JP6474180B1 - Method of pouring groundwater ground board into hardened grout - Google Patents

Abstract

Provided is a method for injecting groundwater groundwater into a groundwater with a hardened grout with little delay in gelation time and sufficient expression of early strength even if the ground is filled and diluted in groundwater. SOLUTION: A hardened grout is added to a liquid A of cement milk containing 500 to 1,200 kg of cement per m 3, and water glass having a concentration of SiO 2 with a molar ratio of 2.5 to 4.0 and a concentration of 20 to 35%. The liquid B is mixed at a ratio of 130 to 500 L with respect to 1 m 3 of the liquid A, and the basic before dilution assuming that the hardened grout is diluted with ground water to a predetermined dilution ratio within 3 times. The delay of the gel time diluted with water at the predetermined dilution rate assumed in comparison with the gel time of blending is within 15 seconds, and the uniaxial compressive strength after 3 hours of dilution with water at the predetermined dilution rate is 0. The above-mentioned hardened grout blended so as to be 15 N / mm 2 or more is poured into the groundwater base plate. [Selection figure] None

Description

  The present invention relates to a method for injecting hardened grout into a groundwater ground plate for injecting hardened grout into the ground under groundwater for water stoppage and ground strengthening. In detail, the present invention has little delay in gelation time even when a grout obtained by proportionally injecting a small amount of high-concentration water glass liquid B into cement milk A is diluted in groundwater, and exhibits early strength. The present invention relates to a method for injecting groundwater groundboard into hardened grout that can be demonstrated.

  Conventionally, a ground injection chemical solution (hereinafter referred to as grout) has been used as a method for stopping the ground under groundwater or strengthening the ground. However, of these, the high water pressure of fluids such as crushing zones and cracks in mountains and the like, underground water in gravel layers, and the prevention of spring water generated during excavation of crushing zones and permeable ground in mountain tunnels (water stoppage) ) Was very difficult. Therefore, an effective still water grout was desired.

  Also, if the ground under the ground water collapses due to natural disasters such as earthquakes, typhoons, heavy rains, etc., or if a water cave (cavity filled with water) occurs due to sediment discharge, etc., it will be quickly reinforced and repaired In this case, it is necessary to inject and fill grout.

  In particular, sediment runoff and water caverns that occur on ground under groundwater such as roads, railways, etc. that are being used (in use) are required to return immediately (usually targeted for 3 hours).

  In addition, among the injection methods, the lot injection method uses a large amount of water for ground drilling and lot removal, so the grout is diluted even if it is not under ground water.

  As described above, ground water under groundwater and water stoppage due to lot injection method, grout to prevent springing and filling water canal, even if diluted in water, there is little delay in gelation time, and There is a need for a grout that develops strength early.

Conventionally, a solution type grout is known as a grout for water stop and ground reinforcement injected into the ground under such ground water (see Non-Patent Document 1, page 38, FIGS. 2, 28, etc.). This solution type grout is composed of high-concentration water glass and sodium aluminate. When diluted with water, the solution type grout has a unique property that the gelation time is short and the homogel strength is about 0.8 N / mm ^2. It was known as a grouting grout, and it also showed a water-stopping effect even in the ground under groundwater.

  However, health hazards to the human body due to sodium aluminate contained in this type of solution-type grout became known, provisional guidelines were established in 1974, and because sodium aluminate has been designated as a deleterious substance, Has been banned (see pages 225 to 235 of Non-Patent Document 1).

  After that, it is difficult to delay the gelation time even if it is diluted in groundwater, and the present situation is that a grout that exhibits an early strength that can withstand the groundwater pressure has not yet appeared.

  When grout is poured into the ground under ground water, the grout is always diluted with water. However, conventionally, even in the case of a grout diluted with a large amount of water, the gelation time and strength (28 days) according to the intended application are based on the values at the time of blending without being considered at the time of design. Is set.

Usually, when a certain level of strength is required, a cement-water glass grout is used, and the present invention also belongs to this. In the cement-water glass grout, generally, when the grout strength is set to ² to 5 N / mm ² , the amount of cement is generally about 200 to 400 kg per 1 m ^{3 of} grout.

[Ground injection]
First, the prior art of a grout combining ground-injected cement and water glass according to the present invention will be described. In Patent Document 1, a grout containing about 0.01 to 0.4 cement of water glass and water glass undiluted solution is pumped separately, and is merged as close as possible to the tip of the injection tube and immediately consolidated. An injection method using water glass and cement, which is a feature, is disclosed (see the claims of Patent Document 1).

The injection method described in Patent Document 1 is a method in which a small amount of cement (60 to 70 kg per 1 m ³ ) is added to water glass, and the gelation time (hereinafter referred to as gel time) is 10 to 20 minutes. It was intended to penetrate into. However, it was never put into practical use.

