JP3003751B2 - Legal construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a method for stabilizing a slope such as a slope.

[0002]

2. Description of the Related Art A method of stabilizing a slope by constructing a method frame typified by a so-called free frame method is disclosed in Showa 5
It has been actively adopted since the beginning of the 0s.

In this free frame method, cement, sand (fine aggregate) and, if necessary, gravel (coarse aggregate) are kneaded with water in a spray gun tank, and an air gun is provided on the outlet side of the tank. The air is fed into the hose by the force of the air,
Mortar or concrete is sprayed on the target surface from a spray nozzle connected to the end of the hose. In this case, a crimped wire net is arranged in parallel along the ground, and a space between the crimped wire nets is connected by a spacer to be self-supporting. The material is sprayed to build a legal framework. Reinforcing bars are arranged in the adjacent side forms.

[0004] As a spraying material, the weight ratio of cement: sand is usually 1: 4 in the case of mortar spraying, and the weight ratio of cement: sand: gravel is 1 in the case of concrete spraying. : 4: 1-2. Furthermore, since the crimped wire mesh is used as the formwork, the rigidity is low and the material transfer distance is 50 m as the maximum height.
The slump value specified in JIS A 1101 is basically set to 0 for reasons such as a long horizontal distance of about 100 m.

[0005] On the other hand, there are molds using water-resistant corrugated cardboard and molds using expanded metal.
Others are basically the same as the free frame method.

[0006]

However, in the case of this type of conventional method for spraying a frame, the following problems remain despite the large number of achievements.

(1) The weight ratio of cement (C): sand (S) is 1: 4, and the spraying method is not sufficiently mixed (poor unit cement) so that the strength is not sufficient. (2) When the poorly-mixed material is blown into the mold with air,
If a large amount of reband loss occurs and is not eliminated, nests are formed and the strength is reduced. (3) If a non-fluid material having a slump value of 0 is used,
It is difficult to go around the back side of the rebar, and it is formed in gaps or nests, resulting in reduced strength.

[0008] Therefore, rich blending (large unit cement amount)
A method of filling a material in the form using a form completely surrounding the cross section of the material is also being developed. However, the so-called pumping method frame method also has the following problems. (B) When the material is pumped through a commonly used 2.5 inch hose, a load of about 20 kg is applied to the worker holding the tip of the hose and the spray nozzle, and the worker holds it at all. However, it is difficult to cast while moving along the ground and formwork,
For this purpose, it is necessary to extend the boom to the prosthesis with a concrete pump truck and drive it through a pipe routed along the boom. It is unsuitable for the construction of mountainous areas where the movement of water is restricted spatially. (B) In order to spread the material all over the formwork or to maintain its quality, it is necessary to vibrate the material with a vibrator. Also inferior. (C) Spreading the material cast from the shoulder over the entire mold is an extremely difficult technique due to the poor fluidity of the material, and it is particularly difficult to fill the horizontal frame. Further, specifically, an unfilled space portion is generated at the upper portion of the horizontal frame on the side of the shoulder. As a result, the method is limited to the construction of a legal frame having a small area. (D) Due to insufficient vibrator application, the quality of the finished frame varies, and the strength is low despite the rich blending.

Accordingly, an object of the present invention is to solve all of the above problems.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide a wet method frame material mainly composed of mortar or concrete, having a cement: sand weight ratio of 1: 1 to less than 4 and a slump value of 8 to 27 cm. Pumping through a pipeline by a pump, and blowing from a spray nozzle at the tip of the pipeline into a formwork fixed to the ground, in the middle of a pipeline between the pump and the spray nozzle, and 5-4 from spray nozzle
This can be solved by blowing air at a distance of 0 m at a rate of 2 to 10 Nm ³ / min, and blowing the wet process frame building material from the spray nozzle while entraining the air.

In this case, the spray can be performed while the worker holds the spray nozzle.

It is preferable that the mold is a punching metal, and the opening ratio is 25 to 60%. Further, in the spray nozzle, it is preferable that air is further ejected forward from the peripheral portion of the flow of the legal frame material in a ring shape.

[0013]

(1) In the present invention, the weight ratio of cement to sand is
Spray a rich material wet composition of 1 to less than 1 to 4. This rich blend results in high strength.

(2) In addition, since the slump value is 8 to 27 cm, the flowability is good, and the slump wraps sufficiently behind the reinforcing bars arranged in the formwork, and the strength due to the formation of nests is reduced. There is no drop. In addition, since there is no or no reband loss and the amount is very small, a decrease in strength can be prevented.

