Manhole joint structure and construction method

Abstract

To provide a joint structure of a manhole capable of suppressing an amount of opening by using a joint structure while allowing an opening between end faces, and to provide a construction method.SOLUTION: A flexible joint structure of a manhole 1 is provided between upper and lower cylindrical bodies 2, 2 stacked in a vertical direction. A joint material 35 made of an elastic material with elasticity is provided between a lower end face 3 and an upper end face 4 which are end faces of the upper and lower cylindrical bodies 2, 2, the joint material 35 is bonded to the lower end face 3 and the upper end face 4 of the upper and lower cylindrical bodies 2, 2, and the joint material 35 is configured to suppress displacement between the lower end face 3 and the upper end face 4. Therefore, when an opening force is applied between the end faces of the upper and lower cylindrical bodies 2, 2 due to an earthquake or the like, the joint material 35 made of an elastic material stretches while allowing opening and the opening force equivalent to a force required for this stretching is absorbed, thereby an amount of opening is suppressed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a manhole joint structure in which cylindrical bodies are overlapped, and a construction method thereof. [Background technology]

[0002] Conventionally, as this type of joint structure, a flexible joint device that is expandable and contractible is provided at the joint portion of the cylindrical body to absorb the displacement of the cylindrical body (for example, FIG. 12 of Patent Document 1).

[0003] The joints between the cylindrical bodies can be a source of water leakage, so it is better to have as few joints as possible. However, reducing the number of joints increases the size of the openings between the cylindrical bodies, and there is a limit to the size of the openings that can be accommodated when using elastic sealing materials at the joints to ensure watertightness and flexibility.

[0004] Furthermore, the amount of opening increases as the outer diameter of the manhole increases, even at the same bending angle, so the larger the diameter of the manhole, the greater the flexibility required of the joint.

[0005] 17 and 18 are schematic explanatory diagrams corresponding to Fig. 12 of Patent Document 1. As shown in the figures, an expandable flexible joint device 102 is provided across the overlapping portion of upper and lower cylindrical bodies 101, 101, and when the upper and lower cylindrical bodies tilt relative to each other due to an earthquake or the like, gaps occur at the overlapping portion as shown in Fig. 17, and groundwater pressure is applied to the flexible joint device 102 from the outside, causing it to bend inward, and when the earthquake ends, as shown in Fig. 18, bent portion 102A of the flexible joint device 102 is pinched in the overlapping portion, which causes a problem of a deterioration in the watertight performance of the flexible joint device 102.

[0006] To solve this problem, there is a manhole joint structure (for example, Patent Document 2) in which an elastic cylindrical body that can expand and contract in the vertical direction is provided across the overlapping part of stacked cylindrical bodies, and an intrusion prevention member that prevents the elastic cylindrical body from intruding into the overlapping part is placed on the outer periphery of the upper and lower cylindrical bodies across the overlapping part, and the elastic cylindrical body is placed on the outer periphery of the intrusion prevention member, and upper and lower mounting parts of the elastic cylindrical body are attached to the upper and lower cylindrical bodies.

[0007] In the manhole joint structure of Patent Document 2, when an earthquake force or the like is applied, the overlapping parts of the cylindrical bodies open, absorbing the force of the earthquake and preventing cracks from occurring in the cylindrical bodies. Furthermore, when the overlapping parts of the cylindrical bodies open, the elastic cylindrical body stretches in the vertical direction, and even in this state, groundwater pressure is applied to the elastic cylindrical body, but the intrusion prevention material prevents the elastic cylindrical body from being pinched by the open overlapping parts, and it can return to its previous state after the earthquake ends.

[0008] However, this type of manhole has the problem that if construction space cannot be secured to avoid existing underground buried objects, the conventional deep-deep type, which requires outside work, cannot be used.

[0009] That is, in Patent Document 1, after the upper and lower cylindrical bodies 101, 101 are stacked inside the shaft, workers inside the shaft must attach an expandable flexible joint device from the outside of the cylindrical bodies, and in Patent Document 2, workers inside the shaft must attach an intrusion prevention member and an elastic cylindrical body to the cylindrical bodies from the outside of the cylindrical bodies, and in order to ensure construction space outside the cylindrical bodies, the shaft must be made larger, making construction difficult at sites where construction space is required.

[0010] Furthermore, when the joint opening becomes large, such as when the lower part of the manhole enters the base layer, conventional displacement limiters that are different from those disclosed in Patent Documents 1 and 2, which allow for the opening, may not be able to provide satisfactory earthquake resistance.

