JP7128503B2 - Earthless auger drilling tool - Google Patents

Description

TECHNICAL FIELD The present invention relates to a non-discharging auger excavating tool, and more particularly to a non-discharging auger excavating tool for forming excavation holes such as foundation piles in the ground by the earth auger construction method.

For example, as an auger excavator for forming a pile hole (excavation hole) for a foundation pile (steel pipe pile) of a house in soft ground, for example, one described in Patent Document 1 is known. This excavator comprises a vertically arranged supporting member, an auger screw (auger excavating tool) for excavating a vertical pile hole in soft ground, and a rotary press-fitting device that raises and lowers the auger screw while rotating it along the supporting member. is provided.
When a pile hole is excavated by the auger excavator, the auger screw is rotated by the rotary press-fitting device, and the rotary press-fitting device is gradually lowered using the vertical support member as a guide. This forms a pile hole in the soft ground.

JP-A-9-328984

However, since this auger excavator employs a screw as an auger excavating tool, excavated soil is discharged to the ground. Therefore, it was necessary to dispose of excavated soil as industrial waste.
In addition, since the soft ground was excavated, the walls of the holes were soft and easily collapsed due to earth pressure. As a result, the collapsed earth and sand accumulated on the bottom surface of the pile hole, making it impossible to insert the foundation pile into the pile hole. In addition, after the foundation work, the earth and sand falling from the hole wall enter the gap between the pile hole and the foundation pile, which may cause a decrease in ground density and ground subsidence.
Furthermore, in excavation work using a screw, there is a risk of an accident, etc., in which a worker on site is caught in the screw exposed to the ground during excavation.
Furthermore, since a large amount of earth and sand adhered to the screw after the foundation work, cleaning work to remove the earth and sand required time and effort.

Therefore, as a result of intensive research, the inventor found that instead of the screw, a hole wall consolidation shaft having a substantially oval cross-sectional shape for consolidating the earth and sand of the hole wall of the pile hole, and a hole wall consolidation shaft at the tip of the hole wall consolidation shaft The inventors have found that all of the above-described problems can be solved by adopting a non-discharging auger drilling tool having a drilling head provided thereon, and have completed the present invention.

That is, according to the present invention, there is no need to dispose of the excavated earth and sand as industrial waste (no soil discharge), and even if the ground is soft, the hole walls of the excavated hole do not collapse easily, and an accident involving workers by the screw does not occur. To provide a non-discharging auger excavating tool which is easy to clean after use, has a simple structure, is hard to break, and is easy to manufacture.

According to the first aspect of the invention, there is provided a non-discharging auger excavating tool that is attached to a rotary press-fitting device of an auger excavator and descends while rotating to form an excavation hole in the ground, and has a substantially perfect circular cross-sectional shape. A circular arc surface portion and a flat surface portion are arranged on the outer peripheral surface, and the earth and sand excavated by the circular arc surface portion are pressed against the wall of the excavation hole in a state of surface contact, thereby consolidating the earth and sand on the wall of the hole. and a drilling head provided at the tip of the hole wall consolidation shaft for excavating the ground.

An auger drilling tool is a drilling tool used in an earth auger construction method for forming a drilling hole in the ground.
The type of ground to be excavated is not limited. In particular, it is suitable for "soft ground" consisting of mud, always soft clay containing a large amount of water, or unconsolidated soft sand. The Ministry of Land, Infrastructure, Transport and Tourism's "Manual for Residential Land Disaster Prevention" lists organic soil, highly organic soil (humus), cohesive soil with an N value of 3 or less, and sandy soil with an N value of 5 or less as criteria for judging soft ground.
The type of auger excavator is arbitrary as long as it does not have a casing that supports the hole wall of the borehole from the inside during excavation. For example, a single-axis earth auger excavator or the like can be employed.
The rotary press fitting device may be either electric or hydraulic.

The term "arc surface portion" as used herein refers to an arc-shaped curved surface in a cross section perpendicular to the length direction of the hole wall consolidation shaft (in a plan view) that can press the hole wall in a state of surface contact. Say.
The term "flat surface portion" as used herein refers to a region in which adjacent arcuate surface portions are linearly connected (notched) in a cross section perpendicular to the length direction of the hole wall consolidation shaft. The abutment of the arc surface portion and flat surface portion may be sharp or chamfered.
"Consolidate the earth and sand on the hole wall" means that the voids ( It refers to a phenomenon in which voids) decrease and the volume of the soil shrinks (density increases).

