KR101594576B1 - Method for preventing leakage of Concrete Dam Structure - Google Patents

Abstract

Disclosed is a method for preventing a water leakage of a concrete dam structure using a grouting method. The disclosed method for preventing a water leakage includes: a step of checking a water leakage from an upper stream surface of the dam structure by filling water inside an inner discharge port of the concrete dam structure; a step of forming an injection hole by drilling a leakage portion of the upper stream surface if water leaks; and a step of injecting grouting material into the injection hole.

Description

[0001] The present invention relates to a method of preventing leakage of a concrete dam structure,

The present invention relates to a method of preventing leakage of a concrete dam structure, and more particularly, to a method of preventing leakage of a concrete dam structure by grouting.

The cracks occur in the joint due to the high heat generated by the reaction between cement and water during the curing process of the concrete dam and the temperature difference between the inside and the surface of the concrete structure. Even after the concrete is hardened, cracks are generated due to the shrinkage of the inner concrete, and leakage is generated through these cracks.

In addition, when moving vehicles such as concrete mixers, cold joints are generated due to long-term load, resulting in leakage, poor compaction, or uneven temperature, causing leakage of joints . Such leaks may cause the dam structure to decay in the long term and weaken its durability.

Generally, after the completion of construction of the dam, separate leakage test is not carried out. To prevent leakage of the concrete dam structure, use a steel plate and a drain. Therefore, in case of leakage after fresh water, it is necessary to locate the leakage area on the downstream side of the dam structure which is not to be flooded, or to insert a packer after perforation or if the leakage is severe, all the fresh water is taken out, , Reinforce the leakage area

In the case of reinforcing the water leakage area on the downstream side in the fresh water state of the dam, it is not blocking the upstream surface cracked portion in which the water directly flows, but only blocking the water outlet, so that the water introduced from the upstream side flows through the inner drain There is a problem that it is impossible to reinforce perfect leakage, such as leaking out to the gallery.

In addition, when epoxy is injected into cracks most commonly used to reinforce existing dam leakage, the reaction time of epoxy is more than 50 minutes, so the epoxy flows down before curing. In the case of leaky sections, There is a problem that the epoxy is pushed out and the construction is difficult. The epoxy can hardly be stretched according to the temperature change even if the epoxy is cured. Therefore, there is a problem that the epoxy is peeled from the inside of the concrete to cause re-cracking.

In addition, when a one-component foamed urethane resin is used, it is hydrophilic and reacts immediately with the water introduced into the cracked portion to exponentiate for a certain period of time. However, there is a problem that self-contraction occurs in the long- There is a great disadvantage that it is not possible to perform the role of the structural reinforcing agent of the dam because there is almost no strength.

Korean Patent No. 10-1432453 is a related prior art document.

The present invention is intended to provide a method for preventing a leakage of a cone-shaped dam structure by confirming a portion expected to leak water before fresh water and reinforcing a portion expected to leak.

According to an aspect of the present invention, there is provided a method of preventing leakage of a concrete dam structure, the method comprising the steps of: confirming whether or not water leaks from the upstream surface of the dam structure by entering an inner drain hole provided in the dam structure; ; Forming an injection hole by performing perforation at a predetermined interval in a leakage area of the upstream surface in accordance with the leakage; And injecting the grout material through the injection hole.

According to another aspect of the present invention, there is provided a method of preventing water leakage in a concrete dam structure, the method comprising: drilling an expected portion of the dam structure to generate an injection hole; Injecting the cement milk into the injection hole when the leakage expectation portion is a horizontal joint portion; And injecting the acrylic resin into the injection hole when the leakage expectation portion is a vertical joint portion.

According to the present invention, it is possible to easily identify the leaking area by filling the inside drain hole provided in the fresh water dam structure with water, that is, water, and by performing grouting on the confirmed leaking area, water leakage after fresh water can be prevented.

Further, according to the present invention, by preventing water leakage after fresh water, it is possible to maximize the productivity of the dam construction, prevent excessive construction cost input, and shorten the air.

