UNDERGROUND STRUCTURES FOR URBAN SOCIETIES - RISK AND CHANCE

Abstract: During the next 20 years world population will increase from 6.5 billion to 10.5 billion people worldwide. This increase will mainly happen in urban areas and will affect urban societies. It is expected that from nowadays 15 mega cities withpopulation exceeding 15 million, there will be a total of 56 mega cities in the year 2030. As a consequence of this development the amount of underground infrastructure will be multiplied with a factor of 5 to 10. This underground infrastructure will provide mass transports, water supply, waste water disposal, communication pipelines and supply of containers in special tubes for warehouses. Such underground infrastructures will be the only possibility to provide functioning of big cities together with acceptable living conditions in a sound environment and under acceptable social conditions. Due to the fact, that also in the future the work style will be divided and specialized, transportation will remain a topic for urban planners. The need for underground space results from limited surface space. This need can be satisfied by using more and more of the underground space together with overcoming resistance of the public. While in the past there has been an opinion that underground structures are expensive, in the future we will see a development whereas underground structures will be considered as an investment with return to the public rather than as cost. The technological development has been very rapid during the past two to three decades. Conventional tunnelling has been conquering its position successful against an increasing use of mechanized tunnelling. The differences between these two technologies did remain while at the same time the compatibility between the two has been significantly improved. Nowadays we can see more and more projects where both of the technologies are successful used in the same project. While underground structures have been considered in the past of being risky due to some spectacular collapses, the underground industry, led by the International Tunnelling Association, together with the International Tunnel Insurance Group has responded to that development by providing risk management guidelines which nowadays became almost a standard tool in many tunnel construction contracts. By managing the risk of underground structures significant improvements resulted in successful projects, such leading to the conclusion that underground structures are equal risk and chance. The presentation will result in giving examples of such successful projects of today and in the future.

Keywords:

Underground infrastructures , Risk management , Urban societies