JP2003056271A - Method and device for preventing scattering of dust at boring time - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for preventing the scattering of dust, etc., erupted to the ground surface together with air at boring time. SOLUTION: In the method, the used air and excavated earth upwardly erupted from a hole to the ground surface through the space between the inner peripheral surface of the hole and a boring body at the time of boring the hole by pneumatically giving blows to a bit by means of a hammer are enclosed in a cover 4 having a cylindrical enclosing wall 3 and a ceiling 2 through which the boring body is passed. Then the erupted earth and air are sent out from a discharge port 8 made through the enclosing wall 3 by changing the direction of the air and earth by giving an active force to them by means of an air flow mixed with water separately supplied into the cover 4 in an almost horizontal direction and jetted from a nozzle 14. The device is provided with a ceiling section, the encircling wall 3, and the nozzle 14 directed to a horizontal direction roughly along the inner peripheral surface of the wall 3. The device is also provided with a water mixing means provided in an air supply passage and the discharge port 8 made through the enclosing wall 3. The ceiling section and wall 3 are formed in a divided state and the divided portions are coupled with each other by means of a connecting fitting 20 at one divided position and a hinge 19 at the other divided position. The inner edge section of the hole 7 of the ceiling section is formed of a layer composed of high modulus flexible fiber groups.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for preventing the scattering of dust ejected on the surface of the ground when drilling with a down-the-hole hammer.

[0002]

2. Description of the Related Art When excavating a pile hole or the like with an auger, it is easy to excavate compressed air from the auger head using a down the hole hammer, but since air is ejected together with soil from the opening of the pile hole on the ground surface. , Dust, sand, and pebbles are scattered around. This will cause damage if there are roads and houses nearby. In the case of an auger with a reader, there is a structure with a strong metal scattering prevention cover on the leader side, but for example when using the auger supported on a rough terrain crane that is easy to use in narrow areas, the leader Since you don't use, you can't use a cover like a reader. In such a case, conventionally, the periphery of the opening where the auger casing is exposed on the surface of the earth has been covered with a frame and a cloth supported by the frame to prevent scattering of dust, sand, pebbles, and the like. Further, as another means, it has been proposed to suppress dust by injecting water into the hole being drilled.

[0003]

However, even if the cloth cover is tough, it has poor durability, and there is a problem that a tear can be formed in a short period of time and the purpose of preventing scattering cannot be achieved. If the cloth is made of metal, the auger does not have a large swing because it does not have a leader, and if the cover and the auger do not have a large gap, the cover is swung and cannot be used. Further, since air, dust, and the like are jetted upward inside the cover, the air will directly go to the gap. Therefore, a large amount of dust or the like is ejected from the gap. In addition, the method of injecting water is not preferable in terms of work because water mixes with the excavated soil to form a mud and closes the holes, resulting in explosive ejection. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for preventing scattering of dust and the like ejected along with air on the ground surface when drilling such as applying a down the hole hammer to an auger without a leader.

[0004]

A first aspect of the present invention is a method, wherein when a bit is hammered by a pneumatic hammer to make a hole, the bit is jetted to the surface of the earth from between the inner peripheral surface of the hole and the hole making body. Enclosing the used air and excavated soil with a cover having a cylindrical surrounding wall and a ceiling through which the drilled body penetrates, and upwards by a jet air flow mixed with water separately supplied in a substantially horizontal direction in the cover. The excavated soil and the air are delivered from the discharge port provided in the surrounding wall by applying a force to the excavated soil being ejected to change its direction (claim 1).

In this method, the direction of the excavated soil ejected to the surface of the earth from between the inner peripheral surface of the hole and the auger side casing or screw which penetrates into the hole by the hole body, that is, the hole is made Although it is approximately upward, the jet air flow mixed with water is sideways and the water is atomized and jetted with the air, so the direction can be changed so that the ejected soil collides with this and does not rise upward, At the same time, the rise of dust is suppressed. As a result, almost no dust leaks to the outside from the gap in the ceiling through which the drill body penetrates. Further, the ejected soil whose direction has been changed mainly collides with the surrounding wall of the cover and substantially descends, and the excavated soil and most of the used air are discharged from the discharge port due to the pressure difference between the inside and the outside. At this stage, most of the dust is bound with water and soars, and the action is greatly reduced, and the amount of dust emitted from the outlet is extremely small.

