Watertight test method

Abstract

To provide a watertight test method with which water-tightness at a joint part of a tubular structure can be evaluated even when water pressure is increased.SOLUTION: A watertight test method according to the present invention is carried out at a joint part obtained by inserting an end of one tubular structure into an end of the other tubular structure to join the tubular structures to each other, and the watertight test method includes: a filling step in which a pair of seal materials are attached to the end of the one tubular structure along an outer periphery, at least two holes penetrating in a thickness direction are provided between the pair of seal materials, the at least two holes include at least one injection hole for injecting water and at least one exhaust hole for exhausting air, and water is injected from the injection hole and air is exhausted from the exhaust hole to fill the space between the pair of seal materials with water; and a pressurization step in which the exhaust hole is sealed and water is further injected from the injection hole to apply predetermined pressure, and thereby the presence or absence of water leakage is determined.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a watertightness test method. [Background technology]

[0002] Precast concrete tubular structures are connected and buried underground to form conduits for electric wires, gas pipes, water and sewerage pipes, communication wiring, etc. Known tubular structures include Hume pipes with a circular cross section and box culverts with a rectangular cross section.

[0003] Conventionally, in tubular structures buried underground, for example, watertightness at the joints of the tubular structures has been an important issue in order to prevent the intrusion of groundwater from the outside. Non-Patent Document 1 discloses a method for testing the watertightness of joints in Hume pipes, in which a device is joined to the outer periphery of the Hume pipe so as to cover the joints, and then the joints are sealed with water from the outside and a specified water pressure is applied to check for the presence or absence of water leakage. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Reinforced Concrete Pipes for Sewerage Jacking Method" by Takayoshi Yamaguchi, published by the Japan Sewage Works Association on July 17, 2018 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for box culverts, in particular, to be buried relatively deep underground, and they are required to be able to withstand higher water pressure. However, when the watertightness test method of Non-Patent Document 1 is applied to a box culvert, when the water pressure is increased (for example, 0.1 MPa), water leaks from the equipment joined to the outer periphery before leaking from the joints, and the watertightness of the joints cannot be accurately evaluated. Therefore, there is a demand for the development of a test method that, when applied to a box culvert, can evaluate the watertightness of the joints even when the water pressure is increased.

[0006] In view of the current situation, an object of the present invention is to provide a watertightness testing method that is capable of evaluating the watertightness of joints in tubular structures even when water pressure is increased. [Means for solving the problem]

[0007] The watertightness testing method of the present invention is a watertightness testing method for a joint portion joined by inserting the end of one tubular structure into the end of the other tubular structure, wherein a pair of sealing materials is attached along the outer circumference of the end of one of the tubular structures, and at least two holes penetrating in the thickness direction are provided between the pair of sealing materials, and the at least two holes are composed of at least one injection hole for injecting water and at least one discharge hole for discharging air, and the method includes a filling process of injecting water from the injection hole and discharging air from the discharge hole to fill the space between the pair of sealing materials with water, and a pressurizing process of sealing the discharge hole and injecting further water from the injection hole, applying a predetermined water pressure, and determining whether or not there is a water leak.

[0008] The watertightness testing method involves injecting water through an injection hole provided between a pair of sealing materials, filling the space between the pair of sealing materials with water, and then injecting further water to apply a predetermined water pressure, making it possible to evaluate the watertightness of the joint of a tubular structure even when the water pressure is increased. Effect of the Invention

[0009] As described above, according to the present invention, a watertightness testing method can be provided that is capable of evaluating the watertightness of joints in tubular structures even when water pressure is increased. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a partial cross-sectional view taken along the axis of one end of a tubular structure 1 used in a watertightness test method according to this embodiment. [Diagram 2] FIG. 2 is a partial cross-sectional view taken along the axis of a joint 2 for carrying out a watertightness test method according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a watertightness test method according to an embodiment of the present invention will be described. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated.

[0012] The watertightness test method according to this embodiment is a method for testing watertightness at a joint 2 formed by inserting an end of one tubular structure 1 into an end of another tubular structure 1'.

[0013] The tubular structures 1, 1' are composed of a tubular main body 11 made of concrete formed around an axis extending in one direction, and an outer steel plate 12 formed so as to cover the outer circumferential surface of the tubular main body 11. The tubular structures 1, 1' may be Hume pipes whose outer and inner circumferential shapes in a cross section intersecting the axis are circular, or may be rectangular box culverts.

[0014] First, one tubular structure 1 will be described. Fig. 1 is a partial cross-sectional view along the axis of the end of one tubular structure 1 used in the watertightness test method according to this embodiment. As shown in Fig. 1, at the end of the tubular structure 1, the outer shell steel plate 12 has a reduced diameter portion 121 formed by reducing the diameter of the outer shell steel plate 12, and this reduced diameter portion 121 is configured to be insertable into the end of the other tubular structure 1'.

