JP2001248164A - Construction method for spraying mixture and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method preventing clogging in a cylinder and enabling a mixture (mortar concrete) to be sprayed at a high altitude or over a great horizontal distance, and an apparatus suitable for use therewith. SOLUTION: A hose 19 for force-feeding a mixture (mortar) 1 is connected to one end of the mixing cylinder 21 of a portable mixing device 17 installed near a nozzle, and a hose 15 for force-feeding aggregate (sand) 8 is connected to the other end. The inside diameter D of the mixing cylinder 21 is equal to or three times the inside diameter d of the hose 15 and a hose 16 for force- feeding cement milk 13 is connected to the cylindrical wall 21a of the cylinder 21 near a connection with the hose 15. Also, the cement milk 13 is supplied from diagonally behind to the aggregate 8 force-fed into the cylinder, and the aggregate 8 and the cement milk 13 separately force-fed into the cylinder are mixed within the cylinder. Their mixture 1 is discharged from the spray nozzle 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mixture of aggregate and cement milk (that is, a mortar obtained by mixing fine aggregate such as sand and cement milk, or a coarse aggregate such as crushed stone and cement milk). The present invention relates to a method of spraying mixed concrete) and an apparatus for spraying a mixture used in the method.

[0002]

2. Description of the Related Art For example, in a slope revegetation protection method in which a vegetation base material is sprayed on a slope, a mortar or concrete spraying method is used to prevent the vegetation base material from flowing out and stably fix the vegetation base material. Is formed on the slope, and a vegetation base material for greening is sprayed in the slope.

[0003] In addition, in order to prevent the collapse of the slope, a net is stretched on the slope and mortar or concrete is sprayed so as to embed the net to construct or repair an elevated railway, an expressway, a mountain tunnel, or the like. In such cases,
Mortar and concrete are sprayed.

[0004] In spraying a mixture such as mortar or concrete, the conventional spraying means for pumping the mixture to a spraying position by a hose has a large frictional resistance between the mixture and the inner surface of the hose. It was difficult to obtain a sufficient discharge pressure, and even if the horizontal distance of spraying was limited to about 100 m in hose length.

In order to eliminate such inconveniences, the present applicant has pumped a mortar material (a batter of sand and a small amount of cement) or a concrete material having a low cement mixing ratio through a hose, and After the cement milk is poured into the mortar material or the concrete material at the latter stage of the pumping process, a method of spraying this mixture, that is, separately pumping the mortar material or the concrete material and the cement milk, mixing and spraying the mixed milk and the separate pumping A spraying method has been proposed (Japanese Patent Publication No. 6-102899).

[0006] According to the above-mentioned separate pressure blowing method, by lowering the cement mixing ratio of a mortar material or a concrete material to be pressure-fed with a hose, the pressure resistance can be reduced and the discharge amount can be increased. The amount is compensated for by the injection of cement milk at the latter stage of the pumping process. According to the conventional method of spraying mortar or concrete, the construction limit is up to a height of 60 m. Construction up to a height of 300 m is possible.

In the separate pressure blowing method, a cylinder is interposed and connected to a portion of the hose for pressure-feeding the mortar material or the concrete material, which is located in front of the tip of the hose, and cement milk is injected into the cylinder. Are connected to mix separately fed mortar material or concrete material and cement milk in a cylinder, and the mixture is sprayed from a nozzle at the end of the hose.

The cylinder used for the above-mentioned mixing is compared with the inner diameter of a mortar material or concrete material pressure-feeding hose so that the cylinder can be sufficiently mixed in the cylinder.
The outer diameter of the cylinder is significantly increased, and as a specific example, the outer diameter of the cylinder is 300 mm (the thickness of the cylinder is 3 mm and the inner diameter is 294 mm) with respect to the inner diameter of the material pressure feeding hose of 42 mm.
And 7 times (49 times in area), and the mortar material or concrete material was mixed with cement milk.

