional area of ​​the pipe is A, then a pressure of 2PAsinθ / 2 will be applied in the direction of arrow S. This force is called thrust force. When such a thrust force is applied to the bend joint D3, in the worst case, the bend joint D3 may come loose or break.

[0014] The piping installation method S1 according to this embodiment is a piping installation method in which precast blocks that withstand the force applied to the joints are buried and placed together with the piping. Figure 1 is a flowchart showing the flow of the piping installation method S1. As shown in the figure, the piping installation method S1 includes steps S11 to S14.

[0015] Step S11 is an excavation process in which the ground at the location where the pipes will be buried is excavated. At least the area including the joint portion of the burial site is excavated to a predetermined depth. The predetermined depth is the depth at which the pipes and joints will be placed. Alternatively, the ground may be excavated to a depth greater than the predetermined depth, and then backfilled to the predetermined depth.

[0016] Step S12 is an arrangement step of arranging, at the excavated embedding location, a pipe including a joint and a precast block that abuts from the outside of the joint and receives the thrust force exerted on the joint by the fluid existing in the pipe. The precast block is a thrust block manufactured in advance. The difference from the thrust block of the prior art is that the thrust block of the prior art is a block constructed by surrounding the periphery of the joint with a formwork after installing the pipe including the joint and pouring concrete thereinto, whereas the precast block is a block manufactured at a block manufacturing factory and transported to the embedding site. Therefore, the material of the precast block is not limited to concrete, and any material that can be manufactured at the manufacturing factory may be used. The shape of the precast block is also arbitrary. In addition to a rectangular parallelepiped shape, a cone-shaped block with a widened bottom surface or side surface may be used to increase the resistance force from the ground. Also, the shape of the portion that abuts the joint may be planar, or may be shaped to fit the outer shape of the abutting joint. Also, the weight of the precast block is arbitrary, but may be a weight calculated to be difficult to move with respect to the assumed thrust force.

[0017] The position where the precast block is arranged is a position where the thrust force exerted on the joint by the fluid existing in the pipe is abutted and received from the outside of the joint. The outside means the outside of the joint pipe. The position for receiving the thrust force will be described with reference to FIG. 3. FIG. 3 is a schematic plan view seen from above of the position of the precast block BL1 arranged on the T-shaped pipe joint PJ. In FIG. 3, when the gravity direction (vertical direction) is taken as the Z direction and the direction orthogonal to the Z direction is taken as the XY direction, an XY plan view is shown. As shown in 301 of FIG. 3, three pipes 10, 20, and 30 are connected by the T-shaped pipe joint PJ. A thrust force is applied to this T-shaped pipe joint PJ in the direction indicated by the arrow S (X direction). This thrust force is the pressure received from the fluid in the pipe 20. Since the pressures from the fluids inside the pipes 10 and 30 cancel each other out, the thrust force is applied only in the direction indicated by the arrow S.

[0018] The precast block BL1 is arranged to abut against the outside of the T-shaped pipe joint PJ at a position for receiving the thrust force in the direction indicated by the arrow S. As shown in 301 of FIG. 3, the precast block BL1 is preferably arranged so as to abut against the precast block BL1 in as wide a range as possible. Thereby, the thrust force can be dispersed and received. By arranging it in this way, even when a thrust force is applied to the precast block BL1, the weight of the precast block BL1 and the resistance force due to the friction or reaction force with the ground can reduce the movement of the T-shaped pipe joint PJ and its detachment from the pipe 20.

[0019] FIG. 4 is a schematic cross-sectional view of the arrangement of the precast blocks shown in FIG. 3. 401 in FIG. 4 is a cross-sectional view taken along the line A-A of 301 in FIG. 3, that is, a cross-sectional view seen in the X direction. As shown in the drawing, the T-shaped pipe joint PJ and the precast block BL1 are in linear contact. The surface of the precast block BL1 that abuts against the T-shaped pipe joint PJ is a flat surface in the illustrated example, but it may be curved according to the outer surface of the T-shaped pipe joint PJ. In addition, in the cross-sectional view of FIG. 4, an example is shown in which there is a partial backfill layer 70 on the excavation surface of the ground layer 60, and the precast block BL1 and the T-shaped pipe joint PJ are arranged on the backfill layer 70.

[0020] By the above method, as shown in FIGS. 3 and 4, a precast block BL1 is arranged at a position for receiving the thrust force received by the joint PJ from the fluid flowing in the pipe by abutting against the outside of the joint PJ, and an arrangement structure in the soil of the pipe including the joint and the precast block is generated.

