Coupled Effects of Burial Depth and Surface Double Cracks on the Uplift Bearing Capacity of Strip Anchor Plates in Red Clay

Prolonged drought can induce shrinkage cracking in near-surface clay foundations, leaving persistent defects that may affect the uplift safety of underground structures before subsequent rainfall events. This study investigates how burial depth regulates the influence of two pre-existing surface cracks on the uplift bearing capacity and failure mechanism of a horizontal strip anchor plate in red clay. A two-dimensional plane-strain model was established in Optum G2 and validated against laboratory pull-out tests under crack-free conditions. Two burial-depth ratios, H/B = 3 and 8, were examined, and 360 cases were generated by varying normalized crack depth (h/B = 0.25–3), spacing (s/B = 0.25–3), and horizontal offset (d/B = 0–6). Under shallow burial, cracks readily intersect the potential sliding zone and the maximum capacity reduction reaches 81.6%, with pronounced transitions around s/B = 1 and d/B = 1. Under deep burial, the principal failure surface remains predominantly a deep elliptical arc and capacity reduction is generally below 15%. Burial depth therefore controls the spatial overlap between the environmentally damaged zone and the anchor-bearing zone. The results provide a mechanical basis for post-drought crack inspection, uplift-safety reassessment, and burial-depth selection. Hydraulic infiltration, suction, moisture evolution, and rainfall intensity are outside the present model.