Sooner or later every drive needs one: the machine stops, the chamber is secured, and people go where the cutters are. In free air when the ground allows it, under compressed air when it does not — either way, a cutterhead intervention is the most safety-critical routine task in tunnelling.
The discipline is in the preparation. Ground treatment verified, face support calculated, gas monitoring continuous, rescue-trained standby crews in place, and every disc, scraper and wear plate inspected against a plan rather than a guess.
Our supervisors have led interventions through Singapore's toughest geology. The record we care about most is simple: everyone comes back up, every time.
