JPH0730627B2 - Spraying method with excellent adhesion and shear resistance, and less dust generation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Object of the Invention" The present invention relates to a spraying method which is excellent in adhesive force and shear resistance and has little dust generation, and has good adhesion properties and sufficient dust generation concentration even with continuous spraying. It is intended to provide a construction method in which spraying is carried out in a reduced atmosphere and the spraying energy is small.

Industrial application field Concrete spraying technology in tunnels and inside structures and structures.

Conventional technology Spraying concrete in a tunnel or the like has the great advantage that concrete can be applied to the ceiling or side walls in a short time without the need to remove the conventional formwork or formwork after construction. , Is being widely adopted in various civil engineering works. However, there are three types of methods conventionally used as such concrete spraying methods: dry type, wet type and semi-wet type.

That is, the wet method is to convey a raw kneaded material obtained by mixing all the constituent materials including substantially all of the mixed water of concrete to be sprayed in a pipeline such as a pipe or a hose and spray it from a nozzle to spray it. There is an advantage that the strength of sprayed concrete obtained by well moistening cement etc. does not vary.

The dry method is a method in which a pipe such as a pipe or a hose for spraying as described above is pumped in a pipe with almost no water added, and the friction resistance in the pipe is small, and it is relatively simple and Since a compact mechanism and pipeline can freely obtain a preferable transport distance, it can be pumped from a position far away from the intended construction position in a mine deeply dug into the ground. It can be used freely.

In contrast to the above-mentioned wet method and dry method, in the semi-wet method which is an intermediate method between them, the water injection position in the dry method is shifted from the nozzle part and the final position is set at the middle of the pipe such as a pipe or hose. It is a method of spraying with water.

The inventors of the present invention have proposed Japanese Unexamined Patent Publication No. 54-142823 (Japanese Patent Publication No. 60-22153) as a technique for solving the above-mentioned problems in the conventional three methods.

That is, a paste in which water is added to a hydraulic substance such as cement or gypsum, or a slurry-like raw kneaded material such as mortar in which sand or a fine-grained material similar thereto is mixed, and coarse aggregate such as gravel or Fine aggregates such as sand or powdery and granular mixture prepared by mixing one or more kinds of powdery substances are pressure-fed by different pipelines, and these different pressure-fused substances are combined and sprayed. It is characterized in that it is a slurry-like raw kneaded product that is sprinkled with cement powder or the like after being appropriately hydrated with a powdery and granular composition such as coarse aggregate or fine aggregate such as sand. It is also mentioned that they are separately pumped, combined and sprayed.

Problems to be Solved by the Invention However, each of the conventional methods described above has problems. That is, in the above-mentioned wet method, the frictional resistance in the pressure-feeding pipeline is large, and therefore the pipeline and mechanism for the pressure-feeding must have sufficient pressure resistance, which inevitably results in a large and strong structure. Even if it is not obtained, and the size and shape of the coarse aggregate are limited and the pipe line and the pumping mechanism are given special consideration, the conveying distance is limited,
There is a drawback that the limit is at most about 50 to 60 m and it is difficult to respond to the actual situation at various construction sites sufficiently.In addition, the strength that is the above-mentioned advantage has the optimum strength. Since it is the highest state, it is practically necessary to secure the pressure-feeding sprayability by increasing the water-cement ratio, and it is difficult to ideally obtain the strength, and it is difficult to exert its preferable merit. The amount of flaking off from the sprayed surface also increases, and there is a disadvantage that the sprayed layer thickness is limited due to drooping and other factors.

On the other hand, in the dry method, the amount of dust generated is large, and even in the case of a mine, the work condition cannot be confirmed unless the work is interrupted every short time. There is a disadvantage in that the strength of the spraying process, which is obtained because the cement and the like do not come into sufficient contact with water, is more variable than in the case of the wet method, and the amount of rebounding is considerably large.

Furthermore, in the semi-wet method, the water friction causes a drastic increase in the flow frictional resistance in the pressure-feeding pipe line, and since the quick-setting agent is mixed in as such, the final water-addition position is 5 to 5 times from the nozzle portion. The limit is about 6 m, and if the water addition position is made larger than this, paste etc. will adhere to the inner surface of the pipe or hose and block the pipeline, making full use of the advantage that the pumping distance in the dry type can be extended. Even if an attempt is made, since a large resistance portion is formed at the portion where the pressure at the end of the pipeline is lowered, a high-performance pumping or pipeline mechanism which is unexpectedly required in the dry method is required. Sufficient encounter kneading with cement and water cannot be obtained.

