Cave Cutting Method for Pillar Construction

The present disclosure relates to a method for excavating a pole erection hole using a casing tube.

A pole erection hole is manually excavated to the depth of about 1.5 m so as not to damage a buried object, and then excavated to a desired depth using a digger derrick truck. Manual excavation work is a time-consuming work with a large burden on the body.

A related method for excavating a pole erection hole is illustrated in. In, a reference signdenotes an earth auger drill, and a reference signdenotes a digger derrick truck. The earth auger drillhung on the tip of a crane of the digger derrick truckis rotated to excavate a pole erection hole (see, for example, Patent Document 1).

Since the earth auger drillalways digs soil and sand by rotation, the dug soil and sand need to be discarded manually or by a heavy machine as needed.

Patent Literature 1: JP 8-177364 A

However, in these related methods for excavating a pole erection hole, there is an issue that, while it takes a lot of time and a burden on the body if the manual excavating work is performed in the initial stage, if the earth auger drillis used from the initial stage avoiding the manual excavation, an excavation force of the earth auger drillbecomes so large that a buried object is damaged.

An object of the present disclosure is to realize excavation of a pole erection hole by a machine to improve the efficiency of excavation work.

A method for excavating a pole erection hole of the present disclosure includes vibrating, by the vibrator, the casing tube to cause the casing tube to penetrate into the ground.

Specifically, the present disclosure is a method for excavating a pole erection hole including

In the present disclosure,

In the present disclosure,

In the present disclosure

The present disclosure further includes

The present disclosure further includes

The present disclosure further includes

Note that, the inventions disclosed above can be combined where possible.

According to the present disclosure, it is possible to realize excavation of a pole erection hole by a machine to improve the efficiency of excavation work.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that, the present disclosure is not limited to the embodiment to be described below. These embodiment example is merely exemplary, and the present disclosure can be implemented in forms of various modifications and improvements based on the knowledge of those skilled in the art. Note that, components having the same reference signs in the present specification and the drawings indicate the same components.

A method for excavating a pole erection hole of the present disclosure will be described with reference to. A vibratorto which a casing tubeis attached is transported by a carrying vehicleto a place where a pole is erected. As the carrying vehicle, a digger derrick truck that has transported an earth auger drill may be used, or the vibrator may be transported by a carry.

The vibratorto which the casing tubeis attached is suspended and disposed on the ground surface. In a case of transportation by a digger derrick truck, the vibratoris suspended by a crane of the digger derrick truck and disposed on the ground surface. In a case of transportation by a carry, the vibrator is suspended by a derrick and disposed on the ground surface.

The shape of the casing tubemay be a cylindrical shape with a hollow in the longitudinal direction inside thereof, and as illustrated in, a cylinder (a) or a square cylinder (b) can be exemplified. With such a shape, there is no sharp portion as compared with the earth auger drill, and the contact portion with a buried object is flat, so that the buried object is hardly damaged even if the casing tubecomes into contact with the buried object. Further, unlike the earth auger drill, a stone is not clogged between the blades.

The vibratorvibrates the casing tubein a vertical direction to cause the casing tubeto penetrate into the ground. The amplitude of vibration obtained by the vibratoris expressed by the following formula.

Amplitude (m)=eccentric moment (kgm)/total weight (kg)   (1)

Here, the total weight (kg) is defined as follows.

Total weight (kg)=vibrator weight (kg)+casing tube weight (kg)   (2)

In a case where a Uras Vibrator having an eccentric moment of 1.2 kgm/weight of 100 kg is used as a vibrator, according to the formulas (1) and (2), generation of vibration in a casing tube having a weight of 160 kg can generate an amplitude of 6 mm or more. It is empirically shown that with an amplitude of 6 mm or more, the casing tube can be penetrated into soil of many types. By adjusting the amplitude of the casing tube by the vibrator, it is possible to cope with various types of soil.

The vibratordesirably includes a sensor that detects contact with a buried object. When the sensor detects that the vibratorcomes in contact with the buried object, the vibration of the vibratoris stopped. This can prevent the casing tube from damaging the buried object.

As a sensor that detects contact with the buried object, a pressure gauge that detects a pressure in a vertical direction can be exemplified. When the casing tubecomes into contact with the buried object, the pressure on the vibratorincreases through the casing tube. When the pressure gauge of the vibratordetects a pressure in the vertical direction larger than a predetermined value, the vibration of the vibratoris stopped. By stopping the vibration of the vibratorupon contact with the buried object, the buried object is not damaged, so that the pole erection hole excavation work can be realized with safety similar to that of the manual excavation work.