(3) Even if there is rebound loss,
Since there is a lot of cement, the loss does not cause a decrease in biting strength. As described above, the strength reduction factor can be eliminated, and the composition of the material itself is rich, so that the strength is high as compared with both the free frame method and the pumping method frame method. .

(4) On the other hand, in the present invention, air is entrained in the material. As a result, the load applied to the hose tip and the nozzle is reduced as compared with the case where air is not entrained, and the worker can carry the load sufficiently regardless of the rich mixture. Therefore, while moving along the mold, the worker can spray while observing the filling state of the material in the mold, and the filling property is excellent, so that the strength and quality per place vary. There is no.

(5) Further, the position for entraining the air is located in the middle of the pipe between the pump and the spray nozzle and at a position separated from the spray nozzle by 5 to 40 m. as a result,
The material is surely uniformized from the entrainment start position of the pipeline to the spray nozzle. This air entrainment has the advantage of removing excess moisture in the material when it is ejected from the spray nozzle, lowering the slump value, and allowing the material to be sprayed as a high-density material, and exhibits a compaction effect. In the conventional free frame method, the material is not pumped but transported by placing the material on air by an air gun provided on the outlet side of the material kneading tank. Although there is an advantage that the worker can hold, since the conveying force of the material relies on air, a portion where the conveying flow is dense and a rough portion occur,
Intermittent conveyance, rebound loss occurs in large quantities,
Material separation occurs and the strength becomes non-uniform. On the other hand, in the present invention, the material is pumped and the air is entrained in the uniform flow of the material, so that even at the time of discharge from the spray nozzle, the material is discharged in a uniform state. There is no problem in the free frame method.

(6) Compared to the case of pumping, even in a place such as a mountain area where a concrete pump truck cannot enter, an operator can hold the nozzle portion and move to any place to move the concrete pump truck. You can build a frame. Further, high-quality spraying can be performed on the spraying material without giving a vibration by a vibrator or the like. In the case of pumping, while excess water is not removed and there is no material consolidation effect at the time of spraying, in the present invention, air is blown together with the material to remove excess moisture at the time of spraying. In addition, since a consolidation effect is exhibited, the strength becomes high.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the construction of an embodiment of the present invention. FIG. 1 is an overall view, in which sand 1 is put into a hopper 3 by a shovel wheel 2 and the like, and is put into a weighing device 5 by a belt conveyor 4. After the measurement, the mixture is put into the mixer 6, and the water from the cement 7 and the water tank 8 is supplied through the water hose 10 by the pump 9 and kneaded by the mixer 6.

This wet material is pressure-fed to a spray nozzle 13 through a pressure-feeding pipeline 12 by a pressure-feeding pump 11 such as a squeeze pump or a piston pump. On the other hand, air is injected into the wet material by the compressor 14 from the Y-shaped pipe 16 provided in the middle of the pressure feed pipe 12 via the air pressure feed pipe 15. As a result, air is entrained in the wet material and is discharged from the spray nozzle 13. Reference numeral 17 denotes an air flow meter, which adjusts the amount of air according to the composition of the material and the state of spraying.

Here, as shown in FIG. 2, the pressure feed pipe line 12 is basically constituted by a metal pipe 12A up to the Y-shaped pipe 16, and is formed by a flexible pressure-resistant hose 12 up to the spray nozzle 13.
B is preferable, but a high-pressure hose can be used instead of the metal tube 12A. The position (corresponding to the length of the pressure-resistant hose 12B) of the Y-shaped pipe 16 for entraining the air is 5 to 5
The length is 40 m, and particularly preferably 10 to 30 m.

If the air injection position (entrainment start position) is close to the spray nozzle 13, the air conveyance distance is short, and the material discharge from the spray nozzle is not stable. Further, it becomes difficult for the worker to move while holding the spray nozzle, which causes a reduction in workability. On the other hand, if the distance is excessively high, there is a possibility that the material may be separated during transportation. In addition, it is preferable to be at least 3 m away from the pressure feed pump 11 in order to stabilize the flow of the discharge material.

As shown in FIG. 4, the unit frames are preferably formed by arranging unit frames 20, preferably made of punched metal, in parallel and adjacent to each other, for example, in a lattice shape. In this case, the adjacent unit forms 20, 20 are connected to each other by a connecting member 21 such as a steel bar or a steel wire, and the reinforcing bar 22 is fixed to the connecting member 21 in the longitudinal direction by a number line or the like. Further, the anchor pin 23 is driven into a necessary place, for example, an intersection, with respect to the ground.

