Long-term Measurements of Traffic Load Induced Settlement of Pavement Surface in Saga Airport Highway, Japan

This study presents the long-term measurements of traffic load induced settlement of pavement surface in Saga airport highway, Japan. In addition, the subground characteristics of the deposit were discussed in associated with their typical properties such as; high sensitivity, high compressibility, and low bearing capacity. The basic features of deposit are characterized to be soft alluvial deposit with thickness 20 - 25 m with natural water contents are much higher than their corresponding liquid limits. Permeability of the salty clay layer is approximated 3 to 5 times of the Ariake clay permeability. The settlement profiles along the Saga airport highway visualized a non uniform differential settlement. Large differential settlement occurred in between the two box culverts supported by end bearing piles. A dynamic impact is considered as one factor affecting the large observed settlement in the central part of the road section between the two box culverts. The observed total settlement was around 0.5 m after 3 years open for traffic; it was mainly accumulated due to consolidation settlement of embankment highway. It can be justified that the settlement induced by traffic loading is approximately around 20% of the total settlement.