A probabilistic analysis using Polynomial Chaos Expansion method is presented to compute the probability density function (PDF) of the ultimate bearing capacity of a strip footing resting on a rock mass and subjected to a vertical/inclined load. The rock is assumed to follow Hoek-Brown failure criterion. The kinematic approach of the limit analysis theory is used. The results of the vertical load case have shown that: (i) the Geological Strength Index GSI and the uniaxial compressive strength of the intact rock σ_c have the most significant weight in the variability of the ultimate bearing capacity, (ii) the non-normality of the input variables has a significant effect on the shape of the PDF of the ultimate bearing capacity and, (iii) a negative correlation between GSI and σ_c leads to less spread out PDF. Finally, it was shown in the inclined load case that the variability of the ultimate bearing capacity decreases with the increase of the footing load inclination.
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