National Freeway No. 1 is being widened for a length of approximately 40 kilometers from the Wugu to Yangmei in northern Taiwan. The widened section adopts an elevated viaduct along both sides of the existing freeway since the entire job site is confined to a narrow area and the freeway has to maintain normal operations and safety conditions while the viaduct is being built. However, during construction of the segment extending from 44 K+700 to 44 K+900, freeway management authority noticed some uplifting and a bulging phenomenon at the freeway shoulder. As a precautionary measure, monitoring instruments were then installed in both the upper and lower side slopes for monitoring the slope behaviors. A few months later, after having received much rainfall, the surface and records indicated unusual symptoms. Hence, management authorities convened a meeting with construction, supervision and design experts to carry out an overall analysis of the situation and determined that the slopes were under a dangerous situation. In response, an emergency repair plan was drawn up and resources mobilized to control and stabilize the slope in the affected area and prevent the occurrence of a major calamity. The entire procedure for crisis-handling, engineering decision and quick mobilization were a rare experience and is reported in this paper.
Keywords: Freeway slopes, Monitoring, Crisis handling, Emergency repair.