How do you get an excavator to breach through a tunnel face?

[George]

I'm looking to learn more about the process and best practices for using an excavator to break through a tunnel face. I've seen it done on a few jobs, but I'd like to understand what actually goes into doing it safely and efficiently.

What factors matter most-ground conditions, machine size, attachment choice, sequencing, or support systems? Are there common mistakes people make when breaching that can cause overbreak or stability issues?

Not looking for shortcuts, just trying to learn how it's typically planned and executed in the field. Appreciate any insight from operators, foremen, or engineers who've been involved in tunnel work.

 

[Sawdust123]

I'm looking to learn more about the process and best practices for using an excavator to break through a tunnel face. I've seen it done on a few jobs, but I'd like to understand what actually goes into doing it safely and efficiently.

What factors matter most-ground conditions, machine size, attachment choice, sequencing, or support systems? Are there common mistakes people make when breaching that can cause overbreak or stability issues?

Not looking for shortcuts, just trying to learn how it's typically planned and executed in the field. Appreciate any insight from operators, foremen, or engineers who've been involved in tunnel work.

From what I've seen, it's way more about planning than brute force, .,knowing the ground, having the right attachment, solid support in place, and taking it slow to avoid overbreak or stability issues.

 

[oraculum]

you don't just drive an excavator into a tunnel face. the face is prepped first-blasted, pre-split, or supported with shotcrete/bolts depending on ground conditions. the excavator (often with a breaker or ripper) then carefully opens and cleans out the face in stages, followed immediately by ground support.

for tunnel-suited excavators and breakers, contractors often source from ritchie bros., ironplanet, or iaa global auction rather than buying new.