  As a practical application, for example, in Non-Patent Document 2, as a liquid A, a total of 500 L obtained by adding water to No. 3 water glass 200-250 L, and as a liquid B, a total of water added to 200-250 kg of cement A water glass suspension grout mixed with 500 L is disclosed (see pages 13, 26, 40, etc. of Non-Patent Document 1).

The water glass-based suspension grout described in Non-Patent Document 2 is a grout having a gel time generally referred to as LW of about 1 minute and a homogel strength of about 3 N / mm ² (material age 28 days). It was used for the purpose of water stoppage and ground strengthening as penetration of large gaps such as gravel layers and splitting (veiling) injection into viscous soil layers.

  In addition, when injecting grout into sandy soil, if the content of silt and clay is 10% or more, even if it is solution type grout, it cannot be infiltrated between soil particles and injected in a split shape (split the ground layer). To inject while).

  This water glass suspension grout is used as a ground pouring method, water glass is used as liquid A, cement is used as a curing agent (liquid B) for gelling water glass, and the main component is water glass. It is a grout that has been put into practical use from the same technical idea as in Patent Document 1.

  However, LW is based on the principle that liquid A and liquid B are injected in equal amounts, the gel time is short and cannot be instantly set, and the rising strength after gel (early strength development) is very high. There was a difficulty of being weak. For this reason, the rising strength after gelation was very weak, and even after gelation, it was press-fitted far away with an infusion pump (a constant amount discharge regardless of the infusion pressure), and could not be kept within the limited range.

  Thereafter, an instantaneous setting method was developed, and an instantaneous setting grout in which a gelation accelerator such as lime was added to LW was produced, but the rising strength after gelation was not improved so much and LW was not significantly different. The reason is that the rising strength immediately after gelation is governed by the gelation strength of water glass, and it takes a long time (about 5 to 8 hours) for the cement to start hardening (non-patent document). 1 P179-181).

  In addition, the instantaneous setting grout was developed as an instantaneous setting method using a double-pipe lot, and the stopping water grout is used to prevent the flow of pressurized water and the prevention of spring water from the permeable ground under the ground water (water stopping). Could not be used as.

  As described above, in the conventional technique, since the rising strength after gelation cannot be increased, there is a great difficulty in that the injection cannot be performed in a limited range. For this reason, at present, LW is hardly used.

[Cavity filling injection]
Next, the prior art of cavity filling injection relating to the present invention will be described. Patent Document 2 filed in 1979 discloses a plastic grout using thixotropic gel based on a completely new concept as a cavity filling (backfill) injection method (Patent Document 2 Patent Request) Refer to the scope of In addition, the plastic grout here has a strength enough to be self-supporting in a stationary state, but a consolidation strength (mayonnaise) that can be easily fluidized when pressurized (added with injection pressure). Is a grout.

  Unlike the above-described LW, the plastic grout described in Patent Document 2 is a so-called main agent (liquid A), and a small amount of water glass (liquid B) is added at a high concentration as a hardener that gels a large amount of cement. The principle is to use the proportional injection method.

Patent Document 3 includes a liquid A which is a cement suspension and a liquid B which is a water glass aqueous solution, and the water glass concentration in 1 L of the liquid B is 20% by weight or more based on SiO _2. A grout material is disclosed, characterized by mixing both AB liquids in such a ratio that the amount of SiO _{2 in} the liquid is about 3.5 to 9 g with respect to 100 cc of the volume of the mixed liquid of A and B. (Refer to claim 1 etc. of claim of patent document 3). The grout material described in Patent Document 3 is intended to shorten the gel time by adding a small amount of a high-concentration B liquid to the A liquid.

Then, Patent Document 4, consists of a liquid B is A liquid and water glass solution is cement suspension, water glass concentration in solution B 1L is in the range of about 160~320g in an amount of SiO ₂ The ratio AB both liquids are mixed so that the amount of SiO ₂ derived from B liquid is about 0.6 to 3.5 g with respect to 100 cc of the volume of B liquid and the volume of water in A liquid. A grout injection method characterized by injecting a grout material is disclosed (see claims of Patent Document 4). The grout injection method described in Patent Document 4 has an advantage that early strength can be obtained, and has a property superior to that of LW in which A liquid and B liquid are mixed and injected in equal amounts. .

Furthermore, Patent Document 5 discloses a grout material containing 200 to 400 kg of cement per 1 m ³ of grout and S / W × 100 ÷ √C of 0.19 to 0.46 as an example. Here, S is the weight of SiO _{2 in} the water glass, W is the remaining capacity excluding SiO ₂ and Na ₂ O in the water glass, and C is the weight of the cement (the claim of the patent document 5) Item 1, Table 4, etc.). The grouting material described in Patent Document 5 is capable of obtaining a higher strength than the grouting material used in the grouting method described in Patent Document 4.

