Some historical references on TU154 say that original design idea (before the drawing board) included ability to operate from unpaved runways, however TU154 was never operating from unpaved runways except for a couple of emergency landings and probably some test flights.
Oversized strong landing gear with extra number of wheels used to achieve low ACN (as most soviet paved runways had very low PCN) and durability for soviet less-than-perfect quality of pavement.
Unpaved runways could be different... You remember 727s used to operate from reasonable gravel and show runways. For real hardcore unpaved job USSR had Antonovs, while Tupolevs were more about bombers and mainline pax.