JP7391655B2 - Backfill injection device and backfill injection method using the same - Google Patents

Description

The present invention relates to a backfilling injection device for injecting a curable chemical solution to fill a cavity formed on the back side of a tunnel lining or under the foundation of a building, and a backfilling injection method using the same.

In existing tunnels, especially tunnels constructed using the sheet pile method, cavities may occur between the tunnel lining concrete and the ground due to gaps remaining between the shoring or sheet pile and the ground. be. Further, under the foundation of a building, a cavity may be formed between the foundation and the ground due to ground subsidence due to a decrease in groundwater.

If this cavity is left unattended, the ground may collapse, causing cracks in the concrete lining of the tunnel, or the foundation may no longer be able to support the structure, causing it to tilt, impeding the safe use of tunnels and structures. There is a fear. Therefore, construction work is being carried out to stabilize tunnels and buildings and ensure safety by injecting hardening chemicals into these cavities to fill them. This construction method is called backfilling.

Examples of hardening chemicals used in this backfilling process include inorganic materials such as mortar and cement, and organic materials such as polyurethane foam. Among these, foamed polyurethane is particularly suitable for tunnel lining concrete because it can be easily prepared at the construction site for backfill injection work, has excellent workability, has high compressive strength, and is lighter than inorganic materials. It is suitably used because it can reduce the load on the body.

Foamed polyurethane is produced by a curable chemical solution prepared by mixing a polyol compound-containing solution and a blowing agent-containing solution A with an isocyanate compound-containing solution B, which is foamed several times more due to the reaction between the A and B solutions. It is produced through a process in which it expands to several tens of times its volume and hardens. For example, according to Patent Document 1, liquid A and liquid B are mixed at a volume ratio of liquid A: liquid B = 1:1.1±0.1. On the other hand, the volume ratio of foamed polyurethane to the curable chemical is called the foaming ratio. In a backfill injection process, when this curable chemical solution is injected into a cavity, polyurethane foam is generated within the cavity, thereby filling the cavity.

Non-Patent Document 1 describes that foamed polyurethane having an expansion ratio of 10 to 30 times and a compressive strength of 0.2 to 1.3 N/mm ² is used to form a cavity (lining back cavity) on the back side of tunnel lining concrete. ) is described. Similarly, Non-Patent Document 2 describes a method of filling cavities formed in the ground with a material having a compressive strength of about 1 N/mm ² . The compressive strength of polyurethane foam can be determined by measuring in accordance with JIS K7220 (2006).

Since the polyol compound contained in Solution A has hygroscopic properties, it may absorb water vapor in the air during backfill injection work and deteriorate in quality. The foamed polyurethane produced by mixing liquid A containing a moisture-absorbed polyol compound with liquid B has a foaming ratio higher than the expected expansion ratio. The higher the expansion ratio of polyurethane foam, the lower its density. A decrease in the density of polyurethane foam results in a decrease in its compressive strength. Foamed polyurethane foamed at a higher magnification than the intended value due to moisture absorption of the polyol compound has a low density, making it impossible to produce foamed polyurethane with sufficient compressive strength to support the ground forming the cavity. .

Japanese Patent Application Publication No. 2018-154764

Public Works Research Institute, Basic Road Technology Research Group (Tunnel Team), “Road Tunnel Deformation Countermeasures Manual (Draft)”, February 2003, Public Works Research Institute Material No. 3877, p. 106-118 Edited by East Nippon Expressway Co., Ltd., "Design and Construction Guidelines for Rear Cavity Injection for Sheet Pile Method Tunnels," First Edition, October 2006, Expressway Research Institute Co., Ltd., p. 11

The present invention was made in order to solve the above-mentioned problem, and by constantly foaming polyurethane foam at a preset ratio in backfill injection, polyurethane foam having the desired compressive strength is always stably produced. An object of the present invention is to provide a backfilling injection device capable of producing a backfilling method and a backfilling method using the same.

The backfill injection device of the present invention, which has been made to achieve the above object, is a backfill injection device for injecting a curable chemical solution, which is a mixture of a solution A containing a polyol compound and a blowing agent, and a solution B containing an isocyanate compound, into a cavity. The injection device includes an injection tube inserted into the cavity, a liquid drug guide compound tube connected to the injection tube and for mixing the liquid A and the liquid B, and a liquid drug guide compound tube connected to the drug liquid guide compound tube. a liquid A transport pipe and a liquid B transport pipe, a liquid A tank and a liquid B tank that store the liquid A and the liquid B, respectively, and a liquid A tank and a liquid B tank that store the liquid A and the liquid B, respectively. a liquid A pressure pump and a liquid B pressure feed pump that pressurize and send the liquid A and the liquid B to the liquid A transport pipe and the liquid B transport pipe respectively; the amount of the liquid A sent by the liquid A pressure pump and the liquid B pressure pump; a pump controller that independently adjusts the amount of the B liquid, and the A liquid tank has an opening whose top surface is open for introducing the A liquid, and a lid covering the opening. wherein the lid and the periphery of the opening do not contact each other at least in one place, forming a gap, an air introduction hole is formed in a part of the lid, and the lid is screwed or fitted into the opening. and/or the lid is an elongated wrap film that is in close contact with the periphery of the opening, and the volume of the amount of the A liquid and the amount of the B liquid contained in the curable chemical solution is controlled by the pump controller. The ratio is adjusted to 1:2.4 to 2.7.

In the backfill injection device, the lid is made of the wrap film made of polyolefin selected from polyethylene, polyvinyl chloride, polyvinylidene chloride, and polyethylene, or a plastic cap that is screwed or fitted into the opening. It is preferable that there be.

In the backfill injection device, the polyol compound is at least one selected from the group consisting of polyhydric alcohols, polyether polyols, and polyester polyols, and the blowing agent is selected from water, hydrofluoroolefins, and hydrochlorofluorocarbon compounds. The isocyanate compound is at least one selected from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, and trimethylene xylylene diisocyanate.

In the backfilling injection method of the present invention, the hardening agent is injected into the cavity using the injection device.

In the backfill injection method, the cured product of the curable chemical has a compressive strength of at least 1.5 N/mm ² and has a volume of 3 to 10 times that of the curable chemical. It may be.

In the backfill injection method, the cavity may be any one selected from a cavity on the back side of a tunnel lining, a cavity under a building foundation, a cavity within a building structure, and a side shaft.

According to the backfill injection device of the present invention, since the liquid A tank that stores liquid A containing a polyol compound and a blowing agent has a lid, the polyol compound exhibiting high hygroscopicity is present in the air within the tank. It is possible to store water vapor while suppressing the amount of absorbed water vapor. According to this, it is possible to prevent an increase in expansion ratio due to moisture absorption of the polyol compound over time and a corresponding decrease in compressive strength, and to stably produce foamed polyurethane having a desired compressive strength.

This backfilling injection device mixes liquid B in an amount that is about 2.5 times the volume of liquid A, so the amount of polyol compound is relatively small compared to the amount of isocyanate compound. Compared to the conventional mixing ratio of liquid A: liquid B = 1:1.1±0.1, the foaming ratio of the polyurethane foam is kept low and the density of the polyurethane foam is increased to 1.5N/mm2 ^or more. Foamed polyurethane that exhibits high compressive strength can be produced within the cavity. Thereby, it is possible to reliably prevent the collapse of the ground forming the lining backside cavity.

