JP6733892B1 - Proportional pouring grout monitor and proportional pouring method for hardened grout using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grout monitor for proportional injection having a mixing backflow prevention mixing mechanism for preventing backflow of A liquid to the B liquid side of an inner tube and for mixing A liquid and B liquid, and a proportional injection method of hardened grout using the grout monitor. I will provide a. SOLUTION: To a liquid A of cement milk containing 500 to 1,200 kg of cement per 1 m3, a liquid B of water glass having a concentration of 18 to 35% with a SiO2 volume of 2.5 to 4.0 is used. In the proportional injection grout monitor 10 for proportional injection using the double tube rod 1, the cured grout mixed with 1 m3 of the liquid A at a ratio of 130 to 500 L was discharged from the inner tube 3 of the double tube rod 1. The liquid B is prevented from flowing back into the inner pipe 3, and a backflow prevention mixing mechanism 5 for mixing the liquid A and the liquid B is provided, and the backflow prevention mixing mechanism 5 is provided at the tip opening of the double pipe rod 1. The end opening closing means for closing, a plurality of discharge holes 4 formed on the side surface of the inner tube 3 of the double-tube rod 1 near the tip, and a cylindrical member made of a stretchable material for closely covering the outer surface of the discharge holes 4 are formed. A cylindrical body 50 is provided. [Selection diagram] Figure 1

Description

TECHNICAL FIELD The present invention relates to a grout monitor used for injecting hard-setting or medium-hardening grout as soft ground injection or groundwater ground bed injection, and a proportional grout injection method using the grout monitor. More specifically, the present invention relates to a grout monitor for proportional injection, which is used when proportionally mixing and injecting a small amount of liquid B, which is a high-concentration water glass liquid, into cement milk liquid A, and a proportional injection method of hardened grout using the grout monitor. ..

Conventionally, cement milk and water glass have been combined for the purpose of strengthening the soil of soil structures such as soft ground, embankment ground, river levees, reservoirs, etc., or preventing groundwater subsidence. An equal amount of hardened grout is injected into the ground. In addition, a grout monitor is used as an equal amount injection device provided at the tip of the double tube rod for the equal amount injection of the hardened grout.

First, the prior art of the grout in which the ground-injection cement and water glass according to the present invention are combined will be described. Patent Document 1 discloses that water glass and a grout containing about 0.01 to 0.4 cement of water glass undiluted solution are separately pumped, and the water is merged as near as possible to the tip of the injection pipe and immediately solidified. An injection method using a characteristic water glass and cement is disclosed (see claims, etc. 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 gelling time (hereinafter, referred to as gel time) is 10 to 20 minutes. It was intended to penetrate into. However, it was never put to practical use.

As a practical application, for example, in Non-Patent Document 1, a total of 500 L obtained by adding water to 200 to 250 L of No. 3 water glass as a liquid A, and water as a liquid B to 200 to 250 kg of ordinary cement were added. A water glass-based suspension grout obtained by mixing a total of 500 L is disclosed (see P26, page 40 of Non-Patent Document 1, etc.).

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

Also, when pouring grout into sandy soil, if it contains 10% or more of silt and clay, even if it is a solution type grout, it cannot penetrate into the soil particles and should be injected in a splitting manner (splitting the ground strata). It will be injected while doing).

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

However, LW is based on the principle that A and B solutions are injected in equal amounts, and the gel time cannot be shortened to give a quick-setting property. Furthermore, the rising strength after gelation (expression of early strength) is extremely low. There was a drawback that it was weak. For this reason, the plastic solidification after gelling and the rising strength after that are very weak, and even after gelation, it is pressed into a distant place by an injection pump (a constant amount is discharged regardless of the injection pressure), and it is limited to a limited range. I couldn't.

After that, a quick-setting method was developed, and a quick-setting grout was obtained by adding a gelation accelerator such as lime to LW, but the rising strength after gelation was not significantly improved and was not much different from LW. 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.

As described above, in the conventional technique, since the rising strength after gelation could not be increased, there was a big problem that the injection could not be performed within a limited range. Therefore, at present, LW is rarely used.

On the other hand, Patent Document 2 filed in 1979 discloses a plastic grout using a thixotropic gel with a completely new idea as a cavity filling (backfilling) injection method (Patent Document 2). (See claims, etc.). The term "plastic grout" as used herein has such strength that it becomes self-supporting in a stationary state, but it has a solidification strength (mayonnaise) that is easily fluidized when pressure is applied (when injection pressure is applied). Shape) is a grout.

Unlike the LW described above, the plastic grout described in Patent Document 2 uses cement as a main agent (liquid A) and a small amount of water glass (liquid B) at a high concentration as a hardening agent for gelling a large amount of cement, so-called. In principle, the proportional injection method is used.

However, since the plastic grout described in Patent Document 2 has a very weak rising strength immediately after gelation, it was unsuitable for use as ground grout for ground injection.

After that, an invention relating to a quick-grouting grout capable of expressing early strength (uniaxial compressive strength after 3 hours is 1.5 N/mm ² or more) by applying the principle of proportional injection by proportional mixing (for example, (Injection method of flash-hardened grout described in Patent Document 3, groundwater baseboard injection method of hardened grout described in Patent Document 4)

However, the method for injecting the quick-setting hardened grout described in Patent Document 3 and the method for injecting the hardened grout to the groundwater baseboard described in Patent Document 4 are ground injection by proportional injection of the quick-setting or medium-setting hardened grout (general). It was found that there is a big problem in construction when it is injected into the surface or deeper than 1 m.

As described in Non-Patent Document 2, the conventional double pipe rod injection method (also referred to as a single-phase double pipe strainer method) has a construction method of a double tube with a special monitor attached. A pipe rod is used to perform drilling with water to a predetermined depth, and the double pipe rod drilled after completion of drilling is used as it is as an injection pipe.

