The Tuas West Extension contracts 1686 & 1687 – highly variable Jurong Formation, karstic cavities, and large bored pile and barrette construction

The $3.5B Tuas West Extension (TWE) in Singapore extended the mass rapid transit (MRT) East-West Line 7.5 km from the existing Joo Koon Station to near the Tuas Second Link to Malaysia. C1686 and 1687 were two of the four TWE main civil works contracts. This paper looks at the high variability of the Jurong Formation and karstic solution cavities found, as well as construction aspects of the large diameter bored piles and barrettes up to about 60+ m depth.