Effect of Short Piles Strengthened in Sand Leveling Over Soft Soils Using 2D Physical Model

This paper studies the efficacy of short piles on soft ground with sand leveling, using a 2D physical model. The study focuses on the geological characteristics of the Mekong Delta, characterized by a substantial layer of soft soil overlaying a 2 ÷ 5m thick stratum of leveling sand. The small (i.e., cross-section is smaller than 30×30 cm) and short piles (i.e., pile length is shorter than 5 m) could be selected for low-rise buildings in such soil conditions. 18 physical models were conducted in this study. The Schneebeli analogue material, foam, and steel bars with square cross sections were used to simulate the sandy, clayey layers and short reinforced concrete piles, respectively. Vertical loading tests were executed on groups of 3 piles, with variable parameters including pile spacing (S), and the distance from the pile tip to the boundary between the two soil layers (H). The results show that under constant S and decreasing H, the deformation beneath the pile tip diminishes. Conversely, under constant S and decreasing H, the deformation beneath the pile tip diminishes. Using a raft increases not only the bearing capacity of the piles but also the deformation in the vertical direction. On the contrary, the deformation expands horizontally in the case of pile groups.