Deformation and stress characteristics of bent-type h-piles in high fill slopes

Taking the ecological restoration slope support project of a tributary in Qingdao as the engineering background, the deformation and mechanical characteristics of bent-type h-piles (h-piles with multiple transverse constraints) in high-fill slopes of soil-rock dual strata were investigated through theoretical model analysis, numerical simulation, and monitored data analysis. The results show that bent-type h-piles present a more reasonable internal force distribution and stronger deformation control capacity. The measured maximum horizontal displacement at the pile top is 8.1 mm, and the maximum bending moment of the pile shaft per unit calculated width is 1423.2 kN·m. Compared with cantilever piles, bent-type h-piles possess higher flexural stiffness, and the alternating positive and negative bending moments along the pile shaft lead to a more rational mechanical state. The flexural stiffness of bent-type h-piles is mainly provided by the rigid frame structure composed of the front and rear piles and the second coupling beam. The internal forces of the piles are mainly distributed below the second coupling beam, which allows the optimization of reinforcement in the upper structure. The full-length reinforcement of the soil between bent-type h-piles has no significant effect on optimizing the internal force and deformation of the structure. When the joints between the coupling beams and the rear piles are designed as fixed connections, the front and rear piles can work together more effectively in bending, and the mechanical and deformation performance is superior to that of hinged connections. The research results can provide a reference for the design and construction of bent-type h-piles in high-fill slope projects with soil-rock dual strata.