Why go Underground
( Presentation / Booklet)
 For hundreds of thousands of years, our natural domain has been a principally two-dimensional space : the surface of the ground. Urged by necessity, curiosity, and even by temerity, we have always tried to escape from this space, either by widening it, which is only possible in a very restrictive sense, or by searching to utilize the third dimension, upwards or downwards. In these efforts, we have always encountered great difficulties that have been overcome thanks only to an astonishing tenacity. So it has been and so it still is in the conquest of the continents, the oceans, or outerspace. So it is for the use of underground space. In this field, as in the others, nature provides many challenges and we must doggedly gather our experiences, draw lessons from failures, improve techniques and use all our resources of inventiveness before succeeding. Underground works have always been difficult but this did not prevent their use at a very early stage of human development, as proved by the discovery of underground excavations that are among the first records of human activity. Of course, nature, and not mankind, is at the origin of the first underground works. Grottos and caves are the result of the action of the rain, the rivers and the sea, and vital necessity drove early humans to settle in these natural cavities, no doubt to find protection from the weather and from attacks. On this point, it is tempting to think that humanity perhaps owes its survival largely to these natural habitats. Cavemens' dwellings were an important landmark in the use of underground space by mankind ; with them, the use of the underground became intentional and active. In every age, considerable use has been made of underground structures for mining and defensive purposes. However, the most rapid increase in the use of underground works only appeared in the 19th and particularly the 20th centuries, thanks to the impetus of economic development. During these periods, there was a dramatic increase in underground space use, in mining, in the field of transportation with the development of roads, waterways, and railways , and in the field of hydroelectric facilities. So, since the dawn of human endeavor - more intensively during the recent centuries, and above all during the last decades - numerous reasons have encouraged mankind to use and develop underground space. For a good understanding of these reasons, it is necessary to keep in mind certain fundamental characteristics of underground space.
• First, the underground medium is a space that can provide the setting for activities or infrastructures that are difficult, impossible, environmentally undesirable or less profitable to install above ground. • Another fundamental characteristic of underground space lies in the natural protection it offers to whatever is placed underground. This protection is simultaneously mechanical, thermal, and acoustic. • On the other hand, the containment created by underground structures has the advantage of protecting the surface environment from the risks and/or disturbances inherent in certain types of activities. • Lastly, another important feature of underground space is its opacity. Thanks to the natural visual screen created by the geological medium, an underground structure is only visible at the point(s) where it connects to the surface. But what are the main reasons today which justify a more intensive and a better-planned use of the underground space?
ITA endorsed Publications Papers Guidelines presented by the ITA WG 4 on Subsurface planning : To go underground Right or Wrong. ATTSU 1978 Roundtable session on the subsurface use in developping countries. ATTSU 1982
Videos Why go underground presented by Harvey Parker during the training session in Istanbul - 2005
Other Publications Papers " Development of Urban Underground Infrastructures in the world",Lecture presented by Andre Assis ITA Past-President in 18th National TAC Conference, Edmonton Canada, 2004
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