Further, according to the present invention, grouting is performed by using a grout material suitable for each of the horizontal joining portion and the vertical joining portion of the dam structure, thereby effectively preventing leakage.

1 is a view for explaining a leakage prevention method of a concrete dam structure according to an embodiment of the present invention.
2 is a schematic view of a dam structure and a cross section of an internal drain and a gallery.
Fig. 3 is a view for explaining the horizontal joint portion of the dam structure and the perforation position in the vertical joint portion.
Fig. 4 is a view for explaining the injection holes generated in the horizontal joint and the vertical joint.
5 is a view for explaining a leakage prevention method of a concrete dam structure according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a leakage prevention method of a concrete dam structure according to an embodiment of the present invention.

As shown in FIG. 1, the leakage prevention method of a concrete dam structure according to an embodiment of the present invention includes a step S110 of confirming whether or not water leaks on the upstream surface of a dam structure, (S120) of injecting holes (S120) and injecting grout material (S130) by performing perforation at a predetermined interval in a leakage area on the upstream surface of the dam structure depending on whether or not the dam is leaked. The area where the leakage phenomenon occurs can be regarded as a leakage area expected to leak after the completion of the fresh water flow. By leaking grouting at the expected area, leakage can be prevented.

The internal drainage is installed inside the dam structure to collect the leakage of the dam structure, and the leakage flows into the passage, that is, the gallery, inside the dam structure through the inner drainage hole. The outlet of the internal drain is located in the gallery. When water is introduced into the inner drain hole formed in the direction of the upstream surface of the dam structure at a predetermined water pressure, that is, water is injected into the inner drain hole, leakage may occur in a weak portion of the joint such as a horizontal joint or a vertical joint.

More specifically, in step S110, a packer is inserted into the outflow portion of the inner drain hole to confirm whether or not there is leakage, and the inner drain hole is filled with the predetermined drain pressure. It is also possible to check the occurrence of leaks on the upstream side after the appendix. The time at which leakage occurs can be used to determine the injection hole spacing of the horizontal joints.

If the leaked portion is a horizontal joint portion of the dam structure, the interval between the injection holes is determined according to the start time of leakage occurrence in step S120, and boring is performed to create an injection hole. The narrower the distance between the injection holes, the higher the degree of reinforcement can be said. For example, as the start time of leak occurrence is delayed after the insertion of internal drainage pipes, that is, the longer the time taken to leak after the drainage, the greater the interval between the injection holes, Can be performed. At this time, the perforation can be performed in the horizontal joint portion and can be performed in parallel with the horizontal joint portion.

If the leaking portion is a vertical joint portion of the dam structure, the injection hole is formed at a predetermined distance from the vertical joint portion at a predetermined distance in a direction perpendicular to the vertical joint portion in step S120. When perforating the vertical joint, unlike the horizontal joint, the vertical joint may expand. Therefore, the perforation is performed at a position spaced from the vertical joint by a predetermined distance. The predetermined distance and angle may be variously determined depending on the construction environment and the like.

In step S130, the cement milk is used as a grout material when the water leakage part is a horizontal joint part of the dam structure, and the acrylic resin is used as a grout material when the water leakage part is a vertical joint part of the dam structure. At this time, the grout material can be injected until the grout material flows out to the inner drainage or leaking area, or until the injection rate is below the threshold value.

According to an embodiment of the present invention, the present invention may further include closing the injection hole with the finishing material and confirming whether or not the leakage occurs when the grout reinjection is completed, and the step S110 may be repeatedly performed to confirm whether or not the leakage occurs.

According to the present invention, it is possible to easily identify the leaking area by filling the inside drain hole provided in the fresh water dam structure with water, that is, water, and by performing grouting on the confirmed leaking area, water leakage after fresh water can be prevented.

Further, according to the present invention, by preventing water leakage after fresh water, it is possible to maximize the productivity of the dam construction, prevent excessive construction cost input, and shorten the air.

2 is a schematic view of a dam structure and a cross section of an internal drain and a gallery.

