Underground Structures, Rock Structures and Rock Mechanics from Ancient Era to the Modern Age
ABSTRACT: Usage of underground space is an old habit for human beings since ancient era. Our ancestors have used caves as a shelter for protection from the wild life and nature, and they excavated caves to extract valuable minerals. They also used them as sanctuaries, tombs or for storage of goods. In addition, they built tunnels to be used as assault systems or to underpass fortifications during ancient warfare. Later on, tunnels were driven to supply water to the towns or to protect the towns from floods. They also built them for communication purposes. Though not knowing the exact time when they were first used, natural underground structures which have several interconnections were also built for underground dwelling purposes through the human history. In the following centuries, due to the need of transportation facilities, transportation tunnels were constructed where new excavation techniques were also used. Navigation canal tunnels, railway tunnels and road tunnels were constructed during that period. All these structures were mostly excavated in rocks. The first excavations were performed manually. Later on, fire technique had been used to excavate more easily. This was followed by the methods in which gunpowder, explosives and tunneling machinery were used. By some means or other, ancient civilizations had used fundamental principles of rock mechanics and applied these principles in the construction of the underground structures. Principles of rock mechanics are the sine qua non for all of these structures and facilities. In this review paper, the history and evaluation of rock mechanics will be given briefly and some examples of historical and monumental underground and rock structures will be presented.