Critical Dynamic Stress and Cumulative Plastic Deformation of Calcareous Sand Filler Based on Shakedown Theory

Calcareous sand is a special marine soil rich in calcium carbonate minerals, characterized by brittle particles. It is, therefore, widely used as filling material the construction of islands and reefs. In this study, series cyclic tri-axial tests were conducted on calcareous taken from reef South China Sea under different confining pressures stress ratio (CSR). Then, applying shakedown theory, cumulative deformation long-term load aircraft was evaluated. Results showed that with increase effective pressure, stress–strain curves change strain-softening to strain-hardening state; volumetric strain shear shrinkage then expansion continuous shrinkage. three response behaviors load: plastic shakedown, creep incremental failure. With rate defining index, study determined critical CSR statuses found them pressure. The empirical formula for established based fitting analysis pressures, taking pressure variable. At early stage load, samples compression. When resilient modulus grew rapidly number loading cycles continued increase, particles crushed, causing fine fill voids among coarse particles, further compacting increasing samples. Hardin’s breakage potential model adopted quantitatively describe particle before after tests. results indicated produced obvious when small. As increased, extent sample first increased thereafter stabilized. This provides theoretical reference assessment dynamic stability subgrade subjected traffic loads.