[0009]

However, the mortar material or concrete material pumped at a constant speed in the hose reaches the inside of the cylinder and, at the same time, suddenly drops in air pressure due to the cylinder diameter being too large. As a result, the flow velocity will be significantly reduced, thereby obstructing the course of the subsequent mortar material or concrete material,
In some cases, so-called clogging occurred inside the cylindrical body, making it impossible to spray the mixture.

In addition, since cement is mixed and fed with sand at the same time, the cement particles gradually adhere to the inner wall of the hose for feeding, and finally the hose is closed, so that it is difficult to supply sand and cement quantitatively. Often became.

On the other hand, for example, in a mortar as a mixture, it is common to set the mixing ratio of cement and sand to 1: 4, but if the final strength can be secured, it is not necessary to set this mixing ratio. What is necessary is just to be able to set the compounding ratio to obtain the desired strength.

At this time, conventionally, since the cement is previously blended into the mortar material, the blending ratio of the cement is determined from the total amount of the cement amount and the cement replenishing amount by the cement milk. It has been very difficult to control the supply amount of cement milk in consideration of the amount of cement preliminarily blended into the mortar material.

[0013] The present invention has been made in view of such circumstances, and compared with the above-described separate pressure blowing method, the mixture is sprayed to a further higher place, or at a horizontal distance. It is an object of the present invention to provide a method of spraying a mixture that can be sprayed to a distant place and that can eliminate clogging in a cylinder as well as a hose for pressure feeding, and an apparatus for spraying a mixture suitable for use in the method. .

[0014]

That is, as a method of spraying a mixture of aggregate and cement milk, the present invention provides a portable mixing apparatus in which a hose having a nozzle for spraying the mixture at its tip is installed near the nozzle. The mixing cylinder is connected concentrically to one end of the mixing cylinder, and an aggregate pressure feeding hose is concentrically connected to the other end of the mixing cylinder, and The inner diameter of the cylindrical body is made to be the same diameter to three times as that of the aggregate pumping hose, and the cement milk pumping hose is connected to the cylindrical wall near the connecting portion of the aggregate pumping hose of the cylindrical body,
Aggregate and cement separately pumped into the cylinder are tilted with respect to the cylinder axis so that the cement milk is supplied diagonally from the rear to the aggregate pumped into the cylinder. It is characterized in that milk and milk are mixed in a cylinder, and the mixture is discharged from a nozzle.

At this time, the mixing ratio of the aggregate and the cement milk can be easily changed only by controlling the supply amount of the cement milk to the portable mixing device (claim 2).

According to the above-mentioned spraying method in which the aggregate and the cement milk are separately fed, the inner diameter of the mixing cylinder is set to be equal to or three times as large as the inner diameter of the hose for feeding the aggregate. Does not cause a rapid decrease in the flow velocity of the aggregate due to the fact that it is too large, whereby it is possible to avoid clogging of the aggregate.

At the same time, a so-called negative pressure action can be generated in the cylinder without lowering the flow velocity of the aggregate, so that the cement milk is accelerated in the cylinder and repeatedly collides with the inner wall of the cylinder. And spread.

On the other hand, the aggregate is pressure-fed without mixing with a cement for increasing the viscosity, so that the pressure-feeding hose is not clogged due to the adhesion of the cement as in the prior art.
The aggregate is in a plasma state and is introduced into the cylinder, and
In addition, the cement milk is supplied so as to cross the aggregate from diagonally rearward, so that the aggregate in the plasma state and the accelerated and diffused cement milk are instantaneously and efficiently mixed in the cylinder. As a mixture, which can be sprayed in a very uniform and high quality.

In addition, cement milk has a low pumping resistance and, even if it is an aggregate, does not contain any cement, so that the pumping resistance of the cement milk is also small, and the hose is clogged as described above. Since there is no such method, it is possible to spray the mixture to a higher place or to spray a distant object at a horizontal distance as compared with the method of the separate pressure spraying method already proposed.

