JP2000120362A - Auger structure for boring machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an auger forward end to stably bite a subsoil and accurately excavate a hole at an expected position by applying the constitution that the external surface of an auger is provided with an excavating casing having a size longer that the auger forward end by a preset size or above and having a rotating function for excavation. SOLUTION: An excavator 1 is suspended from a crane truck 6 and an auger 2 is held with a leader 5 for travel in a long-sized direction. The external surface of the auger 2 is provided with a casing 3 rotating for excavating a subsoil, and an auger forward end 2a is set at a position 5 cm or longer inward from the forward end of the casing 3. In this case, at least the forward end part of the auger 2 and/or the forward end part of the casing 3 is made of a cemented tip having a shock resistance function, and an overlay having a wear resistance function is formed on the external surface of an area above the forward end part. The overlay is applied at a construction site, thereby easily making a compensation for wear. Positioning is made by use of a guide rule 4 and the forward end of an auger 2 while rotating is first made to bite a subsoil. At the same time, the forward end of an auger 2a is guided to an expected position for stabilizing the biting of a subsoil, thereby implementing accurate excavation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the structure of an auger for a drilling machine which performs drilling of ground and kneading with a cement suspension by rotation.

[0002]

2. Description of the Related Art In recent years, holes have been drilled while rotating an auger while pouring a cement-based suspension into the ground from the tip for soil retaining, back protection walls, water blocking walls or ground improvement. Attention has been paid to a construction method that allows the construction of continuous walls in the ground, and it can be applied in narrow spaces in urban areas, and the construction work using this construction method has advantages such as simplifying the work process and shortening the construction period. Became heavily used.

FIG. 2 is an explanatory view showing a basic configuration of a drilling machine used in such a construction method. In the figure, 1 is a drilling machine main body, 2 is an auger provided in the drilling machine, and performs drilling of the ground by rotation of the drilling machine. 4 is a drilling machine by the auger 2 for improving the accuracy of the completed wall. The guide ruler 5 for positioning is a reader that supports the auger 2 and allows it to move in the longitudinal direction. According to the method of erecting the leader 5, the self-standing type in which the lower portion of the leader 5 is fixed to the drilling machine main body 1 to support the auger 2 and the drilling machine main body 1
The auger 2 is roughly divided into a hanging type in which the auger 2 is hung from a crane or the like extending from the hanger.

[0004]

In the drilling machine used in the above method, the ground is drilled by lowering the auger 2 along the leader 5 while rotating the auger 2. However, at the start of drilling, the biting of the auger tip 2a into the ground is not stable, and in some cases, the auger tip 2a dances on the ground, making it impossible to perform accurate drilling at the planned drilling position. There was such a problem. The tendency is more remarkable as the rotation speed of the auger 2 at the start of drilling is higher, and in the suspension type than in the self-standing type.

The present invention has been made in view of the above-mentioned problems of the prior art. By stabilizing the biting of the ground at the tip of the auger, it is possible to perform accurate drilling at a predetermined drilling position. It is intended to provide an auger structure for a drilling machine.

[0006]

An auger structure for a drilling machine according to the present invention comprises an auger for drilling at least the ground by rotation, and an auger surrounding the auger and rotating the auger itself. A basic feature is that the auger guide casing for drilling holes is provided, and the tip of the auger is set inside the tip of the casing.

[0007] According to the above configuration, since the auger guides the auger after the tip of the rotated casing bites into the ground first, the tip of the auger starts to bite into the ground while being guided thereby. The biting of the tip of the auger into the ground is stabilized, and accurate drilling at the planned drilling position can be performed.

[0008] The ground in the present configuration includes, besides the soil, those that are difficult to drill with conventional augers, such as concrete and stone walls. This makes it possible to stabilize the biting of the ground at the tip of the auger by using this configuration. This is because accurate drilling becomes possible.

It is preferable that at least the tip of the auger or at least the tip of the casing is formed of a wear-resistant and impact-resistant cemented carbide tip or is provided with the tip. This is because the wear of the part is the most severe, and with a normal material, the part is frequently replaced, and the labor, time, and cost involved in the replacement are increased. As such, a uniaxial compressive strength of 200 kg / cm
It is desirable that the number be ² or more.