[0011] Therefore, there was a need to develop a waterproof joint structure so that manholes could be used in sites where construction space was not available and the openings were large. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-56462 [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-113882 Summary of the Invention [Problem to be solved by the invention]

[0013] The problem to be solved is to provide a manhole joint structure and construction method that can suppress the amount of opening by using a joint structure while allowing an opening between the end faces. [Means for solving the problem]

[0014] The invention of claim 1 is 、 In a flexible manhole joint structure provided between upper and lower cylindrical bodies stacked in the vertical direction, between the end faces of the upper and lower cylindrical bodies, A filling space is formed in the cylindrical body, the filling space being open to the inner peripheral surface of the cylindrical body. A joint material made of an elastic material having elasticity is provided, The dumbbell-shaped No. 3 test piece obtained after the hardening and curing period of the joint material has passed at 23°C for 28 days has a tensile strength of 0.49 MPa or more, measured in accordance with JIS K6251 at a test temperature of 23°C, a tensile speed of 500 mm / min, and the joint material has a breaking elongation of 400% or more, measured in accordance with JIS K6251 at a test temperature of 23°C, a hardening and curing period of 28 days at 23°C, a tensile speed of 500 mm / min, and the filling space has a vertical width of 20 mm or more and 30 mm or less, a depth of 15 mm or more and 30 mm or less, and the filling space has a thickness of 10 mm or more and 15 mm or less. The joint material is bonded to the end faces of the upper and lower cylindrical bodies, and is configured to suppress displacement between the end faces.

[0015] In the invention of claim 2, a groove is provided on at least one of the end surfaces of the upper and lower cylindrical bodies. At the same time, the filling space is formed in the groove, and the filling space The joint material is provided.

[0016] The invention of claim 3 is characterized in that a socket portion is provided on one end face of the upper and lower cylindrical bodies, and an insertion portion for insertion into the socket portion is provided on the other end face.

[0017] The invention of claim 4 is characterized in that a waterproofing member is provided between the insertion portion and the receiving portion, and this waterproofing member is provided closer to the outer peripheral surface of the cylindrical body than the joint material.

[0018] The invention of claim 5 is as follows: received It is characterized by its downward-facing mouth.

[0019] Furthermore, the invention of claim 6 is characterized in that, in a construction method for providing a manhole joint structure as described in claim 1, after the upper and lower cylindrical bodies are overlapped, the joint material is provided between the end faces of the upper and lower cylindrical bodies from the inside of the cylindrical bodies. [Effects of the Invention]

[0020] According to the configuration of claim 1, when a force is applied to open the end faces of the upper and lower cylindrical bodies due to an earthquake or the like, the joint material made of an elastic body stretches to allow the opening, and the opening force is absorbed by the amount of force required for this stretching, thereby suppressing the amount of opening.

[0021] Furthermore, according to the configuration of claim 2, filling space By providing a joint material, the end faces of the upper and lower cylinders can be bonded with the joint material. filling space The vertical length of the joint material can be secured by the vertical dimension of the above.

[0022] Furthermore, according to the configuration of claim 3, by inserting the insertion portion into the receiving portion to connect the upper and lower cylindrical bodies, work outside the cylindrical body is not required, and the size of the shaft can be reduced.

[0023] Furthermore, according to the configuration of claim 4, the water blocking member can prevent water from entering the cylindrical body.

[0024] Furthermore, according to the configuration of claim 5, it is possible to prevent the intrusion of earth and sand from the outside.

[0025] Furthermore, according to the configuration of claim 6, work outside the cylindrical body becomes unnecessary. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a cross-sectional view showing a first embodiment of the present invention. [Figure 2] FIG. 10 is an enlarged cross-sectional view of the groove portion and its surroundings. [Figure 3] FIG. 10 is a cross-sectional view of the waterproof packing. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. 10 is a cross-sectional view of the same at maximum extraction. [Figure 7] FIG. 4 is a cross-sectional view showing a second embodiment of the present invention. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 10 is a cross-sectional view of the same at maximum extraction. [Figure 11] 10 is an explanatory diagram showing the same as above, in which the left half shows the top surface of the cylinder and the right half shows the bottom surface of the cylinder. [Figure 12] FIG. 10 is a cross-sectional view showing a third embodiment of the present invention. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. 10 is a cross-sectional view of the same at maximum extraction. [Figure 16] FIG. 10 is an enlarged cross-sectional view of the periphery of a filling space showing a fourth embodiment of the present invention. [Figure 17] FIG. 10 is a cross-sectional view showing a conventional example in which the overlapping portion is open. [Figure 18] FIG. 10 is a cross-sectional view of the same as above, showing the state in which the overlapping portions are closed after being opened. DETAILED DESCRIPTION OF THE INVENTION

[0027] Preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following examples do not limit the scope of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential requirements for the present invention. [Example]

[0028] 1 to 6 show Example 1, in which the manhole 1 is an assembly-type manhole in which a plurality of cylindrical bodies 2, 2..., which are cylindrical blocks, are assembled one above the other, and the cylindrical bodies 2 are made of precast concrete or the like. The diameter (inner diameter) of the cylindrical bodies 2 is, for example, about 2000 to 3500 mm. The manhole 1 is buried underground and is subjected to earth pressure. In this example, the cylindrical bodies 2 are one piece that is circumferentially integrated.