The monitor of the injection pipe (double pipe rod) differs depending on the difference in structure and function, and is typically the DDS method, MT method, and LAG method. The former two DDS and MT methods are performed by mixing the liquids A and B in a tube, and the latter LAG method is performed by a tube mixing. These construction methods were developed mainly as a solution-type grout, and are equal amount injection, and are injected at the ground injection pressure (pressure exceeding the ground resistance pressure). The inner tube tip of the grout monitor used in any of the construction methods is not closed.

On the other hand, in the proportional injection described in Patent Document 3, the double tube rod is rotated by forced pressure (see paragraph [0099] of Patent Document 3) to form a disk-shaped grout consolidate (Patent Document 3). Paragraph [0096]), or the double tube rod is pulled up while rotating to form a spiral grout consolidate, and it has been found that there are many problems and the construction cannot be performed.

[problem]
1) When a small amount of B liquid in the inner pipe is mixed with a large amount of A liquid (cement milk) in the outer pipe, the A liquid flows back to the B liquid side of the inner pipe, and the grout gels in the monitor. The grout may become unusable.

2) Since a large amount of A liquid and a small amount of B liquid are discharged in parallel, sufficient mixing cannot be performed within the monitor.

3) In the case of injection under forced pressure, since the rod is rotated, the grout under forced pressure leaks along the gap between the rod and the ground that is generated during drilling, which is easier to enter than the ground. The phenomenon in which the grout leaks is a phenomenon that occurs due to the synergistic action of the forced pressure and the rotation of the rod (a gap easily occurs). Of these, 1) and 2) are the most important problems to be solved in construction.

In the conventional instantaneous setting method (the non-forced pressure of the present invention also corresponds to this), the grout leaks into the gap around the rod at the start of the injection, but the force is not applied and the rod is not rotated. Therefore, even if the gel time is short and is continuously injected, the grout gels with time and the effect of the grout packer is exerted, so that the injection can be performed without taking any special measures.

On the other hand, the injection method of the present invention is mainly intended for the proportion-setting quick-melting grout having a short gel time, an extremely short plasticity retention time, and a remarkably high early strength. In the injection method of the present invention, the liquid A is pumped to the outer pipe of the double-tube rod and a small amount of liquid B is pumped to the inner pipe, and the grout proportionally mixed in the monitor is rotated under forced pressure to rotate the rod into a disk in the ground. Or a cylindrical grout consolidate is formed, or a spiral grout consolidate is formed while pulling up the rod. Thus, the injection method of the present invention aims to strengthen the ground or stop water. Further, under non-compulsive pressure, the injection is not performed while the rod is being rotated/pulled up, and the injection is performed at a predetermined position to stop the water in the ground under groundwater, prevent spring water, or strengthen the ground.

Japanese Patent Publication No. 36-24122 JP, 08-239255, A Patent No. 6371024 Japanese Patent No. 6474180

Gosaburo Miki/Kazuo Shimoda, “Plastic grout injection method”, Nikkan Kensetsu Kogyo Shimbun, July 20, 2001, P26, 40 Kusano Kazuto, "Chemical Liquid Injection Method Handbook", Yoshii Shoten, July 5, 1983, P125-129

Therefore, the present invention has been devised in order to solve the above-mentioned problems, and an object of the present invention is to improve the monitor of the conventional instantaneous setting method so that the liquid A is transferred to the liquid B side of the inner pipe. It is an object of the present invention to provide a grout monitor for proportional injection having a backflow prevention mixing mechanism for preventing backflow and mixing A liquid and B liquid, and a proportional injection method for cured grout using the grout monitor.

The grout monitor for proportional injection according to the first aspect of the present invention is attached to the tip of a double-tube rod composed of an outer tube and an inner tube , and cement milk containing 500 to 1,200 kg of cement per 1 m ³ flowed in through the outer tube. in the a solution 130 to the solution B 18-35% of the concentration of water glass SiO ₂ volume molar ratio 2.5 to 4.0, which is introduced through the inner tube, the a solution 1 m ³ the cured grout mixed at a ratio of 500L a proportion injection grout monitor for proportional injected using the double pipe rod, reflux the solution a discharged from the outer tube to the liquid B-side of the inner tube And a backflow prevention mixing mechanism for mixing the liquid A and the liquid B, wherein the backflow prevention mixing mechanism closes a front end opening of the double tube rod, and It has a plurality of discharge holes formed on the side surface near the tip of the inner pipe of the double pipe rod, and a cylindrical cylindrical body or ring-shaped ring body made of a stretchable material that closely covers the outer surface of the discharge holes. At the same time, the outer tube is provided with a single or a plurality of nozzles, which are discharge holes formed on the side surface, and the tip opening closing means includes a reduced diameter portion formed at the tip opening of the inner tube and the contraction member. A hard ball having a diameter that cannot pass through the diameter portion, the reduced diameter portion can be closed by the hard ball, and the cured grout can be injected from the nozzle.

In the grout monitor for proportional injection according to a second aspect of the present invention, in the first aspect of the present invention, the cylindrical body is fixed by a fixing band so as not to be vertically displaced, and the B liquid discharged from the discharge hole is applied to the cylindrical body. It is characterized in that it is abutted once and injected upward or laterally to be mixed with the liquid A in the outer tube of the double tube.

A method for proportionally injecting a forced pressure of hardened grout according to a third aspect of the present invention uses the proportional injection grout monitor according to claim 1 or 2 to apply a higher forced pressure than a normal ground resistance pressure to the hardened grout on the ground. Is a proportional injection method of the forced pressure of the hardened grout, wherein the injection of the flashing grout is temporarily stopped for a time within 3 times the gel time of the hardened grout to cause the grout to gel and form a grout packer. Then, the double tube rod is rotated a plurality of times at a predetermined position to form a disk-shaped grout consolidate until the forced pressure disappears, and the double tube rod is rotated. A second step of repeatedly moving up and down to the next upper step to form a columnar grout solidified body, and the first step and the second step are defined as one cycle and are sequentially repeated at each injection step. The feature is that the instantaneous grout is injected into the ground until the top injection step.