For specific auger products, BW50K, BW50T, and BW50T manufactured by Sumitomo Electric Industries, Ltd.
D50K, BD50T (all product numbers of the company), and for casing, CS-40KR, CS-40KL, CS-C40, also manufactured by Sumitomo Electric Industries, Ltd.
K, DCS-GM40KR, DCS-GM40KL, D
CS-GCM40K (all product numbers of the company). All of these have a uniaxial compressive strength of 800 kg /
cm ² or more.

For the same reason, it is preferable that at least the outer periphery of the auger above the tip of the auger and the outer periphery of the casing are provided with hardened hardened wear-resistant material.
In order to apply such a build-up, an arc welding, a gas welding, or the like is performed using a hardfacing bar on the surface of these materials. As a result, the abrasion resistance and durability of the hardfacing part are more than three times as large as the material surface, the replacement interval of the equipment is greatly lengthened, and the labor, time and cost involved in replacement are reduced. become. In addition, the outer surface of the auger above the tip of the auger and the material surface of the outer periphery of the casing do not directly wear, so when the outer diameter of the overlaid portion is reduced, a hardfacing bar is used to easily build up on the site. )
Can be done.

A specific example of what kind of build-up bar and the welding method can be applied when performing the above build-up is, for example, HF-80 manufactured by Kobe Steel Ltd.
Using 0K or HF-700 (both are product numbers of the company) by the covered arc welding method, and the company's DWH-8
00 or DWH-600 (both are product numbers of the company) and may be performed by carbon dioxide arc welding.

[0013] Further, by providing a discharge port for discharging the residual soil generated by ground excavation on the outer periphery of the casing, the residual soil (including the lifted and crushed waste) by the auger (screw portion) in the casing is externally provided. It can be drained, the resistance of the auger part is reduced and the penetration efficiency is increased.
In addition, it becomes possible to confirm the missing or bent auger in the casing or the state of the joint. Regarding the installation position of the discharge port, a place with good discharge efficiency may be selected according to the auger wing pitch.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an embodiment of the invention. In the figure, reference numeral 1 denotes a drilling machine main body, 2 denotes an auger provided in the drilling machine and performs drilling of the ground by rotation thereof, and 3 denotes an auger. A casing 4 surrounding the periphery of 2, 4 is a guide ruler for positioning the drilled hole by the auger 2 in order to increase the accuracy of the completed wall, and 5 is supporting the auger 2 in the longitudinal direction while supporting the auger 2. A leader who can move.

The drilling machine main body 1 is suspended by a crane of a crane truck 6 and includes the auger 2, the casing 3, and the leader 5.

The auger 2 has a screw-shaped drilling structure for ground excavation, and is rotated by a driving device 7 provided on an upper portion of the drilling machine main body 1 to drill the ground.
Further, the auger 2 has a hollow configuration, and a number of extraction holes (not shown) are provided on the tip side thereof. Kneading with such as is performed together.

Further, the tip side has a uniaxial compressive strength of 20%.
It is composed of wear-resistant and impact-resistant carbide tips of 0 kg / cm ² or more. This is because the wear of the part is the most severe, and with a normal material, the part is frequently replaced, and the labor, time, and cost involved in the replacement are increased.

The auger 2 above the tip of the auger 2
The outer periphery is provided with hardened hardened wear resistance. As a result, the abrasion resistance and durability of the hardfacing part are more than three times that of the material surface, the replacement interval of the equipment is greatly lengthened, and the labor, time and cost involved in replacement are reduced. become. In addition, since the surface of the material on the outer periphery of the auger 2 above the tip of the auger 2 does not directly wear, when the outer diameter of the overlaid portion is reduced, a hardened overlay is used to easily build up on the site (filled metal). Can be done.

The casing 3 surrounds the periphery of the auger 2 and drills the ground by rotating itself by a driving device 7 provided also in the upper part of the drilling machine main body 1. Drilling of the ground preceding the auger 2 allows the auger 2 to be guided.

Further, the tip side of the casing 3 is formed of a wear-resistant and impact-resistant cemented carbide tip having a uniaxial compressive strength of 200 kg / cm ² or more. This is the same as the reason why a similar tip is used on the tip side of the auger 2 described above.

