Keller executed non-dredged ground improvement method and its first major application of Keller offshore stone column technology.

Offshore stone columns in progress

The project

Located  at the northeastern coast of Singapore, Pulau Tekong, is  the  largest  

remote island  in Singapore. A land  reclamation  contract was  awarded  to 

TOA Corporation and Jan De Nul Joint Venture.

The challenge

In most parts of the project, dredging and filling was adopted to form the 

perimeter bund prior to the construction of the sand key. However, this method  

posed concerns of instability to the existing sand key. Keller proposed Offshore Vibro Replacement to improve the strength and deformation  characteristics of the soft clay prior to sand filling. This also ensure that the foundation for sand key was stable during sand filling and to meet the settlement criteria of the rock revetment structure on the sand bund. 

The solution

Approximately 43,000 linear meters of stone columns were installed using 

Alpha-S and Keller Gravel Jet system. The Gravel Jet system allowed the

construction of columns to 25 m below sea level.

Project facts


Housing and Development Board

Keller business unit(s)

Keller ASEAN

Main contractor(s)

TOA Corporation – Jan De Nul Joint Venture