[0029] The upper and lower cylindrical bodies 2, 2 are stacked in the vertical direction, and a joint portion 5 is provided between the lower end surface 3 and the upper end surface 4, which are the end surfaces of the upper and lower cylindrical bodies 2, 2. A sheet-like cushioning material 6 is placed in this joint portion 5, and this cushioning material 6 is fixed by an adhesive layer 7 (Fig. 2) where adhesive is applied to the upper end surface 4. The joint portion 5 is where the lower end surface 3 and the upper end surface 4 overlap. In this example, the lower end surface 3 and the upper end surface 4 are formed as flat surfaces.

[0030] The joint structure is as follows: In this example, one end 12 of a collar 11 made of a steel pipe is fixed to the lower end of the upper cylindrical body 2, and a socket portion 13 is formed by the portion of the collar 11 that protrudes downward from the lower end surface 3.

[0031] A plurality of steel bolts 14 serving as anchors are provided on the inner peripheral surface of one end side 12 of the collar 11, protruding toward the center of the cylindrical body 2, and reinforcing bars 15, 15 serving as anchors are fixed above and below the bolts 14. When the cylindrical body 2 is molded, the steel bolts 14 and reinforcing bars 15, 15 are integrated into the cylindrical body 2 by inserts, thereby attaching the collar 11 to the cylindrical body 2. The collar 11 is fixed to the cylindrical body 2 so that the outer peripheral surface of the collar 11 and the outer peripheral surface 2G of the cylindrical body 2 are flush with each other.

[0032] Furthermore, on the inner surface of one end side 12 of the collar 11, above and below the bolt 14, embedded water-stopping materials 16, 16 made of swelling rubber or the like are provided.

[0033] An insertion port 21 having a smaller diameter than the outer peripheral surface 2G of the central portion is formed at the upper end of the lower cylindrical body 2, and this insertion port 21 is inserted into and connected to the socket portion 13. In addition, a ring-shaped packing mounting groove 22 is formed on the outer peripheral surface of the insertion port 21 on the upper end surface 4 side, and a ring-shaped watertight packing 23 is fixed in this packing mounting groove 22.

[0034] 3, the waterproof packing 23 has notches 25, 25, 25 provided between a plurality of tongue portions 24, 24, 24, 24 whose outer periphery is inclined in the opposite direction to the insertion direction of the insertion port 21, and the plurality of tongue portions 24, 24, 24, 24 are pressed against the inner periphery of the socket 13. In addition, a sponge-based packing material 26 is disposed between the inner periphery of the tip side of the socket 13 and the outer periphery of the insertion port 21, and this packing material 26 is an intrusion prevention material that prevents the intrusion of soil and sand from the outside.

[0035] Figure 4 shows the extraction of "earthquake motion level 1," with the gap between the bottom end surface 3 and the cushioning material 6 being 20 mm, Figure 5 shows the extraction of "earthquake motion level 2," with the gap between the bottom end surface 3 and the cushioning material 6 being 70 mm, and Figure 6 shows the maximum extraction, with the gap being 140 mm and the length L of the insertion opening 21 being 180 mm, for example. Note that "earthquake motion level 1" assumes seismic waves normalized at 25 kine (cm / s) or more, and "earthquake motion level 2" assumes seismic waves normalized at 50 kine or more, with kine being a unit of measurement for the magnitude of an earthquake and indicating how many centimeters the structure displaces per second.

[0036] An annular groove 31 is formed in at least one of the lower end surface 3 and the upper end surface 4. The groove 31 opens to the inner circumferential surface 2U of the cylindrical body 2 and has a groove bottom 32 parallel to and facing the other lower end surface 3, and a tapered groove inner circumferential surface 33 that widens from the groove bottom 32 toward the upper end surface 4. A joint material 35 is filled in the groove 31 using a filling device such as a caulking gun. The joint material 35 hardens over time and has high elasticity with a predetermined elastic recovery force and high adhesiveness. An anti-adhesion material 36, such as a backup material or bond breaker, is provided on the groove inner circumferential surface 33 to prevent adhesion of the joint material 35. Although the joint material 35 has water-tight properties, the water-tightness of the manhole 1 can be ensured by the water-stopping packing 23 alone.

[0037] As shown in FIG. 2 , in this example, the lower end surface 3, the groove bottom surface 32, and the outer peripheral surface 36G of the anti-adhesion material 36 form a ring-shaped filling space 37 of the joint material 35. The vertical width W of this filling space 37 is 30 mm or less, and the depth D of the filling space 37 is 30 mm or less. When the vertical width W is 30 mm, the vertical width of the groove portion 31 is reduced to less than 30 mm by the thickness of the cushioning material 6 after laying. The vertical width W and depth D are determined so that the highly elastic joint material 35 can suppress displacement between the cylindrical bodies 2, 2, while also taking into consideration the ease of filling the joint material 35. If the filling space 37 were too wide, the filling operation would take a long time or the joint material 35 might drip from the filling space 37 onto the inner surface of the cylindrical body 2. However, by adopting the above dimensions, the filling operation would not be impaired.

