Geoengineering evaluation of man-made antique underground structures improves and provides important information on such structures. Harran City in Şanliurfa Province of Turkey was constructed probably during Sumerian period BC 3000 (5000 years BP). The building stones consisting of limestones of Harran City were extracted from open-pit and underground quarries known as Bazda quarries. Bazda antique underground quarry pillars suffer some structural stability problems in terms of splitting of high pillars, roof falls, plane or wedge sliding and large sinkholes. The authors have initiated a collaborative integrated research program to map the antique underground quarries having working levels up to four floor, in-situ rock characterization, identification of stability problems, some geomechanical properties of surrounding rock. This paper describes the first preliminary studies on Bazda antique underground quarries and discusses its implications in modern geomechanics and geoengineering.
The long-term performance of underground openings is of great importance for civil engineering utilization and also the nuclear waste disposal. Therefore, the geoengineering evaluation of man-made antique underground structures improves and provides important information on such structures. There are several geoengineering studies on such antique underground structures in literature. Turkey also has a number of antique underground openings, such as those in the Cappadocia Region and in Şanliurfa Province. Harran City in the Şanliurfa Province was constructed probably during Sumerian period BC 3000 (5000 years BP). The building stones of Harran City, where there is no rock outcrop, were extracted from open-pit and underground quarries in Tek-Tek Mountain and they are called as Bazda quarries, which are the oldest underground quarry known in Turkey as well as in the world. These quarries are about 7–8 km away from the city and the extracted stones are Eocene aged limestone. Stone blocks from Bazda quarries were used in the construction of Harran ancient city, the temple of Moon and Sun God and the nearby historical Hanel Ba'rür caravanserai and Şuayb City. Underground rooms in Bazda extend more than 50m and pillars are mostly in rectangular or nearly square shape. These quarries have greatest importance for both underground excavation techniques in the past as well as the long-term performance of underground mining.