Due to the soft marine clay above the stable sedimentary soil, the construction had resulted in a few cave-ins at the site. On 3 July 1999, an unused section of the old canal caved in, forming a hole deep. Several I-beams, a compressor and a small machine, which fell into the hole, were retrieved using a crane. It was discovered that some soil had seeped through a gap in the perimeter wall of the station, resulting in the collapse of the structure. The gap was made to accommodate a sewer pipe. In the evening of 22 November, a section of Eu Tong Sen Street collapsed, resulting in its closure along with the neighbouring streets. The collapse formed a hole with a depth of up to . Nobody was injured and the surrounding building structures remained intact. On 2 December, a depression was discovered on the road away from the cave-in site, resulting in another road closure. It was found during an inspection of soil movement above the tunnelling machine underneath the street. One of the lanes remained open for buses. The road was dug open to inspect the utility pipes, cables and the two steel pipes underneath the road. Following the discovery of the cracks on the road, cement mixture was pumped into the ground to stabilise the soil before the road was reopened to traffic on 5 December.