Drained Bearing Capacity of Skirted Circular and Ring Footings with Varying Depths of Skirts

In the present study, the drained bearing capacity factors N'c, N'q and N'gamma for rough base circular and ring footings with and without skirts are determined by using the finite element limit analysis (FELA) method. These footings are provided with skirts to increase the bearing capacity and reduce the settlements. The Mohr-Coulomb model and the associative flow rule are used in the analyses. The friction angle of the soil is varied from phi = 0 degrees to 40 degrees with an increment of 5 degrees. The depth of the skirt (D) is varied from 0.5 to 2.0 times the width of footing (B), i.e., D = 0.5B to 2.0B. The evaluated bearing capacity factors are used for the typical assessment of superposition by considering cohesion, surcharge, and unit weight as three separate components and together. The FELA results are compared with those available in the literature which are in good agreement. The typical failure planes are evaluated from the study, which provides the failure mechanism of circular and ring footings with and without skirts. The FELA results are presented in the form of design charts and tables for practical use. The artificial neural network-multilayer perceptron (ANN-MLP) model has been employed to predict bearing capacity factors and demonstrate the importance of input parameters in each case.