In any of the three methods described above, in order to improve the adhesion of the raw kneaded material and reduce the amount of rebound and peeling, quick setting of sodium silicate, calcium chloride, sodium aluminate, sodium carbonate, etc. It has the disadvantage of requiring a large amount of binder.

The above-mentioned prior application method of the present inventors, which solves the disadvantages of these three conventional methods, enables proper conveyance of concrete material, enables smooth spraying of concrete having a low water-cement ratio, and also has a bounce amount and As a method to reduce the amount of dust generation and to accurately form shotcrete with excellent strength, it has attracted a great deal of attention in various fields and is exhibiting its outstanding effects. According to the results of many on-site constructions, dust generation is unavoidable, so spraying for a long time while maintaining a favorable working environment such as a dust concentration of 5 mg / m ³ or less in a tunnel is unavoidable. There is some difficulty to continue. Further, it is not easy to obtain a preferable spraying work such as maintaining an average rebound rate of 25% or less on a ceiling surface in a tunnel or the like with a low cost of a compounding agent. Particularly in recent years, regarding this kind of spraying method, it is required that all of the following items (1) to (4) are satisfied, and it should be said that this is extremely difficult.

 There is little bounce.

The average bounce rate should be 25% or less in the construction of the upper half section in a solid rock with little spring water.

 Little dust is generated.

The concentration of inhalable dust (dust that has passed through a 7.07 μm cut sizing device) at 5 m from the spraying point should be 5 mg / m ³ or less (measurement condition is no ventilation).

 Must have sufficient strength.

The design standard strength shall be 180 kgf / cm ² or more, and sufficient desired strength should be obtained. In addition, the admixture used should not impair the durability.

It has sufficient workability and is economical.

The spraying capacity must be more than the conventional spraying concrete method. Also, its cost is not significantly higher than that of the conventional shotcrete construction method.

"Structure of Invention" Means for Solving Problems A slurry-like raw kneaded product such as mortar in which water is added to a hydraulic substance such as cement or gypsum and sand or a fine-grained material similar thereto is blended, Coarse aggregate such as gravel, fine aggregate such as sand, or a powder-granular mixture in which one or more kinds of powdery substances are mixed is pressure-fed by each different pipeline, and each of these different pressure-fed products the coalescing per to spray construction, the unit cement amount 330~360kg / m ^3, water-cement ratio of 50% to 60%, a 60% to 70% bone material index to aggregate, quick-setting admixture cement Adhesive force and shear resistance, characterized in that the amount of the composition is 3 to 7%, and that the above-mentioned separate pumped products are combined and then sprayed through a spraying nozzle that gives a swirling motion to the pumped products. Excellent spraying method with less dust generation.

Action Slurry raw kneaded material such as mortar in which water is added to hydraulic materials such as cements or gypsum and sand or fine granules similar thereto, and coarse aggregate such as gravel or sand The fine aggregate or the powder-granular mixture prepared by mixing one or more kinds of the powdery substances is pressure-fed by separate pipes, so that the pressure-feeding can be smoothly carried out even when a considerable pressure-feeding distance is provided.

The initial strength preferred for spraying is as follows: the material to be pumped in each of the separate pipelines has a unit cement amount of 330 kg / m ³ or more as shotcrete, and the quick-setting agent is 3% or more of the cement amount. And the quick-setting agent is 7% of the cement amount
By maintaining the following, long-term strength is also secured, and low cost is achieved by setting the quick-setting agent to 7% or less of the cement amount and the cement amount to 360 kg / m ³ or less.

The water-cement ratio of the sprayed concrete is reduced to 50% or more to reduce the rebound at the time of spraying, and the sprayed concrete in a slump zero state is formed to 60% or less,
Moreover, it reduces drooling on the wall.

By setting the fine aggregate ratio to 60 to 70%, the rebound ratio is reduced as in the case of the water cement ratio.

