The stability of an underground congress center in soft tuffs through an integrated in-situ monitoring, experimental, analytical and numerical methods (Cappadocia, Turkey)

摘要

There are numerous antique and modern rock structures in the Cappadocia Region of Turkey, which are excavated by mankind. In addition to historical and archaeological characteristics of the rock structures in the region, their long-term behavior is also an important data source in terms of rock engineering. Even today, modern underground openings of different sizes and shapes in the region are being used for multi purposes. In several locations of Cappadocia, some stability problems of different scales were observed. One of the modern underground openings in the region is the Avanos Congress Center. Avanos municipality planned to utilize a hill remnant from an abandoned quarry as an underground congress center in 1980s. The rough excavation of the congress center was done. However, the construction has not been completed due to financial problems and also the change of governors and mayors. The excavation has been completed by more than 10 years. The surrounding rock, in which the Congress Center has been excavated, is a very soft Cappadocian tuff and subjected to degradation of material properties, resulting from cycles of wetting-drying and freezing and thawing processes. Furthermore, it is known from previous experimental works that the tuffs of Cappadocia exhibit strong creep behavior. The observations done by the authors inside and outside of this uncompleted congress center revealed that there are some new fracture formation and propagations at several locations in the underground halls as well as at the perimeter of the hill. These cracks are easily recognizable during drying process of rock soon after a rainfall.