[0038] A highly adhesive, highly elastic sealant is used as the joint material 35, such as "Zenistaf Seal" sold by Vertex Construction Co., Ltd. (Kojimachi, Chiyoda-ku, Tokyo). Another highly elastic sealant is "TS Seal" from TS Seal Kogyo Co., Ltd. (Harimayacho, Kochi City, Kochi Prefecture). This "TS Seal" is an elastic material with a three-dimensional network structure formed by the reaction of hydroxyl-terminated liquid polybutadiene with a liquid prepolymer. Another example is "Crazy Rubber" from Sotec Co., Ltd. (Haraki, Ichikawa City, Chiba Prefecture). These sealants are called highly elastic rubber sealants or highly adhesive, highly elastic sealants.

[0039] The "Zenistafseal" is a rubber elastomer whose main component is hydroxyl-terminated polybutadiene, and is used by mixing a base material (base) whose main component is hydroxyl-terminated polybutadiene with a curing agent. The curing agent is mixed at approximately 10% by weight of the base material, and in addition to the base material and curing agent, a primer is used as a solvent as needed. The curing agent contains the isocyanate compound tolylene diisocyanate (TDI), polybutadiene, normal paraffin chloride, and other components.

[0040] The joint material 35 is made of a highly elastic rubber sealing material, and by adopting a joint structure that utilizes the tensile adhesive strength and peel adhesive strength of the highly elastic rubber sealing material, displacement between the stacked upper and lower cylindrical bodies 2, 2 can be effectively suppressed.

[0041] The physical properties of the cured product of "Zenistafseal" are explained in Tables 1 and 2 below.

[0042] [Table 1]

[0043] The test results for Zenistafseal obtained using the test method shown in Table 1 above are shown in Table 2 below. The items, from left to right, are tensile strength (MPa), elongation at break (%), modulus of elasticity (MPa), and hardness (JIS-A). Five tests were conducted for each item, and the average and median values ​​of these five tests are shown.

[0044] The tensile strength (MPa) and elongation at break (%) were measured in accordance with JIS K6251 at a test temperature of 23°C using a 2mm thick dumbbell-shaped No. 3 specimen of "Zenistafseal" that had been cured at 23°C for 28 days. The modulus of elasticity (MPa) and hardness (JIS-A) were measured in accordance with JIS K6253, and the median values ​​were used.

[0045] [Table 2]

[0046] If the tensile strength of the joint material 35 is 0.49 MPa or more, preferably 0.784 MPa or more, the displacement between the upper and lower cylindrical bodies 2, 2 can be effectively suppressed by the joint material 35 with high tensile strength. That is, in JISA5754-1975 (Polysulfide Sealant for Construction) related to joint materials, the sealant should have a tensile adhesive strength of 9.8 N / cm 2 While it is said that the material must pass a tensile strength of at least 0.098 MPa (0.098 MPa), 0.49 MPa is more than five times that of 0.098 MPa, and 0.784 MPa is more than eight times that of 0.098 MPa, resulting in high tensile strength. Its high elasticity prevents displacement between the cylindrical bodies 2, 2 and allows it to absorb applied forces.

[0047] Furthermore, if the joint material 35 has an elongation at break of 400% or more, preferably 500% or more, it will have high elongation and elastic recovery force, effectively suppressing displacement between the upper and lower cylinders 2, 2. In this example, the vertical width W of the filling space 37 is set to 30 mm or less, taking into account the filling properties of the joint material 35. However, if the vertical width W is set to 20 mm, the ratio of 70 mm / 20 mm = 3.5 for the opening size of 70 mm for the aforementioned "earthquake motion level 2." If the elongation at break is 400% or more, the joint material 35 will not break even in "earthquake motion level 2." If the vertical width W of the filling space 37 is set to 15 mm, the ratio of 70 mm / 15 mm = 4.67 for the opening size of 70 mm for the aforementioned "earthquake motion level 2." If the elongation at break is 500% or more, the joint material 35 will not break even in "earthquake motion level 2." Furthermore, construction can be performed within the vertical width of a typical groove-shaped filling space 37, and the filled joint material 35 can suppress displacement between the cylindrical bodies 2, 2 and absorb applied forces.

[0048] Furthermore, since the elastic modulus corresponds to the resistance to deformation of the joint material 35, in other words, the energy required for deformation, if it is 0.609 MPa or more, preferably 0.973 MPa or more, it can effectively suppress displacement between the upper and lower cylindrical bodies 2, 2 and can absorb the energy that occurs when the joints open. Note that these elastic modulus values ​​are calculated by dividing the median elastic modulus (1.39) by the median tensile strength (1.12), and multiplying this by the tensile strength values ​​(0.49) and (0.784).

[0049] In addition, in the joint structure of this embodiment, the length of the insertion port 21 is, for example, 180 mm, which improves flexibility during earthquakes and allows for a 20 mm opening during a level 1 earthquake, a 70 mm opening during a level 2 earthquake, and a 140 mm opening at maximum withdrawal. The 140 mm opening at maximum withdrawal is a length that provides a safety factor twice that of the 70 mm opening during a level 2 earthquake. Furthermore, watertightness is ensured by the ring-shaped waterproof packing 23, which can withstand high water pressures of 0.6 MPa at great depths, and the highly elastic rubber sealing material with excellent elongation capacity prevents localized withdrawal of the joint during an earthquake.