As shown in FIG. 2 (a), an inner drain hole 230 and a gallery 240 are installed in the concrete dam structure 200. It is preferable that the inner drain hole 230 in the direction of the upstream surface 210 rather than the downstream surface 220 is filled with water at a preset pressure before being dewatered to the upstream surface 210 of the dam structure 200, You can identify the leak site.

At this time, the packer 260 is inserted into the drain outlet 250 of the gallery 240 and the inner drain hole 230 is filled. For example, when the height of the dam structure 200 is 50 m, 5kgf / cm < ² > can be performed. The water introduced into the inner drain hole 230 by the water impingement rises upward in the dam structure 200 by the water pressure so that the leaked portion in the horizontal joining portion or the vertical joining portion of the upstream surface 210 of the dam structure If present, leaks may occur in the leaking areas.

Fig. 3 is a view for explaining the horizontal joint portion of the dam structure and the perforation position in the vertical joint portion.

As shown in Fig. 3, in the case where the leakage portion is a horizontal joint portion, perforation is performed on the horizontal joint portion. At this time, the interval of perforation may vary depending on the time of occurrence of leakage after the appendix. The leakage start time in the first horizontal joint is shorter than the start time of the leakage occurring in the second horizontal joint so that the perforation interval in the first horizontal joint is narrower than the perforation interval in the second horizontal joint.

 The perforation interval in the horizontal joint portion and the vertical joint portion can be determined as shown in Table 1 as an embodiment. The perforation interval of the vertical joint may be fixed, unlike the horizontal joint.

Start time of leakage 0 to 30 minutes 30 to 60 minutes 60 to 120 minutes 120 to 180 minutes Over 180 minutes Horizontal Perforation Interval
Vertical Perforation Interval 0.5m
0.5m 1m
0.5m 1.5m
0.5m 2m
0.5m 2.5m
0.5m

On the other hand, in the case where the leaked portion is a vertical joint portion, perforation is performed at a position spaced from the vertical joint by a predetermined distance. If leakage occurs in the second vertical joint, the perforation is performed by tilting it by a predetermined angle in the direction of the vertical joint. That is, the closer to the inside of the injection hole, the closer to the vertical joint. Also, as shown in FIG. 3, the injection holes may be formed by staggering the injection holes on both sides with reference to the vertical joint, or the injection hole may be formed symmetrically with respect to the vertical joint.

As described above, in the case of the horizontal joint, due to the concrete load, even if the perforation is performed on the horizontal joint, the joint of the joint is not loosened, but when the perforation is performed on the vertical joint, the joint of the joint may be loosened. Therefore, it is preferable to perform perforation at a position spaced from the vertical joint by a predetermined distance. It is also preferable to perform the drilling in the direction of the vertical joint to intensively inject the grout material into the vertical joint.

Fig. 4 is a view for explaining the injection holes generated in the horizontal joint and the vertical joint. Fig. 4 (a) is a cross-sectional view of the horizontal joint where the injection hole is created, and shows a cross-sectional view when the horizontal joint is cut parallel to the vertical joint. Fig. 4 (b) is a cross-sectional view of the vertical joint where the injection hole is formed, and shows a cross-sectional view when the vertical joint is cut parallel to the horizontal joint.

38mm크기로 드릴 장비 등을 이용하여 천공을 수행할 수 있는데, 수평 이음부(410)에 지수판이 있을 경우 지수판 200mm 전까지 천공하고, 지수판이 없을 경우 1,000mm를 천공할 수 있다.As shown in FIG. 4 (a), an injection hole 420 is formed in the horizontal joint portion 410 in parallel with the horizontal joint portion 410. As an example,

If the horizontal joint part 410 is provided with a steel plate, the steel plate can be drilled up to 200 mm before the steel plate, or 1,000 mm if there is no steel plate.

