360 GeV/c proton-proton elastic scattering data obtained at the European Hybrid Spectrometer (EHS) are presented. The differential cross sections of elastic and inelastic pp-interactions are studied as a function of the impact parameter. The results are compared to those obtained at other energies. They are interpreted in the framework of a simple geometrical Monte-Carlo model of inelastic collisions considering protons as composite particles having a definite effective radius with valence quarks inside. The model calculations indicate an increase of the effective radii both of protons and of valence quarks and an increase of the proton opacity with increasing energy. Using this model a description of the overlap function for the total cross section is obtained. A mechanism involving interactions of coloured quarks is proposed leading to a splitting of the overlap function for the total cross section into elastic, inelastic and inelastic diffraction components.