A proportional injection method of forced pressure of hardened grout according to a fourth aspect of the present invention uses the grout monitor for proportional injection according to claim 1 or 2 to apply a forced pressure higher than a normal ground resistance pressure to the hardened grout on the ground. Is a proportional injection method of the forced pressure of the hardened grout, wherein the injection of the flashing grout is temporarily stopped for a time within 3 times the gel time of the hardened grout to cause the grout to gel and form a grout packer. After that, the double tube rod is simultaneously rotated and gradually pulled up at a predetermined speed to form a spiral grout consolidate.

The proportional injection method of forced pressure of hardened grout according to a fifth aspect of the present invention uses the grout monitor for proportional injection according to claim 1 or 2, and applies a higher forced pressure than a normal ground resistance pressure to the hardened grout on the ground. Is a proportional injection method of the forced pressure of the hardened grout, wherein the double tube rod is fixed at a predetermined position and the hardened grout is injected into the ground from the nozzle.

According to the first invention or the second invention, the proportional injection grout monitor is provided with the backflow prevention mixing mechanism for preventing the backflow of the A liquid to the B liquid side of the inner tube and for mixing the A liquid and the B liquid. , The problem that A solution may flow back to the B solution side of the inner tube and the grout may gel in the monitor and the grout may become unusable, and the problem of non-uniform mixing of A solution and B solution may be solved. Ground hardening can be achieved with hardened grout.

According to the third invention, since the disc-shaped grout consolidate and the columnar grout consolidate are formed, not only the supporting force equivalent to that of the support pile can be exhibited, but also the strengthening of the entire ground is achieved. can do. Moreover, according to the sixth aspect of the present invention, it is possible to enhance the bearing capacity of a small-scale building such as a detached house, and strengthen the soil structure such as a soft ground or a landfill, a pond or an embankment.

According to the fourth aspect of the present invention, since a three-dimensional spiral grout consolidate is formed in the ground, the effect of suppressing ground subsidence and sediment outflow/movement due to liquefaction becomes high. Therefore, according to the seventh aspect, it is possible to achieve the ground reinforcement of the soft ground, the buried ground, the soil structure such as the reservoir and the embankment.

According to the fifth aspect of the invention, the solution A may flow back to the solution B side of the inner tube and the grout may be gelated in the monitor and the grout may become unusable. The problem can be solved to achieve ground strengthening with uniform hardening grout.

In addition, according to the first to fifth inventions, it is possible to exert an effect not only for stopping water in the ground under groundwater, preventing spring water and strengthening the ground, but also for forming a grout solidified by the anchor construction method.

FIG. 1 is a schematic cross-sectional view schematically showing a configuration of a proportional injection grout monitor according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view schematically showing a case where cured grout is injected under non-forced pressure using the grout monitor according to the second embodiment of the present invention. FIG. 3 is an explanatory view for explaining the forced pressure proportional injection method according to the first embodiment of the present invention, and FIG. 3A shows the grout injected by the forced pressure proportional injection method according to the first embodiment. It is a model vertical sectional view which shows a solid body, and FIG.3(b) is the horizontal model sectional view. FIG. 4 is a schematic vertical sectional view showing a grout solidified body injected by the proportional pressure injection method according to the second embodiment of the present invention.

Hereinafter, a grout monitor for proportional injection according to an embodiment of the present invention and a proportional injection method using the grout monitor will be described.

[Proportional injection grout monitor]
[First Embodiment]
First, a grout monitor for proportional injection 10 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view schematically showing the configuration of a proportional injection grout monitor 10 according to the first embodiment of the present invention.

As shown in FIG. 1, a proportional injection grout monitor 10 (hereinafter, simply referred to as a grout monitor) according to an embodiment of the present invention is attached to the tip of a double-tube rod 1 and flows through two flow paths. It is a grout monitor having a function as a mixing device for mixing liquids.

Although not shown, as the main equipment used in the injection method of the present invention, in addition to the double tube rod 1, a boring machine, an injection pump, a grout mixing tank, etc. are required as in the conventional LW method. Needless to say.

In addition, the holing machine, which is normally used for grout injection in the ground under groundwater, is a rotary type (rotary type) that excavates the ground while rotating with a metal crown attached to the tip of the double pipe rod while passing water. ) Is used.

On the other hand, earth structures such as levees and reservoirs are mostly above groundwater (bottom is below groundwater), but as described in paragraphs [0044] to [0048] of Patent Document 4, a large amount of water is used. When drilling with holes, the ground will be disturbed and rather weakened. Therefore, in the present invention, a method of installing the double pipe rod tube by waterless perforation of waterless digging (impact type) or rotary percussion (rotational impact type) is preferable.

The double pipe rod 1 is a general double pipe rod composed of an outer pipe 2 and an inner pipe 3, and the inside of the outer pipe 2 serves as a second flow passage and the inside of the inner pipe 3 serves as a first flow passage. ..

<Inner tube>
A plurality of discharge holes 4 are bored on the side peripheral surface near the tip of the inner pipe 3, and a cylinder that closes the outer peripheral surface of the inner pipe 3 in close contact with the outer surfaces of the plurality of discharge holes 4 by covering. The cylindrical body 50 is attached. In addition, in order to solve the problem that the above-mentioned A liquid flows back to the B liquid side in the inner pipe 3 and the grout gels in the grout monitor 10, the backflow prevention mixing is performed at the tip portion of the inner pipe 3. A mechanism 5 is provided.

