JP2006225948A - Powder jetting device, its jetting method and construction method of underground structure making use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized powder jetting device capable of easily and efficiently jetting a powder into an excavated groove and its jetting method. <P>SOLUTION: In the powder jetting device jetting the powder into the excavated groove T for constructing an underground structure in the excavated groove T, it is equipped with a jet pipe 1 jetting the powder into excavated groove, the first pipe line 2 making pressure feed of air to the jet pipe 1 and the second pipe line 3 connected to the first pipe line 2 and, at the same time, making air pressure feed of the powder, and it is so constituted that air continuously makes the pressure feed from the first pipe line 2 to jet air from the jet pipe 1 during the fixed time before at least starting of the air pressure feed of the power and the during the fixed time from the direct after the completion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a powder injection apparatus and an injection method thereof, and more particularly to a powder injection apparatus for underground structure construction, an injection method thereof, and an underground structure construction method using the same.

  In general, as a method of constructing a water-blocking wall or a retaining wall, excavate the target ground using an earth auger machine, etc., and mix this cement-based solidified material with a clay mineral suspension such as bentonite and the ground of the target ground. A method of forming a wall body in the ground by stirring and hardening is known, but if a cement-based solidifying material is added, the wall body will not be able to follow the deformation of the ground, etc., and water shielding will be secured for a long time Difficult to do.

  On the other hand, by using the bentonite mud wall construction method that fills the excavation trench with bennite mud using the followability to ground deformation caused by the self-healing properties of bentonite, a clay mineral, without using cement-based solidified material. In some cases, the middle water-impervious wall can be secured for a long period of time.

  Here, it is necessary to add a large amount of bentonite in order that the underground impermeable wall by the bennite mixed soil has the same strength as the ground without adding cement-based solidifying material. However, since clay mineral suspensions are highly viscous, it is difficult to pump liquids when pumping, and mechanical agitation such as an earth auger reduces the stirring efficiency, so a large amount of bentonite cannot be added. There was a problem on top and construction cost.

  Therefore, rather than pumping clay minerals such as bentonite as a suspension, it is pumped into the excavation groove in powder form, thereby delaying the increase in viscosity by delaying the contact with moisture. The clay mineral and the mixed soil are mixed and stirred in the excavation groove efficiently and homogeneously with low viscosity, and without using cement-based solidification material, an underground impermeable wall with the same strength as the ground can be easily and A method of constructing at a low cost has been proposed (see, for example, Patent Document 1).

  However, in order to further improve the water shielding using the method of the present invention, there has been a problem that the work is difficult when the water shielding sheet is provided to construct the water shielding wall. That is, in general, the injection of powder into the excavation groove (specifically, in the mud of the excavation groove) in the above invention is performed simultaneously with excavation of the target ground and mixing and agitation with the in-situ soil (excavation soil). Therefore, even if it tried to arrange | position a water-impervious sheet in an excavation groove after that, it was difficult to arrange | position in the excavation groove of a water-impervious sheet by the viscosity of bentonite, and the operation | work was difficult. Therefore, after excavating the target ground and disposing the water-impervious sheet in the excavation groove, bentonite has to be injected into the mud in the excavation groove.

On the other hand, when powder such as bentonite is injected into the muddy water, the powder and muddy water come into contact with each other in the vicinity of the injection port, and the powder becomes lumpy in the vicinity of the injection port due to an increase in the viscosity of the powder. It stuck to the mouth and closed the injection port, making it difficult to work. In the conventional apparatus, on the premise of the occurrence of a dam that closes the injection port, for example, the clogging of the injection port is prevented by forcibly discharging the dam by the pumping of high-pressure air with a large, high-power compressor.
Japanese Patent Application No. 2004-164157

  However, when a powder injection operation is performed in the excavation groove after the impermeable sheet is disposed in the excavation groove, the work space is narrow in the state in which the impervious sheet is disposed in the excavation groove. In the conventional apparatus, the work efficiency was poor.