Furthermore, according to this backfilling injection device, the amount of polyol compound is too small compared to the amount of isocyanate compound, so even if there is a small amount of spring water or stagnant water that can be used as a foaming agent in the back cavity of the lining, foamed polyurethane It is possible to prevent the foaming ratio from increasing excessively, and to produce polyurethane foam inside the cavity that always stably exhibits high density and high compressive strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic partial cross-sectional side view illustrating a backfilling injection device to which the present invention is applied and a backfilling injection method using the same. Standing time and foaming in the foamed polyurethane of Example 1 obtained using the backfill injection device to which the present invention is applied and the foamed polyurethane of Comparative Example 1 obtained using the backfill injection device to which the present invention is not applied. It is a graph showing correlation with magnification. Foamed polyurethane of Examples 2-1 and 2-2 obtained using a backfill injection device to which the present invention is applied, and Comparative Example 2 obtained using a backfill injection device to which the present invention is not applied. It is a graph showing the correlation between the standing time and the foaming ratio in foamed polyurethane. Foamed polyurethane of Examples 2-1 and 2-2 obtained using a backfill injection device to which the present invention is applied, and Comparative Example 2 obtained using a backfill injection device to which the present invention is not applied. It is a graph showing the correlation between standing time and compressive strength in foamed polyurethane.

Hereinafter, embodiments for carrying out the present invention will be described in detail, but the scope of the present invention is not limited to these embodiments.

FIG. 1 shows a schematic front view of one embodiment of the backfilling injection device of the present invention. The backfill injection device 1 shown in FIG. 1 includes a liquid guide compound pipe 10 having a liquid B transport pipe 12, a liquid A transport pipe 11 and an air introduction pipe 13 connected to each other so as to branch from the liquid B transport pipe, and a liquid A pressure pump 21. and a pump unit 20 having a liquid B pressure pump 22, an air compressor 30, a liquid A tank 51 having a lid 53 at the opening for injecting liquid A and storing liquid A, and a liquid B storing liquid B. It has a liquid tank 52. The pump unit 20 is loaded on an equipment loading vehicle 72. The air compressor 30 is temporarily installed outside the road tunnel 60.

Liquid A contains a polyol compound with high hygroscopicity and a blowing agent. Liquid B contains an isocyanate compound. A curable chemical liquid is prepared by mixing liquid A and liquid B at a specific volume ratio. The curable chemical solution is injected into the cavity 63 that is the object of construction, and foamed polyurethane is generated within the cavity 63.

The A liquid transport pipe 11 is connected to the A liquid pressure pump 21 via the first A liquid tube 41a. The liquid A pressure pump 21 is connected to the liquid A tank 51 via the second liquid A tube 41b. The B liquid transport pipe 12 is connected to the B liquid pressure pump 22 via the first B liquid tube 42a. The B liquid pressure pump 22 is connected to the B liquid tank 52 via the second B liquid tube 42b. The air introduction pipe 13 is connected to the air compressor 30 via an air tube 43.

An injection pipe 14 that is inserted into a hole 64a made in the concrete lining 61 and discharges a hardening chemical into the cavity 63 is connected to the tip of the B liquid transport pipe 12. A Bourdon tube 13b is attached to the air introduction tube 13 to display the air pressure inside the tube. The Bourdon tube 13b is provided so that the injection operator 73 can visually check the pressure inside the air introduction tube 13.

The A liquid transport pipe 11, the B liquid transport pipe 12, and the air introduction pipe 13 each have ball valves 11a, 12a, and 13a that open or close the insides of the pipes.

Both pressure pumps 21 and 22 have motors, and by rotation of the motors, suck liquid A and liquid B from liquid A tank 51 and liquid B tank 52, respectively, and transfer liquid A to liquid transport pipe 11 and liquid B to transport pipe 12. send to The pump unit 20 has a pump controller 23 that controls the operation of both pressure pumps 21 and 22. The pump controller 23 is equipped with an inverter, and operates and stops the motors of both pressure pumps 21 and 22 independently, and also changes the rotational speed of the motors steplessly. Thereby, the amounts of liquid A and liquid B sent by both pressure pumps 21 and 22 are each independently adjusted to desired values. The pump controller 23 is equipped with a switch that generates an electrical signal for controlling both pressure pumps 21 and 22, and a meter that indicates the operating status of the switch. The pump operator 74 can operate both pressure pumps 21 and 22 via the pump controller 23 by operating this manual switch. By operating both pressure pumps 21 and 22, liquid A and liquid B injected into both tanks 51 and 52, respectively, can be sent to liquid A transport pipe 11 and liquid B transport pipe 12, respectively.

Both tanks 51 and 52 have a substantially cylindrical body and a narrowed portion that narrows downward from the body. Both tanks 51 and 52 have openings on their top surfaces. By charging liquid A and liquid B into both tanks 51 and 52, respectively, from this opening, they can be stored. The tips of the narrowed portions of both tanks 51 and 52 are fluid-tightly connected to the second liquid A tube 41b and the second liquid B tube 42b, respectively. The A liquid tank 51 has a lid 53 at its opening.

The lid 53 is a wrap film made of a resin such as polyethylene, polyvinyl chloride, polyvinylidene chloride, and polyolefin, which is exemplified by polyethylene. The lid 53 contacts the periphery of the opening of the A liquid tank 51 and covers the entire surface thereof. The lid 53 and the periphery of the opening of the liquid A tank 51 do not contact each other at least in one place, and a slight gap is formed between them. As a result, even if the A liquid is consumed as the backfill injection process progresses and the liquid level falls, a volume of air corresponding to the volume of the consumed A liquid will flow from this gap into the A liquid tank 51. Introduced into the inner sky. Although the A liquid absorbs water vapor contained in the air in the A liquid tank 51, the absorbed amount is limited to a very small amount present in the A liquid tank 51. Therefore, according to this backfill injection device 1, compared to the conventional backfill injection device in which the polyol compound in the A liquid constantly absorbs water vapor in the atmosphere and deteriorates in quality, the moisture absorption of the A liquid is reduced. It is possible to prevent its deterioration by significantly suppressing it compared to conventional methods. As a result, this backfilling injection device 1 does not unexpectedly increase the foaming ratio of polyurethane foam produced by foaming the curable chemical solution that is a mixture of liquids A and B, and does not unexpectedly reduce its compressive strength. I won't let you. Note that when replenishing the A liquid tank 51 with A liquid, the lid 53 is rolled up to expose the opening of the A liquid tank 51. After the liquid A is injected through this opening, the opening is immediately covered with a lid 53.

As the wrap film for the lid 53, a so-called stretch film made of linear low density polyethylene (LLDPE) may be used. Such a stretch film is stretched to 2 to 3 times its original length by the action of tension in plane directions that move away from each other. When such a lid 53 is used, since the lid 53 is in close contact with the periphery of the opening of the A liquid tank 51, there is no need to form a gap therebetween. In this case, the lid 53 extends to recess into the inner space of the A-liquid tank 51 so as to follow the liquid level of the A-liquid that descends as the A-liquid is consumed. According to this, even if the A liquid is consumed and its liquid level falls, air is not introduced into the A liquid tank 51, so that moisture absorption of the A liquid can be further suppressed.

