INFLUENCE OF THE SEISMIC LOADING DIRECTION ANGLE ON THE STABILITY COEFFICIENT OF SLOPES IN SANDY SOILS

Abstract

The paper investigates the influence of the direction angle of seismic loading on the stability coefficient of slopes composed of sandy soils. The relevance of the study is determined by the high seismic activity in the southern regions of Kazakhstan and the necessity to refine slope stability assessment methods considering the spatial orientation of dynamic forces. The objective of the research is to quantitatively evaluate the variation of the stability coefficient when the seismic force direction changes within the range from 0° to 180°. The analysis was carried out using the limit equilibrium method combined with a pseudostatic approach, taking into account both horizontal and vertical components of acceleration. A parametric study was performed for different values of the internal friction angle and the seismic coefficient. The results demonstrate that the minimum stability coefficient corresponds to inclined loading directions within 30–60°, where the reduction in stability reaches 15–20% compared to the conventional horizontal loading assumption. The obtained findings provide practical recommendations for the design of slopes in seismically active regions.