Evaluation of Bearing Capacity of Strip Footing on Grouted Rockmass Using FELA

The foundation of structures placed over weak rockmass is treated by grouting as one of the techniques which is widely used. In this study, the bearing capacity of strip footing placed over rockmass which is treated with grout is determined using finite element limit analysis (FELA). In FELA, the Hoek and Brown failure criterion is used for rockmass and results have been presented as bearing capacity factor N_σ0 for rockmass considered as weightless (γ = 0). The N_σ0 is evaluated for different Geological strength index (GSI), Hoek and Brown material constant (m_i), and uniaxial compressive strength (UCS) of rockmass. This study attempts to examine the effect of grout in rockmass with varying spacing between grouts, grout hole length (L)-to-footing width (B) ratio, i.e., L/B, the ratio of UCS of grout to rock (σ_g/σ_ci) on N_σ0 of strip footing. The effect of grouting within the width of the footing and extended to some distance from the edge of the footing on the N_σ0 is also evaluated. Results are presented as design charts of bearing capacity factors with reference to different rockmass properties for its use in practice.