JP6677453B2 - External waterproofing repair method for underground structures - Google Patents

Description

  The present invention relates to an outer waterproofing repair method for an underground structure for repairing an outer waterproofing structure in which a waterproof sheet is provided between an underground structure and a ground-side back layer.

  For example, if water leaks inside the lining in an external waterproof structure such as a watertight tunnel, cut the injection hole from the inside of the lining, insert a nozzle into the injection hole, and remove the ground outside the waterproof sheet. Was injected with a waterproofing agent. That is, in the past, the idea was to stop water by directly filling the water gap in the water path of the ground with a water stopping agent.

  As the water stopping agent, for example, the one shown in Patent Document 1 has been used. The water stopping agent of Patent Literature 1 is a one-part water stopping agent that reacts with water to form a cured body that is flexible and compliant, and can exhibit a water stopping effect over a long period of time.

JP 2014-1381 A

  In the conventional repair method, when the flow rate of the groundwater is high, there is a problem that the injection amount becomes enormous because the waterproof agent hardly flows out and hardens.

  From such a viewpoint, an object of the present invention is to provide a method of repairing an underwater waterproof structure of an underground structure, which can repair a leak with a small amount of a waterproofing agent.

The present invention for solving the above-mentioned problems is directed to an outer waterproofing repair method for repairing an outer waterproofing structure in which a waterproof sheet is attached between an underground structure and a ground-side back layer, wherein an injection hole is formed in the underground structure. Drilling step, injecting a waterproofing agent between the underground structure and the waterproof sheet from the injection hole, pressing the waterproof sheet against the ground-side back layer, the waterproof sheet and the ground-side back face An injection step of compressing and eliminating water paths between the layers, wherein the water-stopping agent is a one-pack type, containing a urethane prepolymer having a terminal isocyanate group, and a silicone-based antifoaming agent, the urethane prepolymer having a terminal isocyanate group can et been by reacting a polyol with an organic polyisocyanate, a pressure applied to the waterproof sheet pressing pressure in peripheral pressure, pressure applied to the filling of the waterproofing agent Calculation and, outside these pressure of the larger of the pressure, in addition a pressure loss involved in the construction, underground construction, characterized by further comprising the step of setting the injection pressure of the waterproofing agent This is a waterproof repair method.

  According to such a method, since the waterproofing agent is injected into the portion (between the underground structure and the waterproofing sheet) separated from the ground-side back layer by the waterproofing sheet, it does not flow down the water channel. Therefore, the repair can be performed with a small amount of the waterproofing agent. Further, since the waterproofing agent presses the waterproof sheet against the ground-side back layer and compresses and eliminates the water path between the waterproof sheet and the ground-side back layer, water can be avoided from a damaged portion of the waterproof sheet.

  In the outer waterproofing repair method for an underground structure according to the present invention, a protective layer is previously formed between the underground structure and the waterproof sheet, and in the drilling step, a tip of a drilling machine is attached to the protective layer. It is preferable to stop the drilling machine at the time of reaching. According to such a method, the drilling step can be performed without damaging the waterproof sheet.

  In the outer waterproofing repair method for an underground structure according to the present invention, in the injecting step, a balloon is inserted between the underground structure and the waterproof sheet from the injection hole, and the waterproofing agent is injected into the balloon. Is preferred. According to such a method, it is possible to perform repair with a minimum amount of the waterproofing agent, and it is possible to strongly press the ground-side back layer.

  ADVANTAGE OF THE INVENTION According to this invention, water leakage can be repaired with a small waterproofing agent.

It is a figure for explaining an outside waterproofing repair method of an underground structure concerning a first embodiment of the present invention, (a) is a sectional view showing a state before repair, and (b) is a state after drilling. FIG. 3C is a cross-sectional view showing a state after the injection of the waterproofing agent. It is a figure for explaining an outside waterproofing repair method of an underground structure concerning a second embodiment of the present invention, (a) is a sectional view showing a state before pouring a waterproofing agent, and (b) is waterproof. It is sectional drawing which showed the state after agent injection. It is a figure for explaining an outside waterproofing repair method of an underground structure concerning a third embodiment of the present invention, (a) is a sectional view showing a state before repair, and (b) is a state after drilling. FIG. 3C is a cross-sectional view showing a state after the injection of the waterproofing agent.