<Backflow prevention mixing mechanism>
Specifically, the backflow prevention/mixing mechanism 5 closes a plurality of discharge holes 4, a cylindrical cylindrical body 50 that closely adheres to these discharge holes 4, and covers and closes the tip ends of the outer tube 2 and the inner tube 3. And a tip opening closing means.

The cylindrical body 50 is preferably made of a stretchable material having elasticity such as a rubber material such as soft rubber or a resin material made of plastics. The lower part of the cylindrical body 50 is fixed by a fixing band 6 made of a stretchable material like the cylindrical body 50 so that the cylindrical body 50 is not displaced from the discharge hole 4 by the discharge pressure. Of course, the cylindrical body 50 is not limited to the lower portion, and may be fixed so that any one of the portions does not move vertically.

(Tip opening closing means)
Since the lower part of the cylindrical body 50 is fixed by the fixing band 6, the B liquid discharged from the discharge hole 4 by the pressure of the B liquid flowing through the inner pipe 3 spreads outward by the pressure as described later. It is injected upward from the gap between the cylindrical body 50 and the inner pipe 3. However, a slit may be provided in the longitudinal direction (pipe axis direction) on the side peripheral surface of the cylindrical body 50, and the liquid B may be jetted from there. Further, it is also possible to form a recess around the discharge hole 4 and cover the surface with a ring-shaped ring body so as to eject in the lateral direction.

The outer side of the inner tube 3 is connected to a stopper 7, which is a reduced diameter portion provided inside the tip of the outer tube 2, and the tip of the outer tube is closed (inside the outer tube). The water supplied at the time of excavation is discharged from the opening of the metal crown 8 at the rod tip through the inner pipe 3 and supplied.

Next, after excavation, when a hard ball 7'is put into the inner pipe 3, it is stopped by the stopper 7 and the opening of the inner pipe 3 is closed. Since the outer diameter of a normal double tube rod 1 is 40.5 mm and the inner diameter of the inner tube 3 is 10 mm, the diameter of the hard ball 7'for passing the inside is about 8 mm.

(Hard ball)
The material of the hard balls 7'is not particularly limited, but for example, those made of metal such as steel balls or hard rubber can be preferably used. However, it goes without saying that the hard ball 7'may be made of any material as long as it is a sphere made of a hard member whose diameter does not change.

<Outer tube>
A single or a plurality of nozzles 9 for ejecting a quick-melting grout in which the A liquid and the B liquid are mixed are formed on the side peripheral surface near the tip of the outer tube 2.

[Second Embodiment]
Next, a proportional injection grout monitor 10' (hereinafter, simply referred to as a grout monitor) according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view schematically showing a case where cured grout is injected under non-forced pressure using the grout monitor 10′ according to the second embodiment of the present invention.

As shown in FIG. 2, the grout monitor 10 ′ according to the second embodiment differs from the grout monitor 10 according to the first embodiment described above in that the tip portion of the inner tube 3 is closed in advance, and The point is that the tip of the tube 2 is not closed and is open, and that the nozzle 9 is not provided. Therefore, that point will be mainly described, the same configurations will be denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 2, when the grout monitor 10' is used to inject the hardened grout at a non-compulsive pressure, the hard ball 7'is not used and the tip opening of the inner tube 3 is the inner tube tip opening closing means 7. The liquid B is sprayed upward through the gap between the cylindrical body 50 and the inner pipe 3, and the liquid A and liquid B are mixed from the tip opening of the outer pipe 2 to form the instantaneous or medium-terminity. The connective grout is injected.

The above-described proportional injection grout monitors 10 and 10' according to the first and second embodiments of the present invention are merely one embodiment embodied in carrying out the present invention. Therefore, the technical scope of the present invention should not be limitedly interpreted by the illustrated embodiments.

In particular, the backflow prevention mixing mechanism and the tip opening closing means of the grout monitors 10 and 10' are not limited to those shown in the drawings, and other mechanisms capable of preventing the backflow of the liquid A into the inner tube 3, the outer tube 2 and the inner tube. Needless to say, other closing means capable of closing the tip end opening of No. 3 may be used.

[Proportional injection method of hardening grout]
Next, a method for proportionally injecting hardened grout according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4. The method for proportional injection of hardened grout according to the present invention is divided into forced pressure injection and non-forced pressure injection.

[Forced pressure]
The forced pressure is a pressure higher than the pressure applied during normal ground injection (ground resistance pressure), and the higher the pressure, the higher the directivity of the grout, and the grout can reach a wide range, which is desirable.

Generally, the pressure applied by the ground injection pump is about 3 to 5 MPa (excluding the ultra-high pressure pump for jet grout), though it depends on the standard and capacity of the pump, and the proportional injection method of the hardened grout according to the present invention also produces this pressure. Do in range. It should be noted that, if a high-pressure pump having an improved capacity is realized in the future, it can be used, and therefore the upper limit value of the forced pressure cannot be limited in the proportional grout injection method of the present invention. However, the upper limit value of the forced pressure of the ground injection pump existing at the present time is about 1.5 to 3.0 MPa.

The value of the forced pressure is mainly determined by the discharge amount (injection speed) of the grout per unit time and the size of the nozzle (cross-sectional area), and other factors include the fluidity of the grout (caused by water glass). Viscosity and cement concentration). As a guide, the nozzle diameter is about 2.0 mm to 4.5 mm.

Specifically, for example, when the nozzle diameter is calculated such that the forced pressure is 1.5 MPa at a discharge rate of 15 L with the composition of Example 2 in Table 1 described later, the nozzle diameter per location is 3 mm. There was (experimental value).

The soil material to be injected by the proportional injection method of hardened grout according to the present invention is soft cohesive soil, sandy soil containing silt or clay, soil that cannot be penetrated in a solution form, embankment, landfill, reservoir or levee. It is a soil structure (such as loose and not dense but with voids). Therefore, the injection pressure is generally 0.1 to 0.3 MPa, and at most 0.5 MPa or less.