  Therefore, a main problem of the present invention is to provide a small-sized powder injection device and an injection method thereof, and a method of constructing an underground structure using the same, which enables powder to be easily and efficiently injected into the excavation trench. There is.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
The invention according to claim 1 is a powder injection device for injecting powder into the excavation groove in order to construct an underground structure in the excavation groove, and injects the powder into the excavation groove. An injection pipe; a first pipe that pumps air to the jet pipe; and a second pipe that is connected to the first pipe and feeds the powder by air. It is configured such that air is continuously pumped from the first pipe and air is jetted from the jet pipe for at least a predetermined time before the start of body air pumping and for a predetermined time immediately after the end. This is a powder injection apparatus characterized by the above.

(Function and effect)
An injection pipe that continuously pumps air from the first pipe line for at least a predetermined time before the start of air pressure feeding of powder and for a certain time immediately after the end of air pressure feeding of powder to be described later. With the configuration in which air is injected from the air, when the powder is injected from the injection port while air is being injected from the first pipeline, the air from the first pipeline becomes an air curtain, In the vicinity of the mouth, the powder does not come into contact with the muddy water, so that it is possible to prevent the occurrence of lumps that block the spray nozzle.
Therefore, the powder can be injected into the muddy water at a low pressure. As a result, it is possible to form the underground structure with a device such as a small compressor as compared with the conventional device. . Further, since the powder can be pumped at a low pressure, the injection pipe can use a metal such as a gas pipe or a resin pipe, a resin or a rubber hose, or the like as a material.
The underground structure according to the present invention is a structure constructed by a submergence method for laying underground impermeable walls and sewer pipes, waterworks, urban drainage channels, agricultural waterways, fire prevention water tanks, common ditches, etc. Shall be included.
The powder according to the present invention refers to a powder of a hydraulic solidifying material such as bentonite, a water-absorbing polymer, a polymer flocculant, cement, gypsum, and the like, which reacts with water and aggregates and condenses. To do.

<Invention of Claim 2>
The invention according to claim 2 is configured such that air is continuously fed from the first pipe and air is jetted from the jet pipe while the powder is being pumped by air. 1. A powder injection apparatus according to 1.

(Function and effect)
Even while the powder is being air-pumped, the configuration is such that air is continuously pumped from the first pipe and air is jetted from the jet pipe, thereby further reducing the occurrence of lumps that block the spray port. It can be surely prevented.

<Invention of Claim 3>
The invention according to claim 3 is a method for injecting powder from an injection pipe having an injection port in order to construct an underground structure in the excavation groove, and injecting air from the injection port, The injection pipe is submerged in the muddy water, and the powder is injected while injecting air from the injection port in the muddy water, and after the injection of the powder, air is injected from the injection port, The powder injection method is characterized by pulling up from the muddy water.

(Function and effect)
While injecting air from the injection port, the injection pipe is submerged in the muddy water in the excavation groove, and in this muddy water, the powder is injected while injecting air from the injection port. If the air curtain is pulled up from the mud in the excavation groove, the air curtain reduces the possibility of the mud coming into contact with the vicinity of the injection port. Therefore, it is possible to inject the powder into the muddy water while preventing the powder from swelling and increasing the viscosity. Therefore, an excessive pressure load for injecting the powder is not required, and the powder can be efficiently produced at a low pressure. Can be injected.

<Invention of Claim 4>
The invention described in claim 4 is a method for constructing an underground structure using the powder injection apparatus described in claim 1 or 2 while ejecting powdery bentonite.

According to the present invention, there is an advantage that the powder can be easily and efficiently injected into the excavation groove.

Hereinafter, a powder non-control type injection device and a powder control type injection device which are embodiments of the powder injection device according to the present invention will be described.
<Configuration of powder-uncontrolled spray device>
Based on the example of the water-impervious wall formed of bentonite shown in FIG. 1 and FIG. 5, the configuration of the powder non-control type injection device according to the present invention will be described.
The powder injection apparatus according to the present invention is connected to an injection pipe 1 for injecting powder into the excavation groove T, a first pipe line 2 for feeding air to the injection pipe 1, and the first pipe line 2. And a second pipe 3 for air-feeding the powder.

