JP2000179272A - Auger screw and excavating method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a strong excavation hole wall consolidated to the vicinity of a limit by removably fitting consolidation plates curved so that the diameter from the center of an auger shaft is gradually increased in the reverse direction to the normal rotating direction during the excavation work at the upper positions of a cutter head around the auger shaft. SOLUTION: A gap is formed between the front half portion of each consolidation plate 6a and an excavation hole wall during the excavation forward rotation. A plate with bolt insertion holes is connected to the back face of the consolidation plate 6a, and the consolidation plate 6a can be removably fitted to an auger shaft 1 by connecting the plate and a bracket 7 fixed to the auger shaft 1 with bolts 8. As an excavation proceeds, excavated sediment is lifted and stirred by the actions of spiral plates 4 and spiral vanes 5 and enters the gaps formed between the consolidation plates 6a and the excavation hole wall. Since the diameter of each consolidation plate 6a from the center of the auger shaft 1 is gradually changed, the sediment is pressed to the wall face, and consolidation proceeds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auger screw for excavating a vertical hole as a foundation work in the fields of construction and civil engineering, and more particularly to an auger screw having a function of compacting excavated earth and sand to a wall of the excavation hole. It is about.

[0002]

2. Description of the Related Art Excavation using an auger screw is performed for the purpose of excavating a vertical hole for building a retaining pile such as H-shaped steel, which serves as a foundation of a building, and improving the soil quality at an excavation point. Among such purposes, in particular, as an auger screw for excavating a vertical hole at a large depth, without discharging the excavated earth and sand to the ground, during the actual excavation, such as compacting the excavation hole wall Auger screws are known. An example is shown in Japanese Patent Publication No. 59-38394, and FIG. 7 is a schematic diagram thereof.

The auger screw shown in FIG. 7 is provided with a consolidation plate 32 at the outer edge of a spiral plate 31. According to this,
The consolidation plate 32 consolidates the earth and sand on the wall of the excavation hole. Further, as shown in the figure, since the stirring blades 33 are provided on the peripheral edge of the auger shaft 34, the excavated earth and sand can be kneaded with the bentonite liquid discharged from the tip of the auger shaft 34, and the consolidation earth and sand can be obtained. With appropriate properties can be provided during drilling. Further, in this auger shaft, the upper part of the auger shaft 34 is stepped, which has a larger diameter than the lower part. This is to consolidate the earth and sand that has been excavated near the surface of the ground into the borehole wall.

[0004]

In the consolidation excavation method, from the viewpoint of firmly supporting a column or the like inserted after the excavation work, the void ratio of the concaved excavation hole wall and the surrounding soil is reduced to the consolidation limit. It is desirable to reduce it, but in the above-mentioned conventional auger screw used for this purpose, the consolidation plate is fixed, so for example in soil with a high void ratio such as loam layer, consolidation to the limit May be difficult.

Although it is possible to separate auger screws for different purposes, such as for a loam layer and a gravel layer, the cost of the auger screw body is increased by that amount, and there is a place where several auger screws can be stored. If the soil properties of the work site that are required are unknown, a plurality of auger screws must be transported, resulting in problems such as extra transport costs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, to provide an auger screw suitable for the soil at low cost, and to realize a solid excavation hole wall which is compacted to the limit. It is in.

[0007]