The lid 53 is not limited to a wrap film as long as it can cover the opening of the liquid A tank 51, and may be a hard material made of metal or resin, or a cap that screws or fits into the opening. good. The lid 53 may be a lid that is separate from the liquid A tank 51 and can be attached to and removed from the opening thereof, or a lid that is provided on the liquid A tank 51 via a hinge so that it can be opened and closed. In this case, it is preferable that at least one air introduction hole is opened between the lid 53 and the periphery of the A liquid tank opening or in a part of the lid 53. As the A liquid is consumed, air is introduced into the A liquid tank 51 from this air introduction hole.

When the cap is to be screwed into the opening of the liquid A tank 51, a male screw is formed on the outer circumferential surface of the opening of the liquid A tank 51, and the female screw to be screwed therein is formed on the inner surface of the cap. Examples include those that have. Further, when the cap fits into the opening of the liquid A tank 51, the cap has an inner diameter slightly larger than the diameter of the opening of the liquid A tank 51, and the inner wall surface of the cap and the liquid A tank have a slightly larger inner diameter. The outer circumferential surface of the opening of 51 may have claws that engage with each other, so that they fit together and the cap does not easily come off. Examples of the cap include, in addition to the resins listed above, plastic caps made of polyolefins such as polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polystyrene, polycarbonate, and resins such as phenolic resins.

A sheet-like, film-like, or rod-like moisture-absorbing material may be attached to the A-liquid tank 51 on its inner wall surface and/or on the side of the lid 53 facing the A-liquid. Examples of moisture absorbing materials include calcium oxide, calcium chloride, silica gel, activated carbon, and zeolite.

A backfill injection method of the present invention using the backfill injection device 1 will be explained. First, in the concrete lining 61, at a location where the cavity 63 exists on the back side, a known cavity investigation technique (for example, high-density two-dimensional electric survey method and electromagnetic wave radar survey method) is used to investigate the volume of the cavity 63. Measure. Based on this measured value, the injection amount of the curable chemical solution is calculated and determined. Further, the amounts of liquid A and liquid B required to prepare the curable chemical liquid in this amount to be injected are calculated and determined. Next, a plurality of holes 64a and 64b are formed in the top surface of the concrete lining 61 from the inside of the road tunnel 60 toward the cavity 63 using a drill.

The injection operator 73 closes all the ball valves 11a, 12a, and 13a of the chemical liquid guide composite pipe 10, and gets into the bucket 71a of the aerial work vehicle 71 together with the chemical liquid guiding composite pipe 10. The bucket 71a is raised to near the top of the concrete lining 61. Next, the injection operator 73 inserts the injection tube 14 of the chemical liquid guide composite tube 10 into the drilled hole 64a. Furthermore, in order to prevent the injection pipe 14 from coming out of the drilled hole 64a, a fall prevention ring, which is attached to the injection pipe 14, is inserted into the cavity 63 together with it, and hangs over the opening of the drilled hole 64a on the back side of the lining concrete 61, and an adhesive is installed. The chemical fluid guide composite tube 10 is fixed with a chemical agent, and the gap between the injection tube 14 and the drilled hole 64a is filled with a sealing material 65 such as a rag or caulking material to prevent the hardening chemical fluid injected into the cavity 63 from leaking. Close this gap. Note that a rag may be used as the sealing material 65, and the injection tube 14 may be inserted into the drilled hole 64a while being stuffed with the rag.

Thereafter, the injection operator 73 opens the ball valve 13a of the air introduction pipe 13, visually checks the indicated value of the Bourdon tube 13b, and confirms that the compressed air is being reliably sent. Next, the ball valve 12a of the B liquid transport pipe 12 and the ball valve 11a of the A liquid transport pipe are opened, and the pump operator 74 is verbally instructed to start injection of the foamed polyurethane raw material liquid. The pump operator 74 operates the manual switch of the pump controller 23 to operate both pressure pumps 21 and 22. At this time, the pump operator 74 controls the motors of both pressure pumps 21 and 22 so that the amount (volume) of liquid B to be fed per unit time is 2.4 to 2.7 times that of liquid A. Provide a rotation speed difference between the two.

Liquid A and liquid B are sent to the chemical liquid guide composite tube 10. As a result, liquid A and liquid B, together with the compressed air introduced by the air introduction pipe 13, are in the chemical liquid induction composite pipe 10 so that the volume ratio of liquid A: liquid B is 1:2.4 to 2.7. They are mixed and stirred to prepare a curable chemical solution.

This hardening chemical liquid is discharged from the injection tube 14 and injected into the cavity 63. The hardening chemical liquid flows and spreads radially around the drilled holes 64a on the lining concrete 61 in the cavity 63, and immediately hardens while foaming and expanding, producing foamed polyurethane. The cavity 63 is gradually filled with this foamed polyurethane.

The injection operator 73 visually confirmed that the foamed polyurethane leaked slightly from the drilled hole 64b, which is different from the drilled hole 64a into which the injection pipe 14 was inserted, and the cavity 63 was filled with the foamed polyurethane. judge things. The injection operator 73 immediately instructs the pump operator 74 to stop the operation of both pressure pumps 21 and 22. When the pump operator 74 turns off the switch of the pump controller, the operation of both pressure pumps 21 and 22 is stopped, and the injection of the curable chemical solution is completed.

The injection operator 73 closes the ball valve 11a of the A liquid transport pipe 11 and the ball valve 12a of the B liquid transport pipe 12 while keeping the ball valve 13a of the air introduction pipe 13 open. As a result, a small amount of the curable chemical solution, A liquid, and B liquid remaining in the chemical liquid guiding composite tube 10 is discharged from the chemical liquid guiding composite tube 10 by air pressure, and the remaining liquid or backflow causes the chemical liquid guiding composite tube to This prevents the chemical liquid guiding composite tube 10 from being clogged or from generating polyurethane foam inside the chemical liquid guiding composite tube 10 and causing the chemical liquid guiding composite tube 10 to rupture. Thereafter, the pump operator 74 stops the operation of the air compressor 30, and the injection operator 73 closes the ball valve 13a.

The injection operator 73 removes the injection tube 14 from the B liquid transport tube 12, bends the injection tube 14, and closes the opening of the injection tube 14 so that the curable chemical solution that has been injected and is still fluid does not leak out. , Curing polyurethane foam. In this way, the backfilling process for filling the cavity 63 formed between the back surface of the concrete lining 61 of the road tunnel 60 and the ground 62 with foamed polyurethane is completed.

The curable chemical liquid used in this backfilling injection device 1 preferably has a mixing ratio of liquid A and liquid B in a volume ratio of liquid A:liquid B = 1:2.4 to 2.7, and is 1: The ratio is more preferably 2.4 to 2.6, and even more preferably 1:2.6.