A second aspect of the present invention is a method, wherein when a bit is hammered by a pneumatic hammer to drill a hole, the working air and excavated soil ejected from the space between the inner peripheral surface of the hole and the drilled body to the ground surface. Is surrounded by a cover having a cylindrical surrounding wall and a ceiling through which the drilled body penetrates, and an action force is exerted on the excavated soil that is being ejected upward by a jet air flow separately supplied in the cover in a substantially horizontal direction. It is characterized in that the excavated soil and the air are supplied from the discharge port provided in the surrounding wall and sprinkled with water outside the discharge port (claim 2).

According to this method, the direction of the excavated soil that is ejected is approximately upward, but the jet air flow is lateral, and the direction is changed so that the ejected soil collides with this and does not rise upward. The rise of dust is suppressed. As a result, almost no dust leaks to the outside from the gap in the ceiling through which the auger portion penetrates. Further, the ejected soil whose direction has been changed mainly collides with the surrounding wall of the cover and substantially descends, and the excavated soil and most of the used air are discharged from the discharge port due to the pressure difference between the inside and the outside. Since the water is sprinkled on the outside of the discharge port, the dust discharged from the discharge port is combined with the water by the sprinkling water and the rising dust is suppressed and falls. As a result, the excavated soil is in a state where dust is unlikely to rise even if it is operated with a power shovel or the like.

A third aspect of the present invention is an apparatus, in which a space is provided between a ceiling portion having a vertical hole so that the drilled body penetrates, and a peripheral portion of the drilled body which extends downward from the ceiling portion. An enclosing wall which is surrounded by a space and whose lower end is supported by the ground surface portion, and an air injection nozzle which is provided substantially horizontally at a predetermined height position on the inner surface of the enclosing wall and in a direction substantially along the inner peripheral surface of the enclosing wall. A water mixing unit for mixing water into the supply air provided in the air supply passage for the air injection nozzle, and an outlet for excavated soil and air provided in the surrounding wall (claim 3).

This apparatus is used by installing a surrounding wall on the surface of the earth so as to surround the ground opening position of the drilled hole. The air jetted from the air jet nozzle contains mist-like water mixed with water, becomes a swirling flow that swirls substantially along the inner peripheral surface of the surrounding wall, and goes out from the discharge port to the outside. The air and the excavated soil ejected by the boring pass between the outer periphery of the boring body and the inner periphery of the boring body, and are ejected substantially upward on the ground surface inside the surrounding wall. The jetted air and the excavated soil collide with the airflow jetted from the nozzle to change the direction to a substantially horizontal direction, whereby most of them collide with the inner surface of the surrounding wall and descend downward in a swirling manner. Then, the dust contained in the air flow comes into contact with water and combines with it, so that the effect of rising is lowered. Since the excavated soil and the used air are successively sent to the inside of the ceiling and the surrounding wall, the air and the excavated soil are sent to the outside through the discharge port due to the pressure difference. At this time, the dust that has been generated inside and has a lowered rising action is also sent out together with air or heavy soil, and hardly rises after it goes out to the outside world.

A fourth aspect of the present invention is an apparatus, in which a space is provided between a ceiling portion having a hole in the vertical direction so that the drilled body penetrates, and an outer periphery of the drilled body which extends downward following the ceiling portion. An enclosing wall which is surrounded by a space and whose lower end is supported by the ground surface portion, and an air injection nozzle which is provided substantially horizontally at a predetermined height position on the inner surface of the enclosing wall and in a direction substantially along the inner peripheral surface of the enclosing wall. And a discharge port for excavated soil and air, which is provided at a position lower than the height position of the air injection nozzle of the surrounding wall, and a sprinkling means for spraying water near the outside of the discharge port (claim 4). .

This apparatus is used by installing a surrounding wall on the ground surface so as to surround the ground opening position of the drilled hole. The air jetted from the air jet nozzle becomes a swirling flow that swirls substantially along the inner peripheral surface of the surrounding wall, and goes out from the discharge port to the outside. The air and the excavated soil ejected by the boring pass between the outer periphery of the boring body and the boring and eject substantially upward on the ground surface inside the surrounding wall. The jetted air and the excavated soil collide with the airflow jetted from the nozzle to change the direction to a substantially horizontal direction, whereby most of them collide with the inner surface of the surrounding wall and descend downward in a swirling manner. Since the excavated soil and the used air are successively sent to the inside of the ceiling and the surrounding wall, the air and the excavated soil are sent to the outside through the discharge port due to the pressure difference. At this time, the dust generated inside is also sent out together with the air. Since this dust exits from the discharge port and the exit position and the direction are substantially constant, it can be dropped by spraying it at a substantially fixed position with the spraying means, and scattering can be prevented.

