Litian's New Disc Cutter Powers National Strategic Projects

Chinese Version Source: Liaoning Daily

On May 19, at a project site in Gansu Province, the newly developed disc cutter by Litian Heavy Industry Machinery Co., Ltd. (hereinafter referred to as “Litian Heavy Industry”) easily chewed through extremely hard rock amid the roar of machines.

This efficient and cost-effective cutter has recently been applied to national strategic projects such as the western route of the South-to-North Water Diversion Project and the Sichuan–Tibet Railway, helping to solve the challenges of tunneling through extremely hard rock at high altitudes. With continuous technological improvements, the new disc cutter reduces vibration and noise, improves the tunneling environment, lowers cutter replacement frequency, and decreases the risk of face collapse, cutting construction accident rates by 60%. In a deep-buried tunnel project in Xinjiang, the installation of the new cutter enabled the first continuous excavation with domestically made disc cutters in extremely hard granite, boosting construction efficiency by 30% and generating direct economic benefits exceeding RMB 200 million.

Few could have imagined that such a highly efficient disc cutter was once a longstanding problem for China’s infrastructure industry.

For many, disc cutters are unfamiliar. Simply put, they are the “teeth” of a tunnel boring machine (TBM), responsible for breaking rock during tunneling. Their lifespan and efficiency directly determine project progress and costs. In the past, disc cutters for extremely hard rock excavation relied almost entirely on imports.

“It used to be very difficult,” recalled Yu Lili, Technical Director at Litian Heavy Industry. “Imported cutters were not only expensive but also had long delivery times. Once they broke, we had no choice but to wait. What was worse, during excavation in extremely hard rock, imported cutters had to stop every 8 hours, dragging project schedules and driving costs through the roof.”

Litian Heavy Industry was determined to change this situation. However, as a company specializing in rock drilling tools and TBM cutters, it lacked a complete R&D team and advanced innovation concepts, making it extremely challenging to break through technical barriers.

A turning point came in the spring of 2022. Upon learning of the company’s technical bottleneck, the Science and Technology Bureau of Lianshan District, Huludao, introduced the “Revealing the List, Taking the Lead” policy to the company: “You put forward the challenges, and research teams nationwide will tackle them.” This initiative for the development and application of long-life disc cutters for extremely hard rock (hereinafter referred to as the “new disc cutter” project) quickly attracted research teams from Dalian University of Technology, Southwest Jiaotong University, China Railway 18th Bureau, and China Railway 19th Bureau, along with construction enterprises. The stage was set by the government, problems were posed by the enterprise, and solutions were provided by universities—launching a collaborative innovation drive.

“The drawings were revised countless times. When the prototypes failed, we redesigned them. The samples were improved twice before the third version finally broke the world record for disc cutter tunneling in extremely hard rock in laboratory tests. That’s when we dared to say: ‘We made it!’” said Yu Lili.

By the end of 2023, the new disc cutter achieved its “first battle” in a Gansu project. It maintained continuous excavation of 300 meters and 1,500 hours of operation—far exceeding the 80-meter advance and 500-hour lifespan of conventional cutters. Engineers calculated that, compared with imported products, the price of each cutter dropped from RMB 180,000 to RMB 100,000, saving over RMB 8 million in annual procurement costs per TBM. Cutter replacement frequency dropped from three times per day to once, cutting maintenance costs by 40%. For a single 10-kilometer tunnel, the construction period was shortened by six months, saving more than RMB 30 million in management costs alone.

Today, this new disc cutter has filled the domestic technological gap in TBM cutters for extremely hard rock, becoming a market leader in China. In terms of rock-breaking capacity, lifespan, and load-bearing capacity, it has reached internationally advanced levels, achieving a leap from follower to leader.

“The success of this cutter was by no means the effort of a single enterprise,” said Chen Si, Director of the Lianshan District Science and Technology Bureau. “With the government building the platform, enterprises posing the challenges, and research institutes providing solutions, breakthroughs came faster and also drove regional innovation. Now, our district has 17 high-tech enterprises and 73 technology-based SMEs. Everyone is motivated and pushing innovation forward together.”