[0015] At the end of the tubular structure 1, two pairs of protrusions 13 are formed along the outer periphery on the outer periphery of the reduced diameter portion 121 of the outer shell steel plate 12. A sealing material 3, which will be described later, is attached between the pair of protrusions 13, thereby suppressing the axial positional displacement of the sealing material 3.

[0016] A pair of sealing materials 3 is attached to the end of one of the tubular structures 1 along the outer periphery. More specifically, a pair of sealing materials 3 is attached to the outer periphery of the reduced diameter portion 121 of the outer shell steel plate 12 at the end of the tubular structure 1. The pair of sealing materials 3 are both joint rubber rings 31, 32. The joint rubber rings 31, 32 are arranged to face each other. More specifically, the joint rubber ring 31 arranged on the end edge side of the tubular structure 1 is attached in a direction in which it will be attached when actually buried in the ground, and the other joint rubber ring 32 is attached in a direction opposite to that of the joint rubber ring 31. By attaching the joint rubber rings 31, 32 in this manner, it is possible to evaluate the watertightness against the water pressure (external water pressure) applied from the outside when buried in the ground for use.

[0017] In addition, the rubber rings that can be used for the joints are those specified in Appendix 1 of "W Joint Pipe (N Type) for Jacking Construction Method" published by the National W Joint Pipe Association (October 1, 2020).

[0018] Between the pair of sealing materials 3, two holes 4, 4 are provided penetrating the tubular structure 1 in the thickness direction. One of the two holes 4, 4 is an injection hole 41 for injecting water, and the other is a discharge hole 42 (not shown) for discharging air, and the two holes 4, 4 are provided at positions opposite to each other in the circumferential direction. That is, the two holes 4, 4 are provided at positions symmetrical (approximately 180°) about the axis in a cross section intersecting the axis. A water pressure pump (not shown) is connected to the injection hole 41 from the inner periphery side of the tubular structure 1, and water can be injected at a predetermined water pressure. In addition, a valve (not shown) is provided in the discharge hole 42, and the discharge hole 42 is configured to be sealable. The two holes 4, 4 are water stop agent injection holes. That is, a hole provided in the tubular structure 1 as a water stop agent injection hole is used as the injection hole 41 or the discharge hole 42.

[0019] Next, the joint 2 will be described. FIG. 2 is a partial cross-sectional view along the axis of the joint 2 in which the watertightness test method according to the present embodiment is performed. As shown in FIG. 2, in the joint 2, the end of one tubular structure 1 is inserted into the end of the other tubular structure 1' to be joined. More specifically, at the end of the other tubular structure 1', the outer shell steel plate 12 has an outer peripheral covering portion 122 that covers the outer peripheral surface of the tubular main body portion 11 over the entire circumference, and a tubular protruding portion 123 that protrudes from the end of the outer peripheral covering portion 122 in the direction of the axis, and is joined by inserting the reduced diameter portion 121 at the end of the tubular structure 1 into the tubular protruding portion 123 at the end of the other tubular structure 1'. Note that the tubular structures 1, 1' each have the reduced diameter portion 121 at one end and the tubular protruding portion 123 at the other end, so that they can be connected sequentially.

[0020] The watertightness test method according to this embodiment includes a filling step of filling the space between the pair of sealing materials 3 with water by injecting water through the injection hole 41 and discharging air through the discharge hole 42, and a pressurizing step of sealing the discharge hole 42, injecting more water through the injection hole 41 to apply a predetermined water pressure, and judging the presence or absence of water leakage. In the watertightness test method according to this embodiment, the tubular structures 1, 1' are placed so that the axial direction of the tubular structures 1, 1' is parallel to the mounting surface.

[0021] By configuring the joint portion 2 as described above, in the filling step, water can be injected through the injection hole 41 to fill the space between the pair of sealing materials 3. Then, in the pressurizing step, water can be further injected through the injection hole 41 to apply a predetermined water pressure.

[0022] In the filling step, from the viewpoint of facilitating the discharge of air from the discharge hole 42, it is preferable to arrange the discharge hole 42 at the top and the injection hole 41 at the bottom. At that time, it is determined that the space between the pair of sealing materials 3 is filled with water, for example, when both water and air are discharged from the discharge hole 42 and there is no air pocket.

[0023] In the pressurizing step, the presence or absence of leakage can be determined, for example, by visually observing the outer peripheral surface side or the inner peripheral surface side of the tubular structure 1 for leakage from a pair of sealing materials 3 (joint rubber rings 31, 32). The watertightness test method according to this embodiment can be applied to Hume pipes and box culverts, and the water pressure can be increased until leakage is observed, and tests can be performed even when a water pressure of 0.4 MPa is applied. Note that the watertightness test method according to this embodiment can naturally evaluate the watertightness of the joints of tubular structures even when the water pressure is low.