The proportional injection method of the forced pressure of the hardened grout according to the present embodiment is performed using the grout monitor 10 according to the first embodiment described above.

As shown in FIG. 1, in the proportional pressure injection method according to the present embodiment, since the opening of the outer tube 2 is closed in advance, water is allowed to pass through the inner tube 3 of the double tube rod 1 to a predetermined level. After drilling with a boring machine to the depth of, the hard ball 7'is put into the inner pipe 3 and the tip opening of the inner pipe 3 is closed by water pressure.

As a result, the B liquid discharged from the discharge hole 4 is sprayed upward from the gap between the cylindrical body 50 and the inner pipe 3 which spread outward due to the pressure, and is even with the A liquid flowing in the outer pipe 2. To mix. Then, the single or a plurality of nozzles 9 are discharged as the instantaneous grout, and the instantaneous grout is injected into the ground by the forced pressure.

At this time, in the forced injection proportional injection method according to the present embodiment, there are two injection modes according to the purpose of ground reinforcement, and the first is to inject by rotating or stopping the rod shown in FIG. This is an embodiment, and the second is a second embodiment in which the rod shown in FIG. 4 is pulled up while rotating and injected.

<Proportional injection method of forced pressure according to the first embodiment>
First, a proportional pressure proportional injection method according to the first embodiment will be described with reference to FIG. FIG. 3 is an explanatory view for explaining the forced pressure proportional injection method according to the first embodiment of the present invention, and FIG. 3A shows the grout injected by the forced pressure proportional injection method according to the first embodiment. It is a model vertical sectional view which shows a solid body, and FIG.3(b) is the horizontal model sectional view.

As shown in FIG. 3, in the proportional pressure injecting method according to the first embodiment, as described above, the double tube rod 1 including the above-mentioned grout monitor 10 is rotated or stopped at a predetermined depth. The tip of the double-tube rod 1 is closed to inject the instantaneous grouting into the ground.

At this time, if the injection is carried out with a forced pressure, as shown in FIG. 3A, first, it enters the gap around the rod, which easily penetrates, and the leakage continues. It is considered that this is largely due to the synergistic effect of the forced pressure and the rotation of the rod.

Incidentally, in the conventional ground resistance pressure injection, when the instantaneous connection grout is injected without rotating the rod, it leaks but gels with time to form a grout packer, so there is no particular problem.

(Grout packer forming process)
In the forced injection proportional injection method according to the first embodiment of the present invention, first, the injection of the instantaneous grouting is temporarily stopped for a time within three times the gel time, and the grout is gelated to form the grout packer 11. The grout packer forming step is performed. In addition, when the grout packer 11 is formed to the upper part in the grout packer forming step and the grout does not leak thereafter, the subsequent grout packer forming step may not be performed.

(First step: disk-shaped grout solidified body forming step)
Next, in the proportional injection method of the forced pressure according to the first embodiment, the double tube rod 1 is rotated at a predetermined fixed position (depth) a plurality of times until the forced pressure disappears until a disc-shaped grout is consolidated. A first step, which is a step of forming a disc-shaped grout solid body for forming the body 12, is performed.

Thereafter, on the outside of the disk-shaped grout conglomerate 12, the flash-imparting grout generally enters in a split-splitting manner by an injection pressure to form a split-groove consolidate 14, but the gel time is short and Due to the high early strength, it is possible to keep the grout out of the distance and stay within a limited range.

(Second step: cylindrical grout solidified body forming step)
Next, in the proportional pressure injection method according to the first embodiment, while rotating the double pipe rod 1, the vertical movement is repeated up and down to the next upper step (a position above about 30 cm to 50 cm) to form a cylindrical grout. A second step, which is a columnar grout solidified body forming step of forming the solidified body 13, is performed.

In the forced injection proportional injection method according to the first embodiment, the first step and the second step described above are sequentially repeated for each injection step, and the instantaneous grout is injected into the ground until the top injection step. Go. As a result, the step of injecting the instantaneous grouting into the ground by the proportional pressure proportional injection method according to the first embodiment is completed.

According to the forced pressure proportional injection method according to the first embodiment described above, the disk-shaped grout solidified body 12, the columnar grout solidified body 13, and the grout solidification of the crack intrusion after the forced pressure disappears. A body 14 is formed. For this reason, not only can a bearing force equivalent to that of a generally called support pile be exerted, but also strengthening of the entire ground can be achieved.

For this reason, the proportional injection method of the forced pressure according to the first embodiment aims to strengthen the bearing capacity of small-scale buildings such as detached houses, and to strengthen soil structures such as soft ground and burial ground, and ponds and levees. It can be applied particularly suitably for the purpose.

Moreover, the forced injection proportional injection method according to the first embodiment has a short gel time and a significantly high early strength, so that the disc-shaped grout consolidate 12 and the columnar grout consolidate can be reliably contained in a limited range. The body 13 can be formed. Therefore, the forced injection proportional injection method according to the first embodiment is an extremely effective construction method that is particularly suitable for correcting unevenly submerged ground of a building such as a detached house.

<Proportional injection method of forced pressure according to the second embodiment>
Next, a proportional pressure proportional injection method according to the second embodiment will be described with reference to FIG. FIG. 4 is a schematic vertical cross-sectional view showing a grout solidified body injected by the proportional pressure injection method according to the second embodiment.

(Grout packer forming process)
In the proportional pressure injection method according to the second embodiment of the present invention, similarly to the proportional pressure injection method according to the first embodiment, the injection of the instantaneous grouting is temporarily stopped for a time within three times the gel time. Then, the grout packer forming step of forming the grout packer 11 by gelling the grout is performed. In addition, when the grout packer 11 is formed to the upper part in the grout packer forming step and the grout does not leak thereafter, the subsequent grout packer forming step may not be performed.