However, the object of the invention described in Patent Document 5 is that the early strength development is in the range of 200 to 400 kg of cement per 1 m ^{3 of} grout. The optimum amount of SiO ₂ concentration 20% by volume was determined, and the uniaxial compressive strength after 1 hour was extremely different from 0.021 to 2.18 N / mm ^{2 in} Examples 1 to 21. This indicates that it is not a grout that requires practical early strength.

  The above-described ground injection and cavity filling injection have no technical idea of being diluted by injecting grout into the ground under ground water, and only show the values at the time of blending.

Japanese Patent Publication No. 36-24122 Japanese Patent Application Laid-Open No. 08-239255 Japanese Patent Publication No. 02-4634 Japanese Patent Publication No. 02-43790 JP 2000-290651 A

Mitsuhiro Shibasaki and Kazuo Shimoda, “The latest design and construction of chemical injection method”, Sankaido, September 20, 1985, P38-39, P179-181, P225-235 Goshiro Miki and Kazuo Shimoda, “Plastic grout injection method”, Nikkan Kogyo Kogyo Shimbun, July 20, 2001, P12, 13, 26, 29, 40

  Therefore, the present invention has been devised to solve the above-mentioned problems, and the object of the present invention is to stop water in the ground under groundwater, in particular, stop water such as flowing highly pressurized water and underground water. Introducing groundwater groundwater for hardened grouting, in which the grouting diluted by filling the water cave with little or no spring water injection (water stoppage) from the permeable ground has little delay in gelation time and sufficient expression of early strength. It is to provide an injection method.

The groundwater groundboard injection method for hardened grout according to the first invention is a groundwater groundwater base pouring method for hardened grout that injects hardened grout into the groundwater groundboard, and the hardened grout is 500 to 1,200 kg of cement per 1 m ^3. A liquid B of water glass having a molar ratio of 2.5 to 4.0 with a volume of SiO ₂ and a concentration of 20 to 35% is added to the liquid A containing cement milk in an amount of 130 to 500 L with respect to 1 m ³ of the A liquid. Assuming that the hardened grout is diluted to a predetermined dilution ratio of 3 times or less with ground water, the predetermined dilution ratio is compared with the gel time of the basic composition before dilution. The formulation was such that the delay of the gel time diluted with water was within 15 seconds, and the uniaxial compressive strength after 3 hours of dilution with water at the predetermined dilution ratio was 0.15 N / mm ² or more. Hardened The characterized by injecting underground Underwater ground out.

  According to the present invention, even when the hardened grout injected into the ground under the groundwater is diluted in the groundwater, the gelation time is less delayed and the early strength is sufficiently developed. For this reason, even if the water is stopped in the ground under groundwater, in particular, it is stopped such as flowing highly pressurized water or underground water, spring prevention (water stoppage) injection from the permeable ground, or even when the water cave is filled The water stop and water stop effects can be demonstrated.

  Hereinafter, a method for injecting the groundwater ground board of the hardened grout according to the embodiment of the present invention will be described. First, the hardened grout used for the groundwater ground board injection method of the hardened grout according to the embodiment of the present invention will be described.

[Cured grout]
When grout is injected into the ground under ground water, a phenomenon occurs that it is always diluted. In particular, it was injected into flowing high pressure water such as underground water caused by the height difference of the mountain, the crushing zone of the mountain generated during excavation, the spring water from the permeable ground, or the water tunnel generated in the ground under the groundwater Grout is diluted in many groundwaters.

Therefore, the present invention is not a blended value obtained from the conventional design, but compared with the basic blended cured grout, assuming that the injected grout is diluted within 3 times (volume dilution factor) in the groundwater. Te gelation time (hereinafter, simply referred to as gel time) within the delay of 15 seconds, and, that formulated to uniaxial compressive strength after 3 hours of grout diluted is 0.15 N / mm ² or more Features

  That is, the hardened grout of the present invention has (1) the delay of gelation time is within 15 seconds even if the first injected grout is diluted in groundwater, and (2) the second diluted grout is The two requirements of developing early strength are to be satisfied. Here, the early strength refers to the uniaxial compressive strength after 3 hours.

  In (1) above, particularly in flowing high pressure water, as the gel time is delayed, the dilution increases, the grout flows from the injection point, and the injection range moves. Moreover, dilution becomes large especially in the location where the spring water is generated from the ground. Furthermore, when the hardened grout is injected into the water cave generated in the ground, the grout is injected into the water, and the grout in contact with the water is instantly diluted into a large amount of water. Thus, even when injecting into the ground where the grout is easily diluted with groundwater, as will be described later, if the dilution factor is within 3 times, the gel time delay is ensured within 15 seconds.