[0024] The concrete constituting the tubular structures 1, 1' used in the watertightness test method according to this embodiment is obtained by kneading a cement composition containing cement, coarse aggregate, and fine aggregate with water. The cement, coarse aggregate, and fine aggregate are not particularly limited, and conventionally known materials can be used. The cement composition may also contain other materials such as fibrous materials, admixtures, and admixture agents.

[0025] The size of the tubular structure 1,1' used in the watertightness test method according to the present embodiment is not particularly limited. The length of the tubular structure 1,1' along the axis can be, for example, 300 mm or more and 2430 mm or less. When the tubular structure 1,1' is a Hume pipe, the diameter of the outer circumference of the cross section intersecting the axis can be, for example, 960 mm or more and 3500 mm or less, and the diameter of the inner circumference of the cross section intersecting the axis can be, for example, 800 mm or more and 3000 mm or less. When the tubular structure 1,1' is a box culvert, the distance between the opposing outer surfaces of the cross section intersecting the axis can be, for example, 900 mm or more and 3600 mm or less, and the distance between the opposing inner surfaces of the cross section intersecting the axis can be, for example, 600 mm or more and 3000 mm or less.

[0026] The watertightness test method according to this embodiment injects water from an injection hole provided between a pair of seal materials 3 to fill the space between the pair of seal materials 3, which are rubber rings for joints, and further injects water to apply a predetermined water pressure, thereby making it possible to evaluate the watertightness of the joint 2 of the tubular structures 1,1 even when the water pressure is high. Moreover, the watertightness test method does not require attachment of an instrument to the outer periphery of the joint 2, making it possible to easily evaluate the watertightness.

[0027] In the watertightness test method according to this embodiment, the pair of sealing materials 3 are both joint rubber rings 31, 32. The joint rubber ring 31 is attached in the orientation in which it will be attached when actually buried in the ground, and the other joint rubber ring 32 is attached in the opposite orientation to the joint rubber ring 31, so that the watertightness against external pressure of the joint rubber rings 31, 32 of the joint part 2 can be evaluated.

[0028] In the watertightness test method according to the present embodiment, the two holes 4, 4 are waterstop agent injection holes. With this configuration, there is no need to provide a separate hole in the tubular structure 1, and the watertightness can be easily evaluated.

[0029] In the watertightness test method according to this embodiment, two holes 4, 4 penetrating in the thickness direction are provided at circumferentially opposing positions between a pair of sealing materials 3. This configuration makes it easier to exhaust air from the exhaust hole 42, and makes it easier to fill the space between the pair of sealing materials 3 with water.

[0030] Although an embodiment of the present invention has been described above, the watertightness test method according to the present invention is not limited to this embodiment, and various modifications can be made within the scope of the present invention. In addition, it goes without saying that the configurations of the above and following embodiments may be arbitrarily adopted and combined (the configurations of one embodiment may be applied to the configurations of other embodiments). In addition, the watertightness test method according to the present invention is not limited by the above-mentioned effects.

[0031] In the watertightness test method according to the present invention, the joint rubber rings 31, 32 attached to the end of one of the tubular structures 1 may be attached in the orientation in which they are attached when actually buried in the ground. By attaching the joint rubber rings 31, 32 in this manner, the watertightness of the joint rubber ring 31 against the water pressure (external water pressure) applied from the outside when buried in the ground for use can be evaluated, and the watertightness of the joint rubber ring 32 against the water pressure (internal water pressure) applied from the inside when buried in the ground for use can be evaluated.

[0032] In addition, both of the joint rubber rings 31, 32 may be attached in the opposite direction to the direction in which they are attached when actually buried in the ground. By attaching the joint rubber rings 31, 32 in this manner, the watertightness of the joint rubber ring 31 against the water pressure (internal water pressure) applied from the inside when buried in the ground for use can be evaluated, and the watertightness of the joint rubber ring 32 against the water pressure (external water pressure) applied from the outside when buried in the ground for use can be evaluated.

[0033] In the watertightness test method according to the present invention, at least one of the pair of sealing materials 3 may be a rubber ring for joints. In this case, for example, the rubber ring for joints is attached to the end edge side of the tubular structure 1 in the direction in which it will be attached when actually buried in the ground. The other sealing material is not particularly limited as long as it has a water-stopping property that can withstand the water pressure of the watertightness test, but for example, a rubber ring for joints or the like can be used. In addition, as the rubber ring for joints, a rubber ring for joints specified in Appendix 1 of "W-Joint Pipe (N-Type) for Jacking Method" issued by the National W-Joint Pipe Association (October 1, 2020) can be used.

