Excavation, Moving Forward All the Way - The Beginning and End of China's Shield Tunneling Machine Moving towards the World

Produced by Deep Pupil StudioInterviewer: Our reporter Jiao YangPlanner: Liu Li and Li KunOver the past 20 years, the independently innovative Chinese shield tunneling machine has achieved a perfect comeback from stumbling to advancing all the way, and then entering the world's advanced ranks. There are more and more varieties of shield tunneling machines in China, with more powerful functions, and they are becoming a best-selling "new domestic product" overseas

Produced by Deep Pupil Studio

Interviewer: Our reporter Jiao Yang

Planner: Liu Li and Li Kun

Over the past 20 years, the independently innovative Chinese shield tunneling machine has achieved a perfect comeback from stumbling to advancing all the way, and then entering the world's advanced ranks. There are more and more varieties of shield tunneling machines in China, with more powerful functions, and they are becoming a best-selling "new domestic product" overseas. The latest statistical data shows that as of now, the total number of orders for shield tunneling machines in China has exceeded 5000, with over 4500 machines already manufactured and exported to about 40 countries and regions overseas.

On November 7th, at the Zhengzhou final assembly workshop of China Railway Engineering Equipment Group (hereinafter referred to as China Railway Equipment), the "China Railway 912" and "China Railway 913" shield tunneling machines that have passed customer acceptance are being expedited for disassembly and are about to be shipped to Singapore.

Not long ago, the world's first green shield machine, China Railway 1237, was taken offline from here. It is equipped with continuous excavation technology, rapid mold replacement technology, and will be exported to Italy for use in the construction of the Sicilian high-speed railway tunnel.

This is just a microcosm of the large-scale export of shield tunneling machines in China in recent years. As of 2023, Chinese shield tunneling machines account for 70% of the global market.

In 1995, China first introduced German shield tunneling machines. Over the past 20 years, the independently innovative Chinese shield tunneling machine has achieved a perfect comeback from stumbling to advancing all the way, and then entering the world's advanced ranks.

Drill and Blast and TBM, Two "Fists" to Meet Challenges

Shield tunneling machine is currently the most advanced tunnel excavation equipment, commonly known as "steel pangolin". It integrates high technology such as mechanics, electricity, hydraulics, information, artificial intelligence, and has tens of thousands of components. There are two types of shield tunneling machines, one for soft soil and soft rock tunnels, and the other for hard rock tunnels, also known as TBM (hard rock tunneling machine).

More than half of tunnel projects worldwide use shield tunneling machines for construction.

Sun Yongfu, an academician of the CAE Member, recalled that the first knowledge of tunnel boring machines came from textbooks in the 1950s.

In the 1950s, more than 120 years have passed since the introduction of the principle of shield tunneling. However, Chinese engineering technicians' understanding of tunnel construction still remains limited to the drilling and blasting method.

Using the drilling and blasting method for construction, it is necessary to drill holes and load explosives on the face of the tunnel, then ignite the fire and run to the corner to hide. After the explosion, the supporting arch and concrete should be quickly transported to the newly opened tunnel surface for support, and then the broken rock should be transported out using transportation tools.

The drilling and blasting method is economical and adaptable, but the excavation speed is slow. Until now, a tunnel with a cross-sectional diameter of 10 meters has been constructed using the drilling and blasting method, with an average monthly excavation of only 100 meters.

Is there a better tunnel construction method?

In 1825, under the Thames River in London, Bruno built the world's first shield tunneling method, which was gradually improved and widely used in Europe.

The working principle of a shield tunneling machine is to use a steel structure component to advance along the tunnel axis while excavating the soil. "Li Jianbin, a senior expert of China Railway and former Secretary and Chairman of the Party Committee of China Railway Equipment, explained that the shell of the steel structure component is called a" shield shell ", which serves as temporary support for the excavated and unlined tunnel section, withstanding the soil pressure and underground water pressure of the surrounding soil layer, and blocking groundwater.

Shield, also known as' protection ', refers to the shield shell; 'Construction', also known as' construction ', refers to the assembly of pipe segments.

In a word, excavation, slag removal, lining and other operations are carried out under the cover of the shield shell.

According to geological conditions, shield tunneling machines have types such as soil pressure and mud water balance; According to the size of the tunnel, it is divided into different diameters.

In the 1980s, the spring breeze of reform and opening up was stirring on the land of China.

The constantly emerging new technologies have attracted the attention of the Party Central Committee and the State Council. Senior leaders of Chinese railways are also considering how to make railway tunnel construction catch up with or approach the world level.

In 1987, Sun Yongfu, who was then the Deputy Minister of Railways, was greatly praised when he saw foreign tunneling machines driving at a monthly speed of up to 1300 meters during his inspection of the Gansu Water Diversion Project into Qin, which was constructed by an Italian company.