  In the above (2), the grout diluted with ground water or the like and gelled cannot withstand the water pressure and flow out under the high flow pressure without the expression of the early strength. Therefore, in the present invention, a desired strength expression is achieved as early as possible, it can withstand the water pressure under fluid high pressure, and it is ensured that the injected grout does not flow out.

  The conventional ground grout injection method for hardened grout is based on the principle of equal injection (the same amount of liquid A and liquid B), and liquid A is the main water glass (fixed amount). It has been used for many years as a curing material (amount of cement determined from strength) for gelling water glass (Non-patent Document 2, P12-13). As shown in paragraph [0014], the typical LW formulation has a gel time of around 1 minute and almost no early strength (see Table 1, Comparative Example 3 and Table 2 Comparative Examples 9 and 10 described later). Therefore, it was not possible to stop the spring water from the groundwater foundation board.

  This is because the conventional cured grout cannot simultaneously satisfy the above (1) and (2) due to the injection of an equal amount. On the other hand, in the present invention, for the first time, the above-mentioned (1) is achieved by proportionally injecting a small amount of high-concentration water glass B solution (gelation and expression of early strength of cement) into a large amount of solution A (cement is the main agent). And (2) can be satisfied at the same time, and the fundamental difference between the two is that gel time can be shortened and early strength can be developed.

  That is, the present invention is formulated by presuming that it is diluted in advance and paying attention to achieve the above two requirements at the same time. We have found a ground grinder injection method for hardened grout that can be achieved.

[Groundwater foundation injection method]
Next, a method for injecting groundwater groundboard into the hardened grout according to the embodiment of the present invention will be described. A case where a hardened grout is injected by a rod injection method will be described as an example.

  The rod injection method uses a single tube or double tube rod (length 3m or 1.5m) mounted on a boring machine as a boring rod to drill the ground, and also as an injection tube to inject hard grout as it is This method is used. This rod injection method uses a large amount of water at the time of drilling and at the time of desorption of the rod.

  That is, water (clean water) is sent from the compounding tank through a suction hose, injection pump, injection hose, injection pipe (rod), drilled into the ground, and then the rod is used as an injection pipe to grout (A liquid and B liquid). And pour water into the ground while pushing out with water. At this time, the grout is diluted in the ground while being in contact with water, and the grout diluted in the same manner as the groundwater has a delayed gel time and a significant decrease in the expression of early strength.

  Furthermore, when excavating and injecting by connecting rods with a deep injection depth, when excavating for the length of one rod, pull up each time (every step), switch the grout to water and remove the rod (one rod is removed) After taking out or connecting), water is again pushed out by the grout and injected. For this reason, every time the rod is detached, the grout is diluted with water.

Specifically, for example, suction hose (inner diameter 25 mm) length 2 m, infusion pump, infusion hose (both A liquid and B liquid, 1/2 inch, cross-sectional area 126.6 mm ² ) length 40 m, rod (inner diameter 38 mm, sectional area 650 mm ² ) If the length is 15 m, the water accumulated in these reaches 29L.

  On the other hand, the injection of grout is about 50 L per step, and the water injected into the ground reaches 58% of the grout capacity, and a large amount of water is injected when combined with the water at the time of drilling. . From this, even if it is not the case of injecting into the ground under the ground water in the rod injection method, the grout is included in the technical scope of the present invention because it is diluted with the preceding water.

  In addition, the injection method used in the present invention is not particularly limited, but in the ground grout groundwater injection method of the hardened grout according to the present embodiment, the above-mentioned hardening to the ground under the groundwater by the rod injection method described above. Grout is injected. Of course, in the groundwater ground board injection method of the hardened grout according to the present invention, the case where the groundwater is injected into the ground under the groundwater using other construction methods such as a jet grout method and an anchor method is also applied. Since the rod injection method, the jet grout method and the anchor method use a large amount of water, the present invention can be suitably applied.

  When the above-mentioned hardened grout is injected into the ground under ground water, the degree to which the grout is diluted into ground water affects the presence or absence of flowing water, the pressure and speed of flowing water, the magnitude of spring water, the size of the water channel, etc. Is done.

  Grout injected into the groundwater is sequentially diluted from the point of contact with water, but the maximum dilution ratio is up to 3 times in volume. This is because, in the basic composition of hardened grout, when diluted more than 3 times, sufficient water stoppage or ground strengthening effect cannot be expected. Therefore, in the present invention, the dilution rate is within 3 times. Is the upper limit.

  Specifically, where the groundwater does not flow much in the permeable ground such as the gravel layer, the dilution ratio of water and grout is assumed to be 1.2 to 1.5 times. In the prevention of spring water (water stoppage) and filling of the water cave which are more easily diluted, it is assumed that the maximum dilution ratio is within 3 times. In the rod injection method described above, the dilution factor is assumed to be about 1.1 to 1.3 times.

