On the morning of August 21, 2023, the opening ceremony of the domestically produced largest diameter shield tunneling machine Yunhe, independently developed by CCCC Tianhe and used for the East Line Tunnel of the Beijing East Sixth Ring Road Reconstruction Project, was held as scheduled, marking the completion of China's longest shield tunneling highway tunnel on both tracks and laying a solid foundation for the early opening of the entire line.

The Beijing East Sixth Ring Road Renovation Project is a landmark project for the sub center of Beijing to create an innovative development axis that stitches together urban functions, effectively weaves urban space, and solves the problem of highway segmentation of cities. The project starts from the Beijing Harbin Expressway Interchange in the south and ends at Luyuan North Street in the north. The total length of the route is about 16 kilometers, including a shield tunnel section of 7.4 kilometers, which adopts a separated double tunnel layout. The shield tunnel has an inner diameter of 15.4 meters and adopts a separated double tunnel layout, with 3 lanes per tunnel. It is currently the longest and largest shield tunnel built in China. Its deepest point is located 75 meters underground, making it the deepest underground tunnel in Beijing.

During the excavation, the Canal faced multiple risk sources above and below the ground, and construction was not easy. The tunnel needs to continuously cross 99 risk sources such as the Beijing Harbin Railway, the Beijing Urban Sub center Transportation Hub, and the Beijing Metro Line 6 in operation, and the settlement should be controlled at the millimeter level. According to Lu Xiaoming, the project manager of CCCC Tianhe East Sixth Ring Road, construction difficulties such as super large diameter, ultra long distance, ultra deep soil cover, and ultra sensitive environment require high reliability and engineering adaptability of shield tunneling machines.

For this reason, CCCC Tianhe has tailored the largest shield tunneling machine in China, the Canal, with an excavation diameter of 16.07 meters. Its total length is about 145 meters, total weight is about 4500 tons, and the localization rate has reached over 98%. It is the first domestically produced 16 meter level ultra large diameter shield tunneling machine, and is one of the largest diameter mud water balance shield tunneling machines developed by China with fully independent intellectual property rights. It is equipped with multiple targeted designs such as the global first long-distance excavation without tool replacement technology and mud water layered reverse washing circulation technology independently developed by CCCC Tiantian, For the first time globally, fiber optic wear detection technology has been applied to shield cutting tool detection, achieving a breakthrough in all key core technologies of ultra large diameter shield machine neck locking, becoming a leading global innovation in shield tunneling technology and setting a new milestone. On June 9, 2023, with the joint development of China Communications Tianhe and the Chinese Academy of Sciences, China's first super large shield tunneling machine's main bearing - "Breaking the Wall" - passed the expert group review led by academicians Qian Qihu, Li Yiyi, and others, marking the completion of the last 2% transformation of the domestic shield tunneling machine, successfully completing the last mile of the national production of super large diameter shield tunneling machines in one go!

Since its official launch in August 2021, the Yunhe shield tunneling machine has made great progress and successfully completed the 7.4 kilometer tunnel excavation tasks of starting, passing, receiving, and crossing risk sources, taking 23 months. During the excavation period, a record of the highest daily footage of 24 meters and the highest monthly excavation of 276 rings (552 meters) was set, and the world's leading level of shield tunneling was achieved with "zero risk of starting, zero leakage of approximately 360000 square meters of tunnel, and zero interference to the ground". Undoubtedly, it is a major engineering construction led by equipment manufacturing, with a strong shoulder. The successful application of the Canal once again demonstrates China's strong strength in the development of ultra large diameter shield tunneling machines, and can also provide important leading and demonstration effects for China's future full utilization of underground space.

The successful application of the Canal is inseparable from our professional shield tunneling technical service team and the supporting services of the system. They provide on-site maintenance services 24/7, predict, analyze, and control fault risks in advance, ensuring that the failure rate of shield tunneling machine operation is much lower than the industry average, and controlling the failure rate within 5%. At the same time, the company adheres to the concept of "global fast service" and allocates the parts warehouse to the project department according to actual needs. In case of emergency situations, the parts of the shield tunneling machine need to be replaced. Conventional parts can be solved within one hour at the earliest, greatly improving the excavation construction efficiency of the shield tunneling machine. Zhongtian Hehe Shield Machine has successively served multiple projects worldwide, including the Yunding Tunnel of Malaysia's East Coast Railway, the Yawan High Speed Rail No.1 Tunnel, the Bangladesh National Father Tunnel, and the Tokyo Bay Tunnel in Japan, and has received unanimous praise from owners from various countries.Editor/XingWentao