Reducing differential settlements of approach embankments

Abstract

This paper presents a case history of an approach road remediation project on a low embankment over soft Ariake clay, located in the coastal Saga Plain of Japan. After the road had been opened to traffic for two-and-a-half years, large settlements were observed, and there was significant differential settlement between piled structures and approach road embankments on soft clay. This differential settlement had a significant impact on vehicle ride quality, and necessitated a remediation programme. In the remediation project, a new method called the column approach (CA) method was adopted to support a transitional zone at the interfaces of piled structures and road embankment. With the CA method a transitional zone was designed at these interfaces to be supported by soil-cement columns of varying lengths to smooth out the settlement profile within these zones. Field monitoring was conducted following completion of remediation. The CA method was also compared with two other Japanese code-designated methods:...