<Purification and Curing Principle of Cured Grout>
Next, the gelation / hardening principle of the hardened grout used in the groundwater ground board injection method of the hardened grout according to this embodiment will be briefly described. The groundwater ground board injection method for hardened grout according to the present embodiment is a two-component injection method in which cement milk is used as liquid A and water glass solution is used as liquid B, and these are mixed and injected. Such a two-component grout becomes a sol when the liquid A and the liquid B are mixed, the viscosity increases with the passage of time, the fluidity is lost, and the gel is formed. The time from mixing the two liquids to gelation is the gel time.

  The gelled grout gradually increases in strength after gelation and reaches curing through a plastic consolidated region (plastic holding time). This plastic consolidated region is a cement-type grout (cement milk) and must pass through before any grout is cured (see P26 of Non-Patent Document 2, FIG. 3.1).

  Therefore, the time during which the two-component grout can be injected is the sum of the gel time and the plastic holding time. Accordingly, a grout having a sufficient plastic time (for example, 10 to 20 minutes) is particularly referred to as a plastic grout.

  However, in the composition of the hardened grout used in the groundwater ground board injection method of the hardened grout according to the present embodiment, since the emphasis is placed on early hardness development, the plastic holding time is within 10 seconds and the conventional ground injection method. It is blended so as to be extremely shorter than the blend of the cured grout used.

<Composition of cured grout>
Next, the composition of the hardened grout used in the groundwater ground board injection method of the hardened grout according to the present embodiment will be described in more detail.

In the blending of the hardened grout used in this injection method, it is assumed that the hardened grout is diluted within 3 times, rather than just the composition at the time of design without assuming how much is diluted. In this case, the determination is made by preventing the delay of the gel time and the expression of the early strength at the same time. Specifically, in a state where the grout is diluted to 3 times or less in water, the gel time delay is within 15 seconds from the pre-dilution formulation, and uniaxial compression is performed after 3 hours in the state diluted to the assumed dilution factor. strength is blended so that 0.15 N / mm ² or more. Of course, the long-term (after 28 days) strength of the grout is considered to reach the design strength.

<Formulation before being diluted with water>
The composition of the hardened grout before being diluted with water is 500 to 1,200 kg of cement per 1 m ^{3 of} liquid A, and a molar ratio of 2.5 to 4 at a ratio of 130 to 500 L with respect to B liquid: 1 m ^{3 of} liquid A. 0, mix water glass with SiO ₂ concentration 20-35%.

  The cement to be used is not particularly limited, but ordinary portland cement, blast furnace cement, early-strength cement and the like are preferable. Moreover, you may add the additive which may be added to a normal grout material to A liquid. For example, as additives, slag, fly ash, lime, dispersant (retarding agent), foaming agent, clay minerals such as bentonite, fillers, and the like can be used.

  Here, the reason why the lower limit is 500 kg of the liquid A cement is that if it is less than this value, even if it is adjusted with water glass, the grout diluted with water within 3 times cannot obtain the target early strength. The reason why the upper limit of the cement is 1,200 kg is that when this value is exceeded, the fluidity of the cement milk is impaired and the pressure feeding becomes difficult.

The water glass of B liquid is ₂₀ to 35% in terms of SiO ₂ capacity, and the molar ratio (SiO ₂ / Na ₂ O) is preferably 2.5 to 4.0. This B liquid is adjusted and mixed within the range of the ratio of 130-500L with respect to 1 m < ³ > of A liquid. Here, 30% water glass refers to water glass containing 300 g of SiO ^{2 in} 1 L of solution.

On the other hand, the lower limit value of the mixing ratio of the B liquid water glass (SiO ₂ ) with the A liquid is set to 130 L. If it is less than this value, the uniaxial compressive strength after 3 hours, which is the target early strength, is 1. This is because it does not reach 5 N / mm ² . The reason why the upper limit value of the mixing ratio of the water glass is set to 500 L is that the target early strength can be obtained and the water glass is expensive, so that it is a finite value. In addition, even if it exceeds 500 L of a finite value, if the delay of the gel time and early intensity | strength of this invention are in the range, it can also be used.

  By setting it as the above mixing | blending, in the grout diluted with water within 3 times, the expression of the target early intensity | strength and the delay prevention of the below-mentioned gel time are enabled.

  Gel time depends on the amount of cement and the concentration (amount) of water glass, but the molar ratio of water glass has the most influence. In the present invention, the molar ratio is set in the range of 2.5 to 4.0 from the target gel time.

That is, when the cement amount and the water glass concentration (SiO ₂ amount) are constant, it has been confirmed that the lower the molar ratio, the longer the gel time, and vice versa.

