Avanos municipality (Cappadocia, Turkey) 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. The in-situ investigations 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. The rock is a very soft tuff and it is susceptible to degradation due to process of cycles of wetting-drying and freezing and thawing and creep. An integrated experimental, analytical and numerical analyses and in-situ monitoring program has been undertaken. This program still continues and this paper describes the preliminary findings.