Preferably, at least one of metal, glass, and synthetic resin fibers is added to at least one of the aggregate and the cement milk (claim 3). Thus, the strength of the mortar or concrete is increased.

As a spraying device for the mixture of the aggregate and the cement milk, a hose for feeding the mixture having a nozzle for spraying the mixture at its tip and a hose for feeding the aggregate are provided as a portable mixing device installed near the nozzle. For the mixing cylinder of
Concentrically connected to both ends thereof, the inner diameter of the mixing cylinder is made to be the same diameter to three times the inner diameter of the aggregate pumping hose, and the vicinity of the joint of the aggregate pumping hose of this cylinder is connected. A hose for cement milk pumping is connected to the cylinder wall, and the direction of cement milk discharge by the hose is inclined with respect to the cylinder axis, so that the cement milk is slanted rearward with respect to the aggregate to be pumped into the cylinder. Thus, a composition spraying apparatus suitable for use in the method of claim 1 is provided (claim 4).

At this time, if cement milk diffusion means is provided at the injection port of the cement milk into the cylinder, the cement milk is supplied in a film form into the cylinder, and the aggregate is reliably formed. By contacting with the cement milk and efficiently mixing the two, a more uniform and high-quality mixture can be obtained.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a mixture of aggregate and cement milk (mortar obtained by mixing fine aggregate such as sand and cement milk, or concrete obtained by mixing coarse aggregate such as crushed stone and cement milk). Is a mortar of cement 1: sand 4: water 0.5,
Hereinafter, it is called mortar. 2) shows the molding state of the slope 2 by spraying 1 and the greening protection state of the slope N by spraying the vegetation base material 3.

More specifically, a net 4 such as a wire mesh is
And reinforcing bars 5 are arranged in a grid on the net 4, and the curing sheet 6 is arranged in a space defined by the grid-shaped reinforcing bars 5, while the mortar 1 is arranged so as to cover the grid-shaped reinforcing bars 5. Is sprayed to form a grid-like law frame 2, and then the curing sheet 6 is peeled off, and a vegetation base material 3 containing plant seeds and fertilizer is sprayed into the law frame 2 to protect the slope N from greening. I try to plan.

The spraying device for the mortar 1 has a compressor 9 for sand 8 as fine aggregate, an air compressor 10 connected to the compressor 9, a mixing ratio of cement 11 and water 12 of 1: 0. Pump for pumping cement milk 13
4, sand 8 and cement milk 13 introduced through hoses 15 and 16, and a portable mixing device 17 for mixing these and discharging as mortar 1;
7 comprises a mortar pressure-feeding hose 19 connected to a mortar discharge port 18 (see FIG. 2) 18 and a mortar spray nozzle 20 provided at the end of the hose 19.

The supply amount of the cement milk 13 pumped by the pump 14 is set and changed by a discharge amount gauge provided in the pump 14, and the pump amount is changed according to the pumping amount of the aggregate (sand) 8 measured in advance. By adjusting the discharge amount of the cement milk 13 by 14, the mixing ratio of the sand 8 and the cement milk 13 can be arbitrarily controlled.

The mortar pressure feeding hose 19 has a length including the nozzle 20 of 3 to 20 m so that the spraying range of the mortar 1 around the portable mixing device 17 is about 3 to 20 m. The portable mixing device 17 installed near the nozzle 20 is mainly configured with a mixing cylinder 21 for mixing the sand 8 and the cement milk 13. .

As shown in FIGS. 2 and 3, the mixing cylinder 21 has an inner diameter D slightly larger than the inner diameter d of the sand pressure feeding hose 15 (the same diameter to 3 times as described later). Is fine.)
A male screw part 22 for concentrically connecting a mortar pressure-feeding hose 19 to the outer peripheral surface of the discharge port 18 by gradually narrowing one end side (mortar discharge port 18 side).
On the other end, a male screw portion 23 for concentrically connecting the sand pressure feeding hose 15 is also formed on the other end side, and a cylinder near the connection portion of the sand pressure feeding hose 15 of the cylindrical body 21 is formed. Wall 2
A female screw portion 25 for connecting an injection cock 24 of the cement milk 13 is formed in 1a, and a hose 16 for cement milk pressure feeding is connected to the cock 24.

