The performance of T-shaped deep mixed soil cement column-supported embankments on soft ground

Abstract

T-shape deep mixing (TDM) pile is a new method for soft ground improvement, which has an enlarged head at shallow depth, the pile shape analogous to the letter “T”. In this paper, three-dimensional numerical simulation is used to investigate the load transfer mechanism, failure pattern, and settlement behavior of TDM pile-supported embankments by dividing TDM pile into two parts: the enlarged head part and the pile body part and using the concrete model to simulate the TDM piles. The results reveal that the stress arches exist both in the embankment fill and the soil under the flange, and stress concentration will occur at the variable section of TDM piles, resulting in plastic yielding of the pile body, which in turn leads to load transfer to the soil, and additional stresses in the soil will cause additional compression of soft soil between TDM piles. Parameter analysis indicates that the load transfer, plastic zone, and post-construction settlement are related to the height of the enlarged head (H) and pile spacing (S), while pile length (L) only plays an important role in the post-construction settlement.