  Hereinafter, an outer waterproofing repair method for an underground structure according to the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1A, the outer waterproof structure includes, for example, an underground structure 1 such as a watertight tunnel, a ground-side back layer 2 outside the underground structure 1, an underground structure 1, and a ground-side back surface. A waterproof sheet 3 laid between layers 2 is provided. The ground layer-side rear layer 2 is formed of a ground layer or a back structure (the ground layer in the present embodiment). In general, the ground-side back layer 2 is rarely a steel structure or a concrete structure, and often has an uneven shape such as ground or shotcrete. For this reason, there is often a minute gap between the underground structure 1 and the waterproof sheet 3.

  Many water paths 4 are present in the gap between the ground-side back layer 2 and the waterproof sheet 3 and in the ground-side back layer (back ground) 2. When the waterproof sheet 3 has a hole 5 and the water path 4 is connected to the hole 5, water flows from the hole 5 into a gap between the underground structure 1 and the waterproof sheet 3. If a crack 6 extending from the inner surface 1a to the back surface (outer surface) 1b of the underground structure 1 occurs in the portion where the water has flowed, water leaks inside the underground structure 1 through the crack 6. The outer waterproofing repair method of the first embodiment for repairing at such a location where water leakage occurs includes a drilling step and an injection step.

The drilling step is a step of forming an injection hole 10 in the underground structure 1 as shown in FIG. The injection hole 10 is a hole for injecting the water stopping agent 20, and is a straight through hole extending from the inner surface 1a to the back surface 1b. The injection hole 10 is formed from the inside of the underground structure 1 with a drilling machine such as a drill. The injection hole 10 is formed by inserting a drill in the normal direction of the inner surface 1a from the vicinity of the end of the crack 6 (the location where the water leak occurs) on the inner surface 1a. The drill is inserted by the thickness of the underground structure 1. The thickness dimensions should be grasped by design drawings, non-destructive inspection, and the like. At the start of drilling, the drill is pushed in at a normal drilling speed, and when the desired insertion depth approaches, the drilling speed is reduced to carefully drill the hole. Immediately before penetration, it is preferable to replace the drilling machine and slowly drill while measuring the pushing torque. With such drilling, the injection hole 10 can be formed without making a hole in the waterproof sheet 3.
In addition, when an injection hole is previously formed in the tunnel lining which is an underground structure, the drilling step can be omitted.

  The injection step is a step of injecting the water blocking agent 20 between the underground structure 1 and the waterproof sheet 3 from the injection hole 10. The water stopping agent 20 is determined by the size of the gap between the underground structure 1 and the ground-side back layer 2. The water stopping agent 20 may be a cement-based material or a urethane-based material, and is a non-foamed or low-foamed one having an expansion ratio of about 1.0 to 1.2. Note that a material that causes volume shrinkage cannot be used as the water stopping agent 20. Further, in order to enhance the waterproof performance, it is preferable to use a material having low water permeability as the water stopping agent 20.

  An example of the water stopping agent 20 satisfying such a condition will be described below. The water stopping agent 20 is made of, for example, a one-pack type water stopping agent. As a one-part type water stopping agent, for example, there is “Hicell OS-248” manufactured by Toho Chemical Industry Co., Ltd. This one-pack type water stopping agent contains a urethane prepolymer having a terminal isocyanate group and a silicone-based antifoaming agent. The terminal isocyanate group is obtained by reacting a polyol with an organic polyisocyanate. The polyol contains castor oil-based polyol and polytetramethylene glycol and tetrahydrofuran-neopentyl glycol copolymer as essential components, or castor oil-based polyol and polytetramethylene glycol or tetrahydrofuran-neopentyl glycol copolymer. As essential.

  Further, it is preferable that the polyol further contains a polyether polyol having an oxypropylene group in a polyoxyalkylene chain in an amount of 70% by mass or more based on the total mass of the polyoxyalkylene chain. Further, it is more preferable that the water stopping agent 20 contains a diluent.

  The cured product formed by the reaction of the water-stopping agent 20 with water having such a configuration usually has an expansion ratio of 1.0 to 1.2 (that is, no expansion or low expansion). Due to these features, the water stopping agent 20 is particularly effective in stopping water under high water pressure.

  In addition, a resin may be used in addition to the water stopping agent 20 according to the construction situation. Examples of resins that can be used in this manner include epoxy resins, acrylic resins (such as methyl methacrylate), and styrene resins. When another resin is used in combination, 1 to 50% by mass of the urethane prepolymer used for the water stopping agent 20 can be blended.