(Spiral grout consolidation process)
Next, in the forced injection proportional injection method according to the second embodiment, as shown in FIG. 4, while rotating the double pipe rod 1, the spiral grout solidified body 14 is gradually pulled up at a predetermined speed at the same time. A spiral grout solidified body forming step is performed.

In the forced pressure proportional injection method according to the second embodiment, the spiral grout solidified body forming step described above is performed, and the instantaneous setting grout is injected into the ground up to the uppermost injection step. As a result, the step of injecting the instantaneous grouting into the ground by the proportional pressure proportional injection method according to the second embodiment is completed.

According to the forced injection proportional injection method according to the second embodiment described above, the three-dimensional spiral grout solidified body 14 is formed in the ground. Therefore, according to the forced injection proportional injection method according to the second embodiment, even when compared with the forced injection proportional injection method according to the first embodiment, the ground subsidence and the outflow/movement of sediment caused by liquefaction can be prevented. The suppressing effect is high.

For this reason, the proportional injection method of the forced pressure according to the second embodiment can be more suitably applied to the purpose of strengthening the ground of a soft ground, a buried ground, a pond, an embankment, or the like.

Although the proportional pressure injecting method according to the first and second embodiments of the present invention has been described, the double tube rod 1 is fixed at a predetermined fixed position (depth) by using the grout monitor 10 according to the first embodiment. ) May be rotated a plurality of times to form only the above-mentioned disc-shaped grout solidified body 12. Even so, the ground can be strengthened to some extent.

Next, various conditions for carrying out the forced injection proportional injection method according to the first and second embodiments of the present invention will be described in detail.

(Infusion pump)
The injection pump used in the proportional injection method of the forced pressure according to the first and second embodiments of the present invention is a pump having a large discharge amount to the liquid A and a liquid B if the mixing ratio difference between the liquid A and the liquid B is large. A small pump is used, and two large and small pumps are used together for injection.

On the other hand, when the difference in the mixing ratio between the A liquid and the B liquid is small (for example, when the mixing ratio between the A liquid and the B liquid is 2:1), two systems of liquids (two liquids) are pumped by one unit. It is possible to use a dual pump.

Specifically, when the mixing ratio of the liquid A and the liquid B is 2:1, the double pump is modified so that the cross-sectional area of one cylinder becomes 1/2. As described above, the use of the dual pump allows the two liquids to be pumped by one pump, which reduces labor and is very advantageous in construction (including construction management).

(Rot rotation speed and rotation time)
In the proportional injection method of forced pressure according to the first and second embodiments of the present invention, the number of rotations of the lot of the double-tube rod 1 and its rotation time are determined by the soil quality, the discharge amount of grout and the injection amount (for the improved soil amount). The injection rate), the degree of formation of the disk-shaped, column-shaped, and spiral-shaped grout consolidates 12 to 15 greatly differ, and a clear value cannot be specified.

However, for example, when the diameter of the nozzle 9 is 3 mm under the above-mentioned forced pressure condition and the spiral grout solidified body 14 is formed by the forced pressure proportional pouring method according to the second embodiment, the pouring rate with respect to the soil amount is increased. At 10%, the number of rotations of the lot of the double tube rod 1 is 26 seconds/cycle, and the pulling time is preferably about 80 seconds per 50 cm pulling length of the boring machine (from the experimental value).

[Non-compulsive pressure]
Next, in the proportional grout|pouring method of the hardening grout which concerns on embodiment of this invention, the case where it injects by non-forced pressure is demonstrated. Here, the non-forced pressure (non-forced pressure) refers to a pressure that exceeds the pressure (ground resistance pressure) applied during normal ground injection, but is about the same as the ground resistance pressure.

In the proportional injection method of the non-forced pressure of hardened grout according to the embodiment of the present invention, the method using the grout monitor 10 according to the first embodiment described above and the grout monitor 10 according to the second embodiment described above. There are two methods, one is to use'. In any case, the diameter of the nozzle 9 of the outer tube 2 is set to 2.0 to 4.5 mm as a guide, and 4 to 6 nozzles 9 are provided for use.

When the proportional injection method of the hardened grout is carried out by using the grout monitor 10 under non-compulsive pressure, the instantaneous grout is discharged from the nozzle 9 of the outer tube 2 and the grout monitor 10 is caused to invade in a splitting manner to strengthen the ground.

On the other hand, when performing the proportional injection method of hardened grout using non-forced pressure using the grout monitor 10 ′, the instantaneous connection grout or the intermediate connection grout is discharged from the tip opening of the outer tube 2 and is mainly used under groundwater. Prevent the water from stopping and springing of the ground, and strengthen the ground.

<Cured grout>
Next, a description will be given of the hardened grout used in the method for proportionally injecting the forced and non-forced pressure of the hardened grout according to the embodiment of the present invention. As the cured grout used in the present invention, an instant setting grout or an intermediate setting grout is used.

(Instantaneous grout)
Here, the instantaneous setting grout is an optimal grout for ground strengthening that has the following conditions to be noted that enable the formation of the above-mentioned strong discoid, columnar, and spiral grout solidified bodies. pointing.

(1) The total time of gel time and plastic time is short and it can be injected into a limited range (instantaneous binding)
(2) The gel time is extremely small even when diluted with groundwater, and the strength is great, so it is excellent in stopping water and preventing spring water (bonding property).
(3) Early development of strength is large (4) Long-term strength is extremely high

In contrast, conventional cement-based quick-setting grout has a long plasticizing time, no matter how short the gel time is, so that the grout escapes to a distance outside the limited range due to pressurization, and early strength develops. Also, it is unsuitable for the cured grout according to the present invention because of its low long-term strength.

(Neutral grout)
In addition, the neutral grout (LW) has a large delay in gel time when diluted with water, and the strength after gelation becomes extremely weak. It is completely unsuitable because it is not effective in preventing water.

