Commonly used split-type down-the-hole drilling rigs in tunnel engineering are mainly divided into three categories:
Light-duty rigs: Weighing 3-5 tons, with a drilling diameter of 80-120mm, suitable for soft rock formations and confined spaces.
Medium-duty rigs: Equipped with dual power heads, drilling depths up to 50 meters, highly efficient for medium-hard rock formations.
Heavy-duty rigs: Hydraulic system pressure exceeding 25MPa, with built-in dust removal devices, specifically designed for extremely hard formations such as granite.
Key performance indicators for different construction environments:
Rock properties: For Mohs hardness below 5, an impact energy of 800J is suitable; for Mohs hardness above 6, 1200J is required. Models J and above
Space limitations: Tunnels with a height of less than 3 meters require a folding drill arm design.
Environmental requirements: For urban construction, a hybrid electric system is recommended, with noise levels controlled below 75 decibels.
Three golden rules for operation and maintenance:
Drill rod maintenance: Clean the threads every 8 hours of operation; perform magnetic particle testing after 200 hours of cumulative use.
Lubrication management: Add dedicated grease to the impactor every 2 hours; adjust oil viscosity according to ambient temperature.
Fault prediction: Immediately check the cooling system if the hydraulic oil temperature exceeds 65℃; stop the machine and investigate if pressure fluctuations exceed 15%.