In the devices of the third and fourth aspects of the invention, the ceiling portion and the surrounding wall are divided into a plurality of parts by dividing planes along the central axis direction, and at least one of the dividing positions can be connected and separated. It is preferable that the connecting portion is provided and the other dividing positions are hingedly connected (Claim 5). The ceiling and surrounding wall can be opened and closed around the hinge by disconnecting the connecting part and opening and closing around the hinge, so it can be installed and removed even when the tip of the auger is at the excavated position in the soil.

In the apparatus of the third and fourth inventions, the ceiling portion is made of a flexible fiber group having rigidity in which an inner edge portion of a hole penetrating the drilled body is extended toward an outer peripheral surface of the drilled body. It is preferable that the structure is formed by layers (claim 6). Most of the internal air goes to the outlet, so that the internal pressure does not increase so much, and the layer of the fiber group allows some air to pass through, but hardly allows dust to pass therethrough, so that the dust hardly leaks upward. As the rigid and flexible fibers, palm fibers, synthetic resin or metal monofilaments are preferable.

In the apparatus of the third and fourth inventions, it is preferable that the ceiling portion is made of a wear resistant elastic material in which an inner edge portion of a hole penetrating the drilled body is in contact with an outer peripheral surface of the drilled body. (Claim 7). It is possible to suppress or prevent the leakage of dust from between the drill body and the ceiling. As the abrasion resistant elastic material, it is preferable to use a material of the same quality as that of an automobile tire, or to use an old tire by appropriately cutting it.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.
Will be explained. The device 1 used in the method of the invention is
As shown in FIG. 1, the ceiling 2 and the cylindrical surrounding wall 3 constitute a cover 4, and the ceiling 2 is provided with a circular hole 7 through which a casing 6 of an auger, which is a drilled body 5, can pass. A discharge port 8 and a nozzle 14 are provided on the wall 3.

The ceiling portion 2 is formed in a disk shape having a predetermined diameter and has a circular hole 7 through which the casing 6 can pass in the central portion thereof, and an outer portion 10 thereof is an annular steel plate,
The inner portion 11 is formed of a fiber group layer. The fiber group layer is as thick as a palm tree fiber, and is a state in which synthetic resin monofilaments of a predetermined length having elasticity are aligned, and one end of the fiber is fastened to the outer portion 10 with a presser foot. It is fixed by 12, and the other end extends substantially toward the center of the ceiling and reaches the outer peripheral position of the casing 6. The fiber group layer has a thickness of 10 to 20 m.
It is about m, and the deflection of the casing 6 at the time of drilling can be allowed by elastic deformation, and almost no dust passes through.

The surrounding wall 3 has an annular space 13 of an appropriate width, for example, a width of about 200 mm, inside when the casing 6 (diameter 400 mm) of the hole-drilling body is inserted into the central portion.
Is a steel cylinder having a diameter such that The outer portion 10 of the ceiling portion 2 is fixed to the upper end of the surrounding wall 3 by welding. A discharge port 8 for discharging the used air and excavated soil is provided at a position slightly below the middle of the height of the surrounding wall 3, and compressed air is provided at a position slightly above the lower edge of the discharge port 8. The nozzle 14 for jetting and supplying is opened. The nozzle 14 is provided from the vicinity of the discharge port 8 to the side opposite to the discharge port 8 in a substantially horizontal direction and along the circumferential direction of the annular space 13, and supplies air together with compressed air from the compressor 15. The water supplied by the water mixing means 17 provided in the middle of the passage 16 is injected and supplied. The water mixing means 17 is, for example, a water supply passage 18
Is opened in the air supply passage 16 so as to be sucked by the ejector action, and a supply water amount control valve and a check valve are provided in the water supply passage 18 as needed.