[0021] Returning to FIG. 1, step S13 is a fixing step for fixing the precast block. For example, by using a precast block provided with one or more through holes and passing a fixing rod through the through holes to the ground layer, the precast block can be fixed to the ground layer. However, other methods may be used to fix the precast block.

[0022] Figure 3, section 302 is a plan view of a precast block BL2 with through holes fixed in place. The precast block BL2 has two through holes, and as shown in section 402 of Figure 4, fixing rods 41 and 42 are inserted into each hole and penetrated to the ground layer 60. The material of the fixing rods 41 and 42 is arbitrary, but they must have sufficient strength to withstand thrust forces; for example, hollow steel pipes can be used. In the example shown in Figures 3 and 4, the direction of the through holes, i.e., the direction of the fixing rods 41 and 42, is vertical (Z direction), but depending on the ground, they may be provided horizontally (XY direction). For example, if the layer where the pipes and fittings are to be placed is bedrock or otherwise difficult to drive in fixing rods, through holes may be provided in the horizontal direction of the precast block so that fixing rods can be driven into the horizontal ground layer. Furthermore, it is not always necessary to provide fixing through holes; fixing rods can also be installed between the precast block BL1 without through holes and the ground layer 60. Alternatively, a bracing rod or the like may be placed between the lateral ground layer and the precast block BL1, which does not have a through hole. The direction in which the bracing rod is placed should be in the direction in which the thrust force acts. With this configuration, the precast block BL1 or BL2 can be fixed to the ground layer. Note that step S13 is not necessarily required. In other words, it is not always necessary to fix the precast block to the ground layer.

[0023] Step S14 is the backfilling process, which involves backfilling the placed pipes and precast blocks. This process involves backfilling the excavated ground to its original height.

[0024] Figure 5 is a schematic plan view showing another example of the arrangement of precast blocks. In the example shown in Figure 5, a buffer material 51 is placed at the contact point between the precast block BL and the T-pipe joint PJ. The size of the buffer material 51 is such that it can at least partially, and preferably completely, cover the contact point. The material of the buffer material 51 is arbitrary and can be rubber, resin, etc. By placing the buffer material 51 at the contact point, damage to the joint in contact with the precast block can be prevented.

[0025] Furthermore, it is preferable to position the precast blocks so that their center of gravity lies within the direction plane of the thrust force. Since this embodiment is a construction method, precise positioning is difficult. The direction plane of the thrust force shown here is a plane that aligns with the direction of the thrust force and is substantially parallel to the direction of gravity. Also, the center of gravity of the precast block is not the exact center of gravity but a spherical range that includes the center of gravity. The reason for using a spherical range is to allow for error. In the example shown in Figure 5, arrow S indicates the direction of the thrust force. The dotted line SP on the precast block BL indicates the position of the direction plane of the thrust force when viewed from above, and the center of gravity of the precast block BL is indicated by the black circle GC. Simply put, the central part of the precast block BL (the part of the dotted line SP) should be positioned so that it substantially coincides with the center line of the piping that applies the thrust force. By positioning it in this way, the precast block BL can uniformly receive the thrust force.

[0026] According to the piping construction method S1 described above, when constructing a new piping system including joints, it is only necessary to place pre-fabricated precast blocks at the designated positions of the joints. Therefore, the effort of placing formwork around the joints and pouring concrete into it can be eliminated. In other words, a thrust block (precast block) arrangement structure that is less susceptible to the effects of thrust forces acting on the pipe joints can be easily constructed. This arrangement structure reduces the likelihood of joints coming loose due to thrust forces.

[0027] [Embodiment 2] Other embodiments of the present invention will be described below with reference to the drawings. For the sake of clarity, components having the same function as those described in the above embodiments will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0028] Figure 6 is a flowchart showing the flow of the precast block placement method S2 according to this embodiment. The precast block placement method S2 is a method for newly placing precast blocks at joint locations in existing piping where thrust blocks are not placed. As shown in the figure, the precast block placement method S2 includes steps S21 to S24. Step S21 is an excavation process in which the ground in which the piping including the joint is buried is excavated until the joint is exposed.

[0029] Step S22 is an arrangement step in which a precast block, which will receive the thrust force on the joint from the fluid present in the piping, is placed in contact with the outside of the joint. The method of arranging the precast block is basically the same as the method of arranging the precast block described in Embodiment 1.

[0030] Step S23 is a fixing step in which the precast block is secured. This fixing step is the same as the fixing step described in Embodiment 1. As in Embodiment 1, step S23 is not necessarily required.

[0031] Step S24 is the backfilling process, in which the excavated ground is returned to the surface.

