DOUBLE-ROW PILE REINFORCING ON A CRITICAL SLOPE AT NATIONAL ROAD IN TABANAN, BALI

Abstract

Due to heavy rain, a landslide occurred on the high slope at the National Road in Tabanan, Bali, and is forecasted to reoccur. Thus, the double-row piles will be analyzed as an alternative method to improve allowable bearing capacity (q_a) and slope stability to mitigate this area. This study used various 2D and 3D numerical modeling techniques to analyze the slope model under two variables: the installment of parallel and nonparallel (zigzag) pile configurations and variations in a second-row pile diameter. With the smallest diameter (D = 0.3 m), the first row of piles has a diameter of 0.6 m and a pile spacing of (s) = 4D. The reinforcing piles were installed into the actual slope model. In addition, the second-row pile diameter varies from 0.3 to 0.6 m. Considering the standardized traffic load, PLAXIS and ABAQUS were implemented to numerically analyze the factor of safety (FS) and q_a of the 2D and 3D finite element method (FEM). Compared with the unreinforced reinforcement of two rows of piles arranged in parallel, the FS increased significantly by 33.06% in the 2D FEM and 32.82% in the 3D FEM. Yet, the model with a zigzag configuration enhanced the FS by 33.20% in the 3D FEM. However, the numerical models showed a slight improvement in the q_a in both 2D and 3D FEM. The slope model defined the highest FS and q_a with pile diameter, D2 = 0.6 m (P2D1). Additionally, a rotational type of failure occurred on the slope toe.