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This paper conducts a systematic study on the stress and deformation of ultra-long pile foundations in slope accumulations under sliding loads. Existing research lacks sufficient analysis of the bearing capacity and stability of pile groups under complex load conditions, increasing the risk of overall collapse of engineering structures under landslide effects. To address this, a numerical model of pile foundations in typical slope accumulations was established using finite element analysis software, based on practical engineering applications. The deformation, pile-soil interaction, and overall stability of the pile group foundation were studied under different landslide intensities. The paper focuses on analyzing the load-bearing behavior of rear piles, the impact mechanism of superstructure loads on pile foundations, and the effectiveness of anti-slide pile reinforcement. The study found that rear piles are most adversely affected by loads under landslide conditions, with the maximum internal force occurring near the pile top or sliding surface. The improvement of pile foundation bending moments and horizontal displacement due to superstructure loads is limited, but their impact on shear forces is significant. Additionally, rear anti-slide pile reinforcement is most effective, with the optimal reinforcement distance being 2–4 times the cross-sectional length of the anti-slide pile. The research results provide a theoretical basis for the design and construction of ultra-long pile foundations in slope accumulations and offer reference for the response analysis and optimization design of ultra-long pile foundations under sliding loads. [ABSTRACT FROM AUTHOR]

Due to the improvement of seismic design standards, viscoelastic dampers have been rapidly developed and widely applied in bridge structures. Currently, there is limited research on dynamic reliability analysis of large bridge structures equipped with fractional-order dampers. In this paper, a hybrid method combining the time-domain explicit method and Markov process is proposed for the dynamic reliability analysis of multi-span continuous girder bridges with fractional-order dampers under non-stationary random excitation. This method introduces a fractional damping system and non-stationary random excitation to simulate both the bridge structure and external forces. The response coefficient matrix of the fractional damping structure is solved using the time-domain explicit method, and the response variance is directly calculated using the moment algorithm. The dynamic reliability analysis is then performed by applying the Markov process based on the structural response variance. Compared to traditional methods for structural dynamic reliability analysis, this approach offers higher computational efficiency and greater accuracy. By analyzing the response variance and dynamic reliability of a four-span continuous girder bridge equipped with viscoelastic dampers, the proposed method is validated using the Monte Carlo method. [ABSTRACT FROM AUTHOR]