In this way, in the curable chemical liquid, there is more B liquid than A liquid. Therefore, all of the polyol compound and blowing agent are consumed in the reaction with the isocyanate compound to produce foamed polyurethane. On the other hand, in the isocyanate compounds that are not consumed in the reaction with the polyol compound and the blowing agent, their isocyanate groups react with each other to form multimers of isocyanate compounds, such as dimers and/or trimers. The isocyanate compound polymer is incorporated into the foamed polyurethane.

This foamed polyurethane has a lower expansion ratio than the conventionally known foamed polyurethane for filling cavities. The foamed polyurethane produced according to the present invention has a lower limit of expansion ratio of 3 times, 4 times, 5 times, and 6 times, and an upper limit of 6 times, 7 times, 8 times, 9 times, and 10 times. The combination of the lower limit and upper limit of the expansion ratio is arbitrarily selected from the above upper and lower limits. If the foaming ratio is too low, the density of the foamed polyurethane will be too high, resulting in a high load on structures such as tunnel lining concrete. On the other hand, if the expansion ratio is too high, the density of the polyurethane foam will be too low and it will be difficult to satisfy the compressive strength of 1.5 N/mm ² .

The foaming ratio can be determined by dividing the density of the curable chemical solution obtained by mixing the A liquid and the B liquid by the bulk density of the foamed polyurethane determined in accordance with JIS K7222 (2005). .

The foamed polyurethane prepared for determining the foaming ratio is prepared without any interference during the production process. Specifically, a curable chemical solution prepared by mixing liquids A and B is discharged through a pump into a beaker, which is a non-sealed container without a lid, and left to foam. Produce polyurethane foam for measuring expansion ratio. Foaming a curable chemical under such conditions is called free foaming. The expansion ratio, compressive strength, and density of the foamed polyurethane are determined based on a test piece cut from the foamed polyurethane prepared by this free foaming.

The foamed polyurethane produced by foaming and curing the curable chemical has a relatively low expansion ratio as described above. Therefore, foamed polyurethane, which is a cured product of a curable chemical, has few voids and exhibits high density and high compressive strength. The density of the polyurethane foam is preferably 100 to 250 kg/m ³ , more preferably 110 to 240 kg/m ³ , even more preferably 120 to 130 kg/m ³ . This density is determined based on the apparent core density of JIS K7222 (2005). Specifically, each side of a rectangular parallelepiped test piece of polyurethane foam cut into a size of about 50 mm long x 50 mm wide x 50 mm high is accurately measured, and the volume is calculated. The test piece is then weighed and the weight divided by the volume. Further, the compressive strength is specifically at least 1.5 N/mm ² , preferably 2.0 N/mm ² or more, and more preferably 2.5 N/mm ² or more. This compressive strength is based on JIS K7220 (2006), and the compression test speed is 10% of the pre-test specimen thickness per minute, specifically 4.9 to 5.1 mm/min, more specifically 5 The value is measured as .0 mm/min.

In the present invention, a curable chemical liquid is prepared in which liquid B is present in excess of liquid A containing a foaming agent such as water. Therefore, in the curable chemical liquid, the number of moles of isocyanate groups derived from the isocyanate compound contained in liquid B is preferably 2.5 to 3.5 times, per 1 mole of hydroxyl groups derived from the polyol compound contained in liquid A. is 2.8 to 3.2 times, more preferably 2.9 to 3.1 times.

Even if the curable chemical injected into the cavity comes into contact with spring water or stagnant water in the cavity, and a urea-containing part that is difficult to develop high compressive strength is formed in the polyurethane foam, the curable chemical The excess isocyanate compounds contained therein form trimers that give the foamed polyurethane high compressive strength. Therefore, even if water is present in the cavity, it is possible to produce polyurethane foam having a high compressive strength of 1.5 N/mm ² or more.

The liquid temperature of liquid A and liquid B is preferably kept at 5°C to 40°C while stored in each tank, more preferably 10°C to 35°C, and more preferably 15°C to 25°C. It is more preferable that the temperature is ℃. They are mixed in a specific volume ratio at the liquid temperature to prepare a curable chemical solution. Further, it is preferable that the A liquid and the B liquid are at the same temperature.

According to the backfill injection device 1 of the present invention, not only under clean conditions, but also in the presence of rocks, stones, obstacles such as square timbers and concrete blocks used for tunnel excavation, as well as spring water and stagnant water in the cavity. Even in the case where the compressive strength is 1.5 N/mm ² or more, it is possible to produce polyurethane foam inside the cavity. As a result, it is possible to reliably prevent the collapse of the earth without being crushed by the earth.

Moreover, according to the backfilling injection device 1 of the present invention, the heat generated during the production of polyurethane foam can be suppressed to a lower level than in the past. Therefore, even if the polyurethane foam comes into contact with combustible materials such as dead leaves and branches during the production of the polyurethane foam, it is possible to reliably prevent them from catching fire due to the heat of the polyurethane foam. In this way, according to this backfilling injection device 1, cavity filling work can be performed while ensuring high safety. The internal temperature during production of polyurethane foam produced by the backfilling injection device 1 of the present invention is suppressed to a maximum of 190°C, preferably 180°C. This is because the isocyanate compound in liquid B in the curable chemical solution is excessive, so the frequency of reaction with the polyol compound and blowing agent in liquid A is suppressed, and the heat generation caused by foamed polyurethane formation is suppressed compared to before. it is conceivable that.

The polyol compound contained in Solution A may be a polyhydric alcohol, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-diethyl-1, 3-propanediol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methylpentanediol, 2,2,3-trimethylpentanediol, neopentyl glycol, 1,3-hexanediol, 1,4-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8- Aliphatic polyhydric alcohols such as octanediol, 2-methyl 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, and 1,18-octadecanediol, 1,20-eicosanediol ; alicyclic polyhydric alcohols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; catechol, 4-t-butylcatechol, resorcinol, hydroquinone, 2-t-butylhydroquinone, 2,5-dihydroxytoluene , 2,6-dihydroxytoluene, 3,4-dihydroxytoluene, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, Aromatic polyhydric alcohols such as 2,7-dihydroxynaphthalene, 2,2'-dihydroxydiphenyl, 2,3-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl, bisphenol A, and phloroglycinol; glycerin, diglycerin , trimethylolethane, trimethylolpropane, pentaerythritol, castor oil, sorbitol, and sucrose. These may be used alone or in combination.

The polyol compound may be a polyether polyol. Examples of polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol; polyether diols obtained by adding propylene oxide to propylene glycol, and polyethers obtained by adding propylene oxide to bisphenol A. Examples include polyether triols in which propylene oxide is added to diols and glycerin, polyether tetraols in which propylene oxide is added to the active hydrogen of ethylenediamine, and polyether polyols in which propylene oxide is added to sorbitol and sucrose systems.

The polyol compound may be a polyester polyol. A polyester polyol is obtained by a condensation reaction between a polyhydric carboxylic acid and the above-mentioned polyol compound.