  The injection tube 1 is hollow, and compressed air or powder is injected through the hollow portion. Since the injection pipe 1 is inserted into the excavation groove T filled with muddy water, the powdery bentonite injected from the injection port 1A increases in viscosity by contacting with muddy water. Will come together and a water-impervious wall made of clay mineral will be formed. As will be described later, since powder can be pumped to the injection pipe 1 at a low pressure, a metal or a resin pipe such as a gas pipe, a resin or a rubber hose, or the like can be used as a material.

  A first pipe line 2 that pumps air is connected to the proximal end side of the injection pipe 1. A Y-shaped pipe 8 is attached to the first pipe 2 in the middle thereof, and a second pipe 3 for air-feeding powder is connected to one end of the Y-shaped pipe 8. The proximal end of the first pipe line 2 is connected to the compressor 7 via the pressure reducing valve 5. As the compressor 7, a known type such as a screw type or a reciprocating type can be used.

  The tip of the second pipe 3 is connected to the Y-shaped pipe 8 described above, and the powder is pressure-fed through the first pipe 2 via the Y-shaped pipe 8 to the jet pipe 1 and the jet port. From 1A, powder is injected into the muddy water. The proximal end of the second pipe 3 is connected to the powder supply tank 9. The powder supply tank 9 is a pressure tank for storing powder. A third pipe 4 is connected to the powder supply tank 9, and the third pipe 4 is connected to the proximal end side of the first pipe 2, thereby supplying the supply tank 9. Air is pumped inside. Then, compressed air is sent from the compressor 7 into the powder supply tank 9 via the pressure reducing valve 5, the proximal end side of the first pipe line 2 and the third pipe line 4. The powder is finally injected from the injection port 1 </ b> A of the injection pipe 1 through the second pipe 3 while being conveyed to the air.

  Here, the air is routed through the first pipeline 2 for pressure feeding, while the powder is routed through the proximal end side of the first pipeline 2 for air feeding and the third pipeline 4. Since air is pumped through the second pipe 3, the distance between the paths of the air pumped from the first pipe 2 and the powder pumped from the second pipe 3 is the same. Due to the difference, a time difference occurs during the injection from the injection port 1A, and only air pressure feeding precedes. Therefore, the air from the first pipe line 2 can act as an air curtain for the powder to be jetted, and the jet pipe 1 jets while the jet pipe 1 is submerged in the muddy water, as will be described later. Only air is jetted from the port 1A, and then the powder can be jetted with a time difference, and as a result, it is possible to prevent the powder from becoming lumpy in the vicinity of the jet port 1A.

  The injection port 1A formed in the injection tube 1 is not limited to the tip portion of the injection tube 1, but may be formed on the side surface of the injection tube 1 as shown in FIG. A plurality of them may be formed, or although not shown, they may be formed at one place on the side surface of the injection tube 1.

  Further, as shown in FIG. 6, the injection tube 1 may be a double tube composed of an inner tube 11 and an outer tube 12, and in this case, powder is ejected from the inner tube 11, Air may be ejected and used as an air curtain. Furthermore, although not shown in the figure, the injection pipe 1 is connected to the first pipe 2 and separated into an air dedicated pipe for feeding air and a powder dedicated pipe connected to the second pipe 3 for feeding powder. Then, the air dedicated tube may be placed along or wound around the powder dedicated tube, and the air from the air dedicated tube may be blown near the injection port of the powder dedicated tube.

  In this embodiment, the pressure reducing valve 5 is used. However, the pressure reducing valve 5 is not always necessary, and may not be installed depending on circumstances.

<Construction method of impermeable wall using non-powder controlled spray device>
Before using the non-powder control type injection device, as shown in FIG. 2, a water-impervious sheet 60 is preliminarily placed in the excavation groove T formed in the target ground by a chain cutter excavator (not shown) or the like. Is disposed. At this time, the inside of the excavation groove T is filled with muddy water. As the water shielding sheet 60, for example, a known sheet such as a polyethylene sheet or a rubber asphalt waterproof sheet can be used. Further, the water shielding sheet 60 may be divided and dropped into the excavation groove T according to the length of the excavation groove T. In addition, although 61 has shown the guide wall, in this invention, it is not necessarily required.

