Gran, J. K., Ehrgott Jr, J. Q., & Cargile, J. D. (2009). Cavity expansion experiments with spherical explosive charges in concrete.
Three experiments were conducted with 1-lb explosive spheres embedded in large concrete cylinders with flatpack stress gages and Dremin loop velocity gages surrounding the charge. In two tests, the charge was far from the boundaries and was fully contained. Radial stresses and velocities attenuated with range by approximately 1/r2.5. In the third test the charge was near the top surface of the concrete cylinder, and reflections perturbed the sphericity of the flow.