Polyhydric carboxylic acids that form polyester polyols include oxalic acid, malonic acid, isopropylmalonic acid, succinic acid, methylsuccinic acid, dimethylmalonic acid, ethylsuccinic acid, glutaric acid, β-methylglutaric acid, adipic acid, pimelic acid, and suberin. Acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, octadecanedicarboxylic acid, eicosandicarboxylic acid, maleic acid, fumaric acid aliphatic polycarboxylic acids having 2 to 24 carbon atoms such as itaconic acid, citraconic acid, and mesaconic acid; terephthalic acid, isophthalic acid, orthophthalic acid, dimethyl terephthalate, trimellitic acid, pyromellitic acid, α- Aromatic polycarboxylic acids such as naphthalene dicarboxylic acid, β-naphthalene dicarboxylic acid, and dimethyl 2,6-naphthalene dicarboxylate; such as 1,4-cyclohexane dicarboxylic acid, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Examples include alicyclic polycarboxylic acids. One or more of these polyhydric carboxylic acids are subjected to a condensation reaction with at least one of the above polyol compounds to produce a polyester polyol.

The polyol compound preferably has an average functional group number of 2 to 6 and a number average molecular weight determined from the hydroxyl value of 1000 or less. Specifically, Newport and Sunnix manufactured by Sanyo Chemical Industries, Ltd. are commercially available ("Newport" and "Sunnix" are registered trademarks). More specifically, the polypropylene glycols Newpol PP-200 (number average molecular weight 200 determined from hydroxyl value), Newpol PP-400 (400), Newpol PP-600 (600), and Newpol PP-950. (950); polyoxypropylene glyceryl ether, such as Newport GP-250 (number average molecular weight 250 determined from hydroxyl value), Newport GP-300 (300), Newport GP-400 (420), and Newport PP. -600 (same 600); Polyoxypropylene glycol Sunix PP-200 (number average molecular weight 200 determined from hydroxyl value), Sunix PP-400 (same 400), Sunix PP-600 (same 600), PP-950 (950); Sunnix GP-250 (number average molecular weight determined from hydroxyl value 250), which is polyoxypropylene glyceryl ether, GP-400 (400), and GP-600 (600) can be mentioned.

The content of the polyol compound in liquid A is preferably 10 to 90% by mass, more preferably 15 to 85% by mass, and even more preferably 20 to 80% by mass.

Liquid A contains a foaming agent. Examples of the blowing agent include water; hydrocarbons such as trichloromonofluoromethane, trichlorotrifluoroethane, CHF ₃ , CH ₂ F ₂ , CH ₃ F, and trans-1-chloro-3,3,3-trifluoropropene. Fluoroolefins; dichloromonofluoroethane, chlorodifluoromethane, 1-chloro-1,1-difluoroethane, 1,1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane Hydrochlorofluorocarbon compounds such as

In addition to the polyol compound and the blowing agent, the A liquid may contain an amine catalyst, a trimerization catalyst, a flame retardant, a foam stabilizer, and a plasticizer, if necessary.

The amine catalyst has a function of promoting the production of foamed polyurethane, and reacts with the isocyanate group of the isocyanate compound contained in the B liquid to produce urea. Examples of such amine catalysts include triethylenediamine, 2-methyltriethylenediamine, N,N,N',N'-tetramethylpropylenediamine, and N,N,N',N',N''-pentamethyldiethylenetriamine. , trimethylaminoethylpiperazine, bis-(dimethylaminoethyl)ether, hexahydro-S-triazine, N,N-dimethylaminoethylmorpholine, dimethylaminopropylimidazole, hexamethyltriethylenetetramine, hexamethyltripropylenetetramine, N,N , N-tris(3-dimethylaminopropyl)amine and the like. These may be used alone or in combination. A preferred amine catalyst is triethylene diamine. Since triethylenediamine is solid at room temperature, it is preferably used after being dissolved in the above-mentioned polyol, exemplified by dipropylene glycol. The amount of the amine catalyst is preferably 0.1 to 5 parts by weight based on 100 parts by weight of liquid A.

The trimerization catalyst is contained in the A liquid in order to trimerize the isocyanate compound contained in the B liquid. Examples of such trimerization catalysts include alkaline fatty acid salts and quaternary ammonium, and specifically, alkali metal salts of octylic acid such as potassium octylate are preferred. Since potassium octylate is solid at room temperature, it is preferably used after being dissolved in the above-mentioned polyol, exemplified by triethylene glycol. The trimerization catalyst is preferably used in an amount of 0.1 to 5 parts by mass based on 100 parts by mass of liquid A.

Foamed polyurethane is generated while generating heat inside a closed cavity such as the back of a tunnel lining. Therefore, in order to prevent combustion due to overheating, it is preferable to include a flame retardant in the A liquid. Examples of the flame retardant include halogen compounds, phosphate ester compounds, phosphorus compounds, nitrogen compounds, boron compounds, and sulfur compounds. These may be used alone or in combination. The flame retardant is preferably used in an amount of 1 to 30 parts by mass based on 100 parts by mass of liquid A.

Examples of halogen compounds that are flame retardants include hexabromocyclododecane, 1,1,2,2-tetrabromoethane, 1,2,3,4-tetrabromoethane, and 1,4,5,6-tetrabromo anhydride. Examples include phthalic acid and tetrabromobisphenol A.

Examples of phosphoric acid ester compounds that are flame retardants include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, tricylenyl phosphate, cresyl diphenyl phosphate, Renyl diphenyl phosphate, and non-halogen phosphate esters such as 2-ethylhexyl diphenyl phosphate; tris(β-chloroethyl) phosphate, tris(β-chloropropyl) phosphate, tris(2,3-dibromopropyl) phosphate, tris( 2,3-dichloropropyl) phosphate, tris(1,3-diclosopropyl) phosphate, tris(2-chloroethyl) phosphate, tris(2,4,6-tribromophenyl) phosphate, bis(β-chloroethyl)vinyl Examples include halogen-containing condensed phosphoric acid esters such as phosphonic acid ester and triallyl phosphate.

Phosphorus compounds that are flame retardants include, for example, orthophosphoric acid, ammonium phosphate, ammonium polyphosphate, urea phosphate, guanylurea phosphate, polyphosphorylamide, melamine phosphate, ammonium polyphosphorylamide, phosphoryl trianilide, and phosphorus. Nitriles, tris(2-carbamoylethyl)phosphine, tris(2-carbamoylethyl)phosphine oxide, phosphorylamide, phosphineamide, and vinylphosphonic acid.

Examples of nitrogen-based compounds that are flame retardants include trimethylolmelamine and N-methylolacrylamide. Examples of boron-based compounds that are flame retardants include boric acid, boron phosphate, and ammonium borate. Examples of sulfur compounds that are flame retardants include thiourea, ammonium sulfate, and ammonium sulfamate.

Flame retardant compounds other than those listed above include inorganic compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, antimony trichloride, zinc chloride, tin chloride, tin dioxide, aluminum hydroxide, and magnesium hydroxide. Examples include compounds. When using brominated flame retardants, when using antimony compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, and antimony-containing inorganic compounds such as sodium antimonate as flame retardant aids, the flame retardant effect is reduced. will improve. As the flame retardant, a phosphoric acid ester flame retardant that is liquid at room temperature and has a relatively low specific gravity is particularly preferred. The flame retardant is preferably used in an amount of 1 to 30 parts by mass based on 100 parts by mass of liquid A.