After the completion of the setup, as shown in FIG. 5, the worker carries the hose 12B and sprays the material with the spray nozzle 13 facing the inside of the mold. At that time, the worker can work while observing the filling state of the material into the mold. As shown in FIG. 4, a vegetation sandbag 24 can be piled up, a vegetation base can be formed, a mortar can be sprayed, and the like, as shown in FIG. Further, a wire mesh or the like may be laid on the target slope in advance. For steep terrain, a full-fledged anchor can be driven at the intersection.

As the spray nozzle in the present invention, in addition to a general cone-shaped nozzle, as shown in FIG. 3, a ring pipe 13B is provided around the tip of the spray nozzle body 13A.
It is preferable to use a device in which air A is further injected from the inlet 13C and the air is discharged through an annular gap between the spray nozzle body 13A and the ring tube 13B. Thereby, a flow of air indicated by a broken line can be formed around the flow of the material M. If the air does not flow out, as shown in the figure, a so-called nasal dripping phenomenon in which a part M 'of the material drips from the tip of the nozzle is shown.
On the other hand, when the air flow shown by the broken line is formed,
Blow off the material that is going to hang down in the air,
Or by the air curtain action by the flow of air,
Prevent drooling. Thus, not only the loss of the material but also the soiling of the target slope is prevented, and the adhesion of the material to the workers is also prevented. At the same time, the material discharge speed is accelerated, and the filling property of the mold is improved.

In the present invention, it is preferable to use a punching metal for the crimping wire net used in the free frame method as the mold. Various shapes can be used as the opening shape of the punching metal. For example, a round hole, a long hole, a square hole, a diamond-shaped hole, a cross-shaped hole, or a combination thereof can be used. Is enough. Also, as the aperture ratio,
Preferred is 25-60%, especially 30-45%. If the opening ratio is small, the amount of water released from the sprayed material is reduced, and the weight of the mold is increased, so that the portability to the site is deteriorated. Conversely, when the aperture ratio increases, the amount of the sprayed material that flows out increases, and the rigidity decreases. In particular, in the case of a horizontal frame, the deformation increases. In addition, the amount of the sprayed material flowing out from the opening increases, and the effect of consolidating the material at the initial stage of spraying due to the outflow decreases. Examples of the aperture ratio are shown in FIGS. 6 (26%) and 7 (51%). The diameter of the opening is preferably 5 to 12 mm. The thickness of the punched metal is 0.6
~ 1.2 mm is preferred. If the strength of the formwork is insufficient,
By providing a reinforcing member along the longitudinal direction of the inner surface or the outer surface of the formwork or forming a rib, the strength can be improved. In this embodiment, the punching metal is used.However, it is also possible to use a crimped wire mesh or a welded wire mesh by reducing the opening ratio by making the mesh fine, and increasing the rigidity by increasing the wire diameter. it can.

In the present invention, air is entrained on the material with a rich mixture. In this case, the air can be blown from a plurality of locations in the middle of the pressure feeding pipeline. When the pumpability is enhanced by air, the inner diameter can be increased stepwise toward the end of the pipe, and air can be blown into each of the increased steps. In any case,
The entrained amount of air, 2 to 10 nm ³ / min in total, especially 2 to 7 nm ³ / min is preferred. The discharge pressure is 2 to 1
0 kg / cm ^2, is particularly preferred 5~8kg / cm ^2.

The air entrainment amount and the discharge pressure can be adjusted successively or in advance in response to communication from an operator, according to the blowing condition. The inner diameter of the aforementioned hose 12B is 35-60m
m, particularly preferably 40 to 50 mm, and the inner diameter of the discharge portion of the spray nozzle 13 is preferably 40 to 60 mm. Air flow is 2
When the pressure is less than Nm ³ / min and the pressure is less than 2 kg / cm ² , the discharge force of the material is weak and the filling property of the mold is reduced. On the other hand, if the flow rate exceeds 10 Nm ³ / min and the pressure exceeds 10 kg / cm ² , the material is separated and a large amount of rebound dross is generated, thereby deteriorating the quality.

The slump value of the transfer source is 8 to 27 cm.
It is said. If it is less than 8 cm, the fluidity is poor and the pumping performance by the pump is poor, and the addition of air lowers the slump value at the time of casting from the nozzle, inferior in filling property into the formwork, and the wraparound property of the reinforcing bar to the back side It becomes bad. 27
If it exceeds cm, there is a problem that the amount of sag increases and the amount of outflow from the through holes of the mold increases.

