Estimate the Bearing Capacity of Full-Scale Model Shallow Foundations on Layered-Soil Using PLAXIS


  • Sarah Abdul Hussein Mandeel, Haider M. Mekkiyah, Abbas Fadhil Ibrahim Al-Ameri


in the presented work, a parametric study is conducted with the use of finite element method (FEM) to elaborate the behavior of full-scale foundation resting on the layered soil within vertical concentric loading that simulates the field conditions more accurately. The parameters include the thickness of soil layers, friction angle, cohesion, and the width of foundation which were varied to study their impact on the bearing capacity related to layered soil. The total number of models solved were (158). Different cases such as clay layer overlying sand layer, the sand layer overlying clay soil, there are 2 clay layers with different values of cohesion have been analyzed through varying the thickness of the overlying stratum (H). The behavior of the foundation resting on the homogenous layer was analyzed as a base model. With regard to the case of sand layer overlay clay layer, it was found that the increase of relative density regarding upper sandy layer,the first layer’s thickness and the foundation’s width result in increasing the bearing capacity while in cases of clay layer overlay sandy layer the bearing capacity decreased with decreasing the cohesion of the clay and it was shown that the footing size has no effect. For the two-layer of clay soil with different parameters, it was noticed that bearing capacity depends upon the cohesion of the first layer. Based on the result obtained, two statistical equations are derived with the use of regression analysis for predicting the ultimate bearing capacity. Generally, this is executed through assessing the dependent variable (bearing capacity regarding two soil’s layers) on the basis of independent variables (the ultimate bearing capacity related to the first layer, the thickness of the first layer to foundation width (H/B), the width of the foundation (B) and the shear strength parameters of the second layer.
Keywords: Full-Scale Foundation; Layered Soil; PLAXIS 3D; Ultimate Bearing Capacity; Regression Analysis