  In the above-mentioned cured grout formulation, a molar ratio of 3.0 to 4.0 is selected for instantaneous setting within 20 seconds within a range of several seconds to 1 minute, and a molar ratio of 2 is selected for slow setting over 30 seconds. .5 to 2.8 are selected.

And considering that the expression of early strength is diluted in groundwater, the uniaxial compressive strength after 3 hours is set to a high strength of 1.5 N / mm ² or more.

<Grout after dilution in water: Diluted grout>
Next, the effect of the grout blended on the ground surface as described above on the gel time and early strength development (after 3 hours) of the grout diluted in groundwater (hereinafter referred to as diluted grout) will be described.

When the grout injected into the ground is diluted in groundwater, it will be greatly affected by the dilution factor. In the present invention, it is a condition that the gel time delay of the diluted grout is within 15 seconds and that the early strength after 3 hours after the preparation is 0.15 N / mm ² or more.

For this reason, specifically, 300 kg or more of cement and 24 kg or more of water glass (SiO ₂ amount) are required per 1 m ^{3 of} grout diluted in groundwater. That is, it was found that the early strength after 3 hours does not become 0.15 N / mm ² or more when the water glass (SiO ₂ amount) is less than 24 kg, regardless of the cement amount.

For example, Experiment No. Even if the diluted grout of 27 is 345 kg of cement, if it is 21 kg of water glass (SiO 2 amount), the early strength after 3 hours is 0.09 N / mm ² , which is confirmed to be incompatible.

  The injection pipe used for the groundwater ground board injection method for hardened grout according to the embodiment of the present invention is not particularly limited, but employs the rod injection method described above. In the rod injection method, after drilling in the ground with a rod, it is used as an injection tube as it is. When the gel time of the grout before dilution is 30 seconds or more, a single tube rod is used, and when the gel time of the grout before dilution is 20 seconds or less, a double tube rod is used.

  According to the groundwater ground board injection method of the hardened grout according to the embodiment of the present invention described above, the gelation time is delayed even when the hardened grout injected into the ground under the groundwater is diluted with the groundwater. There is little and early expression of intensity becomes enough. For this reason, even if the water is stopped in the ground under groundwater, in particular, it is stopped such as flowing highly pressurized water or underground water, spring prevention (water stoppage) injection from the permeable ground, or even when the water cave is filled The water stop and water stop effects can be demonstrated.

[Effect confirmation experiment]
Next, examples and comparative examples are given, and the physical properties of the cured grout are evaluated by each test of a grout at the time of blending and a dilute grout obtained by diluting the same with a gel time measurement, a uniaxial compressive strength test, etc. Verify the effect. Each test was conducted at a liquid temperature of 20 ° C. First, the test method of each test will be described.

(1. Measurement of gel time)
The measurement of the grout gel time at the time of compounding puts a predetermined liquid A in a 5 x 30 cm plastic bag, puts the liquid B in a state where the upper part of the plastic bag is closed by hand, and lifts the hand up and down violently. The time from shaking to stirring until loss of fluidity was defined as gel time. Moreover, the dilution grout measured the gel time by adding the dilution water prepared separately simultaneously with mixing of A liquid and B liquid at the time of a mixing | blending.

(2. Uniaxial compressive strength test)
The uniaxial compressive strength test was conducted according to JIS R 5201 (cement physical test method). Specifically, the grout is adjusted by the same method as the gel time measurement, put into a 4 × 4 × 16 cm triple frame before gelation, and wet-cured at 20 ° C. for 1 hour, 3 hours, and 28 days. The mold was removed after the curing period (hour), and the uniaxial compressive strength was measured.

  Next, various test results will be described by giving examples of cured grout. The cement used for the generation of the hardened grout according to the examples is ordinary Portland cement as cement A, blast furnace cement B type as cement B, and ultrafine cement (trade name: Alofix MC (manufactured by Taiheiyo Materials Co., Ltd.)) as cement C. Three types were used. Cement B is a mixture of cement and blast furnace slag at a ratio of 6: 4, and cement C is a mixture of cement and blast furnace slag (average of ultrafine particles of about 4 μm). The mixing ratio of other substances is not disclosed by the manufacturer.

The water glass, the molar ratio as waterglass _{A (SiO 2 / Na 2 O} ) of 30% strength aqueous glass SiO ₂ capacity of 3.5, the molar ratio as water glass B of SiO ₂ of 3.1 Water glass with a capacity of 40%, water glass C as SiO _{2 with} a molar ratio of 2.5, water glass with a capacity of 30%, water glass D as water glass D with a SiO _{2 with} a molar ratio of 3.0 and water glass with a capacity of 40% Different types of water glass were used. The water glass having a capacity of 30% refers to a water glass containing 300 g of SiO _{2 in} 1 L of the solution.

