Vertical Bearing Behaviour of Large Diameter Belled Pile in Collapsible Loess

Measurements were made for 4 large diameter cast-in-place belled piles in collapsible loesswith instruments on shafts and toes.Influences of immersion collapsibility on pile vertical bearingcapacity were analyzed.Law of variation in negative skin friction was obtained.A“3-stage method”foranalyzing load transfer mechanism of large diameter pile during time of immersion test is presented.