Experimental–Numerical Investigation of Embedment Effect on Foundation Behavior Under Vertical Loading

Abstract

Embedded foundations have different behavioral characteristics in comparison to surface ones. In present study, to evaluate the behavioral aspects of five strip foundations with constant width and different embedment depths in sandy soil under monotonic vertical loading, experimental and numerical finite element (FE) modelings were implemented. Based on experimental results, the growth of foundation depth-to-width ratio from 0 to 1.2 caused the increase in ultimate bearing capacity and vertical stiffness for 33% and 23%, respectively. Moreover, regarding to the observed damages, an attempt was made to present an innovative categorization for dominant failure mode as a function of foundation embedment depth. The result of numerical framework designed in accordance with real material and interfaces properties showed a good agreement with experimental behavioral curves as well as ultimate bearing capacity and vertical stiffness. Achieved from FE modeling, the adequate dimensions for underlying soil model were suggested to eliminate any effect of boundary conditions on foundation vertical loading results. Finally, the validity of a common theoretical expression in literature for anticipating vertical stiffness of embedded foundation was explored. It was concluded that for considered domain of foundation embedment depth, the increase rate of vertical stiffness vs. foundation embedment curve achieved through theoretical expression was more than experimental and numerical results.