EFFECTS OF GROUND MOTION INTENSITY IN ASSESSMENT OF SOIL SLOPES IN EARTHFILL DAM

Major earthquakes cause displacements primarily due to seismic accelerations, which affect the frictional strength of underlying soils. It is anticipated that the total displacement of sloped soils in earthfill dams triggered by an earthquake is influenced by the magnitude and frequency of the seismic event. This underscores the importance of numerical simulations that incorporate a broader range of input accelerations. This study examines various earthquake scenarios with differing magnitudes and frequencies that impact a slope of an earth dam prone to landslides. Effective and efficient modeling of soil media is crucial, particularly when pore pressures develop within the soil. In the formulation of the coupled approach, a soil element is represented as a mixture of three components: soil grains, water, and air within the pores. For the mathematical description of the coupled approach, mixture theory is employed, incorporating the concept of volume fractions. In applying the model, the behavior of a soil slope is numerically simulated. The simulation begins with a specified initial degree of water saturation in the soil body, resulting from rainfall. The simulation considers a nonlinear behavior with respect to the water retention curves and material model for the solid state and analysis is performed by ANSYS and PLAXIS. The air pressure is assumed to stay atmospheric in the course of the calculation and matric suction is equal to a negative value of the hydrostatic stress in water pressure. The coupled model allows to take into account the deformations of the soil skeleton and simultaneously considers the pore water pressure change during the earthquake excitation. The boundaries are considered to be of absorbing elements in order to hinder the outward propagating waves. The seismic behavior of the slope gives interesting results considering both deformation and pore water pressure development.