Constants for an elastic–plastic cap model for limestone

Triaxial fracture tests with overburden pressures ranging from 0.69 to 136 MPa were performed to determine the material parameters involved in a cap model for limestone. Three material parameters A, B and C , were evaluated through Powell's optimization method and the remaining parameters through simulation‐curve fitting procedure. The resulting cap model was tested against separate triaxial fracture and hydrostatic compression tests. Modification of the original hardening function, as proposed by DiMaggio and Sandler, provided an improved fit for the experimental data.