[0050] Next, a construction method for the joint structure will be described. After the lower cylindrical body 2 is installed inside the vertical shaft 41 (Fig. 11) in which the manhole 1 will be constructed, the upper cylindrical body 2 is hung from the ground and the socket portion 13 is fitted over the insertion portion 21 to connect them. In this case, there is no need for workers to enter between the cylindrical body 2 and the vertical shaft 41, and the workers can work inside the cylindrical body 2, so there is no need to make the vertical shaft 41 large for work. Therefore, the cost of excavating the vertical shaft 41 can be significantly reduced.

[0051] After stacking the upper and lower cylindrical bodies 2, 2 in this manner, the grooves 31 are filled with joint material 35, which hardens to bond the lower end surface 3 and the upper end surface 4. In this case, too, the work of filling the joint material 35 can be done inside the cylindrical body 2, thereby improving the safety of the work. The joint material 35 is bonded to the groove bottom surface 32 on the upper end surface 4 side and the lower end surface 3.

[0052] In the manhole 1 constructed in this way, when an earthquake force or the like acts on the manhole 1, causing it to tilt and applying a force that tries to open the joints 5, the joint material 35 stretches, allowing the opening to occur, and also absorbs some of the force that opens the joints 5, making it possible to reduce the amount of opening compared to when there is no joint material 35. In this way, the elastic restoring force of the joint material 35, which could not be obtained with conventional sealing materials alone, can absorb some of the force applied when the joints open, and suppress displacement.

[0053] Furthermore, joining the upper and lower cylindrical bodies 2, 2 does not require special work such as welding or tensioning PC material, and a manhole 1 that is watertight and can be used at great depths can be constructed simply by inserting the insertion portion 21 into the receiving portion 13.

[0054] In this embodiment, in accordance with claim 1, in the joint structure of the manhole 1 having flexibility provided between the upper and lower cylindrical bodies 2, 2 stacked in the vertical direction, between the lower end surface 3 and the upper end surface 4 which are the end surfaces of the upper and lower cylindrical bodies 2, 2, A filling space 37 is formed on the inner circumferential surface 2U of the cylindrical body 2, and in this filling space 37 A joint material 35 made of an elastic material having elasticity is provided, A dumbbell-shaped No. 3 test piece obtained after 28 days of hardening and curing at 23°C was measured in accordance with JIS K6251 at a test temperature of 23°C and a tensile speed of 500 mm / min, and the tensile strength of the joint material 35 was 0.49 MPa or more. The joint material 35 had a breaking elongation of 400% or more when measured in accordance with JIS K6251 at a test temperature of 23°C, a hardening and curing period of 28 days at 23°C and a tensile speed of 500 mm / min. The filling space 37 had a vertical width W of 20 mm or more and a depth D of 15 mm or more and a depth D of 15 mm or more and a thickness of 15 mm or less.The joint material 35 is bonded to the bottom end surface 3 and top end surface 4 of the upper and lower cylindrical bodies 2,2, and is configured to suppress displacement between the bottom end surface 3 and top end surface 4. Therefore, when a force is applied to open the end surfaces of the upper and lower cylindrical bodies 2,2 due to an earthquake or the like, the joint material 35 made of an elastic material stretches to allow the opening to occur, and the opening force is absorbed by the amount of force required for this stretching, thereby suppressing the amount of opening. In this way, the upper and lower cylindrical bodies 2,2 are bonded together via the joint material 35 made of an elastic material, which absorbs energy and suppresses displacement.

[0055] In this embodiment, the groove 31 is provided on at least one of the lower end surface 3 and the upper end surface 4 of the upper and lower cylindrical bodies 2, 2, corresponding to claim 2. At the same time, a filling space 37 is formed in the groove portion 31. Since a joint material 35 is provided at the bottom, the lower end surface 3 and the upper end surface 4 of the upper and lower cylindrical bodies 2, 2 can be bonded with the joint material 35, and the vertical length of the joint material 35 can be secured by the vertical dimension of the groove portion 31.

[0056] In this embodiment, in accordance with claim 3, a receiving portion 13 is provided on the lower end surface 3, which is one end surface of the upper and lower cylindrical bodies 2, 2, and an insertion portion 21 to be inserted into the receiving portion 13 is provided on the upper end surface 4, which is the other end surface.Therefore, by inserting the insertion portion 21 into the receiving portion 13 to connect the upper and lower cylindrical bodies 2, 2, work outside the cylindrical body 2 is not required and the size of the vertical shaft 41 can be reduced.

[0057] In this embodiment, in accordance with claim 4, a water-stopping member, a water-stopping gasket 23, is provided between the insertion port 21 and the receiving port 13, and this water-stopping gasket 23 is provided closer to the outer surface of the cylindrical body 2 than the joint material 35, thereby preventing water from entering from the outside.

