In tunnel construction, machines used for manually drilling blast holes are commonly called rock drills or rock excavators. These devices are core tools in tunnel excavation, using impact and rotation to create blast holes in the rock, paving the way for subsequent blasting or support operations. Rock drills are like the "axe" of tunnel engineering; without them, modern tunnel construction would be impossible.
The Working Principle of a Rock Drill
The working principle of a rock drill, seemingly simple, is quite ingenious:
Impact System: High-pressure gas or hydraulic pressure drives the piston in reciprocating motion, generating high-frequency impact force.
Rotation System: Simultaneously drives the drill rod to rotate, causing the drill bit to evenly abrade the rock.
Shavings Removal System: Compressed air or water is used to remove drill cuttings from the hole.
This combination of "hammering + rotation" allows even hard rock to be easily drilled.
Common Types of Rock Drills
Based on their power source, tunnel drilling machines are mainly divided into three categories:
Pneumatic rock drills: Driven by compressed air, simple in structure but noisy.
Hydraulic rock drills: More powerful and efficient, the mainstream choice for modern tunnel engineering.
Electric rock drills: Environmentally friendly and quiet, but with relatively lower power, suitable for specific applications.