JPH11124574A - Grout and grouting work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the constituent mortar undergoes bleeding or separations into components and the grout can not be poured into a cavity without fail due to dilution with water. SOLUTION: In a grout poured into voids or gaps of ground or a structure and at the boundary between ground and a structure, flowable mortar based on a setting developing material is mixed with a flowable swelling liquid containing a montmorillonite clay mineral, whereupon the swelling liquid gels to permit the formation of a nonflowable plastic mass to prevent the mortar from undergoing bleeding, separations into components and dilution water and the pour of the grout into the aimed cavity without fail by limited grouting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to large gaps and cavities in soft ground, fracture zones and cracks (gap) in hard ground such as rock, and cavities at the interface between the ground and structures (backing of tunnels and the like). The present invention relates to a non-flowable plastic grout material to be filled in a place where the ground is weak (to be injected as a pretreatment of the ground injection method) or a gap generated when an injection pipe is installed, and an injection method thereof.

[0002]

2. Description of the Related Art Conventionally, a one-part mortar (main cement) has been used as grout to fill large cavities and gaps.
Is used.

[0003] This mortar contains sand, primary mineral fine powder (rock) as an aggregate (or filler) added to cement in view of the size of the cavity, workability (pumping distance and injection conditions), and grout properties (strength, etc.). , Quartz, lime, dolomite, etc.), clay minerals (bentonite, pottery clay, etc.) and soil generated on site (silt, clay) are used.
More than one kind is used in combination, and further, a foaming agent (air mortar), a dispersant, a retarder, an early strength developing material and the like are added according to the purpose, and are prepared.

[0004]

The above-mentioned conventional mortar injection is performed all in a one-liquid manner (a method in which mortar is prepared at once in a mixing tank and injected by one pump). It is necessary to maintain sufficient fluidity for the mortar to be pumped by pumping, and as a result, breathing (excess water) is inevitably generated, and it takes a long time (2 to 3 hours) for the cement to harden. For a long time, this fluidity is maintained.

[0005] For this reason, the injected mortar (grout) has a problem that after filling, bleeding occurs and the volume decreases, and since it is in a fluid state, material separation occurs and uniform strength cannot be obtained. is there.

[0006] In addition, when there is groundwater at the injection point, there is a problem that the grout material is diluted by water and flows away.
Furthermore, since it is fluid at the time of injection, it easily escapes to an unnecessary distance, and the fatal problem that a desired cavity cannot be reliably filled is included.

[0007] In order to solve such a problem, it is desired to develop a grout material (mortar) capable of reliably filling a predetermined cavity without causing bleeding (volume reduction) or material separation.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a grout material for filling cavities and gaps in the ground, a structure, or an interface between the ground and the structure. By adding a fluid swelling liquid containing a montmorillonite clay mineral to the mortar, a plastic grout material and a grout method are proposed, in which the swelling liquid is gelled to be transformed into a non-flowable plastic. Things.

A conventional mortar containing a hardening material such as cement as a main component and various aggregates and additives is added to a montmorillonite clay mineral (a typical mineral is bentonite. By adding a fluid swelling solution containing simply bentonite), electrolyte ions such as alkaline calcium ions (cations) dissolved from the hardening material are adsorbed on the surface of the bentonite particles (negatively charged), and electrochemically Action (charge replacement)
As a result, the bentonite swelling liquid undergoes a kind of gelling reaction, and the viscosity increases rapidly (short time, which is almost instantaneous), the fluidity is lost, and the bentonite is transformed into a non-flowable plastic grout.

As a result, the grout material is prevented from bleeding, material separation, water dilution and volume shrinkage, and is prevented from undesirably escaping far away, so that the desired cavity is securely filled. , Limited injection is possible.

The bentonite is mainly composed of a montmorillonite clay mineral. Its properties are that it swells and disperses remarkably when it comes in contact with water, and its colloid (particle diameter: 0.001 to 0.01 micron)
And the viscosity also increases significantly.

For this reason, as the swelling ability of bentonite increases, the gelling ability of a hardening material which also exhibits alkalinity, such as cement, increases, and the effect of transforming into a plastic state also increases.

Conventional one-part fluid mortar (Solution A)
In order to add the swollen bentonite solution (solution B) to the non-flowable plastic grout (the strength of the plastic grout), the type and amount of the moisture in the solution A, the hardening material and the aggregate, It is also affected by the type and amount of bentonite (B solution) and the degree of swelling.

