A site investigation has been performed for bridge abutments constructed on soft ground, which are deformed laterally by backfill. In order to prevent lateral movement of bridge abutment, the pile slab is proposed as a countermeasure. This method can effectively prevent the lateral flow of soft ground, since the overburden surcharge due to backfill on soft ground would be effectively delivered to bedrock through the piles in soft ground. This study is consisted of field investigation, evaluation of lateral movement of bridge abutment, and presentation of its countermeasures. The result of this study illustrates that the abutment foundation piles should be designed as not only the active pile but also the passive pile.
Lots of highways and roads have been constructed with rapid growth of industry and augmentation of economic scale in Korea. When embankments or backfills are performed on soft grounds to build the highways and roads, however, significant settlements and lateral flow may take place. Especially, when bridge abutments are constructed on piles in soft ground and backfills, the soft ground will flow laterally and the piles may be deformed due to lateral earth pressures from the soft grounds undergoing lateral flow. The deformation of foundation piles causes the lateral movement of bridge abutments and in turn severe damage of superstructures of the bridge. Therefore, the possibility of lateral movement of bridge abutment should be investigated on design. A bridge abutment, which has been moved laterally due to backfills on soft grounds, is studied to investigate the cause of the movement and to prepare suitable countermeasures.
Hong et al (1994) performed an investigation of lateral movement for the twelve abutments, which were moved laterally, in six sites in Korea.