Hello, everyone.
This is Enta.
It looks like the rainy season is about to begin.
It's been crazy hot this year even before the rainy season started, and it's been raining like crazy.
Let's be extra careful about the rain this year!
But that's beside the point.
When drilled using the double-pipe drilling method, the borehole becomes self-supporting.
Even on a slope that would never be stable with a single borehole, a double-pipe system leaves a gaping hole in the slope and makes it stable, doesn't it?
Often, when a test borehole is drilled in the presence of government officials to prove that a single borehole is not self-supporting,
Assuming that single-hole drilling is not possible, we will bring a standard rotary percussion drill and perform a test drill.
Since it involves the effort of transporting the equipment, if you ultimately decide to use the double-pipe drilling method,
We'll also bring a rotary percussion drill for the test drilling.
However, there’s a major miscalculation here, but,
When drilling with a φ65 single-bit drill versus drilling with the inner bit of a rotary percussion drill,
It does not stand on its own with a single-hole drilling machine, but it may stand on its own with a rotary percussion inner drilling machine.
It's a little hard to see, but the rod on the single-hole drilling machine is about 30 mm in diameter, and the drill bit is 65 mm.
The top part of the picture is single.
The bottom part is an inner bore.
The difference is obvious at a glance, but in the case of single-hole drilling, the gap between the rod and the bit is larger to allow for efficient slurry discharge, and
Slime is continuously discharged. As this happens, the borehole wall is eroded along with the drilling slime and discharged.
In double-pipe inner drilling, when the clearance between the bit and the rod is small, as the drilling slurry is discharged,
It can drill while pressing against the borehole wall and forming the borehole wall.
That said, it's only temporary. (Using water at this point will make it stand on its own even more.)
Inner drilling can proceed while consolidating the borehole walls.
Drilling slurry is discharged, but some of it remains on the borehole wallAs consolidation occurs, the borehole walls become self-supporting.That's the way it is.
For test drilling, rather than using a rotary percussion drill for the inner bore, use a reducer (rod adapter) to
Since drilling with self-drilling rods and similar tools allows for more accurate reproduction of the holes drilled by the original machine,
Showing a non-self-supporting borehole wallYou can do that.
A long time ago, when I was on-site for an inner core drilling project, someone from the local government office said to me, “Huh? It stands on its own!” (lol)
However, please keep in mind that even though we say it’s becoming self-sufficient, this is only a temporary situation.
See you later.
*To general contractors struggling with a shortage of construction crews!
If there's work, I'll get right on it! (From design changes to construction and construction management)
Thank you in advance.