According to a first aspect of the present invention, there is provided an auger screw, wherein a spiral blade is provided intermittently at a position above the cutter head around an auger shaft having a cutter head mounted at a tip thereof, and the auger screw extends from the peripheral surface of the auger shaft. Away,
And a compacting plate curved so that the diameter from the center of the auger shaft gradually increases in the direction opposite to the normal rotation direction during excavation work is detachably attached, and the compacting plate is selectively used according to soil characteristics. Can be. The auger screw of claim 2 is characterized in that the spiral blades and the compacting plate are arranged alternately in the axial direction of the auger shaft, and the agitation of excavated soil and the supply of soil to the outside of the compacting plate are sufficiently performed, A good consolidation hole wall can be realized. The auger screw according to claim 3 is characterized in that a continuous spiral plate is formed in a lower end portion of the auger shaft in a range where the spiral blade and the compacting plate are not arranged, and the earth and sand pulverized by the cutter head portion are smoothly removed. It can be raised and supplied near the consolidation plate. The excavation method according to claim 4 is characterized in that the auger screw according to any one of claims 1 to 3 is used, and an extension shaft is added to the auger screw to perform excavation while constructing a consolidation hole wall. In addition, it is possible to realize an excavation hole wall which is hard to collapse by a continuous operation up to a large depth.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3 show a first embodiment of the present invention. In FIG. 1, a cutter head 2 having a cutter bit 3 at the tip is attached to a lower end of the auger shaft 1, and a spiral plate 4 is formed on the periphery of the auger shaft 1 continuously from the lower end for about one round. Spiral blades 5 having the same inclination as the spiral plate 4 are formed at an upper position at intervals of a central angle of 120 degrees in an auger shaft axis view at an equal pitch and intermittently, and a space between adjacent spiral blades 5 is viewed in a coaxial line. A void 11 is provided. Further, the spiral blades 5 are arranged at intervals in the axial direction of the auger shaft 1 by several sheets, and a bracket 7 for mounting the consolidation plate 6a is arranged between the spiral blade groups. That is, the spiral blade 5 and the compacting plate 6a
Are arranged in a straight line in the axial direction along the side surface of the auger shaft 1 at three places on the circumference, and the gap 11 is arranged between the rows.

Next, the compacting plate 6a of the first embodiment will be described. The shape of the compacting plate 6a is substantially a parallelogram when viewed at right angles to the auger shaft axis shown in FIG. 1, and its side is parallel to the auger shaft axis, and the upper side and the lower side have almost the same inclination as the spiral blade 5 described above. As shown in FIG. 2 when viewed from the axis of the auger shaft, the shape of the curved consolidation plate 6a is such that the diameter from the center of the auger shaft 1 is minimum at the front end when rotating forward (clockwise indicated by an arrow in this figure). , Maximum at the rear end, and gradually changes between them. That is, at the time of the forward rotation of the excavation, the gap 10 with the excavation hole wall 9 is formed in the first half of each of the consolidation plates 6a. On the back surface of the compacting plate 6a, a plate material 1 having a bolt insertion hole 12 is provided.
3 and the plate 13 and the auger shaft 1
The consolidation plate 6a is detachable from the auger shaft 1 by connecting the bracket 7 fixed to the auger shaft 1 with bolts 8.

FIG. 3 is a general outline of an excavator to which the auger screw according to the present invention is attached. The excavating work vehicle 21 includes a winch 22 and a column 23, and a top sheave 25 is provided at an upper end of the column 23, and a guide pipe 24 serving as a guide when the drive unit 27 moves up and down is fixed. Drive unit 2
7 is connected to the winch 22 via a top sheave 25 by a wire 26, and can be moved up and down by the operation of the winch 22. The drive unit 27 generates a rotational torque by hydraulic pressure or the like, and the torque is transmitted to the auger shaft 1 via a rod 28 and an extension shaft 30 connected to a lower end of the drive unit.

Next, the operation and use of the auger screw of the present invention will be described. The excavation work is first started by directly connecting the auger shaft 1 to the connecting portion 29 at the lower end of the driving portion 27. In this state, when the winch 22 is operated to release the wire 26, the driving unit 27 descends by its own weight, and the cutter head 2 attached to the lower end of the auger shaft 1 presses against the ground on which excavation is to be performed. When the drive unit 27 is further operated to apply a rotational torque to the auger shaft 1, excavation is started by the cutter bit 3 at the tip. By gradually lowering the driving unit 27 along the guide pipe 24, the drilling hole gradually becomes deeper.

When excavation progresses and reaches a certain depth,
Due to the action of the spiral plate 4 and the spiral blade 5, the excavated earth and sand rises and is stirred at the same time, and enters the gap 10 formed between the compacting plate 6a and the excavation hole wall 9. Further, due to the effect that the diameter of the consolidating plate 6a from the center of the auger shaft is gradually changing, the earth and sand is pressed against the wall surface and consolidation proceeds. As a result, the soil void ratio on the wall surface and its surroundings is reduced, and the borehole wall 9 is strengthened. Most excavated sediment stays around the borehole in this way, so no or very little sediment must be discharged to the ground.

By the action of the cutter bit 3 attached to the tip of the cutter head 2, even a stratum mixed with cobblestones and boulders can be crushed. Continuous excavation is possible.

When the predetermined excavation depth is not reached with only the auger shaft 1, a rod 28 is used as shown in FIG. 3, and an extension shaft 30 is added between the rod 28 and the auger shaft 1. This makes this possible. Each connecting portion 29 is prevented from coming off through a pin by using a polygonal indigo joint.

