AGEC was engaged by an international developer to undertake a due diligence assessment of a site located approximately 55 kilometres north of Varna, the capital of the Black Sea Coast in an area of Bulgaria noted for its seismic and landslide activity. Seismic coefficient for the area was given in published data as between 0.37 and 0.46g
Our preliminary stability assessment report was compiled from desk top work based on the topographical plan, a local consultant’s site investigation preliminary report, borehole data, published values for geotechnical parameters and a review of landslide risk along Bulgarian Black Sea coast. The purpose of the preliminary report was to provide a general assessment of the stability at the site in order to guide the design of the layout of the major development.
AGEC subsequently undertook a site visit and walkover and compiled a detailed report with recommendations for addressing the findings of the walkover. Whilst it was known that this part of the Black Sea coast is susceptible to landsliding, many of the landslides are of ancient origin. This particular site was found to represent the toe of a large landslide complex but the age of the activity of this landslide was not known at the time of purchasing the site. Based on the AGEC walkover the site was divided into landslide stability units where each unit represents a different state/age of landslide activity. A geotechnical design was compiled in order to arrest any further landslide movement and included large scale toe weighting, drainage adits, ground anchors and specifically tailored geotechnical instrumentation.