JP5191009B2 - Method of investigating cracks on the dike surface - Google Patents

Description

  The present invention relates to a method for investigating the scale of cracks in concrete covering the surface of a levee. More specifically, water is injected into a crack to be investigated, and the spread of cracks in the concrete depending on the water injection state. The present invention relates to a method that can easily evaluate the situation. This technique is useful, for example, for diagnosing deterioration of storm surge banks.

  In recent years, there is concern about the deterioration of the flood control function due to the aging of the high tide embankment, and it is necessary to carry out inspections and repairs to ensure safety. When investigating and inspecting a dike, it is necessary to evaluate the soundness of the concrete covering the surface of the dike body. To that end, it is important to properly grasp the cracks and other deformations in the concrete. . The surface length and width of such a crack can be directly measured. However, even if the surface is a wide crack, the surface may be narrowly closed inside, and the surface may be widened and opened inside even if it is a narrow crack. For this reason, it is impossible to directly measure how much the crack has spread inside the concrete, or whether the crack is open or closed inside. At present, there is no fixed investigation method for the size of cracks (such as the extent of internal expansion).

  As a related prior art, a method has been proposed in which a fluid (such as air) in a crack is vacuum-sucked and a change in the suction pressure is measured with a pressure gauge to detect a defect in a concrete structure (Patent Document). 1).

  However, such a conventional method can estimate whether the crack is open or closed inside, but it is difficult to accurately evaluate the crack scale. In particular, when the investigation object is a dike, water permeability becomes a problem in the evaluation of soundness, but the method of forcibly sucking air in the crack does not necessarily lead to soundness evaluation. This is because an appropriate repair method cannot be found and a repair plan cannot be made unless the water permeability or water imperviousness of cracks is verified and judged according to the actual situation. For these reasons, it is required to develop an investigation method that can be appropriately and easily evaluated for deformation such as cracks occurring in the covering concrete on the dyke surface in accordance with the state of levee installation.

JP 2002-5923 A

  The problem to be solved by the present invention is to appropriately evaluate the scale of cracks in the concrete covered on the surface of the levee (spreading condition in the interior, etc.) so that the soundness of the levee can be diagnosed accurately and easily. .

The present invention includes a container-shaped water injection portion whose peripheral edge of the opening can be in close contact with the concrete surface, a water tank for storing injection water for testing, and a cock for connecting between the water tank and the water injection portion. Using a crack test instrument having a communication pipe, the water injection portion covers at least a part of the investigation target crack generated in the covering concrete of the levee, and the periphery of the opening portion is on the concrete surface. Installed in close contact, water in the water tank is injected into the crack from the water injection part via the communication pipe, and depending on the water injection status,
(A) Even if water is poured with the cock fully open, water continues to enter the crack until the water tank is empty.
(B) If water is poured with the cock fully open, the water will overflow from the middle. Then, when the water is poured in a state where the amount of water to be poured is reduced by squeezing the cock, water continues to enter the crack until the water tank is empty.
(C) When water is poured with the cock fully open, the water overflows from the middle. After that, even if the cock is squeezed and water is injected in a state where the water injection amount is reduced, the water overflows in a short time.
(D) Even if water is poured, water does not enter the cracks and overflows immediately.
Divided into
In the case of (A), opening cracks are distributed over a wide range.
In the case of (B), cracks with a small opening width are distributed over a wide range.
In the case of (C), the range in which the opening cracks are distributed is limited.
In the case of (D), the crack is almost closed.
This is a method for investigating cracks on the dike surface, characterized by evaluating the crack scale.

  Here, it is preferable to use a crack test instrument in which the peripheral edge at the lower end of the water injection part is made of a flexible sealing material and is adapted to the concrete surface with irregularities so as to maintain water tightness. It can also be set as the structure which isolate | separated the water tank and the water injection part, and connected both with the flexible tube.

  The method for investigating a crack on the levee surface according to the present invention is an investigation method for injecting water into a crack to be investigated and classifying and evaluating the crack size on the levee surface according to the water injection condition. (E.g., spread inside) can be accurately evaluated.

  Since the method of the present invention is an investigation method in which water is actually injected into the crack, deterioration diagnosis and soundness evaluation can be performed in accordance with the actual condition of use of the dike. It is possible to determine the water permeability or water-imperviousness of the cracks, thereby making it possible to select an appropriate repair method and make a repair plan. Moreover, it can be carried out with a crack test instrument having a simple structure equipped with a water tank, and there is an advantage that anyone can easily investigate because it does not require difficult operations.

