ABSTRACT

This paper reports the main results of a project developed in cooperation with National Agency for Cultural Heritage Preservation of Georgia, and aimed at envisaging the stability conditions of the Vardzia Monastery slope (rupestrian rock cut city cave in the south-western Georgia). The site has always been affected by instability processes along the entire slope, including small block falls from the upper breccia layer and large collapses from the middle layer. The study involves: rock mechanics characterization, geo-engineering survey, geo-structural and kinematic analysis, rockfalls modelling, geomatic acquisitions and elaboration. The geomechanical characteristics of volcaniclastic and pyroclastic rocks were determined by means of geomechanical field surveys, rock mass classification through scan lines techniques, and laboratory tests on rock blocks and cores. In order to carry out a semi-automatic detection of discontinuities and to implement mitigation activities, a 3D Terrestrial Laser Scanning survey has been carried out. Potential rockfalls have been simulated by the 3D modelling code HY-STONE. The model, used both with a downward and backward approach, allowed the recognition of most critical sectors belonging to the upper part of the cliff (volcanic breccia) and to provide a support for designing both short and long-term mitigation measures. A general master plan for landslide risk reduction and mitigation measures is actually under development for the entire rock cut city of Vardzia.