A bore wall consolidation shaft is a cylindrical attachment for excavating the ground while consolidating the bore wall of an excavation hole. The hole wall consolidation shaft can be directly connected to the output shaft of the rotary press fitting device.
The hole wall consolidation shaft may be either solid or hollow. When the hole wall consolidation shaft is a solid body, even if the ground is not soft, the borehole can be formed with a small pressing force using the own weight of the hole wall consolidation shaft. In addition, when the hole wall consolidation shaft is hollow, it is lighter in weight than a solid one. can be done.
The construction of the drilling head is arbitrary. For example, it may or may not have a digging edge (eg, bullet type).

According to the second aspect of the invention, the cross-sectional shape of the hole wall consolidation shaft is substantially oval with both sides of a perfect circle notched in parallel. is a tool.

Here, the oval shape means that the cross-sectional shape perpendicular to the length direction of the hole wall consolidation shaft is a shape in which both side portions of a perfect circle (portions separated by 180 degrees in the circumferential direction) are notched in parallel. The abutting portion (continuous portion) between the arc surface portion and the flat surface portion may have an acute angle or be chamfered.
The term "elliptical arc surface portion" as used herein refers to an arc-shaped curved surface in cross section (plan view) capable of pressing the hole wall in a state of surface contact.

According to a third aspect of the invention, the hole wall consolidation shaft is a hole wall consolidation hollow body having a hollow interior, and the hole wall consolidation hollow body is attached to an auger shaft attached to the rotary press-fitting device, 3. The non-discharging auger excavating tool according to claim 1 or claim 2, which is detachably connected via a connecting member.

The term "hollow hole wall consolidation shaft" as used herein means a solid hole wall consolidation shaft made of a metal rod, on the axis of which supply holes for drilling water and ground improvement material are formed. Possibly not hollow, but a thinner tubular shaft.

According to the first aspect of the invention, an auger excavator is installed at an excavation site, and a non-discharging auger excavation tool is attached to a rotary press-in device to excavate, for example, soft ground. Earth and sand excavated by the excavation head are excavated through the soft ground and reach the hole wall consolidation shaft, and a plan view between each flat portion of the hole wall consolidation shaft and the excavation hole (pile hole) Then, they enter into a crescent-shaped space (hereinafter referred to as crescent space).
After that, as the auger excavating tool rotates, the earth and sand collected in each crescent space moves to the end of each crescent space opposite to the direction of rotation.
After that, each collected earth and sand is pressed against the hole wall by the arc surface portion of the hole wall consolidation shaft that is in surface contact with the hole wall (drill hole peripheral wall) to consolidate the hole wall. be done.

In this way, the excavated earth and sand generated during excavation is pushed into the hole wall without being discharged outside, so there is no need to dispose of excavated excavated soil as industrial waste (without excavating soil) as in the past. , the borehole walls are compacted and difficult to collapse. As a result, it is no longer necessary to remove the earth and sand that fell into the excavation hole after excavation with a conventional screw, and after the foundation pile is inserted, the earth and sand on the hole wall will not fall into the gap between the excavation hole and the foundation pile. Decrease in ground density, ground subsidence, and loss of foundation pile support caused by

In addition, since there is a space (crescent space) communicating with the atmosphere between the hole wall and the hole wall consolidation shaft, the air smoothly flows into the bottom of the borehole. This ensures that there is no vacuum between the drilling head and the bottom of the drilling hole when the auger drilling tool is withdrawn. As a result, collapsing of the bottom of the borehole wall due to vacuuming of the bottom of the borehole can be eliminated.
In addition, since a long screw that extends over the entire length is not used as in the conventional method, there will be no accident involving a worker with the screw.
Furthermore, cleaning of the auger drilling tool after use is easier than with such a screw-type tool.

In particular, according to the second aspect of the invention, since the shaft for consolidating the hole wall has an oval shape when viewed from above, the length of the arc surface portion for pressing the excavated earth and sand against the hole wall is reduced. The length (length in the circumferential direction of the hole wall consolidation shaft) can be increased. This makes it possible to firmly press the earth and sand accumulated in the crescent space against the hole wall for a long period of time. As a result, the compaction density of the hole wall can be further increased, and the effect of polishing the hole wall can also be obtained, so that the hole wall surface (the peripheral wall surface of the dug hole) can be finished into a curved surface with less unevenness. Therefore, when pulling out the auger drilling tool or inserting, for example, a pile into the drilling hole, the corresponding drilling tool or pile can be smoothly inserted and pulled out.

