CRCHI's first open-type tunnel boring machine (TBM) exported to South Korea has completed its tunneling task, achieving precise breakthrough on the Pyeongtaek-Osong double-track railway project, a key national railway initiative.

The tunnel's surrounding rock consists mainly of high-hardness granite and gneiss, with uniaxial compressive strength reaching up to 207.3 MPa and quartz content between 26.6% and 42%. The highly abrasive rock made excavation extremely difficult. Multiple fractured zones along the route posed further risks, including poor rock stability, collapses, and water inflow.

To address the extremely hard rock geology and special underground assembly conditions, CRCHI conducted multiple rounds of preliminary design studies and developed fully customized components. The equipment features a high-power cutterhead drive system, heavy-duty wear-resistant disc cutters, a strong support and thrust system, and an efficient mucking system. A modular structural design enhances component reliability, rock-breaking capability, machine stability, and underground assembly adaptability.

To ensure efficient project progress, CRCHI assembled a dedicated overseas service team stationed at the construction site, operating around the clock in two shifts. Company officials made multiple visits to the frontline to supervise operations and ensure smooth TBM performance.

Once completed, the Pyeongtaek-Osong double-track tunnel will help ease congestion on several high-speed rail lines, including the Gyeongbu, Honam, and Suseo-Pyeongtaek routes, addressing a key bottleneck in central South Korea's rail network and improving regional commuting efficiency.