China Unveils 'Xianglong,' a Machine That Both Bores and Blasts Through Rock

China Railway Science Industry Group (CRSIC) in Wuhan and Tsinghua University have built the world's first Boring and Blasting Machine (BBM), called 'Xianglong' ('Lucky Dragon'), which combines a tunnel-boring machine (TBM) with the ability to set explosives to blast through solid rock, according to Chinese state media.

Tunnels that cross mixed geology usually need different machines: a Soft Ground TBM uses a rotating shield to cut through soil, clay, sand or gravel, while a Hard Rock TBM has no shield and instead grips the rock wall as heavy cutters grind through solid rock. Xianglong is designed to handle both kinds of ground with a single machine.

The 14.76 ft (4.5 m) diameter cutterhead has a hollow center with built-in drilling equipment that bores holes deep into a rock face; the holes are packed with low-yield, high-velocity explosives and tamped with sand or clay. The controlled blast creates micro-fractures in the rock without throwing out debris, and the force is absorbed by a protective shield before the cutterhead sweeps up and crushes the loosened rock.

Chinese state media said Xianglong can improve excavation efficiency by 30% over conventional boring machines, and that its shield can vary in diameter to fit different tunnel-lining segments — though how the machine performs in practice remains to be seen.