Numerical Simulations and Full Scale Behavior of SDCM and DCM Piles on Soft Bangkok Clay

Abstract

A new kind of reinforced Deep Cement Mixing (DCM) pile, namely: Stiffened Deep Cement Mixing (SDCM) pile is introduced to mitigate the problems due to the low flexural resistance, lack of quality control in the field and unexpected failure of DCM pile. The SDCM pile consists of DCM pile reinforced with precast concrete core pile. Previously, the full scale embankment loading test on soft Bangkok clay improved by SDCM and DCM piles was successfully conducted and monitored. The parameters were also derived from an earlier full scale load tests to failures and subsequent simulations. To continue the study on the behavior of SDCM and DCM piles, the 3D finite element simulations and parametric study have been done. The simulation results of the full scale embankment loading test indicated that the surface settlements decreased with increasing lengths of the concrete core piles from 4 to 6 m but slightly reduced from 6 to 7 m as well as slightly decreased with increasing sectional areas in the SDCM piles. In addition, the lateral movements of the embankment decreased by increasing the lengths (longer than 4 m) and, to a lesser degree, the sectional areas of the concrete core piles in the SDCM piles. The results of the numerical simulations closely agreed with the observed data from full scale field tests and successfully verified the parameters affecting the performances and behavior of both SDCM and DCM piles.