Then, the extension axis P of the female screw portion 25 into the cylinder is inserted through the cylinder axis Q and the cylinder axis Q
For example, at an angle θ of 40 degrees.
While the cement milk 13 is supplied obliquely from the rear to the sand 8 fed into the inside, the inlet of the cement milk 13 into the cylinder 21 by the female screw portion 25 is positioned in the axial direction of the cylinder 21. Squeezing means, and a diffusion means 26 for diffusing the cement milk 13 in the form of a film through the squeezing port.
Is composed.

According to the mortar spraying apparatus having the above structure, the inner diameter D of the mixing cylinder 21 is set to be slightly larger than the inner diameter d of the sand pressure feeding hose 15 so that the cylindrical body 2 can be driven at a constant speed.
The sudden decrease in the flow velocity of the sand 8 fed into the inside 1 does not occur, and the clogging of the sand 8 in the cylindrical body 21 is reliably avoided.

At the same time, a so-called negative pressure action is generated in the cylindrical body 21 without lowering the flow velocity of the sand 8,
The cement milk 13 accelerated and introduced into the cylinder 21 through the cement milk diffusion means 26 is instantaneously converted into a dense film-like cement milk 13, while the sand 8 is made of cement which increases the viscosity as in the related art. Since the sand 8 is pumped without being mixed, the sand 8 is brought into a plasma state and is introduced into the cylinder 21. In addition, the cement milk 13 is supplied so as to cross the sand 8 from obliquely behind. By doing so, the dense film-like cement milk 13 and the sand 8 are instantaneously and efficiently mixed in the cylindrical body 21, and it is synergistic that the above-described clogging of the sand 8 is avoided. Thus, it is possible to make the mortar 1 extremely uniform and of high quality, and spray the mortar 1 from the nozzle 20 onto the slope N.

That is, in comparison with the conventional spraying method in which cement, sand and water are mechanically stirred and the mortar itself is pressure-fed with a hose, the mechanical mortar spraying apparatus having the above-mentioned structure has a mechanical non-uniformity. Because it does not rely on agitation, it is possible to easily and instantly obtain extremely high-quality mortar 1 with less mixing spots, and it is also possible to greatly reduce the rebound loss required by 30% conventionally required. This makes it possible to greatly reduce the amount of sand 8 used.

The cement milk 13 has a low pumping resistance, and the cement 8 is not mixed with the sand 8 even with the sand 8. Therefore, the cement milk 13 also has a low pumping resistance. The mortar 1 can be sprayed to a high place, or the mortar 1 can be sprayed to a distant place at a horizontal distance, and the mortar spraying ability can be greatly improved. .

Incidentally, the inner diameter d of the sand pressure feeding hose 15 is set to 4
2 mm, sand 8 is pumped into the cylinder 21 at 200 kg / batch / 1.5 minutes, and the cement milk pumping hose 16
The inner diameter d1 of the cement milk 13 is 25 mm,
Diffusion pressure is fed into the cylinder 21 at 5 kg / 1.5 minutes, and the length of the cylinder 21 for mixing these is 1000 mm and the inner diameter D is 94
mm and the inner diameter d2 of the mortar pressure feeding hose 19
Is set to 42 mm, and the mortar 1 is pressure-fed from the mortar discharge port 18 to the nozzle 20 in the embodiment.
It has been confirmed that the mortar 1 is sprayed over 00 m or more.

In the above embodiment, the sand 8 is used as the aggregate, and the mortar 1 in which the sand 8 and the cement milk 13 are mixed is sprayed. However, the crushed stone is used instead of the sand 8. It is also possible to spray concrete by mixing crushed stone and cement milk 13.

