Analysis of Consolidated Bearing Capacity of Shallow Foundations Based on Characteristics Method

Abstract

To evaluate the bearing capacity evolution of subsea shallow foundations during operation, an undrained shear strength distribution of clay seabed following full consolidation due to preloading was deduced. The characteristics method was used to derive the stress characteristics equation and to evaluate the consolidated bearing capacity of shallow foundations. The influence of preloading ratio, soil inhomogeneity, effective internal friction angle, and foundation dimension on the consolidated bearing capacity of shallow foundations was investigated. The result shows that the relationship between the relative gain in the consolidated bearing capacity of shallow foundations and the preloading ratio is approximately linear. Meanwhile, the relative gain in consolidated bearing capacity is jointly determined by soil inhomogeneity and effective internal friction angle and is not affected by the foundation dimension individually. The accuracy and effectiveness of the proposed method were verified by comparing it with the results of soil-water coupled finite element analysis. Finally, possible errors between the characteristics solution and finite element model (FEM) results were analyzed. It was found that the discrepancy in the pore pressure calculation was the main reason for the disparity in the prediction of consolidated bearing capacity obtained by two methods. This characteristics solution can quickly and accurately predict the growth of consolidated bearing capacity of shallow foundations, which provides important reference for the optimal design of subsea shallow foundations.

Keywords

• clay seabed
• shallow foundation
• consolidated bearing capacity
• characteristics method
• preloading