Among them, the one which particularly affects the first factor is the degree of swelling of bentonite and its amount, and the second is the amount of water contained in the grout (A + B solution).

[0015] From the above, since whether or not it can be transformed into a non-flowable plastic grout varies greatly depending on the conditions of the liquids A and B, the transformation conditions cannot be specified depending on the content of bentonite.

The term "plastic grout" as used in the present invention means:
It is a non-fluid and does not have fluidity itself, but it easily fluidizes when given a physical action (for example, pressurization or weighting).

[0017]

EXAMPLES As a result of intensive studies, the present inventors have found that a fluidized bentonite swelling liquid is added to a conventional fluidized mortar to gel the swelling liquid, and the fluidized swelling liquid is added to a non-fluid mortar. In addition, by gelling the swelling liquid and transforming it into a non-flowable plastic grout, it prevents breathing, material separation and dilution of water, and also prevents unnecessary escape to a far distance, ensuring that the cavity It has been found that there is an effect that can be filled, and the present invention has been completed as a non-flowable plastic grout.

That is, a fluid swelling liquid containing a montmorillonite clay mineral is added to a conventional one-part fluid mortar containing a hardening material as a main component and various aggregates and additives. In the swelling liquid of bentonite, electrolyte ions such as alkaline calcium ions (cations) dissolved from a hardening material such as cement are adsorbed on the surface of the bentonite particles (negatively charged) and electrochemically act (charge replacement). ) Causes a kind of gelation reaction, causing the viscosity to increase rapidly (short time near instantaneous), loses fluidity and changes to a non-flowable plastic grout,
Material separation and dilution of water are prevented, and unnecessary runaway is prevented, so that the target cavity can be reliably filled.

As a result, it has been found that this non-flowable plastic grout is very effective as a limited injection.

The determination of whether or not a one-part fluid state has been transformed into a non-flowable plastic state depends somewhat on the properties of grout (eg, the particle size and specific gravity of the aggregate). , Cylindrical flow-con measurement (80 mm inside diameter, height on acrylic plate)
After placing a cylinder of 80 mm and filling the mortar in this, gently lift the cylinder and measure the spread of the mortar at that time, that is, measure the diameter and express it in cm.) Is about 13 cm or less, and the spread of the lower part is about 1.7 times or less the spread of the upper part.

It is said that the flow value that can be pumped to a practical distance by a normal grout pump is about 15 cm or more.

Further, since the plastic grout of the present invention is non-flowable, it cannot be applied with a conventional grout pump like a conventional flowable mortar in a one-pack type.

Therefore, in principle, the plastic grout of the present invention is constructed by using a liquid A as a fluid mortar containing a hardening material as a main component and a liquid B as a fluid swelling liquid containing bentonite. By pumping with separate grout pumps and joining and mixing liquids A and B near the inlet,
This is a so-called two-pack construction in which the swelling liquid of the B liquid is gelled and grout that has been transformed into a non-flowable plastic is injected.

However, if there is a pump capable of pumping even non-flowable plastic grout, it is also possible to carry out one-liquid construction.

The hardening developing material used in the liquid A (mortar) of the present invention is a hardly soluble alkali substance, which hardens when mixed with water. Typical examples include cement, cement and slag, slag and lime (slaked lime). , Quicklime) and the like.

The aggregate (or extender) to be added to the liquid A of the present invention includes sand, fly ash, fine powder of primary minerals (rock, quartz, limestone, dolomite, etc.), clay minerals (bentonite, clay, etc.), Site-generated soil (silt, soil containing clay, shield mud, etc.) and the like can be mentioned, and one or more of these aggregates can be used in combination.

Further, a foaming agent, a dispersing agent, a retarder, and an early-strength developing material which have been added to conventional mortars can be added according to the purpose.

The swelling liquid used in the liquid B of the present invention contains a montmorillonite clay mineral as a main component, and a typical example is bentonite.

Although the construction method of the present invention is not particularly limited, it is carried out in principle with two components.

In the injection of the space in the structure or the cavity at the boundary surface between the structure and the ground (including the backing of a tunnel, etc.), the fluid A is separately pumped up to just before a grout hole provided at a target location. A method is generally adopted in which the liquid and the liquid B are mixed and mixed, transformed into a plastic grout, and then injected into a cavity.