The coarse aggregate is set to 15 mm or less to improve the pumpability and to prevent the irregular spraying conditions during spraying.

After the materials pumped in the separate pipes are combined, a swirling motion is given in the nozzle to instantaneously form a preferable mixed state, and a hydraulic substance such as cement is mixed with fine aggregate. Combined with the fact that it is made into a slurry-like raw kneaded product and sent under pressure, the generation of dust during spraying is effectively reduced.

EXAMPLES The present invention as described above will be further described. In the present invention, the present invention intends to satisfy all of the severe requirements such as the above-mentioned requirements.
For this reason, the method of adjusting concrete and mortar, in which the water required for sprayed concrete is added and kneaded in two times according to a certain law, that is, the result of primary kneading with a constant amount of water, results in surface adsorption of cement particles and aggregates. Water becomes shared, and even if the remaining secondary water is added and kneaded, a part of the cement particles adheres and remains on the aggregate surface to improve the aggregate interface, and the remaining cement particles also double. In order to disperse well due to the mixing effect of, the method of separating materials / breathing and improving the workability, strength and other qualities is adopted, and as the spraying method, the adhesion and shear stress required for the construction of sprayed concrete are large. For the purpose of spraying hard-mixed concrete, mortar in concrete is pumped, aggregate is compressed air, then Was pumped to two systems, that spraying is respectively are merged with the nozzle front is in accordance with the application technique by the present applicant described above. However, the inventors of the present invention have been widely involved in such technology regarding selection and management of mortar, selection of composition of aggregate (sand and gravel) and selection of composition with mortar, selection of composition of admixture, physical properties of shotcrete, etc. In addition to repeated examinations, we also studied sand spraying water surface adjustment mechanism, mortar mixer, mortar pump, spraying machine, material measuring machine, and machine organization as a spraying system. That is, the summary of the examination results of such a spraying construction machine is as follows.

 Sand surface water conditioning machine.

Fluctuations in the surface condition of sand (surface water) affect various properties of concrete. Therefore, the following methods can be considered as methods for adjusting the surface water of the sand.

Lay the sand thinly in the stockyard, dry it, and collect it with a shovel before use.

Use a clamshell to collect the sand that is relatively dry and piled up.

A device (rotary dryer) for applying hot air to the wet sand to dry it is used.

A dewatering device (trade name: sand controller) that uses the difference in inertial force when colliding wet sand with velocity energy is used.

Therefore, the present inventors adjusted the surface water of the sand mainly using an efficient sand controller in consideration of the situation at the site.

 Mortar mixer.

The mixer function is the kneading property of mortar (material separation,
Pompability) and curing physical properties are affected. For this reason, a vortex-type forced agitation mixer (trade name: vortex mixer) that can obtain stable SEC mortar was used.

 Mortar pump.

Pump performance (especially pulsation during pumping and quantitativeness of discharge amount) affects the amount of splashed concrete, amount of dust generated, and strength of shotcrete. For this reason, we used a relatively compact squeeze-type mortar pump that has been used extensively.

 Spraying machine.

The performance of aggregate spraying machines (especially the quantification of pulsation and discharge rate during pumping) influences the amount of rebound of sprayed concrete, the amount of dust generated, and the strength.

For this reason, we used a compact, dry rotor-type spraying machine (Menadier GM90) that has a relatively good track record of use.

 Material weighing machine.

The performance of the material weighing machine (particularly the weighing accuracy and operability) affects the amount of splashed concrete, the amount of dust generated, and the strength. For this research and development, a weight measuring machine was used on the mortar side and a volume measuring machine was used on the aggregate side.

 Machine organization as a spraying system.

As the knitting machine for the spraying machine, there were two sets of mortar trolley and aggregate trolley equipped with each material, and a system was adopted in which the required amount of sprayed concrete material was mixed near the face.

The specific flowchart is as shown in FIG.
The sand obtained by the sand surface water conditioner 1 according to the previous term is the weighing machine 20 for the aggregate cart 2 and the weighing machine 30 for the mortar cart 3
Is charged to. Belt feeder 21 provided on the weighing machine 20
The sand and gravel 27 cut out with are mixed in the continuous mixer 22 and then supplied to the spraying machine 25 by the belt conveyor 24 together with the quick-setting agent from the quick-setting agent feeder 23, and the spraying machine 25 through the joining pipe 28. And is sent to the nozzle section 40 of the spraying robot.

