Estimation of Bearing Capacity of Circular Footings on Sands Based on Cone Penetration Test

In the present paper, the estimation of limit unit bearing capacity $q_{bL}$ of axially loaded circular footings on sands based on cone penetration test cone resistance $q_c$ is examined. There are significant uncertainties in the calculation of bearing capacity using the bearing capacity equation. The selection of the value of the soil friction angle $\varphi$ and of the equation for $N_{\gamma }$ accounts for much of the overall uncertainty. The approach proposed in this study can reduce the uncertainties associated with the bearing capacity equation, as no estimation of $\varphi$ or selection of an equation for $N_{\gamma }$ is necessary. Instead, normalized limit unit bearing capacities $q_{bL}∕q_c$ are calculated from non-linear finite element and cone penetration resistance analyses for various soil and footing conditions. Effects of the relative density $D_R$ , the lateral earth pressure ratio $K_0$ , and the footing size are also addressed. It is observed that the normalized limit unit bearing capacity $q_{bL}∕q_c$ decreases as $D_R$ increases and that this rate of decrease of $q_{bL}∕q_c$ varies with $K_0$ . Values of $q_{bL}∕q_c$ are presented both in equation form and in charts. The values of normalized allowable unit load $q_{b,\mathrm{all}}∕q_c$ at a settlement of $25\mathrm{mm}$ for various soil and stress states are also provided.