Abstract:On the basis of the results of the tensile static load test of a large diameter steel pipe pile in Yantian Port and the finite element method,the tensile bearing characteristics of the steel pipe piles in the breccia geology are studied.The results show that by the finite element method,the axial tensile ultimate bearing capacity of SZ1# test pile is 2,297 kN,which has a surplus of 35% compared with the designed tensile bearing capacity of 1,700 kN.The friction coefficients between fully weathered breccia and strongly weathered breccia and steel pipe piles are 0.38 and 0.60,respectively.After the pile is loaded to failure,even if the pile top load increases,the axial force of the pile shaft in the soil section will not increase.At this time,the axial force curves of the pile shaft in the soil section overlap together under different loads.The tensile-lateral friction resistance of the steel pipe pile in fully weathered breccia and strong weathered breccia are 54.29 and 60.81 kPa,respectively.In fully weathered and strong weathered breccia,the relationship between the side friction resistance of the steel pipe piles and the relative pile-soil displacement of approximately follows a softening model and a hyperbolic model,respectively.While in medium-coarse sand and residual soil,it presents a bilinear hardening model.