Table 1 shows the measurement results obtained by mixing a predetermined amount of liquid A and liquid B to produce a hardened grout and performing tests such as gel time measurement and uniaxial compressive strength test. The composition shown in Table 1 is a proportional blend of a small amount of water glass B with a high SiO ₂ concentration with respect to 1 m ^{3 of} liquid A (cement), together with the cement amount per 1 m ^{3 of} grout (liquid A + liquid B) and SiO 2. ₂ quantities are shown.

According to Table 1, the grouts of Examples 1, 2, and ³ are substantially the same as 923 kg of cement A per 1 m ^{3 and} 69, 71, and 69 kg of water glass SiO _{2 of} liquid B, but the gel time is 3, 8 Unlike 10 seconds, the lower the molar ratio, the longer the tendency. In addition, the early strength (uniaxial compressive strength after 3 hours) shows very high values of 10.4, 11.1, 11.5 N / mm ^2, and the 28-day strength is 18.0, 21.7, It showed a high value of 23.2.

That is, according to this experiment, the early strength shows almost the same value even if the molar ratio (SiO ₂ / Na ₂ O) is different, but the long-term strength shows a slightly higher value as the molar ratio is lower. It could be confirmed.

Further, when Example 10 and Example 11 are compared, the composition is the same, but Example 10 which is cement A has a gel time of 15 seconds and an early strength of 5.9 N / mm ² , whereas Example 11 which is cement B has a gel time of 34 seconds and an early strength of 2.6 N / mm ² . However, 28 days strength, Example 10, in 13.0 N / mm ^2, Example 11 has a 20.0N / mm ^2, is than cement A is a high intensity towards the cement B found.

  This is because cement A is ordinary cement, while cement B is blast furnace cement (40% slag is mixed, and the cement component is equivalent to 420 kg), so slag contributes little to gel time and early strength. However, long-term strength has the property of exhibiting excellent strength.

Also, grout in formulation of Comparative Example 1 were per A solution 1 m ^3, cement 400 kg, B solution of water glass 110L, water 60L (SiO ₂ concentration 19%), cement, and poor mixing water glass co. The experimental results show that the gel time is as short as 6 seconds, but the early strength is remarkably inferior at 0.04 N / mm ² .

Further, in Comparative Example 2, the molar ratio of the liquid A and the liquid B and the amount of SiO ₂ are the same as in Example 8, but the SiO ₂ concentration is as low as 15% compared to 23% in Example 8. Therefore, it was found that the expression of the early strength (after 3 hours) was remarkably inferior at 0.61 N / mm ² .

As mentioned above, within 500 to 1,200 kg of cement per 1 m ^{3 of} liquid A and 130 to 500 L (20 to 35% concentration) with respect to 1 m ^{3 of} liquid A, the type and amount of cement and the mole of water glass Experiments were performed to adjust the ratio, SiO ₂ concentration and amount. Thus, as shown in Table 1, it can be selected to several seconds to 1 minute gel time and early strength (unconfined compressive strength after 3 hours) to 1.5 N / mm ² or more and (maximum 11N / mm ²⁾ I was able to confirm that it was possible. In other words, assuming that the grout is diluted into the groundwater by injecting into the ground under the groundwater, the grout used in the present invention is injected into the ground where the fluid highly pressurized water exists before the dilution by the above-described composition. The gel strength can be selected from several seconds to about 1 minute.

On the other hand, the ground injection grout (also referred to as the above-mentioned LW: water glass suspension grout) in which the conventional A liquid and B liquid mixed in the same amount as Comparative Example 3 is a large amount of water glass. It was also confirmed that the gel time was 52 seconds and the early strength was extremely low at 0.04 N / mm ² . This is supported by the fact that the early strength of the conventional ground-injected grout (LW) is due to the consolidation strength of the water glass and not due to the cement.

  Next, Table 2 shows the gel time measurement and the uniaxial compressive strength test results when the grout having the formulation shown in Table 1 is diluted in water.

  As shown in Experiment Nos. 15 to 23 in Table 2, the gel times of the diluted grouts obtained by diluting the grouts of Examples 1, 2, and 3 at dilution ratios of 2, 3, and 3.5 times were 4, 6 and 7 seconds, 11, 16, 18 seconds, 17, 20, and 25 seconds. Thus, it can be seen that the gel time tends to increase as the molar ratio decreases to 3.5, 3.0, and 2.5. However, the gel time delay is 1, 3, 4 seconds, 3, 8, 10 seconds, 7, 10, and 15 seconds, all of which are very small within 15 seconds. It was confirmed that there was no delay. This indicates that it exhibits an extremely excellent effect on water stoppage and ground strengthening under groundwater.