The foam stabilizer can provide uniformly dispersed voids to the foamed polyurethane. Examples of such foam stabilizers include silicone foam stabilizers, and specific examples include polyoxyalkylene dimethyl polysiloxane copolymers. This polyoxyalkylene dimethyl polysiloxane copolymer is often used in rigid foam polyurethane. The foam stabilizer is preferably used in an amount of 1 to 30 parts by mass based on 100 parts by mass of liquid A.

The plasticizer imparts flexibility to the polyurethane foam, allowing it to conform to the complex surface of the hollow earth while forming the polyurethane foam. Such plasticizers include, for example, phthalate esters such as dibutyl phthalate, dioctyl phthalate, and diisononyl phthalate; dibutyl adipate, dioctyl adipate, diisononyl adipate, and bis(2-(2- butoxyethoxy)ethyl); trimellitic acid esters such as tri(2-ethylhexyl) trimellitate; and polyoxyalkylene dialkyl ethers. Among these, polyoxyalkylene dialkyl ethers are preferred because they have little adverse effect on the human body and the environment.

The isocyanate compound contained in liquid B has a plurality of isocyanate groups. Isocyanate compounds include aromatic polyisocyanates, alicyclic polyisocyanates, aliphatic polyisocyanates, and their urethane-modified products, allophanate-modified products, uretdione-modified products, isocyanurate-modified products, carbodiimide-modified products, and uretonimine-modified products. Examples include modified polyisocyanates such as polyisocyanates, urea-modified polyisocyanates, and biuret-modified polyisocyanates.

Examples of aromatic polyisocyanates include diphenylmethane diisocyanate (MDI), polymethylene polyphenyl polyisocyanate (polymeric MDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolylene diisocyanate, and crude tolylene diisocyanate. , naphthalene diisocyanate, diphenylmethane diisocyanate, and trimethylene xylylene diisocyanate. Examples of the alicyclic polyisocyanate include hydrogenated MDI, hydrogenated XDI, hydrogenated TMXDI, isophorone diisocyanate, cyclohexylmethane diisocyanate, and cyclohexane diisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate and [1-(methoxycarbonyl)pentane-1,5-diyl] diisocyanate. These may contain isomers and may be used alone or in combination of multiple types. Moreover, these may be turned into dimers or trimers by the catalyst. Furthermore, the polymeric MDI may contain flame retardants and plasticizers, examples of which include halogenated phosphate esters.

The backfill injection method of the present invention can be applied to not only cavities on the back side of tunnel lining as shown in Fig. 1, but also cavities under building foundations, cavities formed by partial defects in building structures, abandoned mineshafts, and waterways. It can be suitably used to block side shafts such as air raid shelters, and lifeline burial shafts. A buried lifeline pit refers to a horizontal shaft buried underground that accommodates lifelines such as water and sewage pipes, power transmission lines, gas pipes, and communication lines such as telephone lines and optical lines.

An example in which a cavity was filled with foamed polyurethane using the backfill injection device of the present invention, and a comparative example in which a backfill injection device to which the present invention is not applied are shown.

(Example 1)
Solutions A and B for preparing a curable chemical solution used in the backfill injection device of the present invention were prepared as follows.
<Liquid A>
・Polyol compound: polyether polyol (manufactured by Sanyo Chemical Industries, Ltd., product name: SANNIX GP-600), 15% by mass
・Polyol compound: polyether polyol (manufactured by Sanyo Chemical Industries, Ltd., product name: SANNIX GP-300), 24% by mass
・Polyol compound: polyether polyol (manufactured by Sanyo Chemical Industries, Ltd., product name: SANNIX PP-600), 10% by mass
・Foaming agent: tap water, 1% by mass
・Flame retardant: Trischloropropyl phosphate (manufactured by Daihachi Kagaku Kogyo Co., Ltd., trade name: TMCPP), 29% by mass
・Plasticizer: Polyoxyalkylene dialkyl ether (manufactured by Sanyo Chemical Industries, Ltd., trade name: DM-200), 19% by mass
・Amine catalyst: Quaternary ammonium salt (manufactured by San-Apro Co., Ltd., trade name: U-CAT18X), 1.8% by mass
・Amine catalyst: bis(2-dimethylaminoethyl) ether (manufactured by Tosoh Corporation, product name: TOYOCAT-ETS), 0.2% by mass
<Liquid B>
・Isocyanate compound: Polymeric MDI (manufactured by Tosoh Corporation, product name: MR-200, 100% by mass

A rectangular parallelepiped-shaped container (length, width, and height are all 250 mm) with an open top was prepared. In a room at 20°C and 60% humidity, pour liquid A into the liquid A tank 51, which is a 1L container with an opening at the top for injecting liquid A, and use a double wrap film (stock) with the opening as a lid 53. The A-liquid tank 51 was sealed by covering it with NEW Klewrap (manufactured by Kureha Co., Ltd., trade name: NEW KLEWAP) and fixing it with a rubber band. Immediately after that, liquid A and liquid B (both liquid temperature 20°C) were mixed using the backfill injection device shown in Fig. 1 so that liquid A: liquid B = 1:2.4 (volume ratio). While preparing a curable chemical solution (density (D _L ) of the curable chemical solution: 1.18 g/cm ³ ), 200 mL of the curable chemical solution was discharged into the container. Thereby, the curable chemical solution was foamed in the container to generate foamed polyurethane, thereby obtaining foamed polyurethane. A test piece measuring 50 mm x 50 mm x 50 mm (length x width x height) was cut out from this polyurethane foam. This was used as a test piece for which the standing time was 0 hours. The procedure was the same as that for preparing a test piece with a standing time of 0 hours, except that the solution A was allowed to stand for 1 hour, 3 hours, 5 hours, and 23 hours in a room with a humidity of 60% at 20 ° C. Test pieces were prepared after being left standing for 1 hour, 3 hours, 5 hours, and 23 hours.

(Calculation of foaming ratio)
Regarding the foamed polyurethane of Example 1, the mass of the test piece was measured to determine the density. Determine the volume per unit mass (V _L ) of the above-mentioned curable chemical solution from the reciprocal of the density (D _L ), and the volume per unit mass (V _s ) from the reciprocal of the density (D _S ) of each sample. , V _s /V _L , the foaming ratio of the polyurethane foam of Example 1 was calculated. The results are shown in Table 1 and FIG. 2 below.

(Comparative example 1)
Same as Example 1 except that instead of the A liquid tank 51, the A liquid was put into a 1L container with an open top, and immediately after that, the A liquid and the B liquid were mixed with the top left open. Polyurethane foam was obtained under the same conditions and operations, and test pieces were cut out. This was used as a test piece for which the standing time was 0 hours. The same conditions and operations as in Example 1 were carried out, except that the 1L container containing liquid A was left unsealed with the top open for 1 hour, 3 hours, 5 hours, and 23 hours. , test pieces were prepared with standing times of 1 hour, 3 hours, 5 hours, and 23 hours. Regarding the compressive strength and expansion ratio of each polyurethane foam, the results obtained in the same manner as in Example 1 are shown in Table 1 below. Moreover, the results of the obtained expansion ratios are shown in FIG.

