Author: Mehmet SARI, Fuat ÇÖMLEKÇİLER
Publishing Date: 2007
Volume 22 Issue 1-2
Ihlara valley, which is one of the important natural and historical monuments of our country, covers 52 km2 areas on the central Anatolia region of Aksaray city. It is unique in the world in terms of geomorphology, volcanism, hydrothermal activity, history and culture. In this region, the canyon like valleys have been formed since millions of years activities of drainage system of Melendiz river by cutting the above hard ignimbrite shield and the below soft tuff formation and ongoing erosion by atmospheric factors. Kızılkaya ignimbrite has well seen at the north of Kızılkaya village and it was named first time after Beekman (1966). It is usually whitish gray in color, but the weathered surfaces may appear as orange to purple. It has been observed that the table like and columnar structure of Kızılkaya ignimbrite are facing the problems of splitting and fallen blocks on the cliffs due to systematically developed cooling joints and other joints and fractures formed as a result of effective atmospheric conditions. Description of a rock mass is developing a representative model for the geologic, physical and mechanical properties of the rock mass. The most important phase in this process is to quantitatively describe the discontinuity parameters observed in the rock mass in question. In this study, it is aimed to success engineering description of Kızılkaya ignimbrite by taking into account of parameters collected from 75 discontinuity measurements. These parameters include orientation and slope, aperture, persistence, spacing, roughness and wall strength of discontinuities. On the average, discontinuities have a dominant direction of NE-SW with a slope of 87.5o SE, 4.5 cm aperture, 23.6 m persistence and 3.44 m spacing. Schmidt hammer tests were conducted on the field and it was found that Kizilkaya ignimbrite is slightly weathered with a rebound value of 46.8 on fresh surfaces and 39.3 on weathered surfaces. Joint-wall compressive strength was calculated as 50.3 MPa. According to Rock Mass Rating (RMR) classification system (Bieniawski, 1989), the ignimbrite rock mass is finally described as good.
Key Words: Ihlara valley; Kizilkaya ignimbrite; Schmidt hardness; Joint-wall strength; RMR classification.