For determining the bearing capacity of foundations, the existing investigations have been mainly performed by using a linear yield criterion in shear stress ($\tau$)-normal stress (${\sigma }_n$) domain, for instance, the Mohr-Coulomb (MC) and Tresca yield criteria. However, the yield criteria for most granular soils are generally nonlinear with continuously increasing friction angle at decreasing stress level. In the present research, the method of stress characteristics has been employed to compute the ultimate bearing capacity of circular and strip foundations considering a power type (PT) nonlinear yield criterion which depends on three material parameters rather than two in the MC yield criterion. Rigorous solutions have been generated for both rough and smooth footing bases and the results have been expressed in terms of the variation of the bearing capacity factor $N_{\sigma }$ with the changes in different material parameters and the overburden pressure. The slip line patterns and the variation of the vertical normal pressure below the footing base have also been examined. Further, the effectiveness of the PT nonlinear yield criterion in determining the bearing capacity of foundations has been discussed. The solutions obtained have been found to compare well with different computational and experimental results reported in literature.

为了确定地基的承载力，现有的研究主要是通过在剪应力下采用线性屈服准则来进行的（$\tau$）-法向应力（${\sigma }_{ñ}$）域，例如Mohr-Coulomb（MC）和Tresca产量标准。但是，大多数粒状土壤的屈服准则通常是非线性的，并且随着应力水平的降低摩擦角不断增加。在本研究中，应力特性方法已被用于考虑动力类型（PT）非线性屈服准则而计算圆形和条形基础的极限承载力，该准则取决于三个材料参数而不是MC屈服准则中的两个材料参数。对于粗糙和光滑的基础都产生了严格的解决方案，并以承载力因子的变化表示了结果。${ñ}_{\sigma }$随不同材料参数和上覆压力的变化而变化。还研究了滑移线的模式以及立足点下方的垂直法向压力的变化。此外，还讨论了PT非线性屈服准则在确定地基承载力方面的有效性。已经发现获得的解决方案可以与文献中报道的不同计算和实验结果进行很好的比较。