Several large infrastructure projects are at present in progress in Sweden. A substantial proportion of these are tunnels and other underground construction. At the same time, researchers and practitioners are saying that there is a great need of new knowledge regarding the behaviour of the ground and groundwater during underground construction. After a long discussion by the all the Swedish experts in this field, a new research programme will soon start. In this issue, Sustainability goes below ground. A picture is given of the state of research with the help of researchers and those who commission infrastructure projects.
Cities are spreading out over good agricultural land, areas of unstable ground and the bottoms of old lakes. To an increasing extent, cities are becoming vulnerable systems. They can be easily exposed to landslides and flooding. A structured planning of natural and energy resources is necessary. Issues regarding land use are of key importance for the development of infrastructure, construction and industrial activity. In view of the limited areas available for expansion, there will be a lot more underground construction. Our rocks will to an increasing extent be used for transport, storage, parking areas and garages. Research on infrastructure below ground and in rock is greatly neglected. Estimates nevertheless show that each new input of funds into research and development yields a hundred times as much to society in the form of greater growth. According to a recent review by OECD, “Infrastructure investment is the single largest sector for global growth”.
Geosciences may be considered forgotten in spited of the fact that they concern all of us. They are needed in work on tunnels, rock caverns, gravel, sand, clay, groundwater, metals and in many other areas. Geological Survey of Sweden SGU and the Swedish Academy of Sciences are now working to ensure that geosciences will be introduced into the school system. Researchers at Swedish Geotechnical Institute SGI warn: do not build on soft ground! They are of the opinion that far too little geotechnical information is available when new infrastructure projects are started. The overall costs of damage related to soil and rock conditions in Swedish construction amounts to several billions of kronor every year.
Because of expensive oil and climatic threats, the people of Greenland want to change from fossil fuels to hydroelectric power. A completely new underground hydroelectric plant of 15 MW replaces the existing oil based power and heat plants in Greenland’s second city. The intake and discharge are located at a depth that is not affected by winter ice. Great efforts have been taken to reduce the impact on nature which consists of sand and till some way up the steep hillsides. Owing to the geological uncertainties, the underground construction can be seen as an innovation project. The geological forecasts are constantly updated. Time and money are spent on investigating materials in a tunnel project. Tunneling demands special knowledge. Without such knowledge the project may be expensive in the long run. One wildcard in the game is the chemistry of the groundwater and how this interacts with the tunnel works. During construction and operation, the composition of the groundwater is affected. It is essential to devote greater interest to the water chemistry of the underground than is usual at present, say researchers.
The increasingly common delays and cost overruns in tunnel projects may be due to the difficulties in handling geological information. Information on what is to be found in front of the tunnel face is never complete and adjustments must be made the whole time. Researchers are now developing methods for a continual check on tunneling works.