Further, according to the third aspect of the invention, the hole wall consolidation hollow body is detachably connected to the auger shaft attached to the rotary press-fitting device via the connecting member. By using the hollow body as an attachment, an existing auger excavating tool for soft ground can be easily modified to have the effects of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a usage state of an auger excavator equipped with a non-discharging auger excavating tool according to Embodiment 1 of the present invention; 1(a) is a plan view of a non-discharging auger excavating tool according to Embodiment 1 of the present invention. FIG. (b) is a front view of the non-discharging auger excavating tool according to Embodiment 1 of the present invention. 1(a) is a plan view of the non-discharging auger excavating tool according to Embodiment 1 of the present invention in use. FIG. (b) is a front view of the non-discharging auger excavating tool according to the first embodiment of the present invention in use. (a) is a plan view of a state in which excavation (rotation) has progressed by the non-discharging auger excavating tool according to Embodiment 1 of the present invention. (b) is a front view of a state in which excavation by the non-discharging auger excavating tool according to Embodiment 1 of the present invention has progressed. FIG. 2 is an enlarged cross-sectional view of a main part showing a state in which the hole wall of an excavation hole is gradually compacted by the non-discharge auger excavating tool according to Embodiment 1 of the present invention; Fig. 2 is a perspective view of a non-discharging auger excavating tool according to a second embodiment of the present invention;

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Here, an example is taken of an auger excavating tool used in a single-axis earth auger construction method for burying a foundation pile of a wooden house.

In FIG. 1, reference numeral 10 denotes a non-discharging auger excavating tool (hereinafter simply referred to as "auger excavating tool") according to Embodiment 1 of the present invention. It is detachably attached to an earth auger 12 and forms a vertical excavation hole (pile hole) 13 for pressing a foundation pile into the soft ground on which a wooden house is to be built.
As shown in FIG. 1, the auger excavator 11 is of a crawler type used in a single-axis earth auger construction method, and includes a long support member 15 having a vertically extending guide rail 14 fixed to its front side surface. , and the rotary press-fitting device 12 for moving the auger drilling tool 10 up and down along the guide rail 14 while rotating.

The auger drilling tool 10 will now be described in detail with reference to FIGS. 1 and 2. FIG.
The auger drilling tool 10 has an oval cross-sectional shape (perpendicular to the length direction) obtained by notching both sides of a perfect circle in parallel (Fig. 2(a)). A hole wall consolidation hollow body (hole wall consolidation shaft) 18 that consolidates the earth and sand of the hole wall 17 by pressing the hole wall 17 of the hole 13 in a state of surface contact and is detachably connected to the rotary press fitting device 12. and an excavating head 20 provided at the tip (lower end) of the hole wall consolidation hollow body 18 for excavating soft ground.

The hole wall consolidation hollow body 18 has a steel pipe 16 with a diameter of 200 mm, a length of 6,000 mm and a thickness of 30 mm. Both sides of the steel pipe 16 are vertically split and removed, and the vertically elongated side openings are closed with strip-shaped flat steel plates (flat surface portions) 21, respectively. As a result, two circular arc surface portions 18a and two flat surface portions (steel plate 21) are alternately and continuously arranged at predetermined intervals (90° pitch) on the outer peripheral surface of which the cross section is a perfect circle. A pore wall consolidation hollow body 18 of the shape is produced. In addition, the steel pipe 16 can be used by adding a plurality of pipes.
A short narrowed portion 22 made of a steel pipe gradually tapering downward is integrally formed at the lower end opening of the hole wall consolidation hollow body 18 . A thick disk-shaped excavation head 20 having a large number of through holes (not shown) passing through the front and back surfaces is integrally connected to the small-diameter lower end opening of the narrowed portion 22 .

The narrowed portion 22 serves as a bid-up guide for guiding the earth and sand excavated by the excavation head 20 to the pair of left and right crescent spaces a.
Furthermore, a large number of digging blades 23 for excavating soft ground are arranged on the lower surface of the excavating head 20 at a predetermined pitch, and the tip of the auger shaft 19 is detachably attached to the central portion of the excavating head 20. A fitting hole 24 to be fitted is formed.

In addition, the upper end portion of the auger shaft 19 is sandwiched from both sides through a pair of left and right beam frames 25 protruding inward from the facing portion of the inner peripheral surface of the steel pipe 16 at the central portion within the upper end portion of the steel pipe 16. A pair of left and right couplings 26 are arranged (FIGS. 3(a) and 3(b)).
Further, on the inner peripheral surface of the steel pipe 16, on the upper part, the lower end part, and the middle part in the length direction, a set of two pieces (a total of 12 sets) that are spaced apart in parallel to each other are provided. Plate pieces (connecting members) 27 radially protrude inward from the steel pipe 16 at a pitch of 90° in the circumferential direction (FIGS. 2(a) and 2(b)).
Furthermore, on the outer peripheral surface of the auger shaft 19, a total of 12 rectangular plates are provided in the vicinity of the base end portion, the vicinity of the tip portion, and the intermediate portion in the length direction at a pitch of 90° in the circumferential direction. A rotational force transmission plate piece (connecting member) 28 is radially projected.