On the other hand, Experiment No. The expression of the early strength of 15 to 23 shows a tendency to decrease as the dilution rate increases as compared with the strength at the time of blending in Table 1. In addition, Experiment No. with a dilution factor of 3.5 times. Comparative Examples 4, 5, and 6 of 17, ²⁰ , and 23 do not reach 0.10, 0.08, 0.10 N / mm ² and 0.15 N / mm ² . On the other hand, Experiment No. with a dilution ratio of 3 times or less Examples 12, 18 of 15, 16, 18, 19, 21, 22 have an early strength of 0.15 N / mm ² or more. For this reason, it was confirmed that Examples 12 to 18 can sufficiently withstand the water pressure of the fluidized high pressure water and can be used to stop the ground where the fluidized highly pressurized water exists.

The diluted grouts of Examples 12 to 18 are 308 to 462 kg of cement and 23 to 39 kg of water glass per 1 m ^{3 in the} diluted state, whereas Comparative Examples 4 to 6 are in a diluted state. It is as small as 264 kg of cement and 20-23 kg of water glass per 1 m ³ . For this reason, as mentioned above, it is considered that Comparative Examples 4 to 6 do not reach the initial strength of 0.15 N / mm ² .

Further, when Example 19 and Comparative Example 8 are compared, the cement amounts are 308 kg and 345 kg, the water glass is 24 kg and 21 kg, both are almost the same, and the dilution factor is twice, but the early strength is 0. There is a difference between 17 N / mm ² and 0.09 N / mm ² . This is considered to be caused by the difference in the type of cement, and it was confirmed that Example 19 made of cement A was higher than Comparative Example 8 made of cement B.

Further, Examples 21 to 26 are diluted grouts obtained by diluting Examples 6 to 11 in Table 1 with a dilution ratio of 1.2 to 1.5 times. The experimental results show that the gel time delay is 3, 1, 3, 10, 8, 15 seconds, all within 15 seconds. Moreover, the early stage intensity | strength of Examples 21-26 is 0.67, 0.58, 0.40, 1.19, 2.84, 0.61 N / mm < ² > and all exceed 0.15 N / mm < ² >. Yes.

The long-term strengths (28 days) of Examples 12 to 26, which are diluted in water within 3 times and have an early strength of 0.15 N / mm ² or more, are all 1.2 N / mm ² or more (maximum 7. 4N / mm ² ) was obtained, and it was also confirmed that it had sufficient consolidation strength.

By the above, within the range of the basic composition shown in Table 1, etc., assuming that the grout is diluted within 3 times with water, the diluted grout is 308 to 462 kg of cement per 1 m ³ , and the water glass is It mix | blends so that it may be 24-58 kg. As a result, the diluted grout that is assumed to be diluted within 3 times gels within 15 seconds of delay compared to the gel time of the grout before dilution, and the early strength (uniaxial compressive strength after 3 hours) is It was confirmed that blending was possible so as to be 1.5 N / mm ² or more.

  Therefore, by injecting the hardened grout blended assuming that the grout is diluted within 3 times with ground water into the ground or water channel under the ground water, there is little delay in gelation time, and The expression of early strength is sufficient. For this reason, even if the water is stopped in the ground under groundwater, in particular, it is stopped such as flowing highly pressurized water or underground water, spring prevention (water stoppage) injection from the permeable ground, or even when the water cave is filled The water stop and water stop effects can be demonstrated.

According to the experiment shown in Table 2, when the conventional ground injection grout (LW) was diluted to a dilution ratio of 1.3 or 1.5 times as shown in Comparative Examples 9 and 10, it was 52 seconds ( It was confirmed that the gel time as shown in Table 1 was greatly delayed to 72 seconds and 98 seconds. Further, the early strength was 0.001 N / mm ² : measurement was impossible.

  As mentioned above, the groundwater ground board injection method of the hardened grout according to the embodiment of the present invention and the hardened grout used therefor have been described in detail. However, the above-described embodiments are specific embodiments for carrying out the present invention. It is just what was shown. Therefore, the technical scope of the present invention should not be limitedly interpreted by these.

Claims (1)

A method for injecting a hardened grout into a groundwater ground board, and a method for injecting a groundwater ground board into a groundwater base,
The hardened grout is a liquid A of cement milk containing 500 to 1,200 kg of cement per m ³ , and B of water glass having a concentration of SiO ₂ with a molar ratio of 2.5 to 4.0 and a concentration of 20 to 35%. The liquid is mixed at a ratio of 130 to 500 L with respect to 1 m ^{3 of} liquid A,
Assuming that the hardened grout is diluted with ground water to a predetermined dilution ratio of 3 times or less , a delay in gel time diluted with water to the predetermined dilution ratio assumed compared to the gel time of the basic composition before dilution Within 15 seconds, and the hardened grout blended so that the uniaxial compressive strength after 3 hours of dilution with water at the predetermined dilution ratio is 0.15 N / mm ² or more is injected into the groundwater base plate A method for injecting groundwater groundboard into hardened grout.