FIGS. 4 to 6 show a second embodiment according to the present invention. FIG. 4 shows a shape viewed from a right angle to the auger shaft axis when a consolidation plate 6b having a shape different from that of the first embodiment of the present invention is attached to the auger shaft 1, and FIG. The difference from the above-mentioned consolidation plate 6a is that the length of the consolidation surface in the axial direction is long in the axial direction and the width is wide, and the angle formed by the curved consolidation surface and the auger shaft axis center in the axis line view. Is larger than the consolidation plate 6a. Due to this difference, the main compacting plate 6b can more reliably capture the excavated earth and sand during stirring, and as a result, a higher compacting effect than the compacting plate 6a can be obtained. However, since the soil has a consolidation limit, not all of them can be used, and this consolidation plate is suitable for excavation of a soil having a relatively high void ratio such as a loam layer.

FIG. 6 further shows a compacting plate 6c according to a third embodiment. The difference from the consolidation plate 6a is that the diameter from the center of the auger shaft to the consolidation plate 6c is larger, and a higher consolidation state can be realized by the difference from the diameter of the excavation hole formed by the cutter head 2. This is also suitable for excavation of soil having a high void ratio, similarly to the above-mentioned compacting plate 6b.

For example, the exchange from the compacting plate 6a to the compacting plate 6b is easily completed by loosening the bolt 8 and detaching the compacting plate 6a, assembling the compacting plate 6b and tightening the bolt 8 again.

If the underground soil at the excavation site is unknown, it is also possible to carry a replacement compacting plate together with one auger shaft and replace it as needed after the test excavation.

[0019]

As described above, the use of the auger screw according to any one of claims 1 to 3 makes it possible to use a consolidation plate for reinforcing the consolidation of the wall of the excavation hole. And consolidation up to the limit, and as a result, a strong excavation hole wall can be realized.
Only one auger shaft is required. Compared to the case where multiple auger screws are available due to differences in the compacting plate, cost reduction of the auger screw itself, saving of storage space, reduction of transportation cost to the site, etc. The effect is expected. Further, even when the consolidation plate is damaged, only the consolidation plate needs to be replaced with a new one, and there is also an effect that maintenance cost is reduced for the integrated auger screw. As a characteristic of the consolidation drilling method, in addition to being able to prevent the collapse of the borehole wall, there is no or very little excavated earth and sand. Also, efficient excavation by continuous work is possible.
According to the excavation method of claim 4, deep excavation is possible by using an extension shaft according to the excavation depth.
Even in this case, the strength of the excavated section wall and the ease of the residual soil treatment as described above are the same.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment of the present invention.

FIG. 2 is an auger shaft axial view of the first embodiment of the present invention.

FIG. 3 is an overall view of an excavator to which the auger screw of the present invention is attached.

FIG. 4 is a front view of a second embodiment of the present invention.

FIG. 5 is an auger shaft axial view of a second embodiment of the present invention.

FIG. 6 is an axial view of an auger shaft according to a third embodiment of the present invention.

FIG. 7 is a front view showing a conventional example of an auger screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Auger shaft 2 Cutter head 3 Cutter bit 4 Spiral plate 5 Spiral wing 6a, 6b, 6c Compacting plate 7 Bracket 8 Bolt 9 Drilling hole wall 10 Gap 11 Void 12 Bolt insertion hole 13 Plate material 27 Driving part 28 Rod body 29 Connecting part 30 Extension shaft

Claims (4)

[Claims] A spiral blade is intermittently provided at a position above the cutter head around an auger shaft having a cutter head mounted at a tip thereof, and a diameter from the auger shaft center and away from the auger shaft peripheral surface is excavated. An auger screw characterized in that a consolidation plate curved so as to gradually increase in a direction opposite to a normal rotation direction during work is detachably attached. 2. The auger screw according to claim 1, wherein said spiral blades and said compacting plates are alternately arranged in the axial direction of said auger shaft. 3. The auger screw according to claim 1, wherein a continuous spiral plate is formed in a lower end portion of the auger shaft in a range where the spiral blade and the compacting plate are not arranged. 4. An excavation method using the auger screw according to any one of claims 1 to 3, and digging while constructing a consolidation hole wall by adding an extension shaft to the auger screw.