An investigation aimed at categorising and compiling the technical and environmental aspects of cement and chemical grouts has been carried out. This has resulted in a comprehensive compendium, which includes a systematic strategy proposed to be used by the Swedish National Road Administration (SNRA) and the Swedish National Rail Administration in their capacity as civil works contracting authorities. It is intended as a means of support for these Administrations when planning the grouting measures necessary to meet rock sealing requirements and prevent environmentally harmful substances from spreading into the surrounding ground.
Underground construction works are often faced with problems relating to ground water. As a rule, watertightness requirements always apply in Sweden for underground road and railway tunnels. These requirements are set in order to prevent a lowering of the water table, to protect existing installations and building foundations and to ensure a high level of safety in the tunnel. In addition, requirements have been imposed to protect against ground water pollution and other detrimental impact on the environment. The Lundby road tunnel in Gothenburg provides an example that illustrates the high requirements set to prevent water seepage. Recently, major tunnel projects in Scandinavia, such as the railway tunnel through the Hallandsåsen in Sweden and Romeriksporten in Norway have shown the difficulties encountered in maintaining the water table and preventing ground contamination. The combination of extremely high demands on sealing, the large quantity of water being transported through the rock as well as the chemical grouts used to seal the tunnels resulted in major unforeseen environmental damage. At Hallandsåsen this entailed a serious lowering of the groundwater table, extensive surface and ground water pollution, dried-up watercourses and wells, contamination of tunnel workers, local cattle and marine life to noxious substances.