  In the powder supply tank 9, an amount of bentonite necessary for forming a water-impervious wall in the excavation groove T is stored in advance. Thereafter, the compressor 7 is operated to pump air through the first pipe 2 and the injection pipe 1 is submerged in the muddy water while injecting air from the injection port 1A of the injection pipe 1, as shown in FIG. In addition, the injection pipe 1 is inserted as it is into the excavation groove T filled with muddy water.

  At this time, the air from the first pipe line 2 acts as an air curtain for the powder to be injected. That is, when powder is jetted from the jet port 1A in a state where air is not jetted in advance, the powder and mud in the vicinity of the jet port 1A come into contact with each other, and the powder becomes lumps near the jet port 1A. 1A adheres and closes the injection port 1A, but when powder is injected from the injection port 1A in a state where air is previously injected, the air from the first pipe line 2 becomes an air curtain, and the injection port In the vicinity of 1A, the powder does not come into contact with the muddy water, so that the injection port 1A is not blocked.

  Then, while injecting the powder from the injection port 1A of the injection tube 1, as shown in FIG. 3, the injection tube 1 is moved in the groove longitudinal direction in the excavation groove T, and the powder is evenly distributed in the excavation groove T. I will spray. Depending on the case, you may reciprocate the groove longitudinal direction in the excavation groove T, and may inject. In these cases, although not shown in the figure, the powder may be sprayed while pulling up the spray pipe 1 toward the ground surface. Alternatively, as shown in FIG. 4, a plurality of injection pipes 1 are arranged in the excavation groove T with a predetermined interval in the groove longitudinal direction, and the first pipe line is sequentially provided to these injection pipes 1, 1,. 2 or the like may be connected to spray the powder, or a plurality of first pipes 2 may be prepared, and the powder may be sprayed simultaneously or sequentially from the plurality of spray tubes 1, 1,. You may spray.

  Even when the injection of a predetermined amount of powder previously stored in the powder supply tank 9 is completed, adhesion of moisture to the injection port 1A of the injection tube 1 (accordingly, adhesion of powder containing moisture) is prevented. Therefore, air is continuously fed from the first pipe line 2 until it is completely extracted from the muddy water, and air is continuously ejected from the ejection port 1A.

  FIG. 1 only describes the implementation of the powder injection device for one side of the water-impervious sheet 60 in the excavation groove T. Thereafter, the same operation is performed in the excavation groove T on the other side. is there.

  Here, the comparison between the conventional apparatus and the powder injection apparatus according to the present invention will be described. In the conventional apparatus, the air is high-pressure by a high-output compressor on the premise of the occurrence of lumps that block the injection port 1A. In order to prevent the injection port 1A from being blocked. On the other hand, in the powder injection device according to the present invention, the first pipe line 2 for continuously pumping air and the second pipe line 3 for pumping powder air are provided, and the powder air pumping is performed. For at least a certain time before the start of air and for a certain time immediately after the end of air pressure feeding of powder to be described later, air is continuously pumped from the first pipe 2 and air is jetted from the jet pipe 1. By adopting the configuration, it is possible to prevent the occurrence of lumps that block the injection port 1A. Therefore, it is possible to inject powder into muddy water at low pressure (about 0.05 MPa) as well as medium pressure. Can do. As a result, the underground impermeable wall can be formed by a device such as a small compressor as compared with the conventional device. Further, since the powder can be pumped at a low pressure, the injection pipe 1 can use a metal such as a gas pipe or a resin pipe, a resin or a rubber hose, or the like as a material.

<Configuration of powder control type injection device and construction method of impermeable wall using the same>
Based on the example of the water-impervious wall formed of bentonite shown in FIG. 7 to FIG. 9, the configuration of the powder-controlled spray device according to the present invention will be described.
In the powder control type injection device, a two-way valve 6 is attached to the third pipeline 4 in the powder non-control type injection device. Other configurations are substantially the same as those of the powderless control type injection device, and thus description thereof is omitted.