<Cured grout formulation>
Next, a specific composition of the hardened grout used in the proportional injection method of the forced pressure and the non-forced pressure of the hardened grout according to the embodiment of the present invention will be described.

The hardened grout used for the proportional injection method of the forced pressure and the non-forced pressure of the hardened grout according to the embodiment of the present invention is a uniaxial compressive strength after 3 hours as a basic composition for both the instantaneous setting grout and the intermediate setting grout. Target is 1.5 N/mm ² or more.

The quick-setting grout can be distinguished from the intermediate-setting grout by selecting the molar ratio and amount of water glass and the type and amount of cement, so that the quick-setting grout has a gel time (gel time) of 25 seconds or less, The neutral grout has a gel time in the range of more than 25 seconds and less than 60 seconds. It should be noted that in the neutral grout, when the gel time is 60 seconds or more, the compressive strength after 3 hours becomes less than 1.5 N/mm ² , so it is excluded.

Specifically, as the main component A liquid, cement milk prepared by dissolving cement prepared in the range of 500 to 1200 kg per m ³ in water is used. 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 the liquid A. For example, as the additive, slag, fly ash, lime, dispersant (retarder), foaming agent, fine powder limestone, primary mineral such as rock, clay mineral such as bentonite, extender and the like can be used.

The water glass of the liquid B has a SiO ₂ capacity of 18% or more, preferably 25 to 35%, and a molar ratio (SiO ₂ /Na ₂ O) of 2.5 to 4.0 is preferable. This liquid B is adjusted and mixed in the range of 130 to 500 L per 1 m ^{3 of} liquid A. Note that, for example, 30% concentration of water glass refers to water glass in which 300 g of SiO ₂ is contained in 1 L of the solution.

[Effect confirmation experiment]
Next, examples and comparative examples are given to perform physical property evaluation of the instant setting grout and the intermediate setting grout by each of the tests such as gel time measurement, plasticity time measurement and uniaxial compressive strength test described below, and verify the effect of the present invention. To do. Each test was performed at a liquid temperature of 20°C. First, the test method of each test will be described.

(1. Measurement of gel time)
Gel time was measured by placing a prescribed solution A in a 5 x 30 cm plastic bag, then placing solution B with the upper part of the plastic bag closed by hand, and letting go of the solution while shaking it vigorously up and down and stirring. The time until the fluidity was lost was taken as the gel time.

(2. Measurement of plasticizing time)
Since the measuring of the plasticizing time is extremely short and a measuring instrument cannot be used, the plasticizing time is defined as the time during which the grout after the gel time measurement described above is not fluidized even if it is pressed by touch.

(3. Uniaxial compressive strength test)
The uniaxial compressive strength test was conducted according to JIS R 5201 (physical test method for cement). Specifically, the grout was adjusted by the same method as the measurement of gel time, placed in a triplex frame of 4×4×16 cm before gelation, and subjected to wet curing at 20° C. for 1 hour, 3 hours, and 28 days, respectively. After the curing period (hours), the mold was removed and the uniaxial compressive strength was measured.

Next, various test results will be described with reference to examples of instant setting cured grout. The cement used for producing the quick-setting hardened grout according to the example is a mixture of ordinary Portland cement as cement A, blast furnace cement type B as cement B, and 3 parts by weight of ordinary portland cement as cement C and 7 parts by weight of slag. As the cement D, four types of cement were used, which were ordinary Portland cement and a gelation accelerator (lime) added thereto.

For the water glass, water glass A has a molar ratio (SiO ₂ /Na ₂ O) of 3.1 and a volume ratio of SiO ₂ is 40%, and water glass B has a molar ratio (SiO ₂ /Na ₂ O). Of water glass having a volume of 30% of SiO ₂ of 4.0, water glass C having a molar ratio (SiO ₂ /Na ₂ O) of 2.5% of SiO _{2 having} a volume of 30%, and water glass having a molar ratio of D Four kinds of water glass having a SiO ₂ content of 3.0 (SiO ₂ /Na ₂ O) of 40% and a volume of 40% were used. The water glass with a volume of 30% refers to water glass containing 300 g of SiO _{2 in} 1 L of the solution.

According to the above procedure, a predetermined amount of the liquid A and the liquid B were mixed to produce a quick-setting hardened grout, and each test such as gel time measurement, plastic time measurement, and uniaxial compressive strength test was performed. Show.

In the formulation of the instant setting grout (Examples 1 to 4) shown in Table 1, the gel time is 5 seconds to 17 seconds, but the plastic time is as short as 3 seconds to 6 seconds, and the time combined with the gel time is It was confirmed that the time was as short as 8 seconds to 23 seconds. Therefore, it was confirmed that the instant setting grouts (Examples 1 to 4) are termination grouts peculiar to the present invention, which can keep the grouts in a limited range.

The intensity is, in Example 1-4, a uniaxial compressive strength after 3 hours, either indicates 1.5 N / mm ² or more, the uniaxial compressive strength after 28 days, very a 16~21N / mm ² It was confirmed that a high value was obtained.

In addition, in the formulation of the mid-binding grout (Example 5), the gel time was as long as 39 seconds, but the uniaxial compressive strength after 3 hours was 3.11 N/mm ^2, which was about the same as that of the quick-setting grout. Was given.

Although not shown in Table 1, when 0.3 m3 of water was added to 1 m3 of the grout immediately after compounding of Example 5, the gel time was 49 seconds and the delay was extremely small, and the uniaxial compressive strength after 3 hours was 1. 19 N/mm ² was obtained. From these results, it has been confirmed that the neutral grout of Example 5 exerts a sufficient effect for stopping water in the ground under groundwater, in particular, for stopping water flowing under pressure and preventing spring water (patented). See Paragraph [0081] Table 1, Example 9, Paragraph [0091] Table 2, Example 24 of Document 4.