Accordingly, the spraying device having the above-described structure and the sand 8
Alternatively, if crushed stone, cement 11, and water 12 are prepared, the mortar 1 or the concrete can be sprayed at any time without being restricted by the place and time,
It is possible to avoid the problem of concrete peeling accidents in tunnels, which is currently a problem, that is, the time limitation of casting and the poor construction of ready-mixed concrete caused by an excess water-cement ratio. According to the construction method, there is almost no possibility that the quality of the mortar or the concrete structure is deteriorated.

When the 28-day compressive strength of the mortar and concrete by the above-mentioned spraying method was measured, the average was 30 N compared to 15 N / mm ² of the conventional method.
/ Mm ² or more, and it was found that, for example, in a slope protection method using a slope, it is possible to obtain a slope with the same strength as before even with a small slope. A significant cost reduction is achieved.

In the above embodiment, the inner diameter D of the mixing cylinder 21 is set to 2.2 times (4.8 times in area) the inner diameter d of the sand pressure feeding hose 15. A plurality of cylinders 21 having different diameters were prepared, and the mortar spraying experiment was repeated.
In the cylinder 21 up to 0 times (9 times in area), clogging of the sand 8 does not occur at all, and in the cylinder 21 whose cylinder inner diameter D is 4.0 times or more the hose inner diameter d, clogging of the sand 8 often occurs. In the meantime, clogging of the sand 8 has occurred in the cylinder 21 during this time. Conversely, even if the inner diameter D of the mixing cylinder 21 is smaller than the inner diameter d of the hose, clogging of the sand 8 occurs. Because
From this, the inner diameter D of the mixing cylinder 21 is 1.0 to 3.0 times the inner diameter d of the sand pressure feeding hose 15 (9.0 in area).
It is important to set it in the range of (times).

It should be noted that the provision of the cement milk diffusion means 26 is not an essential requirement, that is, FIGS. 4 (A) and 4 (B).
As shown in FIG. 7, the female screw portion 25 may be simply connected to the cylindrical body 21 without narrowing the injection port by the female screw portion 25. In this configuration, the cement milk 13 is diffused. The cylinder 21 is pressure-fed into the cylinder 21
Repeatedly collide with the inner wall and mix with the sand 8.

On the other hand, as shown in FIGS. 5 (A) and 5 (B), the
When the water is provided, the cement milk 13 is formed into a fan-shaped film, as in the case where the mouth of the watering hose is crushed to discharge water.
This film-shaped cement milk 13 is pressure-fed into the cylinder 21 so as to obliquely cross the inside of the cylinder 21, and repeatedly collides with the inner wall of the cylinder 21.
Is diffused in the form of a film, and the contact efficiency with sand is significantly increased. Therefore, it is extremely preferable to provide the cement milk diffusing means 26.

At the time of spraying the mortar or concrete, at least one of metal, glass, and synthetic resin fibers is added to at least one of the aggregate and cement milk, and spraying is conventionally required. There is an advantage that a mortar or concrete structure having extremely high compressive strength and tensile strength can be formed without using a rebar.

In particular, when working at a high place, it is not necessary to transport a heavy reinforcing bar, so that it is possible to carry out the construction very easily and safely.

As the fiber to be added, either a continuous fiber or a fiber cut to a predetermined length can be used, and the fiber can have any thickness depending on the material.

When a fiber having a relatively short fiber length is used, the fiber may be mixed with aggregate or cement milk in advance and then fed under pressure. Then, a hose for feeding the fibers by wind pressure may be connected so that the fibers are added to the mixture of the aggregate and the cement milk.

As a raw material of the metal fiber, steel, stainless steel, or the like is used. Aramid or the like is used as a raw material of the synthetic resin fiber, and a fiber having high tensile strength is preferable.

In addition, each fiber is usually in a volume ratio of 0.01 to 3.0% with respect to mortar or concrete.
It is used at a ratio of about, but can be increased or decreased according to the required strength.