The method frame material of the present invention may be concrete in addition to mortar. In any case, the weight ratio of cement (C): sand (S) is set to 1: 1 to less than 4. When C: S is less than 1: 1, it becomes uneconomical and cracks easily occur. When C: S is 1: 4 or more,
Insufficient strength and impaired pumpability. In the case of concrete, the weight ratio of cement: sand: coarse aggregate is 1: 1 to less than 4: <2. The particle size of the coarse aggregate is preferably 25 mm or less, particularly preferably 15 mm or less. As the coarse aggregate, slag (slowly cooled slag) and the like can be used in addition to gravel. Further, in these materials, a water reducing agent, a foaming agent, a thickening agent and the like are contained in an amount of 3% by weight or less based on the cement, and a mixed material such as hydraulic slag fine powder, charcoal and fly ash is added to the cement. On the other hand, it can be added in a range of 150% by weight or less. The added amount of water is preferably 40 to 65% as W / C. The discharge amount of the legal frame material from the spray nozzle is preferably 2 to 10 Nm ³ / hour.

In order to improve the material transportability, it is optimal to use a rubber hose having a high-molecular-weight polyethylene resin layer on its inner surface and a fiber-reinforced middle part of the thickness as the transport line 12, especially the hose. is there. In addition, when the cement slurry is supplied from the periphery thereof in the middle of the transport pipeline and the material is transported while forming a film of the cement slurry as a thin layer on the inner surface portion of the transport pipeline, transportability is improved. The present inventors have found that. The cement slurry may be introduced from a plurality of places in the transport direction other than one place.

[Experimental Examples] The effects of the present invention will be clarified by showing experimental examples below. (Experimental example 1) Slump value of spraying material, air pressure (source pressure), air flow rate, air injection position (position of Y-shaped pipe), type of spray nozzle (in case of straight pipe and the structure of FIG. 3) Was changed variously, the spraying condition was observed, and the physical properties of the constructed frame were examined.

The spraying material was cement: sand: hydraulic slag fine powder = 1: 3: 0.2, a water reducing agent and a thickener were added at 1% to the weight of cement, and the slump value was adjusted by W / C. , In the range of 5 to 29 cm. As a formwork,
A punching metal having a thickness of 1 mm was used, and the aperture ratio was 41.9% and the hole diameter was 8 mm. In this experimental example, the inner diameter of the hose at the end of the Y-tube is set to 45 mm.

[0034] The spraying condition includes the discharging condition from the spraying nozzle,
The state of the repulsion loss, the state of the cut section of the legal frame, and the appearance state of the sampled core were determined based on the average of the evaluations by the ten experimenters and the dispersion of the evaluation. This situation observation evaluation includes the situation of nest formation, the situation of turning around the rebar, and the like.

(Experimental Example 2) With respect to the cores collected, the correlation between the compressive strength and its variation coefficient and the slump value, and the correlation between the unit volume weight, the amount of air, and the air injection position was as shown in FIGS. FIG.
As a result, it was found that the compressive strength and the coefficient of variation of the core depended on the change of the slump value, the coefficient of variation was small, and the range of the slump value with high compressive strength was about 10 to 25 cm. In FIG. 8, in the case of this experimental example, the compressive strength is 300 kgf / cm ² or more, but this value naturally changes by changing the composition.

In FIG. 9, when the air injection position is 1 m or 50 m, the weight per unit volume tends to be slightly smaller, but it has been found that there is no significant difference in the range of 5 to 30 m.

The amount of air is 2 to 10 Nm ³ /
Minutes was sufficient, and it was found that the unit volume weight increased particularly at about ^{3 to 5} Nm ³ / minute.

From the results of Experimental Examples 1 and 2, the slump value was 8 to 27 cm, and the air pressure (source pressure)
Is 3 to 8 kg / cm ² , air flow is ² to 10 Nm ³ / min,
It has been found that there is no significant difference between the air injection positions at 5 to 30 m from the tip of the spray nozzle. The spray nozzle type is
It was recognized that the structure shown in FIG. 3 was slightly superior in the effect of preventing drooling and in the state of discharge from the spray nozzle.

(Experimental Example 3) When the hole diameter of the punching metal was variously changed, it was found that a hole diameter of about 6 to 10 mm reduced the outflow of the material from the hole and reduced the rebound loss.