A packer (e.g., a handle packer) is inserted into the perforated end, i.e., the inlet of the injection hole 420, and cement milk for grouting is initially injected at a low pressure. If the cement milk escapes into the internal drainage or joint drainage at the time of injection, reintroduction is carried out one hour after stopping the injection. When the cement milk injection speed is lower than the predetermined speed, the injection is completed, and the injection hole is closed using the finishing material. In this case, the predetermined speed may be, for example, 1 L / min, and the finishing material may be a non-shrinking grout material.

The injection rate may vary depending on the conditions of the site, but it is preferable to inject at a rate of 10 l / min or less, and it is preferable to inject at a low pressure. For example, the injection is started at a low pressure of 1 kgf / cm 2 to 3 kgf / cm 2, the injection is stopped when the pressure is increased after the injection, and the pressure is lower than the predetermined rate. In this case, it is preferable to stop the injection when the cement milk injected into the horizontal joint portion flows. It is desirable to continuously measure the injection rate, the injection pressure, and the injection time during the injection.

On the other hand, grouting can be carried out by using cement milk mixed with 1: 1 microcement and water. Microcement is advantageous in that it can be injected up to 30 ㎛ in crack width because the particles are very fine. In addition, micro cement has low viscosity, low bleeding rate and good permeability compared with cement, which is excellent in fluidity and prevention of material separation and is suitable for effective grouting work. And, homoge gel has high strength and 2 ~ 3 times higher compressive strength than dyestuff, so it has good durability and little leaching phenomenon. Since it has 40 ~ 80% greater strength than ordinary cement in strength, it is suitable not only for civil works but also for ground reinforcement requiring high strength.

[Table 2] shows the result of the characteristic test of the microcement used in the present invention, and is a test result conducted by Korea Institute of Construction & Living Environment Test.

10mm크기로 천공을 수행할 수 있다. 수평 이음부(410)와 같이 주입홀(460) 입구에 패커(예를 들어 핸들 패커)를 삽입한 후, 그라우팅을 위한 아크릴 수지를 주입한다. 수평 이음부 또는 균열 부위로 주입한 아크릴 수지가 흘러나오면 주입을 멈추고 마감재를 이용하여 주입홀(450)을 마감한다. The injection hole 450 is formed in the direction of the vertical joint 440 at a position spaced apart from the vertical joint 440 by a predetermined distance as shown in FIG. 4 (b). As an example,

Perforation can be performed with a size of 10 mm. A packer (for example, a handle packer) is inserted into the inlet of the injection hole 460 like the horizontal joint portion 410, and acrylic resin for grouting is injected. When the injected acrylic resin flows into the horizontal joint portion or the crack portion, the injection is stopped and the injection hole 450 is closed using the finishing material.

Unlike other injection solutions, acrylic resin is stable to various chemical environments in ground water and ground as well as various alkali, acid, and organic chemicals, and has the advantage of having durability with no degradation and leaching phenomenon. In addition, since the gel time adjustment can be performed freely within a range of several seconds to several hours, there is an advantage that the injection characteristics such as the type of the injection target and the injection management according to the purpose of injection are easy. Since the acrylic resin forms a highly elastic and flexible gel after injection, the gel exhibits swelling characteristics with respect to water. Therefore, it has excellent order and exponential characteristics as compared with other injection solutions, and also has a secondary strain There is also an effect to cope with the situation properly. In addition, there is an effect of blocking the entrance of water, absorbing existing water and re-entering water to form a new waterproof layer and preventing occurrence of re-leakage.

[Table 3] shows the results of the characteristic tests of PA-100 (polymer backing agent) among the acrylic resins used in the present invention, and is a test result conducted by Korea Institute of Construction & Living Environment Test.

According to the present invention, grouting is performed by using a grout material suitable for each of the horizontal joining portion and the vertical joining portion of the dam structure, thereby effectively preventing leakage of water.

FIG. 5 is a view for explaining a leakage prevention method of a concrete dam structure according to another embodiment of the present invention, wherein the concrete dam structure may be a gravity type dam structure.

As shown in FIG. 5, the leakage prevention method of a concrete dam structure according to another embodiment of the present invention includes a hydraulic test step (S510), a repair part selection step (S520), and a maintenance step (S530).