A few years later, when constructing the Qinling Tunnel, there was a great controversy over whether to introduce the world's most advanced TBM.

In September 1993, the former Ministry of Railways held an expert demonstration meeting in Beijing. Some experts believe that compared to the drilling and blasting method, the cost of tunnel boring machines is too high; Introducing tunnel boring machines is also difficult to promote and apply in the future. In summarizing his speech, Sun Yongfu clearly stated: "In the past, we were familiar with drilling and blasting methods, which was just one fist; in the future, if we master TBM technology, we will have two fists to meet the challenges." Sun Yongfu believes that after mastering TBM technology proficiently, we can improve efficiency and reduce costs.

To improve the level of railway construction in China, it is necessary to absorb advanced technology from the world. After thorough scientific argumentation, the senior management of China's railway has made a major decision to introduce TBM construction for the Qinling Tunnel, while also leading the selection and design.

Shield tunneling machines are typical non-standard designed special products that require customization. In response to the needs of the Qinling Tunnel on the Xikang Railway, the original Ministry of Railways organized experts in design, manufacturing, and construction to determine the main technical requirements for introducing TBM - single track electrified railway, with an open TBM cutter head diameter of 8.8 meters and a unit price of 350 million yuan.

Qinling Tunnel, training to cultivate a group of experts

In July 1997, the 256 meter German TBM arrived at the Qinling Tunnel and was installed and debugged before being put into use.

"When using TBM to build Qinling Tunnel, everyone was very unfamiliar with the selection, design, assembly, commissioning, operation, excavation, diagnosis and maintenance of TBM, as well as the key technology of TBM crossing under different geological conditions." Du Yanliang, an academician of the CAE Member, recalled.

Regarding the core hardware and software technology of TBM in the Qinling Tunnel, German company Weilt prohibits Chinese technical personnel from approaching. This is because at that time, China had developed a mud water type earth pressure balance shield machine with a diameter of 4.35 meters, specifically designed to overcome soft soil foundations, as well as the first half section cutterhead shield machine in China.

They view China as a highly potential competitor and always remain vigilant, "said Zhang Zhiguo, General Manager of China Railway Equipment.

However, as the decision-maker promoting the introduction of TBM, Sun Yongfu's goal is very clear, which is "after we introduce TBM, we must achieve the localization of accessories as soon as possible, and then achieve the localization of the entire machine".

A battle to introduce, digest, absorb, and innovate has begun in the Qinling Mountains.

In order to manage and make good use of this world's most advanced TBM, the former Ministry of Railways organized construction and relevant scientific research units and universities to jointly carry out scientific and technological breakthroughs.

As an academic leader, Du Yanliang, then the Director of the Engineering Machinery Department at Shijiazhuang Railway University, formed a research team and undertook a series of scientific research projects related to TBM excavation technology, monitoring, diagnosis and maintenance technology, and construction technology in unfavorable geological conditions by the former Ministry of Railways. Just by translating and organizing, Du Yanliang and his research team have completed 15 million words of technical documents.

At the time, Wei Xiankun, the engineering commander of China Railway 18th Bureau, wrote a more than 20000 word "Construction Inspection Report for the Fairfield Tunnel" after studying at the Fairfield Tunnel in Switzerland, which played an important reference role in the TBM construction of the Qinling Tunnel.

China Railway Tunnel Bureau has formed a technology research team of 10 people, with an average age of 30 years old. During the TBM assembly process, the technology research team has repeatedly eliminated various complex electrical faults and repaired various electrical components. During the excavation process, the technology research team repeatedly proposed correction suggestions to German experts regarding the unreasonable design issues of the manufacturer, which were adopted.

The high thrust disc shaped hob ring with a diameter of 432mm is often damaged and needs to be replaced. China's scientific research institutions have jointly researched and adopted a low alloy structural steel knife. After running tests, it has been found that in terms of wear rate and service life, it is on par with the products of Germany's Weilt Company, but the price is one-third lower.

The breakthrough of a series of TBM construction techniques and the localization of some supporting components has led to a rapid progress in the excavation of the Qinling Tunnel, setting a record for the highest monthly excavation of 528 meters, with an average machine hour utilization rate of 45%, far exceeding the international average of 40%.

On September 6, 1999, the Qinling Tunnel was completed.

The groundbreaking work and scientific research achievements of the Qinling Tunnel have laid an important foundation for the implementation of other TBM projects in China, and have trained a group of TBM experts, engineers, and technical personnel, "said Du Yanliang.