A method for constructing a water-impervious wall using this powder-controlled spray device will be described below.
As shown in FIG. 7, the difference from the case of the non-powder control type injection device is that the compressor 7 is operated with the two-way valve 6 closed, and air is pumped through the first pipe 2. Then, the jet pipe 1 is submerged in the mud while jetting air from the jet port 1A of the jet pipe 1, and the jet pipe 1 is inserted into the excavation groove T filled with mud as it is. Thereafter, as shown in FIG. 8, in a state where air is being pumped from the first pipe 2, the two-way valve 6 is opened, and air is pumped to the third pipe 4, and the powder is supplied to the second pipe 6. The fuel is injected from the injection port 1 </ b> A of the injection pipe 1 through the pipe 3.

  At this time, the air from the first pipe line 2 acts as an air curtain for the powder to be sprayed, as in the powder uncontrolled spray device, but the jet pipe 1 is submerged in the muddy water. In the meantime, only air is jetted from the jet port 1A of the jet pipe 1, and when the desired position is reached, the two-way valve 6 can be opened and the powder can be jetted. Yes.

  As shown in FIG. 9, when the injection of a predetermined amount of powder has been completed, the two-way valve 6 is closed, the air supply to the third conduit 4 is stopped, and the powder from the injection port 1A is stopped. Stop spraying. On the other hand, even when the powder injection is stopped, the air pressure from the first pipe line 2 continues, and air is continuously injected from the injection port 1A to the injection port 1A of the injection tube 1. In order to prevent moisture adhesion (adhesion of powder containing water accompanying it), air is continuously pumped from the first pipe line 2 until it is completely extracted from the muddy water, and air is continuously injected from the injection port 1A. It is.

  According to this powder control type injection device, the opening and closing operation of the two-way valve 6 causes at least a certain time before the start of powder air pressure feeding and a certain time immediately after the end of the powder air pressure feeding. In addition, air can be continuously injected from the first pipe 2 and air can be injected from the injection pipe 1. As a result, the non-powder control type injection device was premised on using up the bentonite in the powder supply tank 9, but according to the powder control type injection device, regardless of the size of the powder supply tank, The required amount of bentonite can be continuously supplied into the excavation groove T.

  In the powder control type injection device according to the present embodiment, the two-way valve 6 is attached to the third conduit 4, but is not limited thereto, and may be attached to the second conduit 3.

<Other embodiment of powder non-control type or powder control type injection device for constructing impermeable wall>
As another embodiment of the above-described powder injection device, as shown in FIG. 10, the injection pipes 10 and 10 having the injection port 10 </ b> A formed at the tip are disposed on both sides of the water shielding sheet 70 and in the excavation groove T. It is also possible to propose ones that are attached at predetermined intervals in the longitudinal direction of the groove. In this case, as shown in FIG. 4 described above, the first pipe 2 or the like may be sequentially connected to the injection pipes 10, 10,... A plurality of pipes 2 and the like may be prepared, and powder may be sprayed from the plurality of spray pipes 10, 10,... Simultaneously or sequentially. This makes it possible to wrap the dropping operation of the water-impervious sheet 70 and the operation of disposing the injection pipes 10, 10,. In FIG. 11, the injection port 10 </ b> A is formed on the side surface of the injection tube 10.

<Application to sinking method>
Drilling a groove using bentonite mud as a wall-stabilizing liquid, submerging a tube or box culvert connected in advance to a certain length, and fixing it with a hanging bracket at a predetermined position. Powder-injected or powder-controlled injection device for subsidence methods such as the plus method of laying sewer pipes, waterworks, urban drainage channels, agricultural waterways, fire prevention water tanks, joint grooves, etc. by injecting and solidifying The application will be described with reference to FIGS.

  In FIG. 12, in the excavation groove T excavated while being filled with the stabilizing liquid B such as bentonite mud, a plurality of pipe bodies P, P,... An upper supporting member 83 and a lower supporting member 84 such as an H-shaped steel are applied, and this is wrapped around a tubular body P by a wire 85 or the like, and a connecting tubular body PU is integrated via a suspension supporting gevin rod 87. The state of being submerged is shown. Further, FIG. 13 shows a state in which the erection member 88 and the suspension support Gevin rod 87 installed between the guide walls 81 and 81 are connected by the nut 86 and the connection pipe body PU is supported by suspension. Yes. Reference numeral 82 denotes a human hole.