  The water-stopping agent 20 having the above-described structure has a cured material that is more flexible and has a higher follow-up property with respect to displacement such as vibration or displacement at an injection point, as compared with a urethane-based water-stopping agent generally used conventionally. Therefore, it can be expected that the water stop performance will be exhibited for a long time. In addition, "followability" is a concept that indicates the flexibility that the cured product can conform to the deformation behavior when the hardened portion is deformed due to earthquake vibration or the like. “High” means that the cured product is hardly cracked or peeled off from the surface to be adhered even when the cured product is deformed due to vibration or the like.

  Further, since the water-stopping agent 20 is a one-pack type, the workability at an actual construction site is very good as compared with a two-pack type foam-type injection agent.

  The water-stopping agent 20 is not limited to the above-described configuration, and may be a one-pack type water-blocking agent or another two-package type water-blocking agent.

  When injecting such a waterproofing agent 20, an injecting pipe 21 is inserted into the injecting hole 10 to inject the waterproofing agent 20 between the underground structure 1 and the waterproof sheet 3. The injection of the water stopping agent 20 is performed under pressure management. The injection pressure is set as follows. First, the pressure obtained by adding the peripheral pressure (water pressure) and the waterproof sheet pressing pressure, and the pressure related to the filling of the waterproofing agent 20 are calculated, and the injection pressure is set according to the calculated pressures.

  The pressure is set by bringing the generally known Kaiser effect to the waterproof structure. The Kaiser effect means that when plastic deformation is continued in the same direction, once the stress is unloaded and reloaded, AE (acoustic emission) does not occur until the stress value at the unloaded point is reached. (Cracks do not occur). Conventionally, when a waterproof sheet is installed on the back of an underground structure to construct the underground structure, the underground structure is often cast in place. In the case of casting concrete on the wall of an underground structure with a 3m lift, the pressure is about 0.075 MPa even if it is placed in the lower part where the pressure is most applied. Therefore, when a water pressure equal to or less than about 0.075 MPa (approximately 7.5 m in water depth) or less acts, close contact is maintained. Water starts to permeate between the layers and stays between the waterproof sheet and the ground-side rear layer. In a shallow underground structure with a depth of about 2 m, the waterproof sheet and the ground-side back layer can sufficiently adhere to each other with only the pressure of concrete casting, but this is a problem in the case of a deep underground structure.

  In the present embodiment, the injection pressure of the water stopping agent 20 is set in consideration of the above phenomenon. Specifically, the pressure (water pressure) obtained by adding the surrounding water pressure (the expected water pressure of the ground-side back layer 2 at the filling point) and the waterproof sheet pressing pressure (the pressure for pressing the waterproof sheet 3 against the ground-side back layer 2) (Pressure for pushing the waterproof sheet 3 outwardly against the pressure) P1 and pressure (pressure for flowing the water-stopping agent 20) P2 for filling the water-stopping agent 20 are calculated. Then, to the larger one of the calculated pressures P1 and P2, the pressure lost in connection with the construction (the pressure loss in the pipe of the water-stopping agent 20, the pressure loss due to an elbow, or the like, or the pump or the injection device) P3). Set as injection pressure. By setting the injection pressure in this way, the waterproof sheet 3 can be always brought into close contact with the ground-side back layer 2.

  By the way, in order for the waterproof sheet 3 to be in close contact with the ground-side back layer 2, the waterproofing agent 10 needs to sufficiently penetrate into the gap between the underground structure 1 and the waterproof sheet 3. Therefore, from the positional relationship of the underground structure 1, the waterproof sheet 3, and the ground-side back layer 2, the pressure related to permeation (a phenomenon in which the water blocking agent 20 spreads in the gap between the underground structure 1 and the waterproof sheet 3) is calculated. There is a need.

The first case 1 is a case where there is a sufficient gap (a gap of about 5 mm or more) between the underground structure 1 and the waterproof sheet 3. In case 1, it is considered that there is no obstacle related to permeation. Therefore, only the pressure loss P4 generated when the waterproofing agent 20 is filled between the underground structure 1 and the waterproof sheet 3 may be considered. That is, the injection pressure is P1 (or P2) + P3 + P4. In this case, when the permeability (fluidity) of the water stopping agent 20 is high, the pressure loss is considered to be almost zero. In this embodiment, the injection hole 10 is provided at one place. However, when a plurality of injection holes are formed in close proximity, the filling pressure of the water blocking agent injected from the adjacent injection holes is taken into consideration.

  The second case 2 is a case where there is no sufficient gap between the underground structure 1 and the waterproof sheet 3 (when the thickness of the gap is approximately 0 to 5 mm). The case 2 corresponds to the shape of the present embodiment shown in FIG. In this case 2, there is a portion where the waterproof sheet 3 and the underground structure 1 are in contact with each other along the unevenness of the ground-side back layer 2. Is hindered. For this reason, in addition to the above-described loss pressure P4, a pressure P5 for pushing and expanding the contact portion to pass through is applied. That is, the injection pressure is P1 (or P2) + P3 + P4 + P5.

