INFLUENCE OF STRIP FOOTING SIZE ON THE ULTIMATE BEARING CAPACITY FORMULA FOR SANDY SOILS

Abstract

For the estimation of the ultimate bearing capacity (UBC) of footings, most contemporary formulas employ a linear yield function in the shear stress-normal stress space. However, it is well known that the general property in the failure envelopes of sandy soils manifests the non-linear effect of the stress level on the peak friction angle. The focus of this research study is the assessment of the UBC of surface strip footings ascribed to the effect of confining stress level and relative density (D_r) on the shear strength of sandy soils. The rigid plastic finite element method (RPFEM), using the confining stress dependence property of Toyoura sand, is utilized in non-linear finite element analyses. The results of the UBC analyses are ascertained to be consistent with those of the centrifuge experiments in the published references. The ground failure domains in the case of the non-linear shear strength model are gleaned smaller than those in the case of the linear shear strength one. The analysis results are compared with prevailing guidelines, for instance, the Architectural Institute of Japan (AIJ) and the Japan Road Association (JRA), which are developed for the mean shear strength property of sandy soils. The applicability of the UBC formula to effective stress analysis is also discussed, and the modified formula is developed.