Seismic Risk Assessment for the Territory of Armenia and Strategy of its Mitigation

The original methods of seismic risk assessment based on the main factors, defining the high level of seismic risk in Armenia, are used in this paper. Based on the analysis carried out, an assessment is made about the fact, that the capital of Armenia, Yerevan, is the most risk exposed area. A strategy for seismic risk reduction, derived from local peculiarities and the level of seismic risk, is presented. Improving the resisting of existing buildings and constructions to seismic damage, based on the grounds of new technologies elaborated by NSSP RA, is emphasised in this strategy.     

Further Development of the Three-Dimensional Hoek–Brown Yield Criterion

The original Hoek–Brown failure criterion was first introduced in 1980. Since then, it has been further developed and used in different rock mechanics applications. The main advantage of the Hoek–Brown criterion is that its input data are determined from the uniaxial compressive strength, mineralogy and structural properties of the rock. However, its application in the petroleum industry has been limited, partly because it does not take account of the intermediate principal stress in a three-dimensional stress state. In 2005, Priest introduced comprehensive and simplified versions of a new three-dimensional Hoek–Brown yield criterion, which was developed by combining the two-dimensional Hoek–Brown and three-dimensional Drucker–Prager criteria. Until now, direct analytical solutions have not been developed to solve the governing equations and numerical solution strategies have been applied. This paper presents and validates an explicit solution for the comprehensive three-dimensional Hoek–Brown yield criterion, which can be combined with numerical stress modelling codes.