When the auger shaft 19 is attached to the hole wall consolidation hollow body 18 , the auger shaft 19 is inserted into the inner space of the hole wall consolidation hollow body 18 along the axis thereof. As a result, each rotational force transmission plate piece 28 is inserted into the gap between the corresponding set of two rotational force receiving plate pieces 27, and the tip of the auger shaft 19 is fitted into the fitting hole 24 of the excavation head 20. be done. On the other hand, in the upper end portion of the hollow body 18 for hole wall consolidation, the worker clamps the base end portion (upper end portion) of the auger shaft 19 between a pair of right and left couplings 26 and fastens them with bolts. By these, the auger shaft 19 and the hole wall consolidation hollow body 18 are integrally connected.
When drilling a borehole, the rotational force of the auger shaft 19 generated by the rotary press-fitting device 12 is transmitted from each coupling 26 to the bore wall consolidation hollow body 18 via the corresponding beam frame 25 . Further, the torque is transmitted from each torque transmitting plate piece 28 to each of the hole wall consolidation hollow bodies 18 via each torque receiving plate piece 27 .

In this manner, the base end of the auger shaft 19 is bolted to the upper end of the hole wall consolidation hollow body 18 via each coupling 26 , and the tip of the auger shaft 19 is connected to the fitting hole of the drilling head 20 . 24, in the intermediate region of the auger shaft 19 where the bolt tightening tool (spanner or the like) cannot reach, the corresponding torque transmission plate is simply inserted into the gap between the two torque receiving plate pieces 27 of each set. Even with a power transmission structure in which the piece 28 is simply inserted removably, the rotational force of the auger shaft 19 and the vertical driving force of the auger shaft 19 can be transmitted to the hole wall consolidation hollow body 18 without any trouble. be able to.

Next, referring to FIGS. 1 to 5, using the auger excavating tool 10 according to the first embodiment of the present invention, foundation piles of a wooden house built on soft ground are cut by a single-axis earth auger construction method. A method of forming a borehole 13 for burying will be described.
As shown in FIG. 1, first, the auger excavator 11 is placed at the excavation site, and the upper end of the auger shaft 19 is connected to the output shaft of the rotary press-fitting device 12 via a pipe joint (not shown).
Next, after the support member 15 is erected vertically near the excavated portion of the soft ground, the rotary press-in device 12 is operated to rotate the hole wall consolidation hollow body 18 and gradually descend it. As a result, the soft ground is gradually excavated by the excavation head 20 . As the excavated earth and sand b are excavated into the soft ground, the downward truncated conical constriction 22 guides the excavated earth and sand b, which gradually rises up and enters the pair of crescent spaces a from below (Fig. 3(a), ( b)).

Next, as the auger excavating tool 10 rotates, the excavated earth and sand b accumulated in each crescent space a moves to the end of each crescent space a opposite to the rotation direction (Fig. 4A). , (b)).
After that, the excavated earth and sand b collected in the portions of each crescent space a are collected by the circular arc portion 18a of the hole wall consolidation hollow body 18 which is in surface contact with the hole wall 17 of the excavation hole 13 and is oval in plan view. , are pressed by the hole wall 17, and the soil on the inner peripheral portion of the hole wall 17 becomes the consolidation portion c.

In this way, the excavated soil b generated during excavation is pushed into the hole wall 17 without being discharged to the outside of the excavated hole 13, so there is no need to dispose of excavated soil as industrial waste as in the conventional art. Moreover, since the hole wall 17 of the excavation hole 13 is compacted in this way, it is difficult to collapse. As a result, it is not necessary to remove the earth and sand that fell into the excavation hole 13 after the conventional screw excavation. There is no reduction in ground density, ground subsidence, or lowering of foundation pile support caused by falling into the gap between

Since the hole wall consolidation hollow body 18 has an oval shape when viewed from above, the length of the circular arc surface portion 18a that presses the excavated earth and sand b against the hole wall 17 (hole wall consolidation hollow body 18 circumferential length) can be secured. This makes it possible to firmly press the excavated earth and sand b accumulated in the crescent space a against the hole wall 17 for a long time. As a result, the compaction density of the hole wall 17 can be further increased, and the effect of polishing the hole wall 17 can be obtained, so that the hole wall surface (the peripheral wall surface of the dug hole) can be finished into a curved surface with less unevenness. Therefore, when the auger drilling tool 10 is pulled out from the drilling hole 13 or when the foundation pile is inserted (press-fitted) into the drilling hole 13, the corresponding auger drilling tool 10 or foundation pile can be pulled out and inserted smoothly.

