ANALYSIS THE EFFECTS OF THE DEGREE OF SATURATION ON THE SLOPES STABILITY USING MODELLING AND NUMERICAL SIMULATION

Abstract

Soil materials have been often considered in saturated condition for landslide analyses, in which
back pore water pressure has been indicated to be a cause of the landslide. In this paper, numerical simulations
are used to analyze the landslide process at the river bank from the viewpoints of unsaturated soil mechanics. A
coupled hydro-mechanical model is adopted to numerically simulate the landslide process. For the mechanical
behavior, the modified Barcelona Basic Model (BBM) is used in order to take into account the hardening and
softening due to mechanical and hydraulic loading and unloading as well as to describe the shear strength via
critical state line. Modified BBM allows the more realistic description of the behavior of soils, and particularly
clayey soils in case these soils are not saturated. The numerical simulation using a modified BBM model is
compared with the model, which does not account for the states of water saturation such as Drucker-Prager model.
Both models are applied to the numerical simulation of the Red River bank in Vietnam. The evolution of
displacements and the inelastic deformation during the infiltration process are discussed based on the simulation
of dry to the rainy season with the changes of water level. With the model, the authors attempt to point out one of
the possible causes leading to the instability of the river bank.