[0058] In this way, in this embodiment, corresponding to claim 5, received Mouth 13 Since the bottom is facing downward, it is possible to prevent soil and sand from entering from the outside.

[0059] In this way, in this embodiment, corresponding to claim 6, in the construction method for providing the joint structure of the manhole 1 described in claim 1, after the upper and lower cylindrical bodies 2, 2 are overlapped, a joint material 35 is provided from the inside of the cylindrical body 2 between the lower end surface 3 and the upper end surface 4, which are the end surfaces of the upper and lower cylindrical bodies 2, 2, so that work on the outside of the cylindrical body 2 is not required.

[0060] As an effect of the embodiment, the groove inner peripheral surface 33 of the groove 31 is provided with an anti-adhesion material 36 to prevent the joint material 35 from adhering, so that the joint material 35 can be adhered only to the lower end surface 3 and the upper end surface 4. Furthermore, since the joint material 35 is provided in an annular shape in the annular groove 31, it can be adhered uniformly in the circumferential direction.

[0061] Furthermore, the inner diameter of the cylindrical body 2 is, for example, 2000 to 3500 mm, and in the past, it was necessary to leave a distance of about 800 mm between the cylindrical body and the shaft to ensure working space, and it was necessary to provide a shaft 41 that was about 1600 mm larger than the outer diameter of the cylindrical body. However, in this embodiment, the distance between the cylindrical body 2 and the shaft 41 is sufficient to be about 150 mm or less, and construction can be carried out using a shaft 41 that is about 300 mm larger than the outer diameter of the cylindrical body 2. In this way, by having the inner diameter of the cylindrical body 2 be 2000 to 3500 mm and joining the cylindrical bodies 2, 2 together using the receiving portion 13 and the insertion portion 21, the distance between the outer surface 2G of the cylindrical body 2 and the shaft can be 150 mm or less; in other words, the difference between the outer diameter of the cylindrical body 2 and the diameter of the shaft can be 300 mm or less.As a result, when constructing the manhole 1, the area of ​​road occupied on the ground can be reduced, the working radius of the construction crane can be made smaller, the amount of soil discharged can be reduced, and the amount of backfill soil (earth and sand, improved soil, etc.) can be reduced.

[0062] Furthermore, the length L of the insertion portion 21 is 140 mm, which is 105 mm or more, which is 1.5 times the mesh opening amount of 70 mm during a level 2 earthquake, and preferably 180 mm, which is 140 mm or more, which is twice that amount, so that a mesh opening amount that can be adapted to an earthquake can be ensured.

[0063] Furthermore, if a dumbbell-shaped No. 3 test piece obtained after 28 days of hardening and curing at 23°C is subjected to measurement in accordance with JIS K6251 at a test temperature of 23°C and a tensile speed of 500 mm / min, and the tensile strength is 0.49 MPa or more, preferably 0.784 MPa or more, the high elasticity of the joint material 35 can effectively suppress displacement between the upper and lower cylindrical bodies 2, 2.

[0064] Furthermore, the joint material 35 has an elongation at break of 400% or more, preferably 500% or more, measured in accordance with JIS K6251 at a test temperature of 23°C, a hardening curing period of 28 days at 23°C, and a tensile speed of 500 mm / min, so that it has high elongation and elastic recovery force and can effectively suppress displacement between the upper and lower cylindrical bodies 2, 2.

[0065] Furthermore, the vertical dimension of the filling space 37 is set to 15 mm or more and 30 mm or less, and the elongation at break of the joint material 35 is set to 500% or more, preferably the vertical dimension of the filling space 37 is set to 20 mm or more and 30 mm or less, and the elongation at break of the joint material 35 is set to 400% or more, so that the joint material 35 does not break even with a mesh opening of 70 mm at "earthquake motion level 2," can be tolerated, and filling workability can be improved. In this case, taking into account the filling workability of the joint material 35, it is preferable that the depth D is set to 15 mm or more and 30 mm or less. [Example]

[0066] Figures 7 to 11 show a second embodiment of the present invention, in which the same parts as those in the first embodiment are given the same reference numerals and their explanations are omitted. In this example, the cylindrical body 2 is divided in the circumferential direction, and the divided cylindrical bodies 2B, 2B are assembled and used on-site.

[0067] The collar 11, which is made of a steel pipe, has an inner flange 51 formed on the inner circumference of the center side, and this inner flange 51 is made of a ring-shaped steel plate.The inner flange 51 is formed integrally with the collar 11 so that the length from the position of the inner flange 51 to one end of the collar 11 is longer than the length from the inner flange 51 to the other end of the collar 11.

[0068] One end of the collar 11 is the socket portion 13, into which the end of one of the upper and lower cylindrical bodies 2 is inserted and connected, and the other end of the collar 11 is fixed to the end of the other of the upper and lower cylindrical bodies 2, and in this example, the other end, or lower end side 11K, of the collar 11 is fixed to the upper end of the lower cylindrical body 2. The inner peripheral surface at the tip of the socket portion 13 is provided with an oblique chamfered portion 13A, and the inner peripheral surface at the tip of the lower end side 11K of the collar 11 is also provided with an oblique chamfered portion 13A.

