JP2777249B2 - Water stopping method for concrete underground structures - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water stopping method for preventing water leakage from a concrete wall of an underground structure.

2. Description of the Related Art Conventionally, in concrete underground structures such as tunnels, underground tunnels, and basements, groundwater outside the structure is passed through the cracks in concrete walls, free time flaws in concrete work, seams of concrete structures, and the like. There is a problem that water often leaks into the underground room or underground room, so that there is a problem in that the civil engineering work is hindered, and there is a problem in the water discharge treatment after the completion of the structure.

Conventionally, there is no complete and semi-permanent water stopping method as a countermeasure against such flooding.There is no way to collect water from the flooding point to a lowland with a gutter or the like and pump it out of a basement, tunnel, etc. Is repaired from inside by various methods to stop the water. However, the pumping method not only requires enormous expenses for pump drainage, power, water collection and other maintenance costs, but also causes flooding due to power outages and mechanical failures.
There is a problem that pumping out groundwater causes land subsidence, and the conventional method of repairing flood spots removes the concrete at the flood spot on the concrete wall from the inside and removes the concrete at the stripped portion. It is a method of repairing by applying repair concrete or filling it with flooding points such as seams from the inside with other repair materials from the inside, not only impairing the aesthetics of the inner walls of the basement, gallery, etc. Due to vibrations and the passage of time, water is often re-watered from the same location, and it is not a complete and semi-permanent water stoppage method, so it was repaired in the same way every time it was flooded, so a considerable cost was spent is the current situation.

In view of the above-mentioned problems, the present inventor has previously proposed a water stopping method for a concrete underground structure for the purpose of semi-permanently stopping water from a wall such as a basement or a tunnel. As disclosed in Japanese Unexamined Patent Publication No. 62-276129, this water stopping method is to provide a through hole extending from the inside to the outside of the concrete wall at a flood point of a wall such as a tunnel, and to allow a mixed liquid of cement and water to flow through the hole.
Injected into the soil outside the concrete wall through a through hole at a low pressure of about 5 kg / cm ² , gradually increase the cement mixing rate of this injected mixture, and finally mix the coagulant into the mixture, With this, a cement solidification layer is provided on the outside of the concrete wall of the water leakage section, and according to this waterproofing method, 3 to 5 kg /
The mixed liquid of cement and water injected at a low pressure of about ² cm reaches the outside of the concrete wall via the through-hole, and is not dissipated into the underground water outside the wall due to the low pressure. A part of the injected cement mixture stays nearby and penetrates from the outside of the wall toward the inside of the wall due to water pressure on the outside of the wall due to the water pressure on the outside of the wall, clogging and closing the leakage crack. At this time, by gradually increasing the cement mixing rate of the cement mixture to be injected,
Firstly, fine cracks can be plugged, most of the injected mixture is pressed against the concrete outer wall by the water pressure of the groundwater, extensively covering the outer wall and solidified by the last injected coagulant, By injecting from one place, many cracks at the leak location can be closed over a wide area and water can be semipermanently stopped, and underground facilities such as tunnels can be strengthened.

However, the present inventor has performed various experiments thereafter, and as a result, the water stoppage method described above has a water output of, for example, 200/200.
It was confirmed that it was not suitable for a large amount of water such as min.

(Problems to be Solved by the Invention) The present invention seeks to provide a waterproofing method for a concrete underground structure capable of preventing flooding with a large flooding rate, for example, 50 / min or more, particularly 200 / min or more. Things.

(Means for Solving the Problems) According to the present invention, a large amount of water gushing out through a through hole extending from the inside to the outside of the concrete wall due to a crack or the like in the concrete wall surrounding the space in the concrete underground structure is stopped. In doing so, after closing the spout of the through-hole opening on the inner surface of the wall and temporarily stopping water from the spout, a cement mixture is injected into the through-hole from the spout at a pressure of ³ to 5 kg / cm2. And presses the cement mixture against the outer wall surface of the water leaking part by the pressure of groundwater on the outer wall to form a cement solidified layer that spreads on the outer wall surface to stop water. .

(Operation) According to the present invention, when a large amount of groundwater is spouting from the spout of the through hole in the concrete wall into the space of the concrete structure, the spout is closed and the fountain is stopped to thereby stop the through hole. The flow of groundwater inside the ground stops, and the groundwater near the opening of the through-hole outside the concrete wall becomes static. Therefore, the slurry mixture of water and cement injected from the fountain port of the through passage at a low pressure of about 3 to 5 kg / cm ² can be pushed out of the concrete wall through the through passage. Due to the low injection pressure, the mixture extruded to the outside of the concrete wall in this way is not discharged far into the groundwater from the outside surface of the concrete wall, and therefore is not dissipated into the groundwater, Stay along the outer wall surface. Part of the retained cement mixture is pushed into the cracks opening on the outer surface of the concrete wall due to the pressure of the groundwater, and solidifies in the cracks to close the cracks. Most of the cement mixture forms a solidified layer of cement on the outer surface of the concrete wall, which reliably stops the leakage of groundwater and reinforces the concrete wall.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, for example, a large number of cracks 2 generated in a concrete wall 1 of an underground structure such as a mine tunnel are grown to form a through hole 3, and a spout 4 opening to an inner side surface 1a of the concrete wall. From the groundwater 5 outside the concrete wall
When a cement mixture such as a water / cement mixed slurry is injected into the through hole 3 from the ejection port 4 at a low pressure of about 3 to 5 kg / cm ² , It is impossible to overcome the flow of the groundwater in the through-hole 3 and feed the cement mixture to the outside of the concrete wall, and the groundwater is pushed out of the through-hole 3 by the cement mixture and the through-hole is closed with the cement mixture. It is impossible.