The successful introduction of TBM into the Qinling Tunnel has ignited a raging fire in the research and development, manufacturing, and promotion of tunnel boring machines by Chinese enterprises. A large number of competitive shield tunneling machine manufacturing enterprises, represented by China Railway Equipment, China Railway Construction Heavy Industry Group Co., Ltd. (hereinafter referred to as China Railway Construction Heavy Industry), and China Communications Tianhe Machinery Equipment Manufacturing Co., Ltd. (hereinafter referred to as China Communications Tianhe), have successively emerged.

Build a "national brand" to catch up with and surpass the "foreign shield tunneling machine"

Using a "foreign shield tunneling machine" has its advantages, but the further it goes, the more problems it poses.

Chinese parties are not allowed to participate in machine maintenance and maintenance, and warning lines are also set up; The progress of maintenance is entirely up to the foreign party, whether the Chinese side says it or not

There is a problem with the drawings! "Once, while processing a simple trailer steel structure component of an imported shield machine, the Chinese side pointed out the error.

The foreign design personnel have offered exorbitant service conditions, requiring them to be responsible for all travel, accommodation, and accommodation, with a daily consultation fee of $600.

Without core technology, there is no voice.

At the beginning of 2000, China Railway Tunnel Bureau made an advanced and significant decision - to build the Chinese people's own shield tunneling machine!

Since 2002, the Ministry of Science and Technology has continuously included the research and development of multiple key technologies for shield tunneling machines in the "863" plan.

In order to construct Shanghai Metro Line 2, the Shanghai Municipal Government has decided to adopt self-developed shield tunneling machines.

China Railway Tunnel Bureau and Shanghai Tunnel Engineering Co., Ltd. each form a project team, relying on the Shanghai Metro Line 2 project to undertake the research and development of the "863" plan shield tunneling machine project.

A shield tunneling machine has over 20000 components, and the control system alone has over 2000 control points.

Li Jianbin led the project team of China Railway Tunnel Bureau, with the goal of "mastering equipment design concepts, mastering core technologies, and conducting independent research and development", to go deep into the tunnel site, conduct pipe by pipe inspections, and verify components one by one. Compare parameters, verify data, and consult information, often fighting until early morning.

The sword edge is sharpened, and the fragrance of plum blossoms comes from the bitter cold.

After joint research and development, the R&D team has developed heat treatment methods for shield tunneling machine cutterheads and tool alloy steel with broad geological adaptability, as well as integrated technologies for shield tunneling machine hydraulic propulsion system and cutterhead hydraulic drive system, and has launched demonstration applications.

In October 2004, China's first subway earth pressure balance shield machine with fully independent intellectual property rights, the "Pioneer" prototype, started tunneling in the western extension section of Shanghai Metro Line 2, breaking the previous monopoly of "foreign shield machines" in subway construction. It was subsequently applied to subway projects in multiple cities in China. In 2006, this product was listed as a national key new product and won the first prize of the National Science and Technology Progress Award.

Chinese shield tunneling workers are taking advantage of the situation and making efforts in new fields.

After completing the key technology research of the "Pioneer" project, supported by the "863" plan, China Railway Tunnel Bureau and Shanghai Tunnel Engineering Co., Ltd. made further efforts and successively completed the development and application of shield tunneling machines such as key technology research on complex sand and gravel formations, composite soil pressure balance, and large diameter mud water balance.

In 2008, the achievements of Chinese shield tunneling machines reappeared. In April, China's first self-developed composite earth pressure balance shield machine was launched, named "China Railway No.1", and successfully applied in the construction project of Tianjin Metro Line 3; In December, at the construction site of the Dapu Road double track tunnel in Shanghai, a domestically produced large mud water balance shield machine with a diameter of 11.22 meters, the "Jinyue", was waiting to be put into operation.

As a landmark achievement of independent innovation and leapfrog development, "Jinyue" was successfully selected for the "Eleventh Five Year Plan" National Major Science and Technology Achievement Exhibition. From then on, China has entered the ranks of major shield tunneling countries with independent design, manufacturing, and construction technology for large diameter slurry balance shield tunneling machines.

In 2012, the scientific research project of "Key Technologies and Industrialization of Independent Design and Manufacturing of Shield Machine Equipment" won the first prize of the National Science and Technology Progress Award.

The pace of innovation never stops.

Circular shield tunneling machines are more mature in technology and facilitate the unified drive of the cutterhead, while rectangular shield tunneling machines do not yet have larger diameter shield tunneling machines due to the difficulty in coordinating the unified drive of the cutterhead. After more than a year of arduous research and development, Li Jianbin's team overcame the problem of unifying the cutter head drive of special-shaped shield tunneling machines. In 2013, they successfully developed the rectangular shield tunneling machine with the largest cross-section in the world at that time and applied it to the Zhongzhou Avenue Underpass Tunnel Project in Zhengzhou City. At the 2018 National Science and Technology Award Conference, the "Key Technologies and Applications for Design and Manufacturing of Deformed Full Section Tunnel Boring Machines" project, led by China Railway Equipment, won the second prize of the National Science and Technology Progress Award.

