Influence of placement and configuration of small diameter steel pipe pile on slope reinforcement

The main objective of this study is to elucidate slope failure preventive mechanisms of small diameter steel piles. In this research, model tests were conducted on such piles, using large-scale direct shear testing apparatus. Tests were performed under different test conditions: placement of piles in different rows, varying the installation angle of piles, connecting the head of piles, and combination of vertical and slanted piles (coupled piles). In addition, numerical analyses were also performed for the experimental models. The results show enhancement of the improvement effect in the case of piles with connecting heads. In the case of coupled piles, the shearing strength and the bending stiffness were found to be increased. Therefore, it can be inferred that the pile group constructed by combining vertical and slanted piles is the most effective solution for preventing slope failure.