Effect of Soil and Rock Interface Friction on the Bearing Capacity of Strip Footing Placed on Soil Overlying Hoek–Brown Rock Mass

Abstract

In the present study, the ultimate bearing capacity of a strip footing placed on a soil layer overlying a rock mass layer is determined by considering the interface friction angle (δsr) between the soil and rock mass layer. The lower bound finite-element limit analysis in association with the two conic optimization techniques, namely second-order cone programming (SOCP) and power cone programming (PCP) are utilized to model the failure of the soil and rock mass by using the Mohr–Coulomb and Generalized Hoek–Brown yield criteria, respectively. The variation of the magnitude of ultimate bearing capacity is expressed in terms of the efficiency factor (ξsr) with the different magnitudes of soil layer cover ratio (Ts/B). The different magnitudes of ξsr are determined by varying the rock mass strength parameters and soil friction angle. The results are presented as design charts, which can be useful for examining the bearing capacity of the strip footing by taking the effect of underneath rock mass layer. Failure patterns are also studied in detail for some representative cases to understand the stress redistribution in the soil–rock interface at different depths.