Ultimate Bearing Capacity of Rock Mass Foundations Subjected to Seepage Forces Using Modified Hoek-Brown Criterion

The experimental data shows that most rocks behave nonlinearly in nature. The modified nonlinear Hoek-Brown failure criterion was considered to investigate the bearing capacity problem of shallow rigid foundations on rock masses subjected to horizontal seepage forces. Two multi-wedge translational failure mechanisms, including symmetrical and non-symmetrical mechanisms were used in the closed-form of the upper bound method of the limit analysis theory. The symmetrical failure mechanism was used in the case of no seepage, while the seepage effect was considered in the non-symmetrical mechanism. The variation of seepage forces was obtained as a function of gradient ratio i(gamma(w)/gamma(sub)) in the developed formulation. The bearing capacity coefficients N-gamma, N-q and N-sigma are introduced for the case of seepage flow condition. The results show that the magnitude of the bearing capacity coefficients reduces continuously with an increase in the value of gradient ratio i(gamma(w)/gamma(sub)). The obtained results were compared and offered for functional use in foundation engineering.