From Table 1, FIG. 2, and FIG. 3, it became clear that Example 1 suppressed moisture absorption over time and exhibited a low expansion ratio and high compressive strength. On the other hand, in Comparative Example 1, it was revealed that the expansion ratio increased over time and the compressive strength decreased accordingly. In FIG. 2, the solid line is the approximate straight line y=0.036x+8.78 of Example 1, and the broken line is the approximate straight line y=0.281x+8.57 of Comparative Example 1.

(Example 2-1)
In a constant temperature bath at 40°C and 80% humidity, liquid A prepared in the same manner as in Example 1 is placed in a liquid A tank 51, which is a 2L container with an opening at the top for injecting liquid A, and the opening is covered with a lid. The liquid A tank 51 was sealed by covering it with a wrap film 53 (manufactured by Kureha Co., Ltd., trade name: NEW Klewrap) and fixing it with a rubber band. Immediately after that, liquid A and liquid B (both liquid temperature 40°C) were mixed into a curable chemical solution (density of curable chemical liquid ( _DL ): Polyurethane foam was obtained under the same conditions and operations as in Example 1, except that 1.18 g/cm ³ ) was prepared, and a test piece was cut out. This was used as a test piece for which the standing time was 0 hours. The procedure for preparing the test piece with a standing time of 0 hours was repeated, except that the solution A was left standing in a constant temperature bath at 40°C and 80% humidity for 3 hours and 5 hours. Each test piece was prepared for 5 hours. Regarding the expansion ratio of each polyurethane foam, the results obtained in the same manner as in Example 1 are shown in Table 2 and FIG. 3 below.

(compressive strength measurement)
For the foamed polyurethane test pieces of Example 2-1, the compressive strength of each was determined in accordance with JIS K7220 (2006) at a compression test speed of 5.0 mm/min. The results are shown in Table 2 and FIG. 4 below.

(Example 2-2)
Each foaming was carried out in the same manner as in Example 2-1, except that a dehumidifying sheet (manufactured by Technard Co., Ltd., product name: Silica Clean Gekitori MAX Large-sized Sheet) was used and the dehumidifying sheet was fixed to the inside of the wrap film with tape. Polyurethane was obtained and test pieces were cut out. Regarding the compressive strength and expansion ratio of each foamed polyurethane, the results obtained in the same manner as in Example 2-1 are shown in Table 2, FIG. 3, and FIG. 4 below.

(Comparative example 2)
In a constant temperature bath at 40°C and 80% humidity, instead of the A liquid tank 51, put A liquid prepared in the same manner as in Example 2-1 into a 2L container with an open top, and immediately after that, the top was opened. Polyurethane foam was obtained under the same conditions and operations as in Example 2-1, except that Liquid A and Liquid B were mixed as they were, and test pieces were cut out. This was used as a test piece for which the standing time was 0 hours. The conditions and operations were the same as in Example 2-1, except that the 2L container containing liquid A was left unsealed for 3 hours, 5 hours, and 23 hours with the top open. Each test piece was prepared after standing for 3 hours, 5 hours, and 23 hours. Regarding the compressive strength and expansion ratio of each foamed polyurethane, the results obtained in the same manner as in Example 2-1 are shown in Table 2, FIG. 3, and FIG. 4 below.

From Table 2, Figures 3 and 4, Examples 2-1 and 2-2 are stable by suppressing the expansion ratio over time and maintaining high compressive strength even in a relatively high humidity environment of 40°C and 80% humidity. It has become clear that foamed polyurethane can be produced by On the other hand, in Comparative Example 2, the expansion ratio was about twice as high from 0 hours to 5 hours as in the example, and it became clear that a constant expansion ratio and compressive strength could not be obtained. In FIG. 3, the solid line is the approximate straight line y=-0.0268x+8.83 of Example 2-1, the dashed line is the approximate straight line y=0.1134x+8.81 of Example 1-2, and the broken line is the approximate straight line y=0.1134x+8.81 of Comparative Example 2. The approximate straight line y=1.4026x+8.73. In FIG. 4, the solid line is the approximate straight line y=0.0147x+1.91 of Example 2-1, the dashed line is the approximate straight line y=-0.0513x+1.91 of Example 2-2, and the broken line is the approximate straight line y=-0.0513x+1.91 of Example 2-2. The approximate straight line y=-0.2324x+1.82.

(Example 3-1)
Set the liquid temperature of liquid A and liquid B to 20°C, mix them so that liquid A: liquid B = 1:2.4 (volume ratio), and make a curable chemical liquid (density of curable chemical liquid (D _L ): 1 Polyurethane foam was obtained in the same manner as in Example ¹ , except that a polyurethane foam was prepared, and a test piece was cut out. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 3 below.

(Example 3-2)
Except that a curable chemical liquid (density of curable chemical liquid (D _L ): 1.18 g/cm ³ ) was prepared by mixing liquid A: liquid B = 1:2.6 (volume ratio). Polyurethane foam was obtained in the same manner as in Example 3-1, and test pieces were cut out. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 3 below.

(Comparative example 3-1)
Except that a curable chemical liquid (density of curable chemical liquid ( _DL ): 1.18 g/cm ³ ) was prepared by mixing liquid A: liquid B = 1:2.8 (volume ratio). Polyurethane foam was obtained in the same manner as in Example 3-1, and test pieces were cut out. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 3 below.

(Comparative example 3-2)
Except that a curable chemical liquid (density of curable chemical liquid ( _DL ): 1.18 g/cm ³ ) was prepared by mixing liquid A: liquid B = 1:3.0 (volume ratio). Polyurethane foam was obtained in the same manner as in Example 3-1, and test pieces were cut out. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 3 below.

(Comparative example 3-3)
Except that a curable chemical liquid (density of curable chemical liquid (D _L ): 1.17 g/cm ³ ) was prepared by mixing liquid A: liquid B = 1:2.0 (volume ratio). Polyurethane foam was obtained in the same manner as in Example 3-1, and test pieces were cut out. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 3 below.

Table 3 shows the average values of the results obtained with n=3 for Example 3-1 and Example 3-2, respectively. From Table 3, the foamed polyurethane of each example showed higher compressive strength and lower expansion ratio than that of the comparative example.

(Example 4)
An acrylic box (length, width, and height all 250 mm) was prepared as a container. A K-type thermocouple was installed in the center of this acrylic box and connected to a data logger. After keeping the A liquid and B liquid prepared in Example 1 at 40°C, using the backfilling injection device shown in Fig. 1, they were mixed so that the A liquid: B liquid = 1:2.4 (volume ratio). 1000 mL of a curable chemical solution was prepared and discharged into an acrylic box. The temperature inside the foamed polyurethane was measured every 10 seconds from the time when the thermocouple was embedded in the foamed polyurethane produced from the curable chemical solution, and the highest internal temperature at this time was recorded. The results are shown in Table 4.

(Comparative example 4)
The highest internal temperature of polyurethane foam was recorded by operating and measuring in the same manner as in Example 4, except that the A liquid and the B liquid were changed to A liquid: B liquid = 1:2.0 (volume ratio). . The results are shown in Table 4.

Table 4 shows that the maximum internal temperature of the foamed polyurethane obtained in Example 4 was suppressed to within 190° C., and it became clear that foamed polyurethane could be produced while ensuring safety.