Build the world's best shield tunneling machine and move overseas

In 2012, Malaysia planned to purchase 10 shield tunneling machines from European companies for the construction of the MRT (Rapid Transit Line) project. After learning about it, China Railway Equipment is determined to take this opportunity to push Chinese shield tunneling machines to Malaysia.

No matter how it is introduced, Malaysian owners are indifferent, "said Li Jianbin, as there is no single overseas application example of Chinese shield tunneling.

China Railway Equipment did not give up, they invited Malaysian owners to visit China on site.

The development speed of shield tunneling machines in China is amazing! We have seen the manufacturing capacity of China Railway Equipment, and the shield tunneling machines manufactured by China Railway Equipment are widely used in well-known big cities in China, with excellent performance. Through visiting one successful case after another, Malaysian owners are deeply impressed.

In 2012, the "China Railway 50" was exported to Malaysia, becoming the first overseas order for Chinese shield tunneling machines. Through targeted design and improved equipment performance, the completion of a tunnel in Malaysia was advanced by 43 days, setting a local shield construction record and establishing the overseas reputation of Chinese shield tunneling machines.

Subsequently, China Railway Equipment opened up markets in over 30 countries and regions known for their high standards, including Singapore and Italy.

Chinese shield workers understand that only by continuously improving their technical level can they go further.

The pedestrian walkway of the T221 section of the Tongshen East Coast Line in Singapore requires a rectangular design. China Railway Equipment has won this order with its independently developed rectangular shield machine. On March 27, 2017, at the 3rd Urban Underground Space and Tunnel Conference in Singapore, the person in charge of the Tangshen East Coast Line of the Land Transport Authority of Singapore shared the construction experience of China Railway Equipment's rectangular shield pipe jacking machine in a report, and praised this innovative product endlessly.

There are more and more types of shield tunneling machines in China, with more powerful functions.

These "Chinese brand" shield tunneling machines with super large diameters, ability to turn, climbing ability, and extreme cold resistance are becoming popular overseas "new domestic products".

On July 3, 2017, with a vast expanse of blue sky and bright sunshine, the world's first shield tunneling machine, the "Maria", was launched at the headquarters of China Railway Construction Heavy Industry in Changsha, challenging extremely cold weather. This is specifically designed to solve shield tunneling construction in extremely cold conditions in the Russian region.

In the 1950s and 1960s, Soviet subway experts helped China plan and design the first subway - Beijing Metro Line 1. Nowadays, many Russians are inevitably questioning the idea of former 'students' going to Russia to repair subways. China Railway Construction Heavy Industry sincerely invited Russian experts to China for inspection. At the construction site of Beijing Metro Line 8, members of the Russian government and construction unit inspection team were amazed by the high level of "Made in China" and "Built in China", and their firsthand experience of "seeing is believing" completely dispelled their previous doubts and concerns.

On June 8, 2017, Chinese shield tunneling machines obtained a qualification certificate to enter the Russian market.

In order to solve the problem of shield tunneling construction in extremely cold conditions in the Russian region, China Railway Construction Heavy Industry has developed five shield tunneling machines with a diameter of 6.25 meters, named after the five daughters from the popular Russian drama "Dad's Daughters", namely Maria, Dalia, Yevgenin, Garina, and Polina. From June 2018 to January 2019, the five shield tunneling machines completed their excavation in the southwest of Moscow.

November 13, 2018, Beijing, National Museum. The "Great Transformation - Celebrating the 40th Anniversary of Reform and Opening up" large-scale exhibition was launched. The "Garina" earth pressure balance shield tunneling machine, as the only representative of the tunneling machine industry, was selected for this exhibition.

Calm is the tide and the banks are broad. Gentle is the wind and the sail is stretching.

Chinese researchers, with their own pride, are practicing the "Three Transformations", making the Chinese shield tunneling machine from scratch, from existence to excellence, from excellence to strength, and from counterattack to become a well-known "Chinese brand" in the world.

The latest statistical data shows that as of now, the total number of orders for shield tunneling machines in China has exceeded 5000, with over 4500 machines already manufactured and exported to about 40 countries and regions overseas.

"The spring of China's shield machines in full bloom has come, China's shield machine power status has been established, and China's shield machine power status is being established!" Qian Qihu, an academician of the CAE Member and winner of the 2018 National Highest Science and Technology Award, said about the glorious history of China's large shield machine development.

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