GUANGZHOU, June 30 (China News Service) — Feature: How has China achieved leapfrog breakthroughs in cross-sea passage projects?

— An exclusive interview with Zhang Changliang, Deputy Director of the Shenzhen-Zhongshan Link Management Center

By Cai Minjie, China News Service reporter

After more than seven years of construction, the Shenzhen-Zhongshan Link, a super cross-sea cluster project integrating "bridges, islands, tunnels and underwater interchanges," has officially opened to traffic. Like a swimming dragon diving into the sea, or a long dragon lying across the waves, it adds another cross-sea passage to the Guangdong-Hong Kong-Macao Greater Bay Area from east to west.

How will the completion and opening of the Shenzhen-Zhongshan Link rewrite the transportation pattern of the Pearl River Estuary? What are the deep-seated reasons behind China's continuous breakthroughs in cross-sea cluster engineering technology? Zhang Changliang, Deputy Director of the Shenzhen-Zhongshan Link Management Center, accepted an exclusive interview with China News Service's "East-West Question" to explain the construction code behind this cross-sea project, currently the most difficult comprehensive construction project in the world, as well as its significance for further interconnection within the Guangdong-Hong Kong-Macao Greater Bay Area, and to discuss the construction level of China's infrastructure projects such as cross-sea and cross-river passages.

　　The following is an excerpt of the interview transcript:

CNS Reporter: On the map, the mouth of the Pearl River forms an A-shape, dividing the east and west banks of the Pearl River into two. How will the completion and opening of the Shenzhen-Zhongshan Link rewrite the transportation pattern of the Pearl River Estuary? What "technological codes" does the construction of this project contain?

Zhang Changliang: In the transportation network of the Pearl River Estuary in the Guangdong-Hong Kong-Macao Greater Bay Area, the east bank of the Pearl River comprises Shenzhen, Dongguan and Huizhou in Guangdong, while the west bank comprises Zhuhai, Zhongshan and Jiangmen. Although the east and west banks of the Pearl River are only a few dozen nautical miles apart, the lack of a direct connection means one can only take a detour.

The Shenzhen-Zhongshan Link is the most critical "horizontal" in the main transportation framework of the Pearl River Estuary. Starting from Shenzhen in the east and reaching Zhongshan in the west, it directly connects the east and west banks of the Pearl River with a length of 24 kilometers, building a fast-connecting bridge for the Guangdong-Hong Kong-Macao Greater Bay Area. After the completion of the Shenzhen-Zhongshan Link, the journey between the east and west banks of the Pearl River will be shortened from at least two hours to half an hour, further tightening economic ties and personnel exchanges among cities in the Greater Bay Area, and also promoting technological innovation, industrial upgrading, urban integration and sharing of cultural and tourism resources, helping the city cluster of the Guangdong-Hong Kong-Macao Greater Bay Area achieve deep integration.

Shenzhen-Zhongshan Bridge. Photo by Chen Jimin

During the construction of the Shenzhen-Zhongshan Link, a number of internationally pioneering and internationally leading new technologies, new processes and new equipment were developed. It systematically revolutionized the immersed tube tunnel construction process, further expanded China's internationally leading technological advantage in the field of cross-sea cluster engineering, and provided a Chinese solution for cross-strait passage construction worldwide.

During the construction of the island and tunnel project, the construction team developed and built the world's first intelligent steel shell manufacturing production line, immersed tube transport equipment and systems, and intelligent self-compacting concrete pouring equipment and systems, overcoming *** difficulties such as the manufacturing and prefabrication of immersed tube steel shells and ultra-long-distance floating transport and installation. It was the first time worldwide that a steel shell-concrete immersed tube tunnel was applied on a large scale under the seabed, filling gaps in China's industry across the entire chain from structural design, material selection, equipment development to construction technology, and filling gaps in the world industry in terms of application scale.

CNS Reporter: Looking at recent years, in addition to projects spanning the Pearl River Estuary such as the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Link, China has also undertaken many large projects under construction or already built, such as cross-sea and cross-river passages. In your view, what breakthroughs has China achieved in passage construction technology in recent years?

Zhang Changliang: China is the hometown of bridges and has been known as the "nation of bridges" since ancient times. Chinese bridges basically maintained a leading level in ancient times. After the founding of New China, we strove to catch up and, in more than 60 years, caught up with the world's advanced level. Today, China has not only built a number of technically complex highway and railway bridges with high scientific and technological content, but has also mastered a series of core technologies in the structural design, construction and maintenance of different types of bridges.

At present, in the field of bridge engineering construction, China has built a large number of bridges and covers a comprehensive range of types. In terms of bridge design technology, structural systems, engineering materials and new construction equipment, China has achieved comprehensive innovation. At present, in terms of cross-sea bridge projects and cross-sea tunnel projects, as well as cross-sea cluster projects integrating bridges, islands and tunnels represented by the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Link, China ranks at the forefront of the industry.

Shenzhen-Zhongshan Bridge. Photo by Chen Chuhong

In cross-river and cross-sea bridge engineering, China is in a leading position worldwide, especially in the construction technology of long-span bridges such as cable-stayed bridges and suspension bridges. Long-span bridges currently under construction in China include the south navigation channel bridge of the Zhangjinggao Yangtze River Bridge in Jiangsu, with a main span of over 2,300 meters, and the Shiziyang Bridge, with a main span of over 2,100 meters.

