THE EFFECT OF DOUBLE ROW REINFORCEMENT PILE SPACING ON SAND SLOPE

This study aims to evaluate and analyze the improvement of Factor of Safety (FS) using double-row pile addition on the critical sand slope modeling with slope angles 50 o .Experimental and numerical modeling was conducted in this study.The small-scaled slope model of sand soil compacted on the steel container (1.5x1.0x1.0 m) was used in the experimental test.Reinforcement piles using aluminum tubes are installed on compacted sandy soil with Rc 88%.The diameter of the first row of piles is 3.2 cm with a pile spacing (D1) of 10 cm, yet the diameter of the second row is 2.0 cm with varied pile spacing from 2d to 5d.The LVDT was installed on the pile, and the model would gradually be loaded using a hydraulic jack until the slope collapsed.The unreinforced slope bearing capacity (qu) on the loading test was used as the external load to numerically analyze the FS of the 2D and 3D FEM using PLAXIS.The results showed that the FS increased against the unreinforced reinforcement of two rows of piles with external load by 7.18% in the 2D FEM and 29.05% in the 3D FEM.The results obtained for the loaded slopes model with one row of pile reinforcement are 4.38% in 2D FEM and 1.49% in 3D FEM.The slope model with the highest FS was the slope model with pile spacing, D1=2d.The type of slope failure was rotational.