A NEW EMPIRICAL APPROACH TO ESTIMATE THE RATIO OF HORIZONTAL TO VERTICAL IN-SITU STRESS AND EVALUATION OF ITS EFFECT ON THE STABILITY ANALYSIS OF UNDERGROUND SPACES

In-situ stress is one of the most important input data to study stability analysis underground and surface geomechanical projects. The measured vertical has a linear relation with depth. average value unit weight (g) was obtained 0.026 MN/m3 (2.56 ton/m3) using 1041 test results different rocks 0.001 difference 0.027 which reliable coefficient for estimating stress. ratio horizontal (sh) (sv) (K =sh/sv) estimated by theoretical empirical methods. showed that (K) method such as Terzaghi Richard much smaller than 1, estimation K utilizing methods Hoek Brady greater its even approaching 4 in near ground surface. To overcome lack an applicable comprehensive improve shortcomings previous methods, new developed estimate significant number in-situ results. Stability Masjed Soleyman powerhouse caverns carried out numerical modelling five values this study. changes) effect on stresses, displacements, strains, depth plastic zone significantly affect support system design transformer caverns.