China unveils hybrid tunnel boring machine to tackle hard-rock delays

China has introduced a tunnel boring machine that combines mechanical excavation with blasting, aiming to reduce delays in hard rock. The first trial will be at a pumped-storage plant in Henan.

This article was drafted with AI assistance from multiple sources and was reviewed and approved by a human editor before publication.

China has introduced a tunnel boring machine that combines mechanical excavation with blasting, a design intended to overcome delays in difficult rock conditions. The machine, named Xianglong, rolled off the production line in Wuhan on 1 August 2026, according to its developers, Tsinghua University and China Railway Science & Industry Group.

The Xianglong weighs 400 tonnes and has a diameter of 4.5 metres. Its central feature is a ring-shaped cutterhead with an opening in the middle. This opening can be closed with a smaller cutterhead, also equipped with disc cutters, for full-face mechanical excavation, or left open to allow access to the rock face for small equipment such as drills, drainage hoses, and grout injectors.

The machine can switch among three operating modes: full-face excavation, blasting before boring, and boring before blasting. This flexibility is meant to address situations where hard rock slows down conventional tunnel boring machines.

The developers claim that in extremely hard rock, the Xianglong can achieve 30% higher excavation efficiency compared with standard machines. However, this figure comes from tests under special conditions, not from actual site operation.

The first on-site trial is planned at a pumped-storage power plant in Henan province, which is being built by a subsidiary of Power Construction Corporation of China. The machine was built entirely with a domestic supply chain, according to the Hubei provincial government, which announced the development on 2 August 2026.

The announcement comes after a notable incident involving a tunnel boring machine in the Gotthard road tunnel in Switzerland. In June 2025, a large rockfall above the cutterhead of a Herrenknecht machine named Paulina, which weighs about 3,000 tonnes, halted the project. After about 11 months of recovery work, including cement injections, a 250-metre connecting gallery, and counter-excavation, the machine restarted on 18 May 2026.

While the Xianglong is not yet proven in the field, its developers hope that the hybrid approach will reduce the need for such lengthy interventions in difficult geology.