A multilayer boundary element method (BEM) framework for fighter-aircraft loading on damaged war-reserve highways

War-reserve highways provide critical backup operating surfaces when conventional airbases are unavailable, yet fighter-aircraft operations on damaged pavements involve complex shear loading, seasonal stiffness variation, and residual blast damage. This study develops a damage-conditioned multilayer boundary element method (BEM) for rapid structural assessment of damaged war-reserve highways, supporting identification of vulnerable zones and prioritization of inspection and rehabilitation. The proposed boundary-source stress-transfer framework couples nonuniform dual-tire normal and tangential tractions with multilayer stiffness transfer, seasonal compliance, spatially distributed blast damage, crater-edge localization, and stiffness degradation. Dynamic landing and repeated-sortie measures are derived from the mechanical response to support recovery assessment. The formulation reproduces the reference multilayer pavement response with a depth-integrated normalized residual on the order of 10⁻³. Under fighter-aircraft loading, mean shear stress at the first interface increases from approximately 0.030 MPa in winter to 0.038 MPa in summer, while post-blast damage reduces minimum local stiffness retention to approximately 0.13. The damaged summer condition produces the most adverse structural response. The framework establishes a mechanically interpretable connection between aircraft loading, blast-induced degradation, stress transfer, interface demand, recovery assessment, and short-term runway operability.