Coupled hydro-Mechanical Analysis of the Construction of Earth Fills Compacted with Collapsible Soils

This paper shows the results of a fully coupled analysis of the construction of an earth fill compacted with an unsaturated soil subjected to structural collapse. Initially, the formulation of the problem is presented based on the finite element method. Then, the constitutive relations necessary to describe the behavior of the phases of an unsaturated soil are described. Emphasis is given on how to appropriately impose the boundary conditions related to the water flow continuity equation during the construction period. An enhanced limit equilibrium approach is used to compute the safety factor, using the stress and pore pressure fields previously obtained in the finite element analysis. The results show that uncoupled analyses can be against safety in such cases, because they neglect load transfer mechanisms that can only be appropriately simulated with a coupled solution.