A surface evolution model is developed for the detonation propagation dynamics of the HMX-based con-ventional high explosive PBX 9501, which relates the normal surface speed D-n to its local surface curvature kappa. Such surface evolution models are important for the understanding and modification of engineering design calculations for high explosive applications. We describe a series of unconfined PBX 9501 slab geometry experiments of varying thickness, and detail how the steady axial detonation speed and detonation front shape data are obtained. A merit-function based calibration process is then described that uses both the PBX 9501 thickness effect and front shape data to parametrize the D-n - kappa propagation law. The time-dependent PBX 9501 Dn - kappa surface evolution law is then applied to detonation wave propagation in two-dimensional circular arc geometries, systematically examining the effect of arc thickness, inner radius, relaxation dynamics to steady-state propagation and confinement. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.