[0047]

As described above, according to the first aspect of the present invention, a high-quality material that is homogeneously mixed with the aggregate without causing a cement component variation that most affects the strength of the mortar or the like. The present invention provides a method of spraying a mixture which can be sprayed at a higher place or at a horizontal distance farther than before, and in which clogging in a cylinder can be effectively eliminated.

In addition to the above, according to the second aspect of the present invention, there is provided a method of spraying a mixture in which the mixing ratio of aggregate and cement milk can be easily controlled. A method of spraying a mixture capable of constructing a mortar or concrete structure having extremely high compressive strength and tensile strength and a long service life without using a conventionally required heavy reinforcing bar is provided.

According to the fourth aspect of the present invention, there is provided an apparatus for spraying a mixture which is suitable for use in the method of the first to third aspects. The present invention provides a spraying apparatus for a high-quality mixture in which the aggregate and the cement milk are efficiently mixed.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a form diagram showing a molding state of a slope and a greening protection state of a slope by spraying a vegetation base material.

FIG. 2 is a sectional view of a portable mixing device.

FIG. 3 is an end view of a cylindrical body of the portable mixing device as viewed from a mortar discharge port side.

FIGS. 4 (A) and (B) are explanatory diagrams of pressure feeding of cement milk into a cylinder in a configuration without a cement milk diffusing means.

FIGS. 5 (A) and (B) are explanatory views of pressure feeding of cement milk into a cylinder in a configuration provided with cement milk diffusing means.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mixture (mortar), 8 ... Aggregate (sand), 13 ... Cement milk, 15 ... Aggregate pumping hose, 16 ... Cement milk pumping hose, 17 ... Portable mixing device, 19 ... Mixture pumping hose 20 ... mixture spray nozzle, 21 ...
Mixing cylinder, 21a: cylinder wall, 24: cock for adjusting injection amount, 26: cement milk diffusion means, d, D: inner diameter.

Claims (5)

[Claims] 1. A method for spraying a mixture of aggregate and cement milk, wherein a hose having a nozzle for spraying the mixture at a tip thereof is connected to a mixing cylinder of a portable mixing device installed near the nozzle. And a concentrically connected hose to one end of the mixing cylinder, and a condensing hose connected to the other end of the mixing cylinder, and the inner diameter of the mixing cylinder to the aggregate feeding. The same diameter as the inner diameter of the hose for the pipe is set to about 3 times, and a hose for cement milk pumping is connected to the cylindrical wall near the connection part of the aggregate pumping hose of this cylinder, and the aggregate to be pumped into the cylinder is connected to the aggregate. In order to supply cement milk from obliquely backward, the discharge direction of cement milk is inclined with respect to the cylinder axis, and the aggregate and cement milk separately pumped into the cylinder are mixed in the cylinder, A mixture characterized by discharging the mixture from a nozzle Spraying method. 2. The method for spraying a mixture according to claim 1, wherein the amount of cement milk supplied to the portable mixing device is controlled to change the mixing ratio of the aggregate and the cement milk. 3. Spraying the mixture according to claim 1 or 2, wherein at least one of fibers made of metal, glass or synthetic resin is added to at least one of the aggregate and the cement milk. Construction method. 4. An apparatus for spraying a mixture of aggregate and cement milk, wherein a hose for pumping a mixture having a nozzle for spraying the mixture at its tip and a hose for pumping aggregate are installed near the nozzle. The mixing cylinder of the portable mixing device is connected concentrically to both ends of the mixing cylinder, and the inner diameter of the mixing cylinder is made to be the same diameter to three times as the inner diameter of the aggregate pumping hose. A cement milk pumping hose is connected to the cylinder wall near the joint of the aggregate pumping hose of the cylinder, and the direction of cement milk discharge by this hose is inclined with respect to the cylinder axis, so that it is inserted into the cylinder. An apparatus for spraying a mixture, characterized in that cement milk is supplied obliquely rearward to the aggregate to be pumped. 5. The apparatus for spraying a mixture according to claim 4, further comprising means for diffusing cement milk at an inlet of the cement milk into the cylinder.