(Example 5-1)
Set the liquid temperature of liquid A and liquid B to 20°C, mix them so that liquid A: liquid B = 1:2.4 (volume ratio), and make a curable chemical liquid (density of curable chemical liquid (D _L ): 1 Polyurethane foam was obtained in the same manner as in Example 1, except that .17 g/cm ³ ) was prepared. The curing rate of this foamed polyurethane was measured. This measurement was carried out as follows. The time point at which mixing of liquid A and liquid B was started was taken as the starting point of the measurement. After foaming polyurethane was produced, a resin plate was brought into contact with the surface of the polyurethane foam and immediately separated, to observe stickiness (stickiness) due to the adhesion of water contained in the foamed polyurethane immediately after production. The time point when this adhesion was no longer observed was defined as the end point of the measurement. The time from the starting point to the ending point was defined as the curing speed. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 5 below.

(Example 5-2)
Set the liquid temperature of liquid A and liquid B to 20°C, and mix them so that liquid A: liquid B = 1:2.6 (volume ratio) to make a curable chemical liquid (density of curable chemical liquid (D _L ): 1 Polyurethane foam was obtained in the same manner as in Example ¹ , except that a polyurethane foam was prepared, and a test piece was cut out. Further, the curing rate was measured in the same manner as in Example 5-1. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 5 below.

(Comparative Example 5-1)
Set the liquid temperature of liquid A and liquid B to 20°C, and mix them so that liquid A: liquid B = 1:2.2 (volume ratio) to make a curable chemical liquid (density of curable chemical liquid (D _L ): 1 Polyurethane foam was obtained in the same manner as in Example ¹ , except that a polyurethane foam was prepared, and a test piece was cut out. Further, the curing rate was measured in the same manner as in Example 5-1. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 5 below.

(Comparative Example 5-2)
The liquid temperature of liquid A and liquid B is 20°C, and they are mixed so that liquid A: liquid B = 1:2.8 (volume ratio) to make a curable chemical liquid (density of curable chemical liquid ( _DL ): 1 Polyurethane foam was obtained in the same manner as in Example ¹ , except that a polyurethane foam was prepared, and a test piece was cut out. Further, the curing rate was measured in the same manner as in Example 5-1. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 5 below.

(Comparative Example 5-3)
Set the liquid temperature of liquid A and liquid B to 20°C, mix them so that liquid A: liquid B = 1:3.0 (volume ratio), and make a curable chemical liquid (density of curable chemical liquid ( _DL ): 1 Polyurethane foam was obtained in the same manner as in Example ¹ , except that a polyurethane foam was prepared, and a test piece was cut out. Further, the curing rate was measured in the same manner as in Example 5-1. Regarding the compressive strength and expansion ratio of polyurethane foam, the results obtained in the same manner as in Example 2-1 are shown in Table 5 below.

As shown in Table 5, in Example 5-1, the curing speed was fast, especially the top portion dried quickly. Example 5-2 dried in 269 seconds and had a compressive strength of 1.5 N/mm ² or more. In Comparative Example 5-1, the curing speed was fast, but the expansion ratio was 11.26 times, and the compressive strength was less than 1.5 N/mm ² . In Comparative Example 5-2, the vertex and wall portions dried slowly. In Comparative Example 5-3, the curing speed was slower than in each Example, and the surface after curing was in a brittle state.

The backfill injection device and backfill injection method of the present invention can be applied to cavities under building foundations, cavities formed by partial defects in building structures, abandoned mines, waterways, air raid shelters, and lifeline burial pits. It is used to block horizontal shafts.

1 is a backfilling injection device, 10 is a chemical liquid guide composite tube, 11 is an A liquid transport pipe, 11a is a ball valve, 12 is a B liquid transport pipe, 12a is a ball valve, 13 is an air introduction pipe, 13a is a ball valve, 13b is a Bourdon tube, 14 is an injection pipe, 20 is a pump unit, 21 is a liquid A pressure pump, 22 is a liquid B pressure pump, 23 is a pump controller, 30 is an air compressor, 41a is a first liquid A tube, 41b is a second liquid A Tubes, 42a is the first B liquid tube, 42b is the second B liquid tube, 43 is the air tube, 51 is the A liquid tank, 52 is the B liquid tank, 53 is the lid, 60 is the road tunnel, 61 is the lining concrete, 62 is the 63 is a cavity, 64a and 64b are drilling holes, 65 is a sealing material, 71 is an aerial work vehicle, 71a is a bucket, 72 is an equipment loading vehicle, 73 is an injection worker, and 74 is a pump operator. .

Claims (6)

A backfill injection device for injecting a curable chemical solution, which is a mixture of a liquid A containing a polyol compound and a blowing agent, and a liquid B containing an isocyanate compound, into a cavity,
An injection tube inserted into the cavity, a liquid drug guide composite tube connected to the injection tube and for mixing the liquid A and the liquid B, and a liquid A transport pipe and a liquid B connected to the chemical liquid guide composite tube. A liquid transport pipe, a liquid A tank and a liquid B tank storing the liquid A and the liquid B, respectively, and a liquid transport pipe for transporting the liquid A and the liquid B from the liquid A tank and the liquid B tank. The amount of the A liquid and the B liquid sent by the A liquid pressure feeding pump and the B liquid force feeding pump, which are respectively pressurized and sent to the B liquid transport pipe, and the A liquid pressure feeding pump and the B liquid pressure feeding pump are independently controlled. Equipped with a pump controller to adjust the
The liquid A tank has an opening whose top surface is open for charging the liquid A, and a lid covering the opening,
The lid and the periphery of the opening do not contact each other in at least one place to form a gap, an air introduction hole is formed in a part of the lid, and the lid is screwed or fitted into the opening, and /or the lid is an elongated wrap film that is in close contact with the periphery of the opening;
Backfill injection characterized in that the volume ratio between the amount of the liquid A and the amount of the liquid B contained in the curable chemical liquid is adjusted to 1:2.4 to 2.7 by the pump controller. Device. The lid is characterized in that it is the wrap film made of polyolefin selected from polyethylene, polyvinyl chloride, polyvinylidene chloride, and polyethylene, or a plastic cap that screws or fits into the opening. The backfill injection device according to claim 1. The polyol compound is at least one selected from the group consisting of polyhydric alcohols, polyether polyols, and polyester polyols,
The blowing agent is at least one selected from the group consisting of water, hydrofluoroolefins, and hydrochlorofluorocarbon compounds,
The isocyanate compound is from the group consisting of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, and trimethylene xylylene diisocyanate. The backfilling injection device according to claim 1 or 2, characterized in that the backfilling injection device is at least one selected from the group consisting of at least one type of backfilling injection device. A backfilling injection method comprising injecting the hardening agent into the cavity using the injection device according to any one of claims 1 to 3. The cured product of the curable chemical solution is a foamed polyurethane having a compressive strength of at least 1.5 N/mm ² and a volume 3 to 10 times that of the curable chemical solution. The backfill injection method according to claim 4. The backfill injection method according to claim 4 or 5, wherein the cavity is a cavity on the back side of a tunnel lining, a cavity under a foundation of a building, a cavity in a building structure, and/or a side shaft. .

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