  If the crack test equipment is separated from the water tank and the water injection part and connected with a flexible tube, even if the concrete surface to be investigated is inclined, the water tank is vertical and the water injection part is the inclined concrete surface. Therefore, it is possible to investigate on an inclined surface.

Explanatory drawing of the use condition which shows an example of the crack test instrument used with the method of this invention. Explanatory drawing of the use condition which shows the other example of the crack test instrument used with this invention method.

  An example of a crack test instrument used in the method of the present invention and its use state are shown in FIG. This crack test instrument includes a container-like water injection part 10 whose periphery of the opening can be in close contact with the concrete surface, a water tank 12 for storing test injection water, a cock 14 in the middle, and the water tank 12 A communication pipe 16 that connects the water injection section 10 is provided. In this example, the water tank 12, the communication pipe 16, and the water injection part 10 are integrated. In the case of an integral structure, the illustration is omitted in practice, but the water injection part and the water tank are connected by 3 to 4 connecting members arranged so as to surround the communication pipe, and are firmly integrated. It is preferable to do this. A handle 18 is provided at the upper part of the water tank 12 so that the whole can be suspended and transported. Test water can be supplied from the supply port 20 at the top of the water tank.

  The water injection unit 10 is in a state in which the container is turned down so that the opening is downward (thus opening the lower surface and closing the upper surface), and may be a cylindrical type or a rectangular tube type (for example, a box type). A flexible sealing material 22 is attached to the periphery of the opening of the water injection unit 10. For example, a rubber elastic sealing material or a low-rebound cushioning material may be used. This makes it possible to maintain familiarity and watertightness even on uneven concrete surfaces. The water tank 12 has a transparent structure (for example, made of acrylic resin) so that the inside can be seen, and a scale 24 is provided so that the water level can be visually measured. The communication pipe 16 directly connects the water tank 12 and the water injection section 10, and a cock 14 capable of stopping water and adjusting the flow rate is incorporated in the middle of the communication pipe 16. In addition, when the water injection section and the water tank are firmly connected by a connecting member, the communication pipe does not necessarily have a rigid structure.

  The crack investigation method using such a crack test instrument is as follows. The water injection portion 10 is installed so that the opening covers at least a part of the crack 30 to be investigated generated in the concrete covered with the levee and the sealing material 22 around the periphery of the opening is in close contact with the concrete surface. Then, the cock 14 is opened, and the water in the water tank 12 is injected into the crack 30 from the water injection section 10 via the communication pipe 16, and the water injection situation (the amount of water injection and the progress until the water is filled in the crack 30) Observe time etc.).

Depending on the water injection situation, water will continue to enter the crack until the water tank is empty even if water is injected with at least (A) the cock fully open.
(B) If water is poured with the cock fully open, the water will overflow from the middle. Then, when the water is poured in a state where the amount of water to be poured is reduced by squeezing the cock, water continues to enter the crack until the water tank is empty.
(C) When water is poured with the cock fully open, the water overflows from the middle. After that, even if the cock is squeezed and water is injected in a state where the water injection amount is reduced, the water overflows in a short time.
(D) Even if water is poured, water does not enter the cracks and overflows immediately.
Divide into And from those results,
In the case of (A), open cracks are distributed over a wide range, and water permeability at the crack location is high.
In the case of (B), cracks with a small opening width are distributed over a wide range, and the water permeability at the crack location is medium.
In the case of (C), the range in which the opening cracks are distributed is limited, and the water permeability at the crack location is low.
In the case of (D), the crack is almost closed and the water permeability in the crack location is low.
Thus, the crack scale is evaluated in four stages.

  FIG. 2 shows another example of a crack test instrument used in the method of the present invention and its use state. Since the basic configuration is the same as that shown in FIG. 1, the same reference numerals are given to corresponding members and parts for the sake of simplicity. The crack test instrument comprises a container-shaped water injection part 10 whose peripheral edge of the opening can be in close contact with the concrete surface, a water tank 12 for storing test injection water, and a cock 14. The water tank 12 and the water injection part 10 And a communication pipe connecting between the two. In this example, the water tank 12 and the water injection part 10 are separated, and the two are connected by a flexible tube 32. A handle 18 is provided at the top of the water tank 12 to facilitate carrying the water tank, and three legs 34 are provided at the bottom of the water tank so that the water tank 12 can stand on its own.

