Would caution using this, always consult a geotechnical engineer when not certain. Would also point out that I've seen a couple iterations of this chart and it seems to always be within the context of airfield pavements. Don't know that there's much of a relationship for other applications due to bearing capacity being more of a global response for foundations as Ron mentioned rather than the localized response that you'd be more focused on in slab on grade or pavement design.
