China Mega-Diameter Tunnel Boring Machines Leap from Following to Leading

Twenty-five years ago, 95% of China's shield machines were imported. Foreign companies fetched prices of 300 million yuan for a single machine, and even core components were not allowed to be accessed during maintenance. From the rollout of the first domestically produced shield machine, "China Railway No. 1," in 2008, breaking the monopoly, to the reverse export of main bearings to Europe in 2025, in just 17 years, China's shield machines have made the leap from "following" to "leading." Today, two out of every three tunnels worldwide are excavated by Chinese shield machines. The resurgence of this "underground giant" is fueled by five "most" codes, each one revealing unwavering confidence.

The Ultimate Versatile: From "embroidery" to "weightlifting," there's no underground work it can't handle.

China's shield machines are truly the "underground all-around champions": from small-scale tunnels dug in urban utility corridors with the precision of embroidery, without even touching adjacent water pipes, to large-scale tunnels like the 16.66-meter "Cangyuan" behemoth, weighing 5,650 tons, like a mobile steel fortress, capable of easily tackling deep-sea tunnels. Besides conventional circular tunnels, they can also easily handle special-shaped tunnels like rectangular and horseshoe shapes, such as the rectangular tunnel at Shanghai Hongqiao Airport, which is perfectly sized to accommodate subway tracks.

Whether it's hard rock, soft soil, or extreme environments like the seabed, plateaus, or deserts, Chinese companies can provide customized shield machines wherever the need arises. Does the Sichuan-Tibet Railway need tunnels dug on a 40-degree slope? China Railway Construction Heavy Industry's inclined shield machine (TBM) is like an underground rock climber, steadily tunneling along steep slopes. This unique technology is unparalleled globally. The newly developed modular shield machine, developed in 2025, is even more advanced, capable of flexibly switching between hard rock mode and subsea mode within an hour, increasing efficiency by 80% compared to traditional equipment. It has already proven its effectiveness in the Xiamen undersea tunnel. This "one-hour mode switching" technology not only significantly improves construction efficiency but also breaks the industry's convention of "one machine for one task." It is now being incorporated into the International Tunneling Association's new construction standards. Chinese TBMs are not only rapidly advancing in technology but also driving the entire industry forward.

Chinese TBMs are also expanding their application scenarios, including water conservancy, hydropower, and coal mining. At the Jingning Pumped Storage Power Station in Zhejiang Province, China's first ultra-large-diameter raise boring machine, the China Railway 1361, uses an innovative "one-expansion-to-well" process to excavate a shaft with a diameter of 7 meters and a depth of 311 meters in a single operation.

Hardy: Surviving temperatures of -30°C and working tirelessly on the 4,000-meter plateau

The durability of Chinese shield machines is fully demonstrated in extreme environments:

• Arctic tundra: In Russia's Arctic LNG project, extreme temperatures of -30°C can brittle steel. Foreign equipment must shut down three times a day to keep warm, while Chinese shield machines are equipped with built-in anti-freeze armor, preventing the hydraulic oil from freezing and allowing them to operate non-stop 24 hours a day.

• Snowy plateaus: The Erlangshan Tunnel on the Sichuan-Tibet Railway, at an altitude of 4,000 meters, has oxygen levels only 60% of those on the plains, and the rock is as hard as steel. The "high-altitude cutterhead" of Chinese shield machines rotates 50% faster than foreign machines, enabling them to excavate 30 meters of hard rock in a single day, setting a world record.

• Deep-sea high pressure: The Istanbul Strait Tunnel in Turkey, buried 106 meters deep, faces water pressure as intense as the weight of ten elephants. China's shield machine's "normal-pressure cutterhead" underwater cutter change speed is 50% faster than Japan's technology, and it operates stably and trouble-free throughout the entire process, earning it the nickname "Deep Sea Iron Man" by foreign media.

The Yongning, the world's first large-diameter tunnel boring machine capable of steep slope climbing, successfully completed excavation of the No. 2 diversion inclined shaft of the Luoning Pumped Storage Power Station. This inclined shaft, with a gradient of 38.742 degrees and a total length of approximately 873 meters, not only successfully climbed the slope but also achieved a monthly advance of 332 meters and a maximum daily advance of 22.75 meters. Building on the Yongning's success, the China Railway 1285, the world's first high-angle downhill tunnel boring machine for mining, also successfully completed operations at the Huaibei Mining Group's Linhuan Coal Mine, achieving long-distance downhill excavation at a 15-degree slope.