As another sensor that detects contact with a buried object, a speedometer that detects the penetration speed of the vibratorcan be exemplified. When the casing tubecomes into contact with a buried object, the penetration speed of the casing tubeis reduced. When the speedometer of the vibratordetects the penetration speed smaller than a predetermined value, the vibration of the vibratoris stopped. For example, when the penetration distance inseconds is 1 mm, that is, the penetration speed is smaller than 0.1 mm/second, it is determined that the casing tubehas come into contact with the buried object. By stopping the vibration of the vibratorupon contact with the buried object, the buried object is not damaged, so that the pole erection hole excavation work can be realized with safety similar to that of the manual excavation work.

When the casing tubepenetrates to a predetermined depth, the vibration of the vibratoris stopped. In a case of deep excavation, an extension bar is connected between the vibratorand the casing tube.

Therefore, according to the present disclosure, it is possible to realize excavation of a pole erection hole by a machine to improve the efficiency of excavation work.

After the vibration of the vibratoris stopped, the soil inside the casing tubeis lifted together with the casing tubeto discard the soil from a pole erection hole. A soil discarding step will be described with reference to. In, a reference signdenotes a casing tube, and a reference signdenotes soil. When the casing tubeis lifted, the soilinside the casing tubeis also lifted together. When the soilis discharged from the pole erection hole, the pole erection hole is completed.

Therefore, lift of the soiltogether with the casing tubecan improve the efficiency of excavation work.

After the vibration of the vibratoris stopped, the soil inside the casing tubeis stirred and sucked to be discharged from the pole erection hole. A discharging step will be described with reference to. In, a reference signdenotes a casing tube, a reference signdenotes a stirring device, a reference sign-denotes a rotation shaft of the stirring device, a reference sign-denotes nets of the stirring device, and a reference signdenotes a suction pump.

The soil inside the casing tubeis stirred by the stirring deviceto be loosened, and then sucked and discharged by the suction pump. The stirring device may be disposed inside the casing tubebefore excavation, or may be inserted into the casing tubeafter vibration of the vibratoris stopped.

An example of the stirring device may be a drill mechanism as illustrated in. In a case where a drill function is disposed inside the casing tubebefore excavation, it is preferable to dispose the drill mechanism at a position upper than the lowermost portion of the casing tubeso that the drill mechanism does not come into contact with a buried object.

As another example of the stirring device, nets having a tier structure as illustrated inmay be used. In the step structure, the lower nets are coarser and the upper nets are finer. While the rotation shaft-of the stirring device is rotated, soil is pushed out toward the lower portion of the casing tube. The soil is roughly and strongly loosened with a coarse mesh at the lower part of the nets-of the stirring device, and finely loosened with a fine mesh at the upper part of the nets-of the stirring device. By varying the sizes of the meshes of the nets from coarse to fine in the height direction, the soil is easily loosened.

Therefore, the soil inside the casing tubeis stirred, sucked, and discarded, whereby the efficiency of excavation work can be improved.

After the vibration of the vibratoris stopped, a utility pole is connected to the upper surface of the casing tube. In this case, the shape of the casing tubeis desirably a cylindrical shape corresponding to a utility pole. A utility pole connecting step will be described with reference to. In, a reference signdenotes a casing tube, a reference signdenotes a casing tube bolt hole, a reference signdenotes a casing tube bolt, a reference signdenotes a casing tube bolt attachment, a reference signdenotes an attachment bolt, a reference signdenotes an attachment nut, a reference signdenotes soil, a reference signdenotes a utility pole, a reference signdenotes a utility pole bolt hole, a reference signdenotes a utility pole bolt, and a reference signdenotes a utility pole attachment.

As illustrated in, the casing tubeis removed from the vibrator, and the utility poleis disposed on the upper surface of the casing tube. In, the attaching mechanism is omitted. As illustrated in, the casing tube bolt holesare formed in advance in the casing tube, and the utility pole bolt holes are formed in advance in the utility pole. As illustrated in, the casing tube bolt attachmentis fixed to the casing tubewith the casing tube bolts. The utility pole attachmentis fixed to the utility polewith the utility pole bolts. Positions of the casing tube bolt attachmentand the utility pole attachmentare matched and the casing tube bolt attachmentand the utility pole attachmentare fixed with the attachment boltsand the attachment nuts. The attaching mechanism is not limited to that described here. It is only needed that the casing tubeand the utility poleare fixed.

Therefore, the casing tubeis used as a base of a utility pole when the utility pole is erected, so that labor when erecting the utility pole can be saved and the efficiency of excavation work can be improved. In addition, labor of waste soil treatment such as backfill of soil into the gap between the pole erection hole and the utility pole can be saved, so that the efficiency of excavation work can be improved.

As described above, according to the method for excavating a pole erection hole of the present disclosure, it is possible to realize excavation of a pole erection hole by a machine to improve the efficiency of excavation work.

The present disclosure can be applied to various industries including the information communication industry.