  The water injection unit 10 is in a state in which the container is turned down so that the opening is downward (thus opening the lower surface and closing the upper surface), and may be a cylindrical type or a rectangular tube type (for example, a box type). The water tank 12 has a transparent structure (for example, made of acrylic resin) so that the inside can be seen, and a scale 24 is provided so that the water level can be visually measured. Here, an outlet pipe 36 is projected from the bottom of the water tank 12, and the cock 14 is incorporated in the outlet pipe 36. On the other hand, an inlet pipe 38 is projected from the upper part of the water injection part 10. The outlet pipe 36 of the water tank 12 and the inlet pipe 38 of the water injection unit 10 are connected by the flexible tube 32.

  The method of using such a crack test instrument is the same as in the above example. The water tank 12 is erected in a horizontal place near the crack to be measured. On the other hand, the water injection part 10 is installed so that the opening covers at least a part of the crack 30 to be investigated generated in the concrete covered with the levee and the sealing material 22 at the periphery of the opening closely adheres to the concrete surface. Then, the cock 14 is opened, and the water in the water tank 12 is injected into the crack 30 from the water injection section 10 via the flexible tube 32, and the water injection status (the amount of water injected and the elapsed time until the water is filled in the crack). Etc.). Evaluation of the crack scale according to the water injection situation is performed in the same manner as in the above example.

  As described above, when the water injection section 10 and the water tank 12 are connected by the flexible tube 32, the crack scale can be investigated even with inclined concrete because the water injection section 10 can be inclined even if the water injection section 10 is inclined.

  The size of the water tank of the prototype crack test instrument is about 50 cm in height and about 10 cm in diameter. An elastic sealing material was attached to the periphery of the opening of the water injection part so as to be able to adhere to the concrete surface. When the water tank was filled with water and the cock was operated and tested, even if there were some irregularities on the concrete surface, water leakage to the side could be prevented and water could be poured into the cracks . Since no difficult operations were required, anyone could easily test and observe the water injection into the crack. As a result, the spread state and water permeability inside the crack could be roughly grasped, and the crack scale that was not visible from the surface could be appropriately evaluated. In addition, because of its small size and light weight, it could be easily carried by one person and conducted a crack investigation.

  The above example is a method of visually observing a change in the water level in the water tank. This is the crack testing instrument with the simplest structure. However, if measures such as measuring the water level change in the water tank with a water level gauge or water pressure gauge or measuring the amount of water injected with a flow meter are added, it is possible to classify cracks more finely or to perform automatic measurement. It becomes.

10 Water injection section 12 Water tank 14 Cock 16 Communication pipe 30 Crack

Claims (3)

A container-like water injection part whose peripheral edge of the opening can be in close contact with the concrete surface, a water tank for storing injection water for testing, and a communication pipe that includes a cock and connects between the water tank and the water injection part Using the crack test equipment provided, the water injection section covers at least a part of the crack to be investigated occurring in the covering concrete of the levee, and the periphery of the opening is in close contact with the concrete surface. Installed, injected water in the water tank into the crack from the water injection part via the communication pipe, depending on the water injection situation,
(A) Even if water is poured with the cock fully open, water continues to enter the crack until the water tank is empty.
(B) If water is poured with the cock fully open, the water will overflow from the middle. Then, when the water is poured in a state where the amount of water to be poured is reduced by squeezing the cock, water continues to enter the crack until the water tank is empty.
(C) When water is poured with the cock fully open, the water overflows from the middle. After that, even if the cock is squeezed and water is injected in a state where the water injection amount is reduced, the water overflows in a short time.
(D) Even if water is poured, water does not enter the cracks and overflows immediately.
Divided into
In the case of (A), opening cracks are distributed over a wide range.
In the case of (B), cracks with a small opening width are distributed over a wide range.
In the case of (C), the range in which the opening cracks are distributed is limited.
In the case of (D), the crack is almost closed.
A method for investigating cracks on the dike surface, characterized by evaluating the crack size.   The method for investigating cracks on the levee surface according to claim 1, wherein a crack test instrument having a structure in which the periphery of the opening of the water injection portion is made of a flexible sealing material and is adapted to the concrete surface with unevenness to maintain water tightness.   The method for investigating cracks on the levee surface according to claim 2, wherein a crack test instrument having a structure in which the water tank and the water injection portion are separated and connected between each other by a flexible tube is used.

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