The outer periphery of the casing 3 is provided with hardened hardened wear-resistant material. As a result, the abrasion resistance and durability of the hardfacing part are more than three times that of the material surface,
The replacement interval of the equipment is greatly lengthened, and the labor, time, and cost involved in replacement are reduced. Further, since the material surface on the outer periphery of the casing 3 does not wear directly, when the outer diameter of the overlay is reduced, the overlay can be easily formed on site by using a hardened overlay.

In addition, outlets 3a are provided on the outer peripheral surface of the casing 3 at predetermined intervals. The discharge port 3a is for discharging residual soil generated by excavation of the ground. With this configuration, the residual soil (including unloading and crushing waste) by the auger 2 in the casing 3 can be discharged to the outside, The resistance of the portion of the auger 2 is reduced, and the penetration efficiency can be increased. In addition, the auger 2 in the casing 3 can be checked for any missing or bent or bent joints.

In addition to having the structure of the casing 3, the features of the illustrated example are as follows.
As shown in FIG. 1, the point is that the tip of the auger 2 is set inside the tip of the casing 3.

In this configuration, after the drilling of the ground is started while rotating the casing 3, the tip of the casing 3 bites into the ground first, and then the auger tip 2 a is guided to guide the auger 2. Starts to bite into the ground while being guided thereby, so that the biting of the auger tip 2a into the ground is stabilized, and accurate drilling can be performed at the planned drilling position.

The present inventors set the tip of the auger 2 inside the tip of the casing 3 by 0 cm, 3 cm, 5 cm, 20 c
When set at the position of m (both are shown as negative values) and conversely, when set at the position of 5 cm outward (shown as a positive value), drilling to the planned drilling position is possible. An experiment was performed to determine if there was. The results are shown in Table 1 below.
Shown in

[0027]

[Table 1]

From the results shown in Table 1, it can be seen that the auger tip 2a should be set at least 5 cm inward from the tip of the casing 3. This is because the leading end of the casing 3 bites into the ground first due to the preceding drilling of the casing 3, and a play of 5 cm or more occurs before the drilling of the auger 2 to the drilling expected position is started. If not, it is presumed that the casing 3 is not fixed and moves. However, this is a result of performing on the normal dry ground of the Kanto loam layer, and it goes without saying that the result differs depending on the geology and dryness of the ground. When a similar experiment was conducted in other harder ground, the case 3
It was found that good results could be obtained by setting the auger tip 2a about 30 cm to 50 cm inside the tip of the auger. On the other hand, if the auger tip 2a is not set at a position within 1 m inside the casing tip, the earth and sand accumulated in the casing 3 will resist the rotation of the auger 2 and reduce the drilling efficiency.

Incidentally, the auger structure for a drilling machine of the present invention is not limited to the above-described embodiment, and it is a matter of course that various changes can be made without departing from the gist of the present invention.

[0030]

As described above, the first aspect of the present invention is as described above.
According to the auger structure for a drilling machine described in and 2, the ground biting at the tip of the auger can be stabilized,
An excellent effect that it is possible to perform accurate drilling at the planned drilling position is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an example of an embodiment for carrying out the present invention.

FIG. 2 is an explanatory diagram showing a basic configuration of a conventional drilling machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drilling machine main body 2 Auger 2a Auger tip 3 Casing 3a Discharge port 4 Guide ruler 5 Leader 6 Crane truck 7 Drive device

Claims (5)

[Claims] 1. An auger for drilling at least the ground by rotation, and a casing for the auger guide surrounding the auger and drilling the ground by rotating itself. An auger structure for a drilling machine, wherein the auger tip is set inside the tip of the casing. 2. The auger structure for a drilling machine according to claim 1, wherein the tip of the auger is set at least 5 cm inside the tip of the casing. 3. The method according to claim 1, wherein at least a tip of the auger and / or at least a tip of the casing is formed of a wear-resistant and impact-resistant cemented carbide tip. An auger structure for a drilling machine according to claim 1 or 2. 4. An auger outer periphery above at least a tip end of the auger and / or an outer periphery of the casing is provided with hardened hardened wear-resistant material.
Or an auger structure for a drilling machine according to 3. 5. An auger structure for a drilling machine according to claim 1, wherein a discharge port for discharging residual soil generated by ground excavation is provided on an outer periphery of said casing.