[0032] According to the precast block placement method S2 described above, it is only necessary to place pre-manufactured precast blocks in the designated positions of existing joint sections where thrust blocks are not present. Therefore, the effort of placing formwork around the joint and pouring concrete into it can be eliminated. In other words, a new precast block placement structure that is less susceptible to the effects of thrust forces acting on pipe joints can be easily constructed.

[0033] [Embodiment 3] Other embodiments of the present invention will be described below with reference to the drawings. For the sake of convenience, components having the same function as those described in Embodiments 1 and 2 above will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0034] The piping construction method according to this embodiment 3 differs from the piping construction methods described in embodiments 1 and 2 in that it is a construction method for installing piping including fittings and precast blocks for those fittings on the ground (outdoors) or in the interior space of a structure (indoors). The types of fittings, types of piping, and structure and shape of the precast blocks described in this embodiment 3 are the same as those described in embodiment 1, so their explanation is omitted here.

[0035] Figure 7 is a flowchart showing the flow of the piping construction method S3 including joints according to this embodiment. The piping construction method S3 is a method for constructing piping including joints and precast blocks on the ground or in the internal space of a structure. As shown in the figure, the piping construction method S3 includes steps S31 to S33.

[0036] Step S31 is the step of installing piping including fittings on the ground or in the interior space of a structure. The interior space of a structure may be, for example, inside a factory. Step S32 is the step of positioning precast blocks that will receive the thrust force that the fittings receive from the fluid present in the piping by contacting them from the outside of the fittings. Steps S31 and S32 may be performed in parallel, and these two steps together are called the positioning step (positioning process). Step S33 is the step of fixing the precast blocks after the positioning process (fixing process).

[0037] According to the above piping construction method S3, when constructing a new piping system including joints outdoors or indoors, it is only necessary to place pre-fabricated precast blocks at the designated positions of the joints. Therefore, the effort of placing formwork around the joints and pouring concrete into it can be eliminated. In other words, a thrust block (precast block) arrangement structure that is less susceptible to the effects of thrust forces acting on the pipe joints can be easily constructed.

[0038] Figure 8 is a flowchart showing the flow of the precast block placement method S4 according to Embodiment 3. The precast block placement method S4 is a method for placing new precast blocks at joints in a piping system that has already been constructed indoors or outdoors, but where thrust blocks have not been placed at the joints of the piping system.

[0039] As shown in the figure, the precast block placement method S4 includes steps S41 and S42. Step S41 is a placement step in which a precast block that will receive the thrust force on the joint from the fluid present in the piping including the joint is placed in contact with the outside of the joint. Step S42 is a fixing step in which the placed precast block is fixed. In this way, even when a thrust block is to be newly placed in a joint of an already constructed piping system, a precast block that has been manufactured in advance can be placed and fixed, thus eliminating the need to place formwork around the joint and pour concrete into it. In other words, a thrust block (precast block) placement structure that is less susceptible to the effects of thrust force acting on the joint of a pipe can be easily constructed.

[0040] In both the piping construction method S3 shown in Figure 7 and the precast block arrangement method S4 shown in Figure 8, upon completion, an arrangement structure is obtained that includes piping with fittings and precast blocks arranged in contact with the outside of the fittings, wherein a spherical area containing the center of gravity of the precast blocks is arranged within a directional plane substantially aligned with the direction of the thrust force received by the fittings from the fluid flowing through the piping. "Within a directional plane substantially aligned with the direction of the thrust force" means not only a direction strictly parallel to the thrust force, but also a directional plane that includes errors.

[0041] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0042] 〔summary〕 (Aspect 1) The excavation process involves excavating the ground at the location where the pipes will be buried, A placement step involves placing the piping, including the joint, and a precast block that contacts the joint from the outside to receive the thrust force received by the joint from the fluid present in the piping, at the excavated buried location. A piping installation method, including the following.

[0043] (Aspect 2) The piping construction method according to embodiment 1, further comprising a fixing step of fixing the precast blocks after the placement step.

[0044] (Aspect 3) The piping installation method according to embodiment 2, wherein in the fixing step, a fixing rod is passed through a through hole provided in the precast block.

[0045] (Aspect 4) The piping construction method according to any one of embodiments 1 to 3, wherein in the arrangement step, a buffer material is placed at the contact point between the joint and the precast block.

[0046] (Appendix 5) The piping construction method according to any one of embodiments 1 to 4, wherein in the arrangement step, the precast block is arranged such that the center of gravity of the precast block is located within the direction plane of the thrust force.