On the other hand, the sand sent from the weighing machine 30 to the weighing machine 32 via the conveyor 31 is separately supplied to the forced agitation mixer 6 together with the cement sent from the cement hopper 33 via the conveyor 34 and measured by the weighing machine 35. is, the appropriately guided to Morutaruponbu 38 via the agitator 37 from the mixer 36, is sent to the merging pipe 28, 7 kg / cm ² about the high pressure air supply source 2
It is designed so that it will be joined with the above-mentioned aggregate that is pumped by 6 and sprayed. Appropriate admixtures are also supplied from the admixture tanks 39 and 39a to the above-mentioned forced agitation mixer 36.

The mode in which the equipment according to the above flow chart is installed in a vehicle such as a truck is as described above using two carts shown in FIGS. 2 to 4 and 5 to 7. The frame has a cab 41 as a mortar truck
A series of equipment from the cement hopper 33, the sand hopper 32 to the mortar pump 38 is mounted on the 42, while in the aggregate cart of FIGS. 5 to 7, the weighing machine 20, the belt feeder 21, and the continuous machine as described above are installed. A mixer 22, a belt conveyor 24 and a spraying machine 25 are mounted. Figures 8 and 9 show the situation in which mortar and other materials adjusted outside the mine are loaded into the mine by a truck and sprayed. That is, as shown in FIG. 8, the fine aggregate from the aggregate stockyard 45 outside the mine is treated by the surface water conditioning machine 1 as described above, and the adhered water is made uniform and mixed with the cement from the cement silo 47. It is loaded into the mechanism 48 and once adjusted as cement is stably and uniformly attached to the peripheral surface of the aggregate,
Moreover, the mortar made by adding the secondary water is received in the truck 49 having the dry storage chamber 49a and the mortar storage chamber 49b, and the truck 49 is used as the spray robot 4 in the mine as shown in FIG. It is carried and sprayed by the spraying mechanism 25.

That is, in contrast to the one shown in FIGS. 2 to 7 described above, in particular, the trolley shown in FIGS. 5 to 7 is equipped with a continuous mixer 22 to adjust mortar in a mine and spraying is performed. In FIG. 9, the mixing mechanism 48 provided outside the pit kneads and adjusts the mortar as mortar, and the mortar is accommodated in the mortar storage chamber 49b of the mortar trolley and the spray robot 4 together with the aggregate from the dry storage chamber 49a. Spraying mechanism 2
It is sent to 5 and is sprayed.

However, with the equipment as described above, various preliminary experiments were repeated, the mortar basic composition and the amount of the quick-setting admixture for carrying out the factory experiments were determined, and further the results of the factory experiments and on-site analysis were analyzed and considered and considered. As a result, it was confirmed that it is the reason for obtaining a preferable result that the mixing composition shown in Table 1 below is adopted as the mixing ratio of the shotcrete.

That is, as the coarse aggregate, it has been conventionally performed to generally use a coarse aggregate of 15 mm or less, and in the present invention, such a coarse aggregate is adopted. If used, the spraying condition will be considerably disturbed by this coarse coarse aggregate.

Next, sprayed concrete having a high slump value is likely to cause dripping or exfoliation after spraying, and in the present invention, by spraying as this slump value zero state, it is possible to obtain a construction without such disadvantages. Therefore, it cannot be said that the concrete composition in the state of zero slump value is at least extremely difficult because it cannot be pumped by the conventional general technique for spraying. As described above, the slurry-like raw kneaded product and the powder-granular compound are pressure-fed by separate pipe lines, and they are combined in the state immediately before spraying, whereby the pumpability can be sufficiently ensured. It should be noted that, after the coalescence, by passing through a spray nozzle that gives a swirling motion to the pumped product, the compounds pumped separately can be momentarily mixed and sprayed in the slump zero state as described above.

Next, the unit amount of cement is 330 to 360 kg / m ³ . That is, in order to obtain a certain strength as shotcrete, it is necessary to mix at least 330 kg / m ³ or more of cement. Regarding the upper limit, the one of the present invention is also a large object to obtain shotcrete at low cost,
The use of cement for g / m ³ or more leads to higher costs, so this is the upper limit.

