Numerical Solution for Heave of Expansive Soils


Civil Engineering, Khaje Nasir Toosi University of Technology


A numerical solution for heave prediction is developed within the context theories for both saturated and unsaturated soil behaviors. Basically, lowering the potential level of compressing on a saturated layer will cause heaving due to water absorption. This water absorption is in an opposite way, similar to water dissipation as what happens during unloading in consolidation process. However, in unsaturated layers any change of the stability of potential energy level wilt cause the tendency of change in particle interconnection forces. So, any change by either distressing or the variation of moisture ratio will lead to soil heave. In this paper a finite element solution is employed for predicting the heave in saturated soil similar to unloading in consolidation. Also, in the case of unsaturated soil, equivalent soil suction as negative pore water pressures is applied to soil elements as equivalent nodal forces. To show the potential of this method, test results were compared with those obtained from computations. These comparisons show that the presented method is capable of predicting the heave phenomenon quite well.