[0047] (Aspect 6) An arrangement structure in the ground for a pipe including a joint and a precast block, wherein the precast block is positioned to receive the thrust force received by the joint from the fluid flowing inside the pipe by contacting the joint from the outside.

[0048] (Aspect 7) The arrangement structure according to embodiment 6, wherein the precast block is fixed in the soil by fixing rods that pass through through holes provided in the precast block.

[0049] (Pattern 8) A method for arranging precast blocks, comprising: an excavation step of excavating the ground in which a pipe including a joint is buried until the joint is exposed; and an arrangement step of arranging a precast block that will receive thrust force from the fluid present in the pipe, by bringing it into contact with the outside of the joint.

[0050] (Aspect 9) A piping construction method including a fitting, comprising: a placement step of arranging a pipe including the fitting and a precast block that contacts and receives the thrust force received by the fitting from the fluid present in the pipe from the outside of the fitting; and a fixing step of fixing the precast block after the placement step.

[0051] (Aspect 10) The piping installation method according to embodiment 9, wherein in the fixing step, a fixing rod is passed through a through hole provided in the precast block.

[0052] (Aspect 11) The piping construction method according to embodiment 9 or 10, wherein in the arrangement step, a buffer material is placed at the contact point between the joint and the precast block.

[0053] (Aspect 12) An arrangement structure comprising a pipe including a joint and a precast block positioned in contact with the outside of the joint, characterized in that a spherical area including the center of gravity of the precast block is positioned in a directional plane substantially aligned with the direction of the thrust force received by the joint from the fluid flowing through the pipe.

[0054] (Aspect 13) A method for arranging a precast block, comprising: an arrangement step of arranging a precast block that will receive thrust forces from a fluid present inside a pipe including the joint, by bringing the precast block into contact with the outside of the joint; and a fixing step of fixing the arranged precast block. [Explanation of symbols]

[0055] 10, 20, 30... Piping 41,42...Fixing rod 51...Cushioning material 60...ground layer 70... (Partial) backfill layer PJ...T-shaped pipe fitting BL... Precast Block

Claims

1. A piping installation method including fittings, The excavation process involves excavating the ground at the location where the pipes will be buried, A placement step involves placing the piping, including the joint, and a precast block that contacts the joint from the outside to receive the thrust force received by the joint from the fluid present in the piping, at the excavated buried location. A piping installation method, including the following.

2. The piping construction method according to claim 1, further comprising a fixing step of fixing the precast blocks after the placement step.

3. The piping installation method according to claim 2, wherein in the fixing step, a fixing rod is passed through a through hole provided in the precast block.

4. The piping construction method according to any one of claims 1 to 3, wherein in the arrangement step, a buffer material is placed at the contact point between the joint and the precast block.

5. The piping construction method according to any one of claims 1 to 3, wherein in the arrangement step, the precast block is arranged such that the center of gravity of the precast block is located within the direction plane of the thrust force.

6. A burrowed arrangement structure of piping including fittings and precast blocks, An arrangement structure in which the precast block is positioned to receive the thrust force that the joint receives from the fluid flowing inside the pipe by contacting it from the outside of the joint.

7. The arrangement structure according to claim 6, wherein the precast block is fixed in the soil by fixing rods that pass through through holes provided in the precast block.

8. An excavation process in which the ground in which the pipe, including the joint, is buried is excavated until the joint is exposed, The arrangement step involves positioning a precast block, which will receive the thrust force on the joint from the fluid present in the piping, by bringing it into contact with the outside of the joint. A method for arranging precast blocks, including the method described above.

9. A piping installation method including fittings, A placement step of arranging a pipe including the aforementioned joint and a precast block that contacts and receives the thrust force received by the joint from the fluid present in the pipe from the outside of the joint, A fixing step is performed after the arrangement step, in which the precast blocks are fixed in place. A piping installation method, including the following.

10. The piping installation method according to claim 9, wherein in the fixing step, a fixing rod is passed through a through hole provided in the precast block.

11. The piping construction method according to claim 9 or 10, wherein in the arrangement step, a buffer material is placed at the contact point between the joint and the precast block.

12. A configuration structure including piping with fittings and a precast block positioned in contact with the outside of the fittings, The arrangement structure is characterized in that a spherical area containing the center of gravity of the precast block is arranged in a directional plane substantially aligned with the direction of the thrust force received by the joint from the fluid flowing through the piping.

13. A placement step involves positioning a precast block, which will absorb the thrust force received by the fitting from the fluid present inside the piping including the fitting, by bringing it into contact with the outside of the fitting. A fixing step for fixing the placed precast blocks, A method for arranging precast blocks, including the method described above.

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