  When the waterproofing agent 20 is injected at the pressure set as described above (the pressure of the case 2), the waterproofing agent 20 is moved between the underground structure 1 and the waterproof sheet 3 as shown in FIG. Is filled. The waterproofing agent 20 expands the volume of the region between the underground structure 1 and the waterproof sheet 3 so that the waterproof sheet 3 is brought into close contact with the surface of the ground-side back layer 2 and the waterproof sheet 3 is pressed at a predetermined pressure. Press against the back layer 2 on the ground side. As a result, the gap between the waterproof sheet 3 and the ground-side back layer 2 disappears, and the water path 4 at that portion disappears. Further, the ground-side back layer 2 around the water blocking agent 20 is compressed, and the water path 4 inside is compressed, so that the water path 4 is crushed and disappears. In the damaged portion of the waterproof sheet 3, the waterproofing agent 20 is also filled on the ground-side back layer 2 side, and may directly fill the gap of the water path 4.

  According to such an outer waterproofing repair method, since the waterproofing agent 20 is injected into the portion (between the underground structure 1 and the waterproof sheet 3) separated from the ground-side back layer 2 by the waterproof sheet 3, It does not flow into the back layer 2. Therefore, since the water stopping agent 20 is not flushed to the water path 4, it can be repaired with a small amount of the water stopping agent 20.

  In addition, since the water blocking agent 20 presses the ground layer-side back layer 2 via the waterproof sheet 3 and compresses and eliminates the water path 4 in the pressed area, the flow of water is moved away from the waterproof sheet 3. Can be changed. Thereby, water can be avoided from the damaged portion (hole 5) of the waterproof sheet 3. Further, the inside of the hole 5 (the underground structure 1 side) is filled with the waterproofing agent 20, so that the hole 5 is closed from the inside. Therefore, it is difficult for water to flow from the hole 5 to the underground structure 1 side.

  Next, an outer waterproofing repair method for an underground structure according to a second embodiment of the present invention will be described with reference to FIG. In the outer waterproofing repair method of the second embodiment, the waterproofing agent 20 is filled via the balloon 22. The drilling step is the same as in the first embodiment. The balloon 22 is formed of a rubber bag and is inflated by filling the waterproofing agent 20. The balloon 22 has a pressure resistance greater than the injection pressure of the water blocking agent 20.

  In the injection step, a balloon 22 is inserted into the injection hole 10 as shown in FIG. The tip of the balloon 22 is made to reach between the underground structure 1 and the waterproof sheet 3. Then, the injection tube 23 is connected to the balloon 22.

  Thereafter, as shown in FIG. 2B, the water stopping agent 20 is injected into the balloon 22. The water stopping agent 20 is supplied from the injection tube 23 into the balloon 22 at a predetermined pressure. The injection pressure of the water stopping agent 20 is set to a value obtained by adding a pressure for inflating the balloon 22 to the injection pressure of the first embodiment. As the injection of the waterproofing agent 20 proceeds, the tip of the balloon 22 expands in the gap between the underground structure 1 and the waterproof sheet 3, and presses the waterproof sheet 3 against the surface of the ground-side back layer 2. That is, in the present embodiment, the waterproofing agent 20 presses the waterproof sheet 3 onto the surface of the ground-side back layer 2 via the balloon 22. As a result, the ground-side back layer 2 around the water blocking agent 20 is compressed, and the water path 4 therein is also compressed, so that the water path 4 is crushed and disappears.

  According to the outer waterproofing repair method of the present embodiment, in addition to the same operation and effect as the first embodiment, the following operation and effect can be obtained. In the present embodiment, since the water blocking agent 20 is injected into the balloon 22, the water blocking agent 20 is separated from the ground-side back layer 2 by the balloon 22 and the waterproof sheet 3. Even if the waterproof sheet 3 has a large break, the waterproofing agent 20 is separated from the ground-side back layer 2 by the balloon 22. Therefore, it is possible to reliably prevent the water stopping agent 20 from flowing out to the ground-side back layer 2.

  Even in the case of a waterproof structure without a waterproof sheet, if a balloon is arranged between the underground structure and the ground-side back layer, the waterproofing agent does not flow out to the ground-side back layer, and the underground structure does not flow out. It can be filled between the object and the ground side back layer. Thus, the ground layer on the ground side can be compressed, and the water path near the balloon can be eliminated.

