Hello, everyone.
This is Enta.
I'm heading to Akita today to run some errands. By car...
It really is a long drive, isn't it? My butt's gonna fall off, lol.
But that's beside the point.
This time, we'll be discussing drilling methods.
This is an older post, but since it's so popular, I'll repost it here too lol
Drilling Methods
Drilling Machines and Drilling Methods for Slopes and Anchor Works
The drilling methods used by anchor installers and rebar installers (rock bolt installers) are basicallySingleかDouble。
AirかHydraulicsThat would be the case.
Broadly speaking,Air Drilling = Single; Hydraulic Drilling = Double That's how it works.
*Single-hole drilling = single-pipe drilling
*Double drilling = drilling through two pipes
Single-Pipe Drilling (Single-Pipe Boring)
- Down-the-Hole Hammer -
Down-the-hole hammers are one type of hammer used for single-hole drilling, even for large-diameter holes.
Personally, my on-site construction experience is limited to down-the-hole hammers up to 600 mm.
When it comes to large-diameter piles, I think 600 or 500 are commonly used. For diameters larger than that, I believe the all-casing method is typically used (such as the Benoto method).
I use it quite often as an anchor, and one of its distinctive features is that it has a hammer attached to the tip.
Overall, it looks like this. This part of the hammer is the tip.
Air pressure is applied to the tip, and the impact is generated by the resulting recoil force.
The tip is equipped with an air vent to remove slurry (fragments of rock and other materials produced during drilling), and
It works like this: you strike it with a hammer while letting air out from here.
This method is best suited for hard or soft rock—that is, rock that is hard and where the borehole wall (the wall of the hole after drilling) does not collapse.
Also, since the hammer makes a fairly low-pitched "thud-thud-thud-thud" sound when striking with its tip, the noise level is low.
Because the drill bit has a large head, if the borehole wall collapses, the bit can become stuck or experience jamming (when the bit is constricted by borehole slime or other materials and can no longer rotate).
On the downside, since it's air drilling, it creates a tremendous amount of dust.
Also, since compressor pressure is critical, I think it’s best to use a down-the-hole hammer with a diameter of at least 90 mm—and for an Airman model, at least a PDS655S or higher is recommended.
Hokuetsu Kogyo Co., Ltd. AirmanHere
It’s not that you can’t use it at lower settings, but the impact force drops significantly, and the drilling power decreases.
Even 50 horsepower is sufficient, but there’s a huge difference compared to 100 horsepower or more.
The standard way to deal with dust is to install a dust collector, but it’s debatable whether it can actually keep up with the dust (lol) (In reality, it’s not even enough to give you peace of mind).
Also, the compressors are huge and consume an insane amount of fuel—like 200 liters a day or so...
However,It's incredibly strong against bedrock!!The hammer head looks like this, and you should replace it when it wears out. ↓↓ However, if the main body becomes worn or cracked, you’ll need to replace it.
Hammers and drill bits are all consumables, and they wear out much faster than you might think.
Installation Characteristics
Single-hole drilling is relatively easy to perform, making it ideal for beginners.
If you are planning to start drilling for rebar insertion or similar work, we recommend using a suspended drilling rig (rock drill type).
In the cost estimation documents,Site Conditions IThis is a drilling method.
Please note that while we can drill single holes, we cannot drill double-wall pipes.
In fact, single-hole drilling requires some skill.
For example, if there’s soil, it definitely makes digging harder, and if there’s water, the air has a hard time returning (making it harder to dig), and so on.
This is a real problem. In the worst-case scenario, some contractors won’t even install the rebar and will just hammer it in.
In the worst-case scenario, cement slurry might not reach the entire length of the tie rod.
If drilling cannot be performed using a single-pipe drilling method, please submit a request for consultation to the local government office to switch to a double-pipe drilling method.
In such cases, drilling a test hole is an effective approach.
See you later.