Further, the water-cement ratio (W / C) is 50 to 60%, and if it is less than 50%, rebound is increased, which is not preferable.
On the other hand, if the W / C exceeds 60%, it becomes difficult to obtain the above kneaded product in the slump zero state.

Fine aggregate ratio, that is, the ratio of fine aggregate to coarse aggregate (S / a)
Is 60 to 70%, and if the S / a deviates from the range of 60 to 70%, the rebound rate increases in any case.

Finally, it is essential to mix 3 to 7% of the amount of cement for the quick-setting agent, and if it is less than 3%, an appropriate early strength cannot be obtained in such a spraying construction, and it will be difficult for the ceiling surface in the tunnel. There is a tendency for peeling to easily occur during spraying. On the other hand, if this quick-setting agent reaches 7% or more of the amount of cement, not only the cost increases but also the long-term strength deteriorates, so this should be the upper limit.

Note that the one according to the present invention can be appropriately added with a water reducing agent, a thickener, etc. depending on the temperature conditions during spraying construction, the situation of the local ground, etc., but as the amount, the water reducing agent is 0.75% of the cement amount, The upper limit of the thickener is 0.2%, and the addition of more than this causes an increase in cost and is not preferable.

Further, in the present invention, the above-mentioned compound is combined with the above-mentioned merging pipe 28 to be merged, and then a swirling motion is given by a nozzle as shown in FIG. That is, in FIG. 10, the rubber pressure-resistant hose 50 itself is used as a nozzle, and a steel pipe 51 and a jig 52 for preventing the bending of the hose 50 are attached to the end portion thereof, and within a range corresponding to the steel pipe 51. It has a spiral guide piece 53 attached to it and is suitable mainly for spraying by a robot.

The one shown in FIG. 11 is suitable for work. A separate pressure-resistant hose 55 is attached to the end of the pressure-resistant hose 50 with a joint 54, and a reinforcing bar 57 is arranged to the hose 55 via a fixing plate 56. Set up
Mounting the spiral guide piece in the hose 55 is the same as that shown in FIG.

These rubber nozzles are materials with little adhesion of mortar, quick-setting adhesive, etc., and even if they adhere, they can be easily removed. Is less likely to be clogged, and the increase in the material feed rate due to the reduction in the cross section of the nozzle and the resulting dust generation are suppressed.

Further, FIGS. 12 and 13 show another nozzle using a vinyl chloride pipe or a steel pipe, respectively, and the latter adopts a taper pipe. The spiral guide piece 53 is attached to the inside as described above.

Further, FIG. 14 shows a nozzle provided with a guide tube 58 at the tip thereof. That is, a large-diameter guide pipe 58 made of steel or the like is attached by a rib 59, and a spiral guide piece is attached in the nozzle.
Suppresses the scattering of materials and dust and enables efficient spraying. Further, the one shown in FIG. 15 is provided so as to be slidable with respect to the nozzle 60 of the guide tube 58 by the operating means 61, and the spraying distance between the guide tube 58 and the wall surface to be sprayed is appropriately adjusted. Is made to be done. The operating means 61 is preferably provided with a cover 62.

However, in FIG. 16, the air discharge nozzle 63 is provided at the tip of the nozzle 60, and an air curtain is formed on the peripheral side of the material ejected from the nozzle 60 by the pressurized air supplied by the pressure-feeding hose 64. The scattering of materials and dust is the same as that of the guide tube 58, and in any case, a spiral guide piece is provided in the nozzle 60.

That is, it is clear that the spraying by these nozzles effectively mixes the materials sent from the two systems immediately after being combined by the merging pipe 28 immediately before the spraying, and the swirling flow causes the scattering of the materials. Also suppresses the generation of dust. Further, the adhesion state of the material on the wall surface is also improved.

A concrete construction example of the present invention is as follows.

Construction Example 1 unit cement weight is 350 kg / m ^3, water 181.3kg / m ³ (W / C is 51.8
%), Sand 1088.9kg / m ^3, gravel 762.7kg / m ³ (S / a is 60
%), Including a cement-based quick-setting admixture as a quick-setting admixture in an amount of 5% of the amount of cement, including a ceiling surface excavated with a height of 5 m and a width of 7 m by the equipment as shown in FIG. It was sprayed in the hannel under no ventilation condition.

