Maybe. Color me skeptical on this one.
However.
They should try sideways-looking x-ray/gamma rays to see the entire cross-section. If I were the pyramid contractor, I’d build the outer walls of expensive, hard-to-cut-and-fit-transport-rock, and the inside of rubble and sand. Line the small walkways with rock.
wouldn’t rubble be prone to subsidence due to great vertical pressure due to great load? and sand be prone to some compaction, as well as liquefaction in inclement weather and escaping through narrow cracks in outer walls over time? in fact sand due to lack of rigidity of form could redirect the load vectors to the outer walls from the inside, introducing a new collapse mode? just wondering, not a civil engineer.