Abstract: The impact of the weakened long-term durability performance on the stability of in-service slopes was studied. Initially, a mechanical performance degradation model was developed for slope support structures based on the classical durability principle of concrete structures. This model was validated using results from indoor durability accelerated tests. Subsequently, the algorithm for anchor elements connecting blocks with different displacement modes was investigated and expanded based on the Hybrid Discontinuous Deformation Analysis (HDDA) method. Utilizing this HDDA method in conjunction with the finite element method for comparison, a computational framework for analyzing weakened in-service slope stability was established. By applying the aforementioned method, a case study involving a highway slope in Zhejiang Province was conducted. The findings revealed that, under given environments, the slope support structures may experience rusting, cracking, and eventual fracture failure within 30-60 years. Assuming that the ultimate bearing capacity of anchor rods remains intact, the slope safety coefficient decreases over time. Taking into account the progressive durability deterioration and fracture of the anchor rods, there is a significant reduction in the slope safety coefficient, necessitating preemptive reinforcement measures to meet safety requirements. Furthermore, the results highlight the flexibility of the HDDA method in modeling and achieving reasonable outcomes, indicating its potential for further practical applications.

Key words: slope durability, slope stability, support structures, Hybrid Discontinuous Deformation Analysis (HDDA), finite element method, safety of factor