[0069] The collar 11 with the integral inner flange 51 is divided in the circumferential direction, and for example, the two divided collars 11B, 11B are assembled on-site by welding or the like for use. This allows even large diameter collars that cannot be transported as a single unit to be transported to the site and assembled for installation.

[0070] 11, examples of the connection structure for the circumferential end faces of the split cylindrical bodies 2B, 2B obtained by dividing the cylindrical body 2 into two include adhesive, mechanical connection, and a combination of adhesive and mechanical connection. The mechanical connection structure uses bolt connections or cotter joint fittings 42. When rigidly connecting the circumferential end faces of the split cylindrical bodies 2B, 2B, the rigid connection can be made using a means having a connection strength greater than or equal to the concrete strength of the cylindrical body 2.

[0071] The insertion port 21, which has a smaller diameter than the outer peripheral surface 2G of the central portion, is formed at the lower end of the upper cylindrical body 2, and this insertion port 21 is inserted into and connected to the receiving port 13. The outer peripheral surface of the insertion port 21 has the packing mounting groove 22 formed in an annular shape on the lower end surface 3 side, and the watertight packing 23 is fixed in this packing mounting groove 22.

[0072] At the upper end of the lower cylindrical body 2, a small diameter section 52 having a smaller diameter than the outer peripheral surface 2G at the center side is formed, and the gasket mounting groove 22 is formed on the outer peripheral surface at the tip side (upper end side) of this small diameter section 52, and a watertight gasket 23 is fixed in this gasket mounting groove 22.

[0073] A nut body 53 is provided on the upper end surface 4 of the lower cylindrical body 2 by insert molding, and the small diameter portion 52 of the lower cylindrical body 2 is attached to the lower end side 11 of the collar 11. K With the inner flange 51 overlapping the upper end surface 4, a fixing bolt 54 inserted through the inner flange 51 is screwed into the nut body 53, thereby fixing the collar 11 to the upper end surface 4 of the lower cylindrical body 2. After applying adhesive 55 to the upper end surface 4, the inner flange 51 is overlapped and adhered. The cushioning material 6 is attached to the upper surface of the inner flange 51 by adhesion or the like.

[0074] The upper end surface 4, which is at least one of the lower end surface 3 and the upper end surface 4, is provided with the grooves 31, and the grooves 31 are filled with a joint material 35.

[0075] Next, a method for constructing the joint structure will be described. Two divided cylindrical bodies 2B, 2B are assembled on-site to form the cylindrical body 2, two divided collars 11B, 11B are assembled on-site to form the collar 11, and the collar 11 is attached to the cylindrical body 2.

[0076] After the lower cylindrical body 2 is installed in the vertical shaft 41 where the manhole 1 is constructed, the upper cylindrical body 2 is hung down from the ground, and the insertion portion 21 is fitted into the socket portion 13 to connect them, and after the connection, the groove portion 31 is filled with a joint material 35.

[0077] In this way, this embodiment also provides the same effects as those of the above-described embodiment 1. Furthermore, in this embodiment, by dividing the cylindrical body 2 and the collar 11, construction can be performed using a cylindrical body 2 with a large diameter. [Example]

[0078] Figures 12 to 15 show a third embodiment of the present invention, in which the same parts as those in the above-mentioned embodiments are given the same symbols and their explanations are omitted. In this example, the upper and lower cylindrical bodies 2, 2 are connected by stacking without using collars.

[0079] The lower end of the upper cylinder 2, one of the upper and lower cylinders 2, 2, is provided with a receiving portion 61 having an inner peripheral surface 61U and a bottom surface 61T which is the inner end surface, and the upper end of the lower cylinder 2, the other, is provided with an insertion portion 62 having an outer peripheral surface 62G and a bottom surface 62T which is the outer end surface.

[0080] An inner peripheral surface 61U of the socket portion 61 has a larger diameter than an inner peripheral surface 2U on the central side of the cylindrical body 2, and an outer peripheral surface 62G of the insertion portion 62 has a smaller diameter than the outer peripheral surface 2G on the central side of the cylindrical body 2, and the outer peripheral surface 62G is formed to be slightly smaller than the inner peripheral surface 61U. In addition, the radial thicknesses of the tip sides of the socket portion 61 and the insertion portion 62 are approximately the same and are approximately half the thickness of the cylindrical body 2.

[0081] The packing mounting groove 22 is formed on the tip side of the outer peripheral surface 62G, and a watertight packing 23 is fixed in this packing mounting groove 22.

[0082] The groove 31 is provided in at least one of the bottom surface 61T serving as an end surface and the end surface 62S of the insertion port 62 serving as an end surface, and the groove 31 is filled with a joint material 35.

[0083] The cushioning material 6 is attached to the bottom surface 62T of the insertion portion 62 by adhesive or the like. In this example, the joint portion 5 is provided between the tip surface 61S of the receiving portion 61 and the bottom surface 62T of the insertion portion 62, and the joint portion 5 is provided between the bottom surface 61T of the receiving portion 61 and the tip surface 62S of the insertion portion 62.