(Experimental Example 4) The correlation between the constituent material of the mold and the spraying method was examined.
As for the unit weight, the results shown in FIGS.
As for the 28-day strength, the results shown in FIGS. 13 and 15 were obtained. From the results of FIG. 10 and FIG. 13, it can be seen that the combined air system of the present invention has a lower unit volume weight than the all-air system and the pumping system in the conventional free frame method, regardless of which mold is used. It turned out to be bigger. FIG.
1, FIG. 12, FIG. 14 and FIG. 15 show that the punching metal has a larger unit volume weight than a crimped wire mesh.

(Experimental Example 5) The difference due to the spraying method was evaluated based on the coefficient of variation of the unit volume weight shown in FIG. 14 and the coefficient of variation of the core compressive strength shown in FIG. It was found that a legal framework with little variation could be constructed.

[0042]

As described above, according to the present invention, the operation and effect described in the above-mentioned operation column can be obtained.
It is possible to construct a legal framework with excellent strength and little variation in quality. In addition, advantages such as excellent workability such as holding by a nozzle man are provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining an overall example of a method of the present invention.

FIG. 2 is an explanatory diagram showing a material and air pumping system.

FIG. 3 is a vertical sectional view of an example of a spray nozzle.

FIG. 4 is a perspective view of a construction state of a legal frame.

FIG. 5 is a perspective view of a spraying state.

FIG. 6 is an explanatory view of a hole opening state of a punching metal.

FIG. 7 is an explanatory diagram of a hole opening state of another punching metal.

FIG. 8 is a graph of an experimental result.

FIG. 9 is a graph of an experimental result.

FIG. 10 is a graph of an experimental result.

FIG. 11 is a graph of an experimental result.

FIG. 12 is a graph of an experimental result.

FIG. 13 is a graph of an experimental result.

FIG. 14 is a graph of an experimental result.

FIG. 15 is a graph of an experimental result.

FIG. 16 is a graph of an experimental result.

[Explanation of symbols]

1 ... sand, 6 ... mixer, 7 ... cement, 8 ... water tank,
Reference numeral 11: pumping pump, 12: pumping line, 13: spray nozzle, 14: compressor, 15: air pumping tube, 16:
Y-shaped tube, 20: unit mold (punched metal), A: air, M: material.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeo Ogo 4-2-2-5 Kudankita, Chiyoda-ku, Tokyo Inside Light Industry Co., Ltd. (72) Inventor Masao Kima 4-2-2 Kudankita, Chiyoda-ku, Tokyo 35 Light Industry Co., Ltd. (72) Inventor Masanao Abe 4-2-2, Kudankita, Chiyoda-ku, Tokyo Light Industry Co., Ltd. (72) Inventor Junichi Inoue 4-2-235, Kudankita, Chiyoda-ku, Tokyo Light Industry Co., Ltd. (72) Inventor Kazuyuki Niwa 4-2-35 Kudankita, Chiyoda-ku, Tokyo Light Industry Co., Ltd. (72) Inventor Tomoyuki Yamane 4-35, Kudankita, Chiyoda-ku, Tokyo Light Inside Industrial Co., Ltd. (72) Inventor Yuri Chiaki 4-2-2-5 Kudankita, Chiyoda-ku, Tokyo Inside Light Industry Co., Ltd. (72) Inventor Yoko Xie Sen, Tokyo 4-35, Kudankita, Ta-ku, Light Industry Co., Ltd. (56) References JP-A-53-38105 (JP, A) JP-A-61-64956 (JP, A) JP-A-61-254719 (JP) JP-A-55-126614 (JP, A) JP-B-49-11162 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 17/20 104

Claims (4)

(57) [Claims] 1. A mortar or concrete as a main component,
Cement: sand weight ratio is less than 1: 1 to 4 and wet method frame construction material having a slump value of 8 to 27 cm is pumped through a pipe by a pump, and is discharged from a spray nozzle at the tip of the pipe. At the position in the middle of the pipe between the pump and the spray nozzle and at a distance of 5 to 40 m from the spray nozzle,
Up to 10 nm ³ / min amounts have been blown air, Law frame construction method, characterized in that blowing the wet process frame build material from the spray nozzle while entrain the air. 2. The method according to claim 1, wherein the spraying nozzle sprays while being held by an operator. 3. The method according to claim 1, wherein the mold is a punched metal and has an opening ratio of 25 to 60%. 4. The method according to claim 1, wherein air is blown forward from the peripheral portion of the flow of the frame material in a ring shape.