In the water pressure test step (S510), a packer is installed in the outlet port of the internal drainage hole in the direction of the upstream surface located inside the gallery, and water is supplied at a predetermined water pressure. At this time, it is possible to perform the appendage with a plurality of internal drainage holes, measure the water pressure of each drainage hole, and measure the time of occurrence of the leakage on the upstream side after the appendix.

In the repairing site selection step (S520), the site where leakage occurs on the upstream side is a site expected to leak water after freshwater, so the site where the leakage occurred is selected as a maintenance site, and the leakage occurrence site may be a horizontal joint or a vertical joint.

In the repairing step (S530), if the selected repair part is a horizontal joint part, the puncturing interval is determined according to the occurrence time of the leak. Then, perforation is performed in the horizontal joint portion according to the determined perforation interval to create an injection hole. A packer is inserted into the injection hole to inject cement milk for grouting.

In the repairing step (S530), if the selected repair part is a vertical joint part, a position spaced apart from the vertical joint part by a predetermined distance is determined as a puncturing position, and the hole is tilted by inclining toward the vertical joint part to produce an injection hole. A packer is inserted into the injection hole and an acrylic resin is injected for grouting.

That is, when the leakage expectation portion is a horizontal joint portion, cement milk is injected into the injection hole formed on the horizontal joint portion, and when the expected water leakage portion is a vertical joint portion, the injection hole is formed at a position spaced from the vertical joint portion by a predetermined distance The acrylic resin is injected.

According to the embodiment, after the maintenance step S530 is performed, the water pressure test may be performed in the same manner as in step S510 to confirm whether or not the water leakage continues. If the leakage continues, it is preferable to repeat the maintenance site selection step (S520) and the maintenance step (S530) until leakage does not occur.

On the other hand, in the water pressure test step (S510), when water leakage occurs on the upstream surface at the time of filling, it may not be possible to fill up to the length of the internal drain hole, that is, the highest position of the internal drain hole. In this case, leakage can not occur in the part that is not attached, and in the repair part selection step (S520), the repair part may be partially missing. Therefore, it is preferable that the water pressure test step (S510) is performed again after the maintenance step (S530), the water is filled in the inner drain, and the water leakage is confirmed to re-determine the maintenance part.

In addition, since the leaking area may become more fragile when the lehr is performed at the water pressure test step (510), it is desirable to perform the lehr at a water pressure lower than a threshold value determined according to the construction environment or the like.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains. Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (10)

In a leakage prevention method for a concrete dam structure,
Confirming whether or not the upper surface of the dam structure is leaked by filling an internal drain hole provided in the dam structure to collect the leakage of the dam structure;
Forming an injection hole by performing perforation at a leakage area of the upstream surface according to whether the leakage occurs; And
Injecting the grout material into the injection hole,
The step of checking whether or not the leak
Inserting a packer into an outlet of the internal drain;
Filling the inner drain with a predetermined water pressure; And
And confirming the leakage start time after the addition,
The water introduced into the inner drain hole by the water filling is raised upward in the dam structure by water pressure,
The step of creating the injection hole
Wherein when the water leakage portion is a horizontal joint portion of the dam structure, the interval between the injection holes is increased as the water leakage start time is delayed to generate the injection hole on the horizontal joint portion,
Wherein the injection hole is inclined by a predetermined angle in the direction of the vertical joint at a position spaced from the vertical joint by a predetermined distance when the water leakage portion is a vertical joint portion of the dam structure
How to prevent leakage.
delete delete delete The method according to claim 1,
The step of creating the injection hole
The injection holes are formed on both sides of the vertical joint portion,
How to prevent leakage.
The method according to claim 1,
The step of injecting the grout material with the injection hole
Injecting cement milk or acrylic resin into the injection hole
How to prevent leakage.
delete The method according to claim 1,
The grout material is injected until the grout material flows out to the inner drain or the water leakage portion or until the injection speed becomes a threshold value or less,
The leakage prevention method
Closing the injection hole with a finishing material and confirming whether or not it is leaked
How to prevent leakage.


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