In a cavity or a large gap in the ground, a hole is drilled to a target location by boring or the like, and an injection pipe is provided for injection.

When the injection tube is a single tube, the liquids A and B are merged and mixed in front of the injection tube, and when the injection tube is a double tube,
A method is adopted in which the liquids A and B are combined and mixed at the tip to transform into a plastic grout and injected.

In the case of using for the ground injection method, injection is performed by using an injection pipe of the injection method.

Hereinafter, the grout of the present invention will be described in more detail with reference to examples.

The materials used in the experiments were cement (normal Portland), slag (trade name of cement as water slag), lime (industrial slaked lime) as a hardening material of liquid A, and bentonite (a clay mineral as an aggregate). A domestic product such as Toyoma Yoko's 200-mesh product name "Asama" and a 200-mesh American product), porcelain clay, and microsand were used as the primary mineral fine powder. An animal protein system was used as the foaming agent.

The bentonite described above was used as the montmorillonite clay mineral of the liquid B.

"Experiment-1"

The fluidity and breathing of the liquid A of the present invention (corresponding to a conventional mortar) were measured, and the results shown in Table 1 were obtained.

[0039]

[Table 1]

The experiment of fluidity was carried out by the above-mentioned cylindrical flow-con measurement, and the breathing was measured 3 hours after leaving still in a 500 ml measuring cylinder, and expressed in% as a unit.

From the experimental results shown in Table 1, at a flow value of 15 cm or more, which is said to be the limit at which mortar is pumped by a grout pump, breathing is about 1% or more, and the most suitable fluidity (flow value of about 20 to 30 cm) is 2%. It can be seen that there is about 5%.

Incidentally, the flow value and the breathing are different depending on the composition, particularly the kind of the aggregate.

As an exception, air mortar (No. 10, No. 1)
In 1), water is contained in bubbles, so no breathing occurs.

The composition (No. 3) in which no aggregate is used is shown for reference. As described above, a one-part fluid mortar (excluding air mortar) cannot completely prevent the occurrence of breathing when the flow value is about 15 cm or more.

"Experiment-2"

Solution A (fluid mortar) in Experiment 1 above
An experiment was conducted in which a swelling solution of bentonite was added as a liquid B to transform into a non-flowable plastic grout, and the results are shown in Table 2.

[0047]

[Table 2]

As shown in Table 2, when the fluid B was added to the fluid A, the fluid was almost instantaneously transformed into a non-flowable plastic grout having no breathing.

According to this example, the state of the transformed plastic grout is 13 to 9 cm in the lower part and 7.
It showed a cone of 7-7.8 cm.

The upper value is the inner diameter of the flow cone 8.0
Slightly smaller than cm is the effect of the weight of the grout.

That is, the expansion liquid B of bentonite is
Electrolyte ions such as alkaline calcium ions (cations) dissolved from a material such as cement in solution A are adsorbed on the surface of the bentonite particles (negatively charged) and a kind of gel is formed by electrochemical action (charge substitution). This causes a chemical reaction (including moisture in the grout), rapidly increasing the viscosity (short time near instantaneous), losing fluidity, and transforming into non-flowable plastic grout.

"Experiment-3"

In order to see how the grout of the present invention fills the cavities, the following experiment was also performed.

The experimental device is a prefabricated iron made of 40 cm wide and 1 cm long.
A 20 cm, 80 cm high container (one side is a transparent acrylic plate) has an inlet at the bottom of one side and an outlet at the top of the other side.

On the other hand, the liquid A and the liquid B are separately prepared in separate mortar mixers (for 200 liters), and two grout pumps are connected to the respective mixers with injection hoses. The device is such that it is merged and mixed before the injection hole of the injection hose and injected into the container.

"Comparative Example-1"

In an empty filling container (assuming a cavity without water)
Solution A (corresponding to a conventional mortar) having the composition of Example 8 was prepared, and a total of 200 liters was injected at a rate of 40 liters per minute by one injection pump.
The filling angle was about 5 degrees.

The amount of grout injected and consolidated is about 1
It was 95 liters.

After consolidation, the extruded grout was examined for the consolidation state of the grout. As a result, it was found that the aggregate (microsand) was somewhat larger in the lower part and somewhat smaller in the upper part, and the material was separated.