[0034] In one embodiment, one of the pair of sealing materials 3 may be a joint rubber ring and the other a joining rubber ring. In the case of such a configuration, the test is conducted under less favorable conditions than when actually buried underground, so that it is possible to evaluate the watertightness with more consideration given to safety.

[0035] Furthermore, the pair of sealing materials 3 may be rubber seals such as joint rubber rings or joining rubber rings, or may be silicone seals, fluorine seals, methane seals, or the like.

[0036] In the watertightness test method according to the present invention, the two holes 4, 4 do not have to be waterstop agent injection holes. That is, a hole may be formed in the tubular structure 1 separately.

[0037] In the watertightness test method according to the present invention, the two holes 4, 4 (injection hole 41, discharge hole 42) do not have to be provided at opposing positions in the circumferential direction. Specifically, in the case of a Hume pipe having a circular cross section, the discharge hole 42 may be oriented at the 12 o'clock position, and the injection hole 41 may be provided in any direction from 1 o'clock to 11 o'clock. In the case of a box culvert having a rectangular cross section, the surface provided with the discharge hole 42 may be the upper surface, and the injection hole 41 may be provided on any one of the other three surfaces. Three or more holes penetrating in the thickness direction may be provided between the pair of sealing materials 3. Of the three or more holes, at least one hole is an injection hole and at least one hole is a discharge hole.

[0038] In the watertightness test method according to the present invention, the tubular structures 1, 1' may be placed so that the axial direction of the tubular structures 1, 1' is perpendicular to the placement surface.

[0039] In the watertightness test method according to the present invention, the tubular structures 1, 1' may not have an outer shell steel plate 12. Specifically, the tubular main body 11 may be configured to be reduced in diameter at the end of one tubular structure 1 so as to be insertable into the end of the other tubular structure 1'. In this case, the pair of sealing materials 3 are attached to the outer circumferential surface of the tubular main body 11. The other tubular structure 1' may have an embedded collar that is embedded in the outer circumferential surface of the tubular main body 11 at the end of the tubular structure 1' and protrudes in the direction of the axis. The reduced-diameter end of one tubular structure 1 is joined by being inserted into the embedded collar at the end of the tubular structure 1'.

[0040] The present disclosure includes the following aspects. [1] A method for testing watertightness of a joint formed by inserting the end of one tubular structure into the end of the other tubular structure, comprising: A pair of sealing materials is attached to the end of the one tubular structure along an outer periphery, and at least two holes are provided between the pair of sealing materials and penetrating in a thickness direction; The at least two holes include at least one injection hole for injecting water and at least one exhaust hole for exhausting air, a filling step of filling the space between the pair of sealing materials with water by injecting water through the injection hole and discharging air through the discharge hole; a pressurizing step of sealing the discharge hole and injecting water through the injection hole to apply a predetermined water pressure and determine whether or not there is a water leak; A watertightness test method comprising: [2] The watertightness test method described in [1], wherein at least one of the pair of sealing materials is a rubber ring for a joint. [3] A watertightness test method as described in [1] or [2], wherein the pair of sealing materials are both rubber rings for joints. [4] The watertightness test method according to any one of [1] to [3], wherein the at least two holes are watertight agent injection holes. [5] A watertightness testing method according to any one of [1] to [4], wherein two holes penetrating in the thickness direction are provided between the pair of sealing materials at opposing positions in the circumferential direction. [Explanation of symbols]

[0041] 1,1' tubular structure 2 Joint 3. Sealing material 4 holes 31,32 Rubber ring for joint 41 Injection hole

Claims

1. A method for testing watertightness of a joint formed by inserting an end of one tubular structure into an end of another tubular structure, comprising the steps of: A pair of sealing materials is attached to the end of the one tubular structure along an outer periphery, and at least two holes are provided between the pair of sealing materials and penetrating in a thickness direction; The at least two holes include at least one injection hole for injecting water and at least one exhaust hole for exhausting air, a filling step of filling the space between the pair of sealing materials with water by injecting water through the injection hole and discharging air through the discharge hole; a pressurizing step of sealing the discharge hole and injecting water through the injection hole to apply a predetermined water pressure and determine whether or not there is a water leak; A watertightness test method comprising:

2. The watertightness test method according to claim 1 , wherein at least one of the pair of sealing materials is a rubber ring for a joint.

3. The watertightness test method according to claim 1 or 2, wherein the pair of sealing materials are both rubber rings for joints.

4. The watertightness test method according to claim 1 or 2, wherein the at least two holes are watertight agent injection holes.

5. The watertightness test method according to claim 1 or 2, wherein two holes penetrating in the thickness direction are provided between the pair of sealing materials at positions opposing each other in the circumferential direction.

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