At-rest lateral earth pressure, Active lateral earth pressure, passive lateral earth pressure, cohesionless soils, nonlinearity, slip-failure surface, lateral stress distribution, retaining walls, variational limit equilibrium method, compacted soil, critical-state friction, experimental investigation, over-consolidation ratio, particle-scale behavior, micromechanics, plane-strain, silica sand, analytical modeling, constant-volume friction, pore pressure coefficient A, limit equilibrium, static angle of repose.