Theoretical Analysis and Field Investigation on Bearing Characteristics of the Long-Core SDCM Pile Under Vertical Load in Multilayered Soil

The long-core SDCM pile is a typical type of stiffened deep cement mixing (SDCM) pile, it could be widely exploited in coastal geotechnical engineering because of its high bearing capacity, low settlement, green, and economic advantages. The long-core SDCM pile is constituted by a PHC pipe pile and cemented soil, the height of the PHC pipe pile is upward than the depth of the cemented soil reinforcement. This study implements a theoretical approach to load transfer analysis of the long-core SDCM pile under vertical load in layer soil. Herein, the shear constitutive models of the DCM pile-PHC pipe pile interface and the fictitious soil pile-PHC pipe pile interface are double exponential models, the compression constitutive model of the soil under the pile and the shear constitutive models of the DCM pile–soil interface and the fictitious soil pile–soil interface are ideal elastic–plastic models. The results obtained from this calculation model can match well with the data from on-site tests and other analytical solutions. The theoretical model is used to analyze the key parameters L_D/L_P, D_D/D_P, E_c, and E_p of the long-core SDCM pile. The L_D/L_P and D_D/D_P are the critical parameters affecting the bearing characteristics, and the minor settlement is affected by the changes of E_c and E_p.