Study on the behavior of short pile groups on weak geology with sand leveling using a small-scale physical model with Schneebeli analog material

Abstract

This paper focuses on the behavior of pile groups on soft ground with sand leveling on a 2D small-scale model using the analog soil of Schneebeli. The Mekong Delta has many areas where low-rise buildings are built on soft ground with a sand backfill layer of thickness between 2 - 5m. The option of using small (section smaller than 30×30 cm) and short (length shorter than 5m) piles driven into the sandy soil layer can be applied to low-rise buildings with the above geological conditions. In the small-scale model, we use Schneebeli analog soil to replace the leveling sand and foam instead of the weak clay layer. Short reinforced concrete piles are replaced by steel bars with a square cross-section. The vertical loading tests were carried out on 3-piles groups. Experimental parameters are changed in the test program, including the pile spacing s, and the distance from the tip of the pile to the boundary of the two soils, H, whereas the thickness of the soil layers is unchanged. If the pile group has no footing when the pile spacing s is unchanged, and the distance from the tip of the pile to the boundary of the two soils, H decreases, the deformed soil area under the pile tip decreases. If H is fixed and s is increased, soil failure under the pile tips becomes more and more localized. When the pile group has a footing, the bearing capacity of the pile group increases. As a result, however, the vertical deformation of the foam layer also increases in both the vertical and horizontal directions.

Keywords: Schneebeli soil analog; pile group; vertical loading test; sand leveling; weak soil.