Further, when the solution A of Example 9 was injected under the same conditions, the grout was filled at an inclination angle of about 4 degrees over the entire area, and the material separation of the aggregate was smaller than that of Example 8.

Next, when the liquid A was injected into the injection container filled with water (assuming a cavity under the groundwater) under the same conditions as in Example 8, the grout in contact with the water was not diluted. Was filled flat.

The amount of caking injected was about 190 liters, but about 15% of the upper part was diluted with water, and there was no practical strength (strength enough to be broken by the water pressure of the water hose). .

After consolidation, the consolidation state of the grout was excerpted, and it was found that the aggregate was large in the lower part and small in the upper part.

On the other hand, when the solution A of Example 9 was also poured into the container containing water, the grout in contact with the water was diluted and the material was severely separated. Aggregate and cement precipitated at the bottom, and bubbles were formed. The phenomenon of separation and floating on the water surface was observed.

The grout was filled over the entire container.

The amount of caking injected was about 180 liters, but about 30% of the upper part was diluted with water and had no practical strength.

From the above experiments, since the conventional one-part mortar is fluid, if it is pressurized, it will run unnecessarily far away as far as possible and cannot be filled at the intended location.

In a cavity where groundwater is present, grout is diluted when it comes into contact with water, and the material is separated (uneven strength).
It was confirmed that the yield (injection amount) deteriorated.

[Example]

Solution A and Solution B of the formulation of Example 8 were separately mixed into an empty injection container by using a mortar mixer, and 200 liters were injected at a rate of 20 liters per minute (total 40 liters) using two injection pumps. However, the grout was filled in a state of being filled, the grout injected earlier was pushed out by the grout injected later, and it became a Yamagata castle centered around the injection, the inclination angle was about 35 degrees .

The amount of grout injected was almost 200 liters (the same as the injected amount).

After solidification, the solidified state of the grout was excerpted. As a result, there was no material separation of aggregate or cement and the strength was uniform.

When the composition of Example 9 was injected under the same conditions as in Example 8, the grout had a mountain shape centered around the injection hole, and the inclination angles were almost the same.

After consolidation, the grout was excerpted and the consolidation state of the grout was observed. As a result, the air and the materials (aggregate and cement) were uniform without separation, and the consolidation strength did not vary.

Next, when a grout was poured into a grouting vessel filled with water under the same conditions as in Example 8, a part of the grout was in contact with the water, such as the surface of the grout. The inclination angle and the amount of consolidation grout were almost the same.

After solidification, the solidified state of the grout was excerpted. Except for a very small part of the surface, there was no material separation of aggregate or cement and the strength was uniform.

When the composition of Example 9 was poured into a container filled with water under the same conditions as in Example 8, only a small part (1-2%) of the surface of the grout in contact with water was diluted, Although a small amount of bubbles floated on the water surface, there was no material separation in the consolidated state as a whole, and uniform strength was confirmed.

As described above, the fluid mortar (solution A)
In addition, if a non-flowable plastic grout obtained by adding a flowable bentonite swelling liquid (solution B) is injected into the cavity, there is no breathing. Could be filled.

In particular, even in a cavity where groundwater exists,
Without being diluted in water, without causing material separation,
Uniform strength was obtained.

[0080]

As described above, according to the grout material and grout injection method of the present invention, it is possible to prevent bleeding, material separation and dilution of water, to obtain uniform strength, and to run unnecessarily far away. And ensure that the desired cavity is filled.

Claims (2)

[Claims] 1. A grout material for filling cavities and gaps at the ground, a structure, and a boundary surface between the ground and the structure, wherein a montmorillonite clay mineral is mixed with a flowable mortar containing a hardening material as a main component. A plastic grout material characterized in that the swelling liquid is gelled by adding the swelling liquid of (1) to transform into a non-flowable plastic state. 2. A grouting method in which a grout material is injected and filled into the ground, the structure, and the voids and gaps at the boundary surface between the ground and the structure, wherein a fluid mortar mainly containing a hardening material is used as an A liquid, The fluid swelling liquid mixed with the montmorillonite viscous mineral is used as the liquid B, pumped by separate pumps, and the liquid A and the liquid B are mixed and mixed near the injection port, whereby the liquid B is swollen. A grout injection method characterized by injecting a grout material which has been gelled and transformed into a non-flowable plastic state.