installed lifts to allow barrier-free access to the station. Station construction The contract for the construction of the station was awarded to a joint venture comprising Taisei Corporation, Shimizu and Marubeni at S$70.723 million (US$ million in ) in May 1984. Construction of the station began on 28 May 1984. The station was built right in the city centre. With a short construction schedule, the various stages of construction had to be overlapped. This required coordination between various subcontractors while overcoming space constraints at the site. The buildings of the Standard Chartered Bank and the Indian Overseas Bank had to be demolished as well as an underground carpark. During the diversion of utilities at the site, the contractors used the utilities departments' records to determine the location of utilities; they were found to be inaccurate and outdated during surveying. The soil conditions at the site consisted of silty clay in between sandstone with boulders of varying sizes. With the high-rise buildings in the area, it was difficult to determine suitable locations for the installation of temporary ground support systems (including the piles and working deck). About 450 piles were installed in pre-bored holes that supported the station's temporary work deck covering 40% of the site. The piles were installed via rock augers that penetrated into boulders, supplemented by using a "down-the-hole" (DTH) percussion machine. Before the piles were installed, grout was injected via a central tube in the rock auger to stabilise the soil. Due to the instability of the rock auger when drilling into the boulders, the size of the drilling holes had to be minimised as much as possible. The DTH machine pre-bored the holes before allowing the augers to drill into the ground; this slowed down drilling rates. As the DTH machine was intended to drill in only hard ground, the machine becomes bogged in wet weather due to the machine's inability to discharge the drill cuttings (mud slurry). An air lift and a tremie pipe at the bottom of the drilling hole were used to remove the mud slurry. During the station's excavation, the boulders had to be broken apart, through treatment with a cracking agent, hydraulic rock splitters or giant breakers. Some boulders were removed via explosives; this had to be used with caution due to the surrounding buildings. While the boulders were hard, they were brittle and easily broken. In conjunction with the station's