The hardened grout used in the method of proportional injection of the forced pressure and the non-forced pressure of the hardened grout according to the embodiment of the present invention has been described above. As described above, although the hardened grout used in the proportional injection method according to the embodiment of the present invention is composed of only two components of the cement milk of the A liquid and the water glass of the B liquid, the desired gel time, It can be said that it is a quick-setting fukuroto or a mid-flowing grout having a unique property capable of determining early strength.

In other words, the proportional injection method according to the embodiment of the present invention uses the above-mentioned instantaneous setting fugue with the unique property to form the above-mentioned disc-shaped, columnar, and spiral-shaped strong grout solids. It has become possible to strengthen the ground by forming

Further, according to the proportional injection method according to the embodiment of the present invention, the use of the instantaneous fugulout or the intermediate poultry grout having the above-mentioned unique properties allows the water to stop the ground under the groundwater, especially, the flow cover. It is possible to stop pressured water, prevent spring water, and strengthen the ground.

In addition, the quick-setting grout of Comparative Example 1 in which the gelation accelerator (lime) was added to the conventional LW mixed with the liquid A and the liquid B in the same amount had a gel time of 10 seconds but a plastic time of 21 seconds. It was also confirmed that the time was long and the time combined with the gel time was very long, 31 seconds.

Moreover, the uniaxial compressive strength after 3 hours was a very small value of 0.04 N/mm ² . This value is the gelled value of the water glass component, and at this point the cement has not yet hardened and strength development has occurred. As evidence, although not shown in the Examples, the uniaxial compressive strength after 3 hours of adjusting the gel time to 10 seconds with lime only, excluding cement from the formulation of Comparative Example 1, is approximately equal to 0.04 N/mm ^2. Was confirmed.

1: Double tube rod 2: Outer tube 3: Inner tube 4: Discharge hole 5: Backflow prevention mixing mechanism 50: Cylindrical body 6: Fixed band 7: Inner tube tip opening stopper (reduced diameter section: tip opening closing means)
7': Hard ball (tip opening closing means)
7": Inner tube tip opening closing means (tip opening closing means)
8: Metal crown 9; Nozzle (ejection hole)
10, 10': Grout monitor (grouting monitor for proportional injection)
11: grout packer 12: disk-shaped grout solid body 13: cylindrical grout solid body 14: split grout solid body 15: spiral grout solid body

Claims (5)

It was attached to the tip of a double pipe rod consisting of an outer pipe and an inner pipe, and was introduced through the inner pipe into a liquid A of cement milk containing 500 to 1,200 kg of cement per 1 m ³ which was introduced through the outer pipe . solution B 18-35% of the concentration of water glass SiO ₂ volume of molar ratio 2.5 to 4.0, a liquid 1m said dual curing grout mixed at a ratio of 130~500L respect ³ A grout monitor for proportional injection for proportional injection using a tube rod,
Thereby preventing the liquid A discharged from the outer tube to flow back into the liquid B-side of the inner tube, provided with a backflow prevention mixing mechanism for mixing the liquid B and the solution A,
The backflow prevention mixing mechanism includes a tip opening closing means for closing a tip opening of the double tube rod, a plurality of discharge holes formed on a side surface of the inner tube of the double tube rod near the tip, and the discharge holes. With a cylindrical cylindrical body or a ring-shaped ring body made of a stretchable material that closely coats the outer surface of ,
The outer tube is provided with a single or a plurality of nozzles, which are discharge holes formed on the side surface,
The distal end opening closing means has a reduced diameter portion formed in the distal end opening of the inner tube, and a hard ball having a diameter that cannot pass through the reduced diameter portion,
A grout monitor for proportional injection, characterized in that the reduced diameter portion can be closed by the hard ball and the hardened grout can be injected from the nozzle. The cylindrical body is fixed by a fixing band so as not to be vertically displaced, and the liquid B discharged from the discharge hole once comes into contact with the cylindrical body and is jetted upward or laterally to form the double pipe. The grout monitor for proportional injection according to claim 1, wherein the grout monitor is configured to be mixed with the liquid A in the outer tube. A proportional injection method for forced pressure of hardened grout, which uses the grout monitor for proportional injection according to claim 1 or 2 to inject the hardened grout into the ground by applying a higher forced pressure than a normal ground resistance pressure,
For a time within 3 times the gel time of the cured grout, the injection of the quick-setting grout is temporarily stopped, the grout is gelated, and a grout packer is formed,
A first step of forming a disc-shaped grout consolidate until the forced pressure disappears by rotating the double tube rod a plurality of times at a predetermined position,
A second step of rotating the double tube rod and repeatedly moving up and down until the next upper step to form a columnar grout consolidate;
The proportional injection method of forced pressure of hardened grout, characterized in that the first step and the second step are sequentially repeated for each injection step, and the instantaneous setting grout is injected into the ground until the uppermost injection step. A proportional injection method for forced pressure of hardened grout, which uses the grout monitor for proportional injection according to claim 1 or 2 to inject the hardened grout into the ground by applying a higher forced pressure than a normal ground resistance pressure,
For a time within 3 times the gel time of the cured grout, the injection of the quick-setting grout is temporarily stopped, the grout is gelated, and a grout packer is formed,
A method for proportionally injecting a forced pressure of hardened grout, characterized in that the double tube rod is rotated and at the same time gradually pulled up at a predetermined speed to form a spiral grout solidified body. A proportional injection method for forced pressure of hardened grout, which uses the grout monitor for proportional injection according to claim 1 or 2 to inject the hardened grout into the ground by applying a higher forced pressure than a normal ground resistance pressure,
A method for proportionally injecting a forced pressure of hardened grout, wherein the double tube rod is fixed at a predetermined position and the hardened grout is injected into the ground from the nozzle.

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