Furthermore, since there is a space (crescent space a) communicating with the atmosphere between the hole wall 17 and the hole wall consolidation hollow body 18 , external air flows smoothly to the bottom of the excavated hole 13 . This prevents a vacuum between the drilling head 20 and the bottom of the drilling hole 13 when the auger drilling tool 10 is withdrawn. As a result, collapse of the bottom portion of the hole wall 17 due to the vacuumization of the bottom portion of the excavated hole 13 can be eliminated during this extraction.
In addition, since a conventional screw is not used, there is no chance of a worker getting caught in the screw.
Furthermore, compared to such a screw-type tool, cleaning work of the auger drilling tool 10 after use is facilitated.

Furthermore, since the hole wall consolidation hollow body 18 is lighter than the solid one, it is possible to use a low-output rotary press-fitting device 12 while it is a consolidation tool that comes into surface contact with the hole wall 17 . In addition, the structure is simple, hard to break, and easy to manufacture.
In addition, since a configuration is adopted in which the hole wall consolidation hollow body 18 is detachably connected to the auger shaft 19 attached to the rotary press-fitting device 12 via the rotational force receiving plate piece 27 and the rotational force transmitting plate piece 28, the hole is By using the wall consolidation hollow body 18 as an attachment, the existing auger drilling tool 10 can be easily modified to have the effect of the present invention.

Next, an auger drilling tool according to a second embodiment of the invention will be described with reference to FIG.
As shown in FIG. 6, the feature of the auger drilling tool 10A of the second embodiment is that the auger shaft 19 is omitted, and instead of the hole wall consolidation hollow body 18, the hole wall consolidation shaft is an elongated solid metal rod. 18A, and instead of the excavation head 20, a short cylindrical excavation head 20A is adopted.

The hole wall consolidation shaft 18A has two arcuate surface portions 18a and two flat surface portions 18b alternately arranged at a pitch of 90° in the circumferential direction on the outer peripheral surface of the hole wall consolidation shaft 18A whose cross section is a perfect circle. are arranged (adjacent) to The base end (upper end) of the hole wall consolidation shaft 18A is directly and detachably connected to the output shaft of the rotary press-fitting device 12 .
The body of the drilling head 20A is formed with threads 20a similar to the threads of a bolt.
A supply hole 30 is formed along the axial line of the hole wall consolidation shaft 18A and the excavation head 20A over the entire length thereof for blowing out excavation water and ground improvement material from the tip of the excavation head 20A.
Since the solid hole wall consolidation shaft 18A is used in this manner, the excavated hole 13 can be formed with a small pressing force using the own weight of the hole wall consolidation shaft 18A even on the ground that is not soft. can.
Since other configurations, functions and effects can be assumed from the first embodiment, description thereof is omitted.

INDUSTRIAL APPLICABILITY This invention is useful as a technique for forming pile holes such as foundation piles in soft ground by the earth auger method.

10, 10A non-discharging auger drilling tool,
11 auger excavators,
12 rotary press fitting device,
13 drill holes,
17 pore walls,
18 Hole wall consolidation hollow body (bore wall consolidation shaft),
18A hole wall consolidation shaft,
18a arc surface portion,
18b flat surface portion,
19 auger shaft,
20 drilling heads,
21 steel plate (flat portion),
27 rotational force receiving plate piece (connecting member),
28 rotational force transmission plate piece (connection member),
b Excavation earth and sand.

Claims (3)

A non-discharging auger excavating tool that is attached to a rotary press-fitting device of an auger excavator and descends while rotating to form an excavation hole in the ground,
The cross-sectional shape is approximately a perfect circle, and an arc surface portion and a flat surface portion are arranged on the outer peripheral surface. a hole wall consolidation shaft for consolidating earth and sand on the hole wall;
a drilling head provided at the tip of the hole wall consolidation shaft for drilling the ground ;
The cross-sectional shape of the hole wall consolidation shaft is a non-discharging auger excavating tool in which two circular arc surface portions and two flat surface portions are alternately and continuously arranged at a pitch of 90° . In the cross-sectional shape, the length of the arc surface portion is longer than the length of the flat surface portion
The non-discharge auger drilling tool according to claim 1. The shaft for hole wall consolidation is a hollow body for hole wall consolidation having a cavity inside,
3. The non-discharging auger excavating tool according to claim 1, wherein the hole wall consolidation hollow body is detachably connected via a connecting member to an auger shaft attached to the rotary press-fitting device.

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