  Then, in a state where the connecting pipe body PU is suspended and supported, the powder injection device according to the present invention is operated, and the air from the first pipe line 2 is used as an air curtain, and the powder is supplied to the injection pipe 1. It is injected from the injection port 1A, a required amount of bentonite is supplied into the excavation groove T, and then the bentonite is solidified. At this time, the injection pipe 1 may be moved in the groove longitudinal direction in the excavation groove T, and powder may be evenly injected into the excavation groove T, or the groove longitudinal direction in the excavation groove T may be reciprocated. , You may spray. Further, a plurality of injection pipes 1 may be prepared, and bentonite may be simultaneously injected into the excavation groove T. About others, since it is the same as construction of a impermeable wall, explanation is omitted.

  By using this method, in the conventional subsidence method, excess solid water is generated by injecting solidified liquid such as cement milk into bentonite mud, which becomes industrial waste and raises construction costs. However, the amount of industrial waste can be reduced by injecting powdered bentonite using the powder injection device according to the present invention and solidifying it.

It is explanatory drawing of the powder injection apparatus of the state before the start of powder injection. It is explanatory drawing of the powder-injection apparatus in the state which is injecting powder. It is explanatory drawing of the powder injection apparatus of the state after completion | finish of powder injection. It is explanatory drawing which shows the state by which the water shielding sheet was arrange | positioned in the excavation groove. It is explanatory drawing for demonstrating the injection method using an injection pipe. It is explanatory drawing for demonstrating the other injection method using an injection pipe. It is a modification of the position of the injection port of an injection pipe. It is explanatory drawing of other embodiment of a powder injection apparatus. It is a modification of the position of the injection port of the injection pipe. It is a modification of the position of the injection port of an injection pipe. It is explanatory drawing of other embodiment of a powder injection apparatus. It is a longitudinal cross-sectional view of the excavation groove in the state which is injecting powder from the powder injection apparatus in the submergence method. It is the longitudinal cross-sectional view of the excavation groove shown from the other direction in the state which is injecting powder from the powder injection apparatus in the construction method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Injection pipe, 1A ... Injection port, 2 ... 1st pipe line, 3 ... 2nd pipe line, 4 ... 3rd pipe line, 5 ... Pressure reducing valve, 6 ... Two-way valve, 7 ... Compressor, 8 DESCRIPTION OF SYMBOLS Y pipe, 9 ... Powder supply tank, 10 ... Injection pipe, 10A ... Injection port, 11 ... Inner pipe, 12 ... Outer pipe, 60 ... Water shielding sheet, 61 ... Guide wall, 70 ... Water shielding sheet, 81 ... guide wall, 82 ... human hole, 83 ... upper support material, 84 ... lower support material, 85 ... wire, 86 ... nut, 87 ... gevin rod for suspension support, 88 ... installation member, P ... tube, PU ... connection Tube, T ... excavation groove.

Claims (4)

A powder injection device for injecting powder into the excavation groove to construct an underground structure in the excavation groove,
An injection pipe that injects the powder into the excavation groove, a first pipe that pumps air into the jet pipe, and a first pipe that is connected to the first pipe and that feeds the powder by air. Two conduits,
A structure in which air is continuously pumped from the first pipe and air is jetted from the jet pipe for at least a predetermined time before the start of air pressure feeding of the powder and for a certain time immediately after the end. And
The powder injection apparatus characterized by the above-mentioned.   2. The powder injection device according to claim 1, wherein air is continuously supplied from the first pipe and air is injected from the injection pipe while the powder is being supplied by air. A method for injecting powder from an injection pipe having an injection port to construct an underground structure in a drilling groove,
While jetting air from the jet port, submerge the jet pipe in the muddy water of the excavation groove,
In this muddy water, the powder is jetted while jetting air from the jet port,
After the spraying of the powder is finished, the air is ejected from the ejection port, and the mud in the excavation groove is pulled up.
The powder injection method characterized by the above-mentioned.   A method for constructing an underground structure using the powder injection device according to claim 1 or 2 while jetting powdered bentonite.

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