The idea of a tunnel more than 400km long might seem far fetched, even when it is being proposed for water transport rather than a rail or road link. After all, the main Gotthard tunnel for the AlpTransit project in Switzerland is considered long at just under 60km.
But Han Moning, a personal friend of some of China’s most senior figures, has spent a lifetime working with tunnelling machines and has confidence in the development of technology. He argues strongly for their use in China and, most particularly, believes that the development of the TBM will eventually allow very long tunnels to be bored. A water tunnel of some 70km plus is already under construction in China, he points out (T&TI July 2000).
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There are other good reasons for his interest. China needs to move water from the saturated and flood prone south to the dry north. In their path lie mountains topping 4,000m, part of the great Himalayan and sister ranges of the Tibetan plateau. So long tunnels are vital to tap into the tributaries of the great Yangtse river, the world’s third largest, and pour the water into the Yellow River, historically the “mother” river of the northern half of the country.
Transfer scheme
Official investigations into a transfer scheme have been under way for nearly four decades and include several large tunnels. Recently a number of official statements have advanced the idea of linking the rivers with details of a three stage connection of the rivers publicised. Two of these would link the downstream eastern end of the rivers while the third would tap the high mountain waters.
The Design Institute of the Yellow River Commission is looking at bores up to 130km long for this scheme, says Han. “But the plans would involve construction of many high dams in order to divert the water northwards.” And building such dams in remote mountain valleys at 3,000m altitude would be difficult, he adds.
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By GlobalDataHe has identified instead a number of possible links that would tap into rivers at 3,600m altitude on the southern side and discharge, at 3,400m altitude, into tributaries feeding the Yellow River. They involve passing under mountain cover for up to 1,500m and creating unheard of lengths of tunnel. They are unlikely to become reality at this point.
Western machine experts point to the supply and maintenance constraints on tunnelling machines as the limiting factor on very long tunnels. Not much more than 20km is possible for a drive, however robust and resilient a machine, once the difficulties of supplying power, air and materials to the face are considered. The logistics of mucking out must be thought about too. Perhaps, they say in response to Han’s notions, access points at intervals might make it a possibility.
Leap forward
It should not be forgotten, however, that the seemingly impossible has been achieved in China in the last few decades. Once few would have thought a largely subsistence rural country with a long way to go in modernisation, could produce an atomic bomb, a space programme, and even a commercial satellite service. The determination to open up the western side of the country, now that the eastern seaboard has made huge strides, is encapsulated in the latest five year plan. Investment in tunnels will be a major element in this plan.
Han’s speculations are based on studies of machines made throughout the 1960s and 1970s. He headed a research programme to develop tunnel machines within the country, part of a scientific research programme instigated by Zhou Enlai. This was not as successful as the atomic programme but not without results either.
Han is also well versed in western machines and has pushed for their use on projects in China, despite the expense, rather than use solely traditional drill and blast.
His involvement began with a technical training in Moscow because he was born and brought up in Siberia, the son of leading communists, exiled abroad. He specialised in hydropower studies at the Moscow Power Institute’s hydropower department which meant an obvious assignment to such projects when he returned to China in 1954. First though he needed to learn better Chinese, having spoken Russian for much of his life.
“For two years I was a teacher at the Tsing Hua University,” he explains. And then in 1956 he was assigned as engineer to various construction projects including a major hydropower scheme in Jianxi province creating a, then, large scale, 54m high dam. “Of course now they are 300m,” he says.
In 1960 he moved to Beijing and the Construction Research Institute where one of his colleagues was Li Peng, who had been personally adopted by Zhou EnLai in his youth and who went on to become premier of China in the 1990s. He was a key supporter, among other things of the huge Three Gorges dam project now half way through.
During the early 1960s, he says, Zhou EnLai was pressing for the country to modernise and develop higher technology. One scheme was for research into tunnelling and the use of mechanised systems, and Han was assigned to this task at the Institute, beginning in 1964.
First machine
“We decided to make a machine,” he recalls, though perhaps a ‘shield’ would be a better description. This was for the Ministry of Water Resources & Hydropower and was 3.4m in diameter. “We went on to make 52 different machines up until 1978,” he says. some of which were TBMs.
However “the quality of the machines was not good and in practice most of them did not work well”, says Han. But valuable experience was gained, though coinciding with the period of the Cultural Revolution may not have helped technological research. Various leaders such as Deng Zhao Peng, who favoured modernisation by technology, were in and out of influence.
In the early 1980s “a new machine was made”, Han says. The 5.8m diameter TBM used a cutterhead at the front and had 680kW power. This was tested on a water supply project in the Hebei province, after the engineers had been persuaded to go for a tunnel rather than a channel as originally proposed. The rock was good quality limestone, he recalls, and not prone to falls, and the machine drive allowed the engineers to dispense with a planned concrete segment lining. The drive was 1,480m and successfully completed, though Han does not say over what period of time.
Two more machines were made and the first one went on to a subsequent project.
“But another project at that time saw a machine stopping and starting,” says Han, because of poor quality and a lack of spare parts and consumables. The overall impression gained by the Chinese engineers was that it was better to stick with known methods.
Links with West
By now China was looking to better links with the West to accelerate technological development.
Robbins was given an order for two machines, Han recalls, in 1983. And in the 1990s came some major TBM projects using Robbins and other makes such as Wirth from Germany. The Chinese were very keen to develop a manufacturing arrangement with Robbins for four machines, he says, “but up to now it has not happened.”
He thinks the agreement would work well and points to a deal that Zhu Rongji, the current premier, had made while chief in Shanghai. This was with Framatome and involved six soft ground shields for the metro. The first was imported, the second assembled and the last four had components manufactured and assembled in Shanghai to the French designs. At this time Deng Xiaoping was also restored to authority and was again pressing for technological advance.
From the mid-1980s onwards, Han was concerned with other equipment, as well as tunnelling machines, for the Electrical & Power Ministry. And in 1985 he returned to Russia, working in the Chinese embassy in Moscow as a technology counsellor for three years. The Russians had made some advances with their own TBMs he says, particularly on the Leningrad (now St Petersburg) metro.
In the 1990s Han was partly retired, but he still backs the cause for tunnel machines, trying to persuade what he believes is a conservative minded profession to take them up. As might be expected, traditional drill and blast methods are seen as being much cheaper and can use larger labour forces; a potent argument in a country with 1,200M people.
Han argues that the TBM can allow straighter and more efficient routing of tunnels and is cost effective. He is pleased to see that machine performance is being proven by various contracts which have gone to western contractors under new rules prevailing in the 1990s. Impregilo’s Yellow River water transfer project is particularly notable, he points out.
He has familiarised himself with all kinds of western machines in that time and says he has three champions: Wirth for very hard ground, Robbins for medium ground and Japanese machines for soft ground.
They and others could well be needed in the future. China is likely to build a large number of tunnels in the next two decades; six cities are planning metros including a major extension of the Beijing system if the Olympics are awarded to the city for 2008. And, the campaign to develop the huge western area of the country implies a large number of tunnels for railways metros and roads. Not to mention, of course, those water transfer tunnels.
Related Files
Map of China
Water Transfer Tunnels