Cutting-Edge: Five Technologies at the World's Top, Others Chase to Learn

Once, key components of shield machines, such as the "heart" (main bearing) and "brain" (intelligent system), were dependent on imports. Now, Chinese companies have overcome these bottlenecks one by one, achieving global leadership:

• The Strongest "Heart": In 2025, China Railway Equipment's new generation of main bearings will be unveiled, boasting a lifespan exceeding 18,000 hours, significantly surpassing the 15,000 hours of similar German products. These bearings are already being supplied in large quantities to Europe, achieving "reverse technology export" of core components from China to developed countries. Products with a diameter of 5 meters can withstand a pressure of 3,000 tons, equivalent to 300 elephants standing on them, yet the cost is 60% lower than that of Germany. This technological breakthrough has also driven collaborative upgrades among over 1,200 supporting enterprises in special steel and precision machining, building a comprehensive industrial chain encompassing "complete machine R&D, component development, and material breakthroughs."

• The Most Accurate "Brain": Equipped with the BeiDou + inertial navigation system, shield machines can achieve millimeter-level tunneling accuracy. Just like the construction of Shenzhen Metro Line 14, it steadily excavated a tunnel beneath a seven-story residential building, leaving the fish tanks of the residents above completely still. Its nickname, "Underground Embroidery Needle," is well-deserved.

• Efficient Excavation Handling System: The excavation handling system developed by China's shield machines can quickly and efficiently separate and transport excavation generated under diverse geological conditions. For example, when working in complex soft soil, excavation can easily become sticky and have poor fluidity. The excavation handling system of China's shield machines uses specialized mixing and screening devices to precisely control the excavation's moisture content within a reasonable range, resulting in a 35% increase in excavation efficiency compared to similar foreign equipment. This significantly reduces the risk of blockages during construction and ensures continuous excavation operations.

• Intelligent Tool Wear Monitoring Technology: During high-intensity excavation, the wear of the shield machine's cutterhead is difficult to monitor in real time. Previously, manual inspections required machine shutdowns, severely impacting construction progress. China's intelligent tool wear monitoring technology, utilizing sensors and image recognition technology, allows for accurate and real-time monitoring of tool wear without stopping the shield machine. For example, during the excavation of the West Tianshan Extra-Long Tunnel, the "Wensu" TBM utilized this technology to predict tool wear in advance and replace tools promptly, avoiding sudden failures caused by excessive tool wear and increasing excavation efficiency by 20%.

• Advanced segment assembly technology: Segment assembly is a critical step in shield construction and directly impacts the quality of tunnel construction. The advanced segment assembly technology employed by Chinese shield machines uses automated and digital control to minimize segment splicing errors. For example, during the construction of the Chongtai Yangtze River Tunnel, the horizontal position error of the segment assembly was controlled within ±5 mm, and the vertical error within ±3 mm, far exceeding international standards. This ensures the tunnel's waterproofness and stability, effectively extending its service life.

In addition, my country has also achieved significant breakthroughs in the field of ultra-large diameter shield machines. In January 2024, the "Linghang" shield machine rolled off the production line, becoming the world's largest diameter high-speed rail slurry shield machine. In October 2024, the "Jianghai" shield machine rolled off the production line, becoming my country's first independently developed ultra-large-diameter shield machine. From the "Chunfeng" machine, with a 15.8-meter excavation diameter, to the "Jinghua" machine, with a 16.07-meter diameter, and finally to the "Cangyuan" machine, with a diameter exceeding 16.6 meters, China's ultra-large-diameter shield machines have made the leap from "following" to "leading."

Best Value: Pay the Price of One, Get the Work of 1.5

"High Quality and Low Price" doesn't even begin to describe the price-performance advantage of Chinese TBMs; to say they offer "crushing value" is no exaggeration:

• Price-wise, similar equipment is over 30% cheaper than German and Japanese counterparts. For the price of one German TBM, you can buy 1.5 Chinese TBMs, each with a three-year on-site warranty.