  Next, an outer waterproofing repair method for an underground structure according to a third embodiment of the present invention will be described with reference to FIG. The outer waterproof structure according to the third embodiment includes a protective layer 7 as shown in FIG. The protective layer 7 is disposed between the underground structure 1 and the waterproof sheet 3. The protective layer 7 serves as a spacer for securing a space between the underground structure 1 and the waterproof sheet 3. The provision of the protective layer 7 prevents the tip of the drill for drilling the underground structure 1 from coming into contact with the waterproof sheet 3 even if it protrudes toward the ground. The protective layer 7 is a sheet-like member made of, for example, a nonwoven fabric or a bubble cushioning material. The protective layer 7 is thicker than the waterproof sheet 3. The protective layer 7 is laid so as to cover the outer peripheral surface of the underground structure 1.

  In the drilling step, the drilling machine is stopped when the tip of the drill (a drilling machine) reaches the protective layer 7. Specifically, in the drilling step of the present embodiment, similarly to the first embodiment, the drill is pushed at a normal drilling speed at the start of drilling, and when the desired insertion depth approaches, the drilling is performed. Reduce the hole speed and carefully drill holes. At this time, it is preferable to replace the drilling machine immediately before the penetration and to perform the drilling while measuring the pushing torque.

  In the injection step, the water stopping agent 20 is injected between the underground structure 1 and the protective layer 7. The water stopping agent 20 is supplied at a predetermined pressure through the injection hole 10. The supply pressure of the water stopping agent 20 is set to a value obtained by adding the pressure for spreading the protective layer 7 to the supply pressure of the first embodiment. As the injection of the water stopping agent 20 proceeds, the protective layer 7 is spread out together with the waterproof sheet 3 and pressed against the surface of the ground-side back layer 2. Thereby, the ground-side back layer 2 around the water blocking agent 20 is compressed, and the water path 4 inside the ground-side back layer 2 around the water stopping agent 20 is crushed and disappears.

  According to the outer waterproofing repair method of the present embodiment, in addition to obtaining the same operational effects as the first embodiment, even if the drill slightly protrudes from the back surface of the underground structure 1 in the drilling step, the protective layer 7 Since it is present, the effect that the waterproof sheet 3 can be reliably prevented from being damaged can be obtained. In addition, also in this embodiment, you may inject the water stopping agent 20 through the balloon 22 like the second embodiment.

  The embodiments for carrying out the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and design changes can be made as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, the case where the underground structure 1 is a lining of a watertight tunnel has been described as an example, but the underground structure 1 is not limited to the lining of a watertight tunnel. For example, the present invention can be applied to a structural body in an underground part of a building.

  In addition, in the above-described embodiment, the injection hole 10 is formed at one location near the water leaking portion of the crack 6, but is not limited to one location, and a plurality of injection holes 10 may be provided.

DESCRIPTION OF SYMBOLS 1 Underground structure 2 Ground side back layer 3 Waterproof sheet 4 Water path 7 Protective layer 10 Injection hole 20 Waterproofing agent 22 Balloon

Claims (3)

An outer waterproofing repair method for repairing an outer waterproofing structure in which a waterproofing sheet is attached between an underground structure and a ground layer side back layer,
Drilling step of forming an injection hole in the underground structure,
A waterproofing agent is injected between the underground structure and the waterproof sheet from the injection hole, and the waterproof sheet is pressed against the ground-side back layer, and a water path between the waterproof sheet and the ground-side back layer is formed. And an injection step of compressing and eliminating
The water-stopping agent is a one-part type and contains a urethane prepolymer having a terminal isocyanate group and a silicone-based antifoaming agent, and the urethane prepolymer having a terminal isocyanate group reacts a polyol with an organic polyisocyanate. Obtained by
A pressure applied waterproof sheet pressing pressure in peripheral pressure, to calculate the pressure according to the filling of the waterproofing agent, the pressure of the larger of these pressures, in addition to pressure loss involved in the construction, the A method of repairing an underwater waterproof structure of an underground structure , further comprising a step of setting a pressure at which a waterproofing agent is injected . A protective layer is formed in advance between the underground structure and the waterproof sheet,
The method according to claim 1, wherein in the drilling step, the drilling machine is stopped when a tip of the drilling machine reaches the protective layer. The said injection | pouring process inserts a balloon between the said underground structure and the said waterproof sheet from the said injection hole, and injects the said waterproofing agent into the said balloon. The Claim 1 or Claim 2 characterized by the above-mentioned. Waterproofing repair method for underground structures described above.

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