“…(a) Theoretical predictions for contact stresses in punch indentation (spherical expansion) and radial de formation (cylindrical expansion) by using Mohr-Coulomb and critical state models; S, punch indentation; C, radial expansion (afterNguyen 1977). ( ) Experimental contact stresses using a variable geometry penetrometer; P, punch indentation; C, radial expansion, (c) Influence of a radial expansion (membrane) on punch indentation (punch) contact pressure (afterHettiaratchi et al (1973)).…”