[0084] In this way, this embodiment also provides the same effects as the above-described embodiments. [Example]

[0085] FIG. 16 shows a fourth embodiment of the present invention, in which the same parts as those in the above-described embodiments are given the same reference numerals and their explanations are omitted. In this embodiment, a joint material 35 is provided without providing a groove portion.

[0086] As shown in the figure, an annular spacer 71 is provided between the lower end face 3 and the upper end face 4, and the anti-adhesion material 36 is provided on the inner peripheral surface 72 of this spacer 71. Then, the joint material 35 is filled into the filling space 73 formed by the lower end face 3, the upper end face 4, and the inner peripheral surface 72 of the spacer 71, and the joint material 35 is adhered to the lower end face 3 and the upper end face 4. Before filling the joint material 35, the anti-adhesion material 36 is provided on the inner peripheral surface 72.

[0087] In this way, the spacer 71 forms the filling space 73, and the thickness of the spacer 71 determines the vertical dimension of the joint material 35, so that the vertical dimension of the joint material 35 can be set according to the opening amount, which varies depending on the height position of the manhole 1. Note that the vertical width W and depth D of the filling space 73 shown in Fig. 16 can also be set in the same way as the filling space 37 of Example 1.

[0088] In this way, this embodiment also provides the same functions and effects as the above-described embodiments.

[0089] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention. For example, in the embodiment, the groove is provided on the inner peripheral surface of the end face of the cylindrical body. Ta. Furthermore, grooves may be provided in a continuous manner on both end surfaces of the upper and lower cylinders, and the joint material may be filled into both grooves. Furthermore, while the manhole has been described with an example of a cylindrical body having a flat circular shape, the cylinder may also have a flat rectangular shape. In the examples, the cylinder is divided into two parts, but it may be divided into three or more parts. Furthermore, while the manhole has been described with an example of a cylindrical body having a flat circular shape, the cylinder may also have a flat rectangular shape. Furthermore, when a groove is provided on the lower end surface, which is one of the lower and upper end surfaces, a ring-shaped filling space of the joint material is formed by the upper end surface, which is the other of the lower and upper end surfaces, the groove bottom of the groove on the lower end surface, and the outer peripheral surface of the anti-adhesion material. Furthermore, when grooves are provided on both the lower and upper end surfaces, a ring-shaped filling space of the joint material is formed by the groove bottom of the groove on the lower end surface, the groove bottom of the groove on the upper end surface, and the outer peripheral surface of the anti-adhesion material. [Explanation of symbols]

[0090] 1 manhole 2 cylinders 2U inner surface 3 Lower end face (end face) 4 Upper end surface (end surface) 5 Joint 13 Receptacle 21 Insertion port 23 Water-stopping packing (water-stopping material) 31 Groove 35 Joint sealant 37 Filling space 61 Receptacle 62 Insertion port W vertical width D Depth

Claims

1. A flexible manhole joint structure provided between upper and lower cylindrical bodies stacked in the vertical direction, A filling space is formed between the end faces of the upper and lower cylindrical bodies, the filling space being open to the inner peripheral surface of the cylindrical body, and a joint material made of an elastic body having elasticity is provided in the filling space, The joint sealant was cured at 23°C for 28 days, and the dumbbell-shaped No. 3 test piece obtained was measured in accordance with JIS K6251 at a test temperature of 23°C and a tensile speed of 500 mm / min. The tensile strength was 0.49 MPa or more. The joint material has an elongation at break of 400% or more when measured in accordance with JIS K6251 at a test temperature of 23°C, a hardening curing period of 28 days at 23°C, and a tensile speed of 500 mm / min. The vertical width of the filling space is 20 mm or more and 30 mm or less, and the depth of the filling space is 15 mm or more and 30 mm or less, A manhole joint structure characterized in that the joint material in the filling space is adhered to the end faces of the upper and lower cylindrical bodies, and the joint material is configured to suppress displacement between the end faces.

2. A manhole joint structure as described in claim 1, characterized in that a groove portion is provided on at least one of the end faces of the upper and lower cylindrical bodies, the filling space is formed in the groove portion, and the joint material is provided in this filling space.

3. A manhole joint structure as described in claim 1 or 2, characterized in that a receiving portion is provided on one end face of the upper and lower cylindrical bodies, and an insertion portion for insertion into the receiving portion is provided on the other end face.

4. 4. A manhole joint structure according to claim 3, wherein a water-stopping member is provided between the insertion portion and the receiving portion, and the water-stopping member is provided closer to the outer peripheral surface of the cylindrical body than the joint material.

5. 4. A manhole joint structure according to claim 3, wherein the socket portion faces downward.

6. 2. The method for installing the manhole joint structure according to claim 1, A construction method for a manhole joint structure, characterized in that after the upper and lower cylindrical bodies are overlapped, the joint material is provided between the end faces of the upper and lower cylindrical bodies from the inside of the cylindrical bodies.

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