关键词: 预应力锚索, 锚索腐蚀性能, 锦屏一级水电站, 锚固边坡, 可靠度

Abstract: Degradation of pre-stressed cable’s performance caused by corrosion has significant effect on slope stability. In this research, two typical failure modes of pre-stressed cables in the presence of corrosion are identified, and the corresponding time-dependent anchored force models are established. The representative section Ⅱ₁-Ⅱ₁of abutment slope at the left bank of Jinping I-stage Hydropower Station is taken as an example to illustrate the time-dependent slope stability and reliability of the slope excavated to elevation 1780 m and reinforced with three shear-resistant concrete plugs and pre-stressed cables under three conditions. Results indicate that the corrosion of pre-stressed cables has significant effect on both the stability and reliability of anchored slope. In the early stage (the first 120 years) of cable’s service life, the variations in the factor of safety and probability of slope failure are relatively small; whereas in the later stage, the variations increased sharply and the stability condition deteriorates rapidly. Hence, reasonable periodical maintenance is required for the in-service anchored structures such as pre-stressed cables subject to corrosive underground environments. In addition, the influences of variabilities and cross-correlations of shear strength parameters of rock masses and structural planes on the slope stability can be effectively accounted for in the slope reliability analysis.

Key words: pre-stressed cable, cable corrosion, Jinping I-stage Hydropower Station, anchored slope, reliability