Therefore, first, as shown in FIG. 2, a plurality of short pipes 7, 8 of 25 mm in diameter are installed at the jet port 4 by using a fixing material 9 such as quick-setting mortar, and water is discharged from these short pipes.
Aggregate to 7,8. The short pipes 7 and 8 are provided with valves 10 and 11 respectively, and after being fixed, the valves 10 and 11 are closed to stop the water from flowing out from the jet port 4.

However, when the water output is large and the water pressure is high,
It is practically impossible to reliably seal the spout 4 only by itself, and the water blocking by the fixing member 9 is temporary, as indicated by an arrow 12 through a gap inside or around the fixing member 9. A considerable amount of water leakage occurs.

Therefore, as a next step, as shown in FIG.
The short tube 7 for mortar injection is connected to a manual mortar pump (not shown) by a pressure-resistant hose 15, and the pump 16
As shown in the figure, a mixed slurry of water, cement and a quick setting agent is injected into the through-hole 3 through the short pipe 7 at a low pressure of about 3 to 5 kg / cm ² .

This coagulant mixture flows toward the fixing material 9 as indicated by arrow 17 by the groundwater flowing out through the through-hole 3, and the fixing material 9
Is press-fitted into the inside of the fixing member 9 and its surroundings, and solidifies to stop water leakage from the inside of the fixing member 9 and the surroundings.

In this way, by closing the spout 4 and stopping the fountain, the flow of the underground water in the through hole 3 is stopped, and the underground water near the through hole opening 18 outside the concrete wall is brought into a hydrostatic state. In this state, as shown in FIG. 4, a mixed slurry of cement and water is used as a cement mixed solution at a low pressure of about 3 to 5 kg / cm ² by a pump and through a short pipe 7 as shown by an arrow 18 in the through hole 3. Inject into

This mixed liquid pushes out the water in the through-hole 3 to the outside of the concrete wall through the opening 18, and the cement mixed liquid is also pushed out into the still water underground water outside the concrete wall. It is not released and diffused.
Pressed towards 1b, which causes the cement mixture to
As shown by arrow 19, it spreads along the outer wall surface 1b and stays there,
A part thereof is pushed into the many cracks 2 opened on the outer wall surface 1b by hydrostatic pressure, and closes these cracks. In this way, if the water leakage from the water leaking point, for example, about 1 m away from the jet port 4 is also stopped, the injection of the cement mixture is stopped using this as a guide.

Further, the time when the injection is stopped can be determined based on the rising state or the injection amount of the cement mixture.

When the cement mixture has been injected, the valve 10 of the short pipe 7 for mortar injection is closed to prevent backflow of the cement mixture, disconnection from the pump, and curing of the cement mixture for about one day to cure the cement mixture. And complete the water stoppage.

(Effects of the Invention) According to the present invention, it is possible to quickly and reliably semi-permanently stop a large amount of water, which has been almost impossible in the past, in a short construction period.

Further, according to the method of the present invention, a small-sized manual mortar pump can be used for injecting a cement or a coagulant mixture, and therefore, it can be easily carried into and out of a construction site such as 20 m underground. In addition, there is an advantage that there is no problem such as power wiring.

[Brief description of the drawings]

 1 to 4 are schematic diagrams for explaining the method of the present invention. DESCRIPTION OF SYMBOLS 1 ... Concrete wall 2 ... Crack 3 ... Through hole 4 ... Spout 5 ... Groundwater 7 ... Short pipe for mortar injection 8 ... Short pipe for water concentration, 9 ... Fixing material 10,11 …… Valve, 15… Pressure-resistant hose

Claims (1)

(57) [Claims] When a large amount of water spouting through a through hole extending from the inside to the outside of a concrete wall formed by a crack or the like surrounding a space in a concrete underground structure and the like is stopped, a large amount of water is discharged to the inner surface of the wall. After closing the spout of the open through hole and temporarily stopping the water from the spout,
The cement mixture is injected into the through hole at a pressure of ³ to 5 kg / cm ² from the spout and extruded to the outside of the wall. A waterproofing method for a concrete underground structure, wherein the waterproofing is performed by forming a solidified cement layer on an outer surface.