The spraying pressure P is 2.8 kgf / cm ² , and the spraying capacity per hour is sprayed with a working efficiency of 6 m ³ under the condition that the hose length is 80 m, and at the time of continuous spraying for 8 minutes 30 seconds, the spray nozzle a 2.9 mg / m ³ as a result of measuring the dust rate in more 5m behind in the tunnel, no ventilation conditions in a dusting even if less, also be made to the preferred spray construction a rebound rate 25.0% I was able to.

Note 203kg In this compression strength things 9.3 kg / cm ² after 3 hours, 13.8 kg / cm ² in 6 hours, 24 hours 74.6kg / cm ^2, 3 days /
cm ² , 268 kg / cm ² after 7 days, 371 kg / cm after 28 days
It was confirmed that it reached ² and that it had a preferable strength.

Construction Example 2 Concrete with the composition shown in Table 2 below was sprayed on the upper half-section face of a two-lane road tunnel (cross-sectional area 48 m ² ) under conditions where the outside air temperature was about 25 ° C. The quick-setting agent is a cement-based mineral (trade name: Natomic No. 5),
The water reducing agent is mainly composed of alkylallyl sulfonate (trade name: Sin Ace).

Table 3 below shows the results of three measurements of the bounce rate during the above construction.

The dust generation rate under non-ventilated condition was 4.85 mg / m ^{3 on} average for three times, and the compression strength measurement results after 3 hours, 6 hours, and 24 hours were as follows. It looks like the table.

The respective compressive strengths after 3 days, 7 days and 28 days are shown in Table 5 below.

Construction Example 3 Unlike the construction example 2, in the cold season when the outside air temperature was 8 ° C., spraying was also performed using a thickener. The composition of shotcrete is as shown in Table 6 below, and the unit cement amount is 350 kg / m ³ , which is the lower limit of the range of the present invention.

Note that the quick-setting agent and the water-reducing agent were the same as those used in Working Example 2, and the thickening agent used was one containing cellulose ether as the main component (trade name: NATOM CLEAN).

The results of the rebound rate test for three times are shown in Table 7 below.

Moreover, the measurement result of dust generated under non-ventilated condition over 3 times was 5.8 mg / m ^{3 at the} first time, which was slightly high, but at the second time, it was 4.
5 mg / m ^3, 3 time regardless of a continuous spraying both even 5 mg / m ³ or less and 4.6 mg / m ^3, that only the first is high due to something like or circumstances in equipment, long It is clear that even after hours of operation, levels below 5 mg / m ³ can be maintained. Regarding the strength of the shotcrete obtained,
As mentioned above, a thickener that should satisfy the generated dust and rebound rate was used, and there was particular concern about the long-term strength. Regarding the strength 7 days and 28 days after spraying, the ceiling surface (crown part) and both side walls The measurement results of the parts are as shown in Table 8 below, and it was confirmed that all were favorable results.

Construction Example 4 Similar to Construction Example 2 described above, spraying construction with a composition as shown in Table 9 below was carried out in a tunnel having a cross-sectional area of 48 m ² .

W / C: 51.8% Mortar W / C: 45% S / A: 60% Mortar S / C: 1.75 Accelerator: Natomic No.5 (Addition amount, C × 5%) Admixture: Sine ace high performance water reducing agent (Addition amount C x 0.75
%) The outside is sunny, the mine temperature is 25-27 ℃, and the humidity is 84%.
Under the conditions, the hose length is 80m and the spray pressure is 3.0-4.0kg /
cm ^2, and the average number of times the dust amount measurement results leading to spray ends from 5 minutes after the spraying start is at 4.6 mg / m ^3, both 5 mg / m ³
Satisfy the following:

Alternatively, the bounce rate is 22.1%, which is also preferable. However, the compressive strength of this shotcrete was 13.6 kg / cm ² after 3 hours and 22.1 kg / cm ² after 24 hours, 24
The time after an 125.0kg / cm ^2, 3 days after 196.0kg / cm ² at the crown (ceiling), 242.0kg / cm ² in the side wall, 7 days after 255 kg / cm ² at the crown, 281kg / cm ² next by side walls , 375 kg / cm ² in crown after 28 days, reached 393kg / cm ² in the side wall,
It was confirmed that all had sufficient strength.

