Based on the field testing results of two large-diameter filling piles in soils of sandstone and mudstone under a power plant

the load transfer mechanism and vertical load bearing behavior of the piles are discussed.The analysis shows that the piles mainly behave as frictional ones and their vertical load bearing capacity is mainly provided by side frictional resistance.A method is presented for identification of the axial load bearing capacity of large-diameter filling piles in soils of sandstone and mudstone by controlling the pile settlement.