Jenny Yan speaks of tunnelling in China 18 Apr 2019

Professor Jenny Jinxiu Yan is currently one of four Vice Presidents of the ITA. During the coming ITA General Assembly, on Wednesday 8 May 2019, in Naples, the new President of the International Tunnelling and Underground Space Association will be elected for the next three years. This time, the election will be very exciting as Jenny Yan of China and Eric Leca of France will compete in the Presidential election. Both candidates have an impressive background and are well known as heart and soul tunnellers. With Yan there is not only the prospect of the first woman President but the first woman to stand for the post in the history of the international tunnelling association. Yan is also representing China as the country with the greatest degree by far of tunnel construction activities worldwide and is active within the national and international tunnelling family.

Jenny Jinxiu Yan welcomes conference delegates in Chuzhou, China

Yan has been involved in the tunnelling industry for more than 30 years and is also currently Vice President of the Chinese Tunnelling and Underground Works Society (CCES) and is Deputy General Manager of the China Railway Academy Company. As the team leader for research, consulting and design, she has been involved in the most challenging railway, highway, metro and water tunnel projects in China, Malaysia, Laos, Nepal and Morocco and has provided technical support for tunnelling projects in many other countries, especially for the early project stages. Yan has delivered nearly 30 international keynotes, lectures and presentations over the past five years in Asia, Europe, North America and Latin America.

A discussion with Yan immediately quantifies the extraordinary extent of tunnelling activity in China since the country started to open up 40 years ago. By the end of 2017, China had built and put into service 127,000km of railway, including 25,000km of high-speed connections, with 14,700 tunnels on the lines adding to a total of 15,781km. Of 4.77 million kilometres of highways built, there are 16,281 tunnels totalling 15,240km.

The Queershan Tunnel changes the most dangerous road in China into a comfortable ten-minute drive

Transit growth in China continues and has accelerated in recent years. By the end of 2017, there were 165 rail-transit lines in 34 cities totalling 5,033km with 3,884km underground. “Rapid transit is ideal for China’s big cities and is unchallenged in its ability to transport large numbers of people at high frequency and quickly over short distance,” said Yan, “and they avoid traffic jams.”

“The progress of tunnelling in China would not have been possible without the knowledge and experience sharing and the strong support from the international tunnelling industry,” said Yan. “All the involvement and contributions are important for the progress and it is very much appreciated by the Chinese industry. Meanwhile, the experiences and lessons learned by the Chinese over the past 40 years are very costly and of value to countries planning similar projects. In return, we are ready to share these experiences internationally, through conferences, symposia, workshops and other media, like what we have been helped in the past.”

The following are some of the outstanding examples of rail and highway tunnels built by Chinese contractors in China and overseas.

At 32.7km, the Guanjiao Tunnel is the longest railway tunnel in China

Queershan highway tunnel

The Queershan project conquered a great number of technical problems during construction. Aligned on the National Road 317 (G317), built in 1951, the tunnel is part of an important transportation route to the high altitude and cold plateau regions of Tibet. Due to 10 months of snowfall per year and natural events including avalanches and landslides, the Queershan Mountain section of G317 is known as the most dangerous road in China.

At an altitude of 4,378m above sea level, the 7km long tunnel and its 7km long pilot tunnel, is the highest long highway tunnel in the world. The tunnel was completed 15 years after the launch of the project and opened to traffic in September 2017. Vehicles now pass through the Queershan in about 10 minutes and no longer have to navigate more than two hours on dangerous mountain roads.

New Guanjiao railway tunnel

The 33km long New Guanjiao railway tunnel is a key project on the second line of the Xining-Golmud section of the Qinghai-Tibet Railway. It is the longest railway tunnel in China and built again at high altitude, the new twin-tube tunnel, with a single track in each tube, was an epic undertaking. Electric freight and passenger rail services running at design speeds of up to 160km/hr, reduces the travel time for the tunnel section from two hours to 20min and greatly boosts the economic development of Qinghai Province and the Tibet Autonomous Region.

Qamchiq railway tunnel shortens travelling time in Uzbekistan

Qamchiq railway tunnel, Uzbekistan

China and Uzbekistan worked together to build the longest railway tunnel in Central Asia. Completed and put into operation in June 2016, the 19.2km long tunnel goes through the Qurama Mountains and is part of the 169km long Angren-Pap railway line, a major state project by Uzbekistan to connect the capital city Tashkent with the eastern city of Namangan. The travelling time for the section of the tunnel is shortened from 2.5 hours to 17 minutes. Although excavation difficulties were encountered, the project was completed in 900 days and nearly 100 days ahead of schedule. It was a major contribution to the national economic and social development of Uzbekistan.

Along with the tunnels completed and in service, about another 20,000km of tunnels are to be built in the near future. Most of them are quite challenging, since the easier ones have already been implemented. “The challenges include not only the big size of the tunnels, such as super long tunnels, very deep tunnels, large cross section tunnels, tunnels at very high altitude, but also tunnelling in very complex conditions, such as tunnelling in active faults, extreme sequencing ground, permafrost, high geothermal ground as well as in remote locations,” said Yan. “China will need help and involvement from the international tunnelling industry to overcome these challenges together.”

Jenny Jinxiu Yan on site

“My first involvement in the ITA was in 1990, during the 16th ITA General Assembly in Chengdu, China, which is nearly 30 years ago. I deeply understand the extreme importance for international exchanges and cooperation, in which ITA plays a key role. I have been a link between the Chinese tunnelling industry and the ITA for many years.”

The Chinese Tunnel and Underground Works Conference (CTUC) is organized every two years, with the most recent in November 2018. For the past two events, international sessions were jointly organized by CCES (China Civil Engineering Society) and the ITA and five ITA Presidents and Past Presidents gave lectures in the session of 2016 and major tunnelling projects worldwide have been addressed in 2018. The CTUC has grown rapidly, in line with the experiences and lessons to be shared from the vast number of projects in China. The number of participants of the CTUC has also been increased from 1,300 in 2016, to 1,700 in 2018, and to an anticipated 2,000 or more at CTUC in 2020. In 2020, the CTUC will be turned into a full international conference.