AbstractApre`s un bref rappel de l'histoire des ouvrages souterrains de l'antiquitéa`nos jours, les auteurs s'attachenta`l'équilibre entre l'offre et la demande d'ouvrages souterrains. La demande vient de la maitrise de l'e´nergie, de la sauvegarde de l'environnement, de la de´fense civile et du manque d'espace au centre des villes. Les inge´nieurs portent la responsabilite´de rendre l'offre attrayante graˆce aux innovations, mais la base de l'offre est toujours la Nature. La pre´vision des travaux souterrains pour les prochaines de´cennies est divise´e en deux parties. D'abord une extrapolation des ouvrages classiques: tunnels de circulation plus longs et plus profonds sous les montagnes et sous les de´troits, cavernes de porte´e plus grande, recours beaucoup plus large au sous-sol dans les villes. En s'e´cartant davantage des ouvrages classiques, des cavernes vont accueillir des re´servoirs infe´rieurs de centrales de pompage, des re´servoirs pour un stockage saisonnier d'eau chaude, des de´chets radioactifs, etc. Beaucoup d'installations dangereuses devraienteˆtre mises en souterrain, et au voisinage des villes le volume entier de collines ou de plateaux pourraiteˆtre syste´matiquement lotia`trois dimensions pour des usages varie´s. Ainsi le rythme de la construction ne devrait pas aller en diminuant.

RésuméIn order to forecast the evolution of underground works within a few decades ahead, this article provides a short review of their history, from antiquity to the present. It emphasizes the sudden appearance of novel uses as well as the striking reemergence of uses that have been wrongly deemed obsolete. Thus, the authors are aware of venturing into an era of uncertainty.At any time, the works undertaken fit the balance of supply and demand for underground works. Energy conservation, environmental protection, and civil defense—all of which are highly political issues—are the chief components of the demand, together with the lack of space in the city centers.But no demand will arise where the offered supply is insufficiently attractive. It is the responsibility of engineers to make such offers attractive, through novel tunnelling methods, from geotechnical investigations to machines, including analyses. And upstream of any engineer's task, the actual basis for this offer is the geological structure of subsurface space. “Nature, to be commanded, must be obeyed”: Francis Bacon's principle applies here more than in any other field.Extrapolation of today's classical works is investigated in terms of four categories: (1)transalpine tunnels for quicker and cheaper transportation through the Alps, as well as through other mountain ranges in Asia and America; (2)submarine tunnels, following the achievement of Japan's Seikan Tunnel, to provide safe crossings of straits, without regard for weather hazards; (3)rock caverns, which must reach wider spans, following the model of large natural caves in thick limestone beds; and (4) the moreurban underground works, including commercial, cultural, and sporting centers, cold and freezer storage, and civil defense shelters.Farther from the realm of classical underground works, some very large tunnels and caverns have been proposed and more or less studied—e.g. lower reservoirs for pump storage hydropower, hot water reservoirs for seasonal heat storage, underground disposal of radioactive waste, and condensation of vapor from an atomic plant station in the event of coolant loss or some other accident. It must be considered that many hazardous plants, including atomic plants, should be sited underground.Another direction for development is the systematic three-dimensional allotment of the subsurface space inside a hill or beneath tableland. The single-level example from Kansas City has been extended to Minneapolis, which has two or three levels, and to St. John, Newfoundland, which has five or six levels. The Monte Carlo Rock is referred to as a European candidate for such development.In conclusion, whatever the uncertainties about the pace of underground works among the various countries and uses, it would be quite surprising if the volume of such works did not increase within the next decades; for the benefit not only of the tunnelling community, but of the entire human community.