Editor's Note: National heavy equipment is the foundation of a nation's confidence. As the "underground aircraft carrier" of the engineering machinery sector, the tunnel boring machine was once called "a money printer for foreigners." Over the past decade and more, Chinese high-end equipment manufacturers represented by CRCHI have, through independent innovation, turned the foreigners' "money printer" into a "machine of national pride" for China!

Recently, the editorial team specially planned the "National Heavy Equipment" series to tell the story of China's major equipment progressing from following and running abreast to leading the world.

# Following #

Pressing Ahead  Catching Up from Behind

In the 1840s, the shield tunneling method and its boring equipment were born and continued to develop in the West. In the 1960s, China attempted to independently develop tunneling equipment, but due to factors such as a weak foundational industrial base, the localization of tunneling equipment progressed slowly.

In the late 1980s, as large-scale urban subway construction was launched in Beijing, Shanghai, Guangzhou and other cities, foreign tunneling equipment and tunnel construction technologies continuously flowed into China. The concept of building tunnels with the shield method became increasingly recognized by the industry, but at that time all shield machines relied on imports, and China's shield machine manufacturing industry faced the pain of being strangled at the throat. When building the Xikang Railway tunnel, two TBMs (full-face rock tunnel boring machines) were introduced at a cost of more than 600 million yuan at the time. Not only was the price expensive, but the service could not keep up and the delivery cycle was long, leaving China constrained at every turn.

In the early 21st century, China officially launched independent research and development of key technologies for tunneling equipment and the localization of complete machines. The first 973 Program project in the shield technology field was approved and implemented, and shield machine/TBM technology was included in the "National Medium- and Long-Term Plan for Science and Technology Development." China's leading enterprises continuously accelerated their efforts. In this process, on the basis of earlier technological accumulation and engineering applications, China Railway Construction invested heavily to establish a shield industry base in Changsha, Hunan, to independently develop domestic shield machine/TBM products, gradually forming a path of independent research and development with its own characteristics. CRCHI thus came into being.

The world's largest high-end underground engineering equipment manufacturing base — CRCHI Changsha Second Industrial Park

In 2010, CRCHI's first earth pressure balance shield machine, "Pathfinder No. 19," made its debut, setting the highest localization rate among domestic shield machines at the time and being successfully applied in the Changsha subway project, which forced "foreign shields" to cut prices by 30% in China. Domestic-brand shield machine products gradually entered the domestic subway tunnel engineering market, and product performance was gradually recognized by the market, opening the curtain on the impressive replacement of imports by domestic shield machines.

# Running Abreast #

Continuous Innovation  Replacing Imports

China's complex and changeable geological environment is a challenge for tunnel engineering construction, and at the same time a testing ground for the engineering application of tunneling equipment, providing the most valuable data for the continuous technical upgrading of tunneling equipment products and construction methods. At the same time, the deepening of underground engineering construction in China has created huge market demand for tunneling equipment.

During the "12th Five-Year Plan" period, following shield machine products and technologies, TBM technology was written into the "National 12th Five-Year Plan for Science and Technology Development" and received support from the National "863 Program" and "973 Program." Among the research achievements, China Railway Construction's large-diameter TBM product was successfully applied in the central Jilin Songhua River water diversion project, completing the tunnel 14 months ahead of schedule. Its main performance indicators reached or even exceeded those of similar foreign-brand products, breaking the history of foreign monopoly on TBMs and setting a record for TBM tunnel construction speed at the same cross-section in China.

During excavation, the first domestic large-diameter open-type rock tunnel boring machine (TBM) achieved a maximum daily advance of 86.5 meters, a maximum monthly advance of 1,209.8 meters, and an average monthly advance of 661.6 meters, setting a new domestic record for open-type TBM construction. It set the record for construction with the same TBM cross-section: the TBM availability rate averaged 94.70% monthly and reached as high as 98.06%, while the TBM utilization rate averaged 56.85% monthly and reached as high as 66.86%. The TBM construction level reached the international leading standard.

The first domestic large-diameter open-type rock tunnel boring machine (TBM), supported by the National "863 Program," rolled off the production line at CRCHI

As the domestic shield machine/TBM industry continues to grow and strengthen, with technological research and development strength and market competitiveness continuously improving, the domestic brands' share of China's newly added market quickly rose to more than 90%. Product types and engineering track records have been continuously enriched, and domestic tunneling machine brands and industrial bases represented by CRCHI have continuously demonstrated their value and set new manufacturing legends.

"Jinghua," the largest-diameter domestic shield machine

Today, conventional domestic tunneling machine products have achieved fully independent design and manufacturing, covering infrastructure and energy fields such as subways, railways and water diversion. Product types and specifications have gradually become more complete, and series have been continuously improved. Product types include shield machines, TBMs, pipe jacking machines, multi-mode tunneling machines and others, enabling horizontal, inclined and vertical excavation, with a full series of diameters from 0.5 meters to 23 meters. Cross-section shapes have expanded from the conventional single circle to special shapes such as rectangular and horseshoe-shaped.

The first domestic permanent-magnet-driven rectangular pipe jacking machine, independently developed by CRCHI, successfully rolled off the production line in Changsha, Hunan

Through the efforts of domestic tunneling machine manufacturers, domestic tunneling machines have risen against the market trend and overtaken competitors on the curve. The world's first inclined-shaft dual-mode TBM, the world's first permanent magnet synchronous drive shield machine, the world's first large-depth variable-diameter open-type TBM, the largest-diameter domestic shield machine, the first domestic large-diameter open-type TBM, the first domestic double-shield TBM... a large number of major technical equipment have earned the halo of being the world's first or China's first, supporting a new height for Made in China, and a large number of flagship products have reached world-leading technical levels.

# Leading #

Rooted in China, Serving the World

Entering the "13th Five-Year Plan" period, domestic tunneling machine manufacturers have continuously increased investment in technological research and development, shortened new product development cycles, continuously improved product technical performance indicators, upgraded and transformed processing and manufacturing capabilities, innovated and optimized product engineering application service methods, and vigorously expanded product application fields. Domestic equipment has occupied an absolute advantage in performance, cost, quality, after-sales service and other aspects.

CRCHI's "Five Golden Flowers" shield machines exported to Russia

CRCHI's 11-meter-class large-diameter earth pressure balance shield machine exported to Russia

At present, Chinese tunneling machines have been successfully exported to Russia, Turkey, Singapore, the United Arab Emirates, Italy, France and many other countries and regions. In 2021, CRCHI ranked 1st among the world's top 5 full-face tunnel boring machine manufacturers, 30th among the world's top 50 construction machinery manufacturers, and 5th among Chinese construction machinery manufacturers.

As China's "Belt and Road" initiative continues to advance, more and more domestic tunneling machines are going abroad and toward the world, writing a new chapter for Made in China and creating better lives for local people.