Numerical Evaluation of Settlement of Strip Footing Resting on Cavity and Weak Soil Profile

Abstract

This study numerically investigates the effects of different subsurface sources of weaknesses within a soil profile on the settlement of a strip footing using the finite element method (FEM). During the first phase of the study, the influences of size, shape, depth, and distance of cavity from the center of the footing are evaluated. It is noted that the settlement of foundation is increased when the cavity is located at smaller depths and closer to its center. It is concluded that there is a critical zone, where the risk level of settlement (especially differential settlement) due to the cavity is high. The depth of this critical zone is found to be 2.5B (where B is the width of the footing) below the simulated loading area. In the second phase of the study, increasing the degree of weakness of a certain low stiffness layer within the soil profile below the loaded area is simulated as another factor that increases the settlement risks. It is shown that the depth of this weak layer highly controls the settlement of footing even if it is situated at depths >2.5B

Keywords

• numerical modeling;
• settlement;
• weak soils;
• cavity;
• strip footing