Statistical analysis of pipe pile behavior in soft soil

Statistics of static loading tests for 5470 prestressed concrete pipe piles in soft soil regions are presented in this paper. The data shows that the pipe piles with a diameter of 400mm and 500mm are widely used, which account for 28.21% and 45.79% of all statistical piles respectively. The recommended design value of the length is in the range of 10-45m and the length-diameter ratio should not exceed 90 with regard of the stability of the pile. Moreover, the silty clay stratum is the most common bearing stratum for pipe pile which is usually designed as end-bearing friction pile. For the pipe piles with bearing stratum of silty clay, some important observations can be made. The range of the limiting load capacity is 150-6000kN, corresponding to the pile top stress of 10-30MPa. The concrete strength of the pipe pile is far from the ultimate value under the limiting load capacity, resulting in the initial failure occurring at the pile-soil interface. In addition, the expression between limiting load stratum and pile length is given using polynomial curve fitting, which has higher fitting accuracy. The results of this paper can be used in preliminary design of pipe pile.