The cover 4 can be attached to and detached from the installation position even when the auger tip is in the ground.
For example, the ceiling portion 2 and the surrounding wall 3 are divided into two by a sectional plane in a direction along the central axis, one of the divided portions is connected by a hinge 19, and the other divided portion is connected and can be opened. It is connected with. In the figure, reference numeral 29 indicates a dividing point. As a result, the connecting metal fitting 20 side of the cover 4 is attached to the hinge 1
You can open and close around 9. Further, the cover 4 is, for example, two cylindrical members 22 serving as engaging support portions 21 for supporting so as to be supported by a power shovel or the like and can be easily moved, at appropriate positions on the outer surface of the surrounding wall 3. It is welded. Thereby, the cylindrical member 22 portion can be supported and moved by the upward pin on the power shovel side. Further, the discharge port 8 is provided with a discharge guide plate 23 slightly projecting into the inner annular space 13 and a discharge guide portion 24 surrounding the outer side from above and both sides as necessary.

As shown in FIG. 3, the apparatus 1 thus constructed has, for example, an excavated hole 26 when the down-the-hole hammer 25 is applied to the auger (drilling body 5) without a leader. The cover 4 is installed at the ground surface opening of the above and used. The air supplied from the nozzle 14 is 0.7-1.
The pressure is set to about 4 MPa and 3 m ³ / min. This compressed air can be diverted from the compressed air source (compressor 15) used for the down the hole hammer 25. Further, the water does not need to be pressurized, and is sucked by the ejector action to be atomized and mixed in the air. The compressed air containing water that has entered the cover 4 is guided to the inner surface of the surrounding wall 3 and becomes a swirl flow,
Generally, it flows toward the outlet 8.

Then, the excavated soil and air coming out from the gap between the casing 6 and the inner peripheral surface of the excavated hole 26 are jetted substantially upward in the cover 4. By colliding with the swirling flow containing the water, the upward jetted soil is redirected in a substantially horizontal direction and hits the inner surface of the surrounding wall, weakens the kinetic energy, goes to the discharge port 8 together with the air flow, and is discharged to the outside. . The fine powder in the excavated soil becomes dust and tries to fly up in the cover 4, but since the fiber group layer of the ceiling 2 has an air outflow resistance, a large amount of air does not flow out, so the dust is large. The portion is not blocked by the fiber group layer and does not leak from the ceiling portion 2, but is discharged from the discharge port 8. And dust is the discharge port 8
When it goes out, it comes into contact with the supplied water and combines with it, so that it hardly rises. The excavated soil from the discharge port 8 is appropriately removed from the vicinity of the discharge port 8 with a power shovel or the like. In addition, 27 in FIG. 3 is a rough terrain crane.

As another embodiment of the present invention, the cover 4
The water mixing means 17 is not provided in the air supply passage 16 of the compressed air nozzle 14 that opens inside, but a water sprinkling means (not shown) is provided near the outlet of the discharge port 8. This is because the excavated soil and the air discharged from the discharge port 8 contain dust, and if left unattended, the dust rises up at the outlet of the discharge port 8. Will not be scattered in. The water spray nozzle may be manually operated, but since the direction in which dust is emitted is almost constant, it may be fixedly installed at a low position.

Further, in the above-mentioned embodiment, the inner edge portion of the circular hole in the ceiling portion is formed of the fiber group layer having rigidity and elasticity, but in some cases, it may be formed of rubber. In that case,
It may be made of a material having excellent wear resistance such as an automobile tire, or an old tire may be appropriately cut and reused.

According to the above-described embodiment, a simple device can be used to prevent scattering of dust that blows up with the used air at the time of boring and the dust that rises at that time, and the amount of added water is not so large. Since it does not flow into the dug hole, there is no explosive ejection due to the muddy water blocking the outlet of the hole 26.

Further, in the above-described embodiment, an example of drilling with an auger without a leader has been shown, but even with a leader, the same method and apparatus can be applied to prevent dust, and the conventional method can be used. Compared with the conventional large-sized cover, it does not require a large-sized cover or a large-sized dust collector to be used.

[0025]

According to the first and second aspects of the present invention, dust is easily prevented from scattering when the down-the-hole hammer is applied to the drilled body regardless of the presence of the leader. The invention described in claims 3 and 4 has a relatively simple configuration, and has an effect that dust scattering can be reliably prevented when the down-the-hole hammer is applied to the drilled body regardless of the presence or absence of the leader. The invention according to claim 5 is
Even if the tip of the auger is in the soil after the start of drilling, it can be attached and removed as it is. The invention according to claim 6 has an effect of preventing dust from leaking upward. The invention according to claim 7 has an effect of good durability.