In cross-river and cross-sea tunnel engineering, the undersea tunnel of the Hong Kong-Zhuhai-Macao Bridge, already completed and open to traffic, has a total length of about 6.7 kilometers and is a two-way, six-lane reinforced concrete immersed tube tunnel, and is the world's deepest undersea tunnel (its deepest point is 46 meters below sea level); the undersea tunnel of the Shenzhen-Zhongshan Link, soon to open to traffic, has a total length of 6.8 kilometers and is a two-way, eight-lane steel shell-concrete immersed tube tunnel, currently the world's longest and widest undersea steel shell-concrete immersed tube tunnel. Whether in long-span bridges or in the technical field of long-span and ultra-long tunnel engineering, China is currently at the world's forefront.

Shenzhen-Zhongshan Tunnel. Photo by Chen Jimin

In addition, China has made breakthroughs in engineering materials, construction technology and equipment, providing standards and processes that can be used as references for the construction of similar cross-river and cross-sea passages overseas.

CNS Reporter: In your view, what are the deep-seated reasons behind China's continuous breakthroughs in engineering technology?

Zhang Changliang: From a batch of large cross-river and cross-sea projects built in the Pearl River Delta and Yangtze River Delta regions, such as the Humen Bridge, the Jiangyin Yangtze River Bridge in Jiangsu, the Sutong Yangtze River Highway Bridge, the Hangzhou Bay Bridge, the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Link, to the canyon-spanning bridges that have radiated to the southwest and northwest regions in recent years, China's major transportation projects are advancing toward "leading across the board," and are crossing mountains and seas to go global, lighting up one dazzling "Chinese landmark" after another.

The overall improvement in the construction of China's major transportation projects has benefited from the enhancement of the country's comprehensive national strength and policy support. Over more than 40 years of reform and opening up, all-round economic and social development has meant that engineers are no longer "wanting to do something but unable to do it," but instead have sufficient confidence, experience and resources to "get it done" and "get it done with high quality."

CNS Reporter: There are also many cross-sea and cross-river cluster projects overseas, such as the Chesapeake Bay Bridge in the United States and the Øresund Bridge. For us, what reference significance do the construction technologies of these overseas cross-sea and cross-river cluster projects have?

Zhang Changliang: Before the construction of the Shenzhen-Zhongshan Link project, the most instructive references were the existing cross-sea cluster projects worldwide, such as the Chesapeake Bay Bridge in the United States, the Øresund Bridge, the Geoje-Busan connecting bridge in South Korea, and the Hong Kong-Zhuhai-Macao Bridge. In the early stage, we conducted research on the design, construction parties and construction management of these projects, which provided some references for the construction of the Shenzhen-Zhongshan Link cross-sea cluster project.

Taking immersed tube tunnel construction as an example, in 1910 the United States first used the immersed tube method to build a railway tunnel crossing Detroit, and the Netherlands built the Rotterdam Maas River Tunnel in 1942, the world's first immersed tube tunnel using rectangular box-type concrete tube segments, which became the mainstream structure of immersed tube tunnels after the 1980s. To adapt to the technical characteristics of undersea tunnels such as extra width, variable width, deep burial and large back-silting, the Shenzhen-Zhongshan Link adopted a steel shell-concrete structural form, the first application of this structural form in China. Although there are also steel shell-concrete immersed tube tunnels overseas, their length and width are very short, and there are great differences in force mechanisms and key structures. Therefore, the successful construction of the Shenzhen-Zhongshan Link immersed tube tunnel provides the world with a brand-new construction solution for undersea immersed tube tunnels.

West artificial island of the Shenzhen-Zhongshan Link. Photo by Chen Jimin

CNS Reporter: In your view, in what directions will China's cross-river and cross-sea cluster projects develop in the future?

Zhang Changliang: In recent years, through the construction of the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Link, China has provided "Chinese solutions" to the problems faced by the industry in the design, construction technology and equipment development of cross-sea cluster projects. Now, we have shifted from "how to build" to "how to build with high quality," and to how to make good use of new quality productive forces. To study and demonstrate cross-sea project plans for ultra-long and ultra-deep sea areas such as the Qiongzhou Strait, our technology and equipment need to be upgraded further, and we need to overcome more and more difficult technical challenges. This is also the direction in which Chinese engineers are advancing and striving.

At the same time, in the intelligent construction of cross-sea cluster projects, there will be a complete change from fragmented, extensive and mechanically copied projects toward high quality, high efficiency, cost savings, safety and environmental protection, and intelligence, thereby leading the construction and development of transportation infrastructure in an all-round way. (End)

Interviewee profile:

Zhang Changliang. Photo by Chen Chuhong

Zhang Changliang is currently Deputy Director of the Shenzhen-Zhongshan Link Management Center and a professor-level senior engineer. During his work on the Shenzhen-Zhongshan Link, he was responsible for the construction of the world's first two-way, eight-lane steel shell immersed tube ultra-long undersea tunnel, promoted intelligent manufacturing and smart construction, and formed world-class island and tunnel construction technology. Together with his team, he filled industry gaps in areas such as steel shell prefabrication and immersed tube floating transport and installation, achieved world records including millimeter-level installation accuracy of large tube segments under deep-water conditions, and developed a number of world-first equipment and systems, further consolidating China's leading level in the field of cross-sea cluster engineering.