"Effects of the Invention" When the present invention as described above is used, the adhesion property is improved with respect to the spraying work in a tunnel of this kind,
This is an invention which is capable of performing construction with less dust generation even by continuous spraying, ensuring favorable economic efficiency, and achieving stable operation, and which has a great industrial effect.

[Brief description of drawings]

The drawings show the technical contents of the present invention. Fig. 1 is a flow chart of a shotcrete plant according to the present invention, and Figs. 2 to 4 are plan views, lateral side faces and vertical side views of the mortar truck. 5 to 7 are a plan view, a lateral side view and a vertical side view of the aggregate cart, and FIG. 8 is an outside of the mine where mortar is adjusted outside the mine and is carried into the outside of the mine for spraying. FIG. 9 is a side view of the equipment, FIG. 9 is a side view of the working condition in the mine, and FIGS. 10 to 16 are partially cutaway side views of the spray nozzle used in the present invention. However, in these drawings, 1 is a surface water conditioner, 2 is an aggregate cart, 3 is a mortar cart, 4 is a spray robot, 20 is a weighing machine, 21 is a belt feeder, 22 is gravel, 23 is a quick setting feeder, 24 Is a belt conveyor, 28 is a confluent pipe, 30 is a weighing machine, 31 is a conveyor, 32 is a weighing machine, 33 is a cement hopper, 34 is a conveyor, 35 is a cement weighing machine, 36 is a forced stirring mixer, 37 is an agitator, 39, 39a is an admixture tank, 4
1 is cab, 42 is frame, 45 is aggregate stockyard, 4
7 is a cement silo, 48 is a mixer, 49 is a truck, 49a is its dry storage chamber, 49b is its mortar storage chamber, 50 is a rubber pressure hose, 51 is a steel pipe, 52 is a bend prevention jig, and 53 is a spiral. -Shaped guide piece, 54 is a joint, 55 is a separate pressure resistant hose, 56 is a fixing plate, 57 is a reinforcing bar, 58 is a guide tube, 59 is a rib, 60 is a nozzle, 61 is an operating means, 62 is a cover, 63 is an air The discharge nozzle 64 is a pressure-feeding hose.

Front page continuation (72) Inventor Kunihiko Ito 3774 Jindaiji, Mitaka City, Tokyo Obayashi Corporation Mitaka Dormitory (72) Inventor Hiroyasu Kitayama 1027-1 Nishiobuchi, Osuka Town, Ogasa County, Shizuoka Prefecture (72) Inventor Taiji Mihara, Matsudo, Chiba Prefecture 3-28-1 Tokiwadaira, Shimizu Shimizu Construction Co., Ltd. Matsudo Dormitory (72) Inventor Takayuki Tokunaga 4351-6 Fukaku, Omiya-shi, Saitama Prefecture (72) Masatsugu Nagasawa 1-70 Asamacho, Omiya-shi, Saitama 203 Maison de Osawa 203 ( 72) Inventor Masayoshi Takahashi 1-331, Yoshino-cho, Omiya City, Saitama Prefecture (56) References Japanese Patent Publication Sho 60-22153 (JP, B2)

Claims (1)

[Claims] 1. A slurry-like raw kneaded material such as mortar in which water is added to a hydraulic substance such as cement or gypsum, and sand or a fine-grained material in accordance with this is mixed, and coarse aggregate such as gravel or The fine aggregate such as sand or the powder-granular mixture prepared by mixing one or more of the powdery substances is pumped by separate pipe lines,
The unit cement amount is 330 to 360 kg / m ³ , and the water cement ratio is 5 when combining these different pumped products and spraying.
0-60%, the ratio of fine aggregate to aggregate is 60-70%, the quick-setting admixture has a composition of 3-7% of the amount of cement, and the above-mentioned separate pumped products are combined and then A spraying method that is excellent in adhesive force and shear resistance, and that generates little dust, characterized by performing spraying through a spraying nozzle that gives a swirling motion to the material to be pumped.