[Brief description of drawings]

1 shows an embodiment of an apparatus used in the method of the present invention, (a) is a schematic plan view, and (b) is a schematic front view.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a schematic side view showing a usage state of the apparatus of the same embodiment.

[Explanation of symbols]

1 Dust scattering prevention device 2 ceiling 3 surrounding wall 4 Cover 5 Drilled body 6 casing 7 circular holes 8 outlets 10 Outer part 11 Inside part 12 presser foot 13 ring space 14 nozzles 15 Compressor 16 Air supply passage 17 Water mixing means 18 Water supply passage 19 hinges 20 connection fittings 21 Engagement support 22 Cylindrical member 23 Discharge guide plate 24 Discharge guide 25 Down the Hole Hammer 26 drilled holes 27 Rough terrain crane

Claims (7)

[Claims] 1. A cylindrical surrounding wall for use air and excavated soil, which are ejected to the surface of the ground from between the inner peripheral surface of the hole and the hole-drilling body when the bit is hammered by a pneumatic hammer to drill the hole. And a ceiling having a hole through which the drilled body penetrates, and a force is applied to the excavated soil that is being ejected upward by a jet air flow mixed with water separately supplied in a substantially horizontal direction in the cover. And exchanging excavated soil and air from an outlet provided in the surrounding wall, and a method for preventing dust scattering during drilling. 2. A cylindrical surrounding wall for use air and excavated soil, which are ejected to the surface of the ground from between the inner peripheral surface of the hole and the drilled body when the bit is hammered by a pneumatic hammer to drill the hole. And a ceiling having a hole through which the drilled body penetrates, and is provided on the surrounding wall by exerting a force on the excavated soil being jetted upward by a jet air flow separately supplied in a substantially horizontal direction in the lid. A method for preventing dust scattering at the time of drilling, characterized in that excavated soil and air are sent from the discharge port and water is sprinkled on the outside of the discharge port. 3. A lower end having a ceiling portion having a vertical hole through which the drilled body penetrates, and extending downwardly from the ceiling portion and surrounding the drilled body outer periphery with a space therebetween. A surrounding wall supported on the ground surface, an air injection nozzle provided substantially horizontally at a predetermined height position on the inner surface of the surrounding wall and in a direction substantially along the inner peripheral surface of the surrounding wall, and air for the air injection nozzle. A dust scattering prevention device at the time of boring, comprising a water mixing unit provided in a supply passage for mixing water with supply air, and an outlet for excavated soil and air provided in the surrounding wall. 4. A lower end having a ceiling portion having a vertical hole through which the drilled body penetrates, and extending downwardly from the ceiling portion and surrounding the drilled body outer periphery with a space therebetween. A surrounding wall supported on the ground surface, an air injection nozzle provided substantially horizontally at a predetermined height position on the inner surface of the surrounding wall and in a direction substantially along the inner peripheral surface of the surrounding wall, and the air of the surrounding wall. A dust scattering prevention device at the time of drilling, comprising a discharge port for excavated soil and air provided below a height position of a spray nozzle, and a sprinkling means for spraying water near the discharge port. 5. The dust scattering prevention device at the time of drilling according to claim 3 or 4, wherein the ceiling portion and the surrounding wall are divided into a plurality of parts by dividing planes along the central axis direction, A dust scattering prevention device at the time of drilling, characterized in that at least one of the dividing positions is provided with a connecting portion that can be connected and separated, and the other dividing positions are hingedly connected. 6. The dust scattering prevention device at the time of drilling according to claim 3, claim 4, or claim 5, wherein the ceiling portion has an inner edge portion of a hole passing through the drilled body outside the drilled body. A dust scattering prevention device at the time of drilling, characterized by being formed of a layer of a flexible fiber group having rigidity extending toward the peripheral surface. 7. The dust scattering prevention device at the time of drilling according to claim 3, 4, or 5, wherein the ceiling portion has an inner edge portion of a hole through which the drilled body penetrates outside the drilled body. A dust scattering prevention device at the time of drilling, characterized by being formed of a wear-resistant elastic material in contact with the peripheral surface.