• 3D rotational wedge failure mechanism yields higher safety factors than 2D analyses, providing more realistic stability predictions for constrained slopes.
• The presence of open and vertical cracks significantly reduces slope stability, highlighting the importance of crack modeling in engineering practice.
• Temperature-dependent shear strength assessment reveals unique response curves for different unsaturated soils, underscoring the need for soil-specific thermal design.
• Integration of particle swarm optimization with limit analysis enables accurate and efficient safety factor computation for complex slope scenarios.