• Efficiency-wise, on the Singapore Cross Island Line MRT project, Chinese TBMs achieved 20% faster excavation speeds than Japanese equipment, saving the client 120 million yuan in three years.

• Service-wise, while foreign companies often wait two weeks for after-sales response, Chinese companies guarantee 24-hour on-site service. A Turkish customer commented, "The best thing about Chinese equipment isn't just the affordability, but the immediate availability of repairs if it breaks down. This is unimaginable in Europe."

In terms of cost control, Chinese TBMs have reduced production costs through collaborative innovation across the entire industry chain. Taking China Railway Equipment as an example, it has united more than 1,200 supporting enterprises to form an industrial cluster, realizing the localization of key components, making China's shield machines more competitive in price.

Daring to Take on Challenges Domestically, Pioneer Overseas

Domestic projects focus on the most challenging ones:

• In April 2025, a tunnel boring machine (TBM) on the China-Nepal Railway successfully crossed the Himalayan fault zone. This 2,000-ton hard rock shield machine, capable of tackling granite with a hardness of 12 degrees, achieved an average daily advance of 15 meters, a 40-fold increase in efficiency compared to traditional blasting methods.

• The Hong Kong-Zhuhai-Macao Bridge undersea tunnel, traversing 16 layers of complex geology at a depth of 48 meters, achieved an accuracy of less than 5 centimeters, significantly reducing the travel time from Zhuhai to Hong Kong from 3 hours to 40 minutes.

• The "Yunqing" TBM at Guangzhou Baiyun Airport traversed a busy runway, precisely controlling ground subsidence to within 0.5 millimeters, setting an international record.

Overseas projects: Conquering the most demanding markets:

• In the first half of 2025, China's TBM exports continued to grow, with overseas market expansion becoming a new growth driver. China Railway Industry signed new overseas contracts worth 1.89 billion yuan, a year-on-year increase of 5.24%. The majority of these orders came from shield machines/TBMs in Western Europe, the Middle East, and Oceania. Exports are expected to reach 170-200 units by 2025, accounting for over 70% of global shield machine exports. Exports cover over 50 Belt and Road countries.

• In developed markets like Singapore and Israel, Chinese shield machines are outperforming established European companies thanks to their high precision.

• In Nigeria, Africa, tunnels dug by Chinese shield machines have eliminated the troublesome "sea view" in Lagos during the rainy season.

• In Dubai, a subway tunnel carved out of the desert has become a symbol of "infrastructure miracles."

Chinese shield machines have also been exported to countries such as Australia and Italy. The "Patigalang" shield machine, with a 15.7-meter excavation diameter, was exported to Australia and is the largest diameter shield machine exported by my country. The world's first green tunnel boring machine "China Railway No. 1237" was exported to Italy for the construction of a high-speed railway tunnel in Sicily, Italy, representing the international market's recognition of China's green tunnel boring machine.

These five "mosts" embody the Chinese people's unwavering tenacity and relentless drive to never give up. Today, faced with new challenges like reliability verification for ultra-deep tunnels, China's shield machines continue to forge ahead. This unwavering drive to never be satisfied is the key to their continued leadership. Their rise has not only reduced China's tunnel construction costs by 40%, but has also propelled global infrastructure into an era of "high efficiency and low cost." Southeast Asia's urban subways, Africa's cross-river tunnels, and Europe's deep-sea pipelines have all been accelerated by their technological breakthroughs. China's shield machines are no longer just tunnel-digging machines; they are the mobile calling cards of "China Bull," carrying China's confidence and strength wherever they go.

Data Description

1. Global market share and export data: Refer to "A Panoramic Analysis of the Tunnel Boring Machine Industry Market Share and Supply Chain," July 24, 2025;

2. China Railway Industry's newly signed contract value data: Sourced from the first-half operating data announcement released by China Railway Industry on July 30, 2025;

3. China-Nepal Railway data: Refer to the relevant report in "China Infrastructure News," May 8, 2025;

4. Haitai Yangtze River Tunnel "Cangyuan" Tunnel Boring Machine data: Compiled from the "Engineering Construction Bulletin," August 11 and 12, 2025;

5. Guangzhou Baiyun Airport "Yunqing" Tunnel Boring Machine data: Sourced from the relevant content in "Municipal Engineering Weekly," August 8, 2025