Clarke Quay MRT station

Clarke Quay MRT station is an underground Mass Rapid Transit (MRT) station on the North East line (NEL) in Singapore. Situated along Eu Tong Sen Street, near the junction of Merchant Road and North Canal Road, it is at the south of the Singapore River underneath The Central. The station serves Clarke Quay and Boat Quay, as well as other landmarks such as Hong Lim Park, The Riverwalk and the Swissotel Merchant Court.

First announced in March 1996, the station was planned to serve the redevelopment of the Singapore River. Explosives were used in the construction of bored tunnels between this station and Dhoby Ghaut station. Clarke Quay station was completed on 20 June 2003. The curvilinear features of the station entrances are designed to symbolise the flowing waters of the Singapore River. The station features an Art-in-Transit public artwork The Reflections by Chua Ek Kay.

History
The North East line (NEL) project, which was first proposed in 1984, received government approval in January 1996. Clarke Quay station was among the sixteen NEL stations announced by communications minister Mah Bow Tan that March. The Land Transport Authority (LTA) Deputy Chief Executive and his colleagues visited Clarke Quay in 1995. During their visit, they decided there should be a station built under Ellenborough Market, which lay along the proposed NEL route. The Urban Redevelopment Authority (URA) agreed, saying the proposed station would "realise the tremendous commercial and aesthetic potential" of the Singapore River.

Some property developers felt the station was not as "centrally located" to serve the developments near Robertson Quay. Others, such as DBS Land and Far East Organisation, supported the proposed station as it would fill a "major gap" in transportation access to the area. The station opened on 20 June 2003 along with the other NEL stations.

Station construction
The contract for the design and construction of Clarke Quay station and tunnels was awarded to a joint venture of Nishimatsu Construction, Lum Chang Building Contractors and Bachy Soletanche Singapore. Stallholders of the Ellenborough Market had to move out by 31 March 1997 as the market would be demolished for the station. Due to the soft marine clay, a dam was built around the station site, and the contiguous concrete wall panels were installed via diaphragm walling.

The contractors had to monitor and minimise any ground movement of the heritage shophouses by the river and the Thong Chai building. Some of the perimeter walls were also installed near the river wall. The APG building located along New Bridge Road was detected to be settling unevenly because it had a separate foundations. Following a thorough survey of the building, the LTA engineers deemed it safe for use and made repairs and restorations.

Tunnels construction
The NEL tunnels cross the Singapore River near Coleman Bridge. This was the second MRT river crossing, though the first to use the tunnel boring machine (TBM) beneath the riverbed. Compared to the cut-and-cover method, the TBM was considered less time-consuming, had lower risks of tunnel flooding, and minimised environmental damage to Clarke Quay and the river. As the tunnels were only 10 m below the riverbed, it was decided to further lower the tunnels and the station by 4.4 m. The TBM had to tunnel through a layer of marine clay with varying thickness, loose fluvial sands and weathered sedimentary rocks that could create varying resistance to the TBM. Hence, it was essential to maintain effective control of the excavation rate to keep the TBM in alignment. While initially opposed by the management of Clarke Quay, the launch shaft was located at the former Whampoa Garden due to optimal soil conditions.

Explosives were used for the hard rock under Fort Canning Hill when workers tunnelled between Clarke Quay and Dhoby Ghaut. Sensitive structures, such as an underground enclosed reservoir atop Fort Canning and a telecom microwave tower, were closely monitored. A minor ground settlement at Fort Canning Country Club created a large void above the TBM. As a result, grout was pumped in to prevent further settlement. The tunnelling also encountered a huge inflow of water, and pipes were drilled into the rock face to channel the water out and prevent water from seeping into the rock cracks.

The tunnel excavation also exposed a layer of sand in the rock face directly underneath the Oxley Rise flyover, causing slow settlement under the flyover. As survey teams established monitoring points at the flyover, pit bosses and miners hammered timber into the ground to stop ground loss. The ground was filled with chemical grout to add strength and cohesion to the soil before tunnelling resumed. Explosives were also used for another hard rock under the North-South line (NSL) tunnels near Dhoby Ghaut station as the manual excavation was too slow. Jet-grout arches supported the NSL tunnels while tunnelling near Dhoby Ghaut station.

Details
Clarke Quay station serves the North East line (NEL) of the Singapore MRT and is between the Chinatown and Dhoby Ghaut stations. The station code is NE5. Being part of the NEL, the station is operated by SBS Transit. The station operates daily from about 5:45   am to 12:25    am. Train frequencies vary from 2.5 to 5 minutes.

Located along Eu Tong Sen Street on the south bank of the Singapore River, the station is near the junction of Merchant Road and North Canal Road. The station is underneath The Central, a retail and residential development owned by the Far East organisation. Other developments surrounding the station include Hong Lim Park, Speaker's Corner, Clarke Quay, Boat Quay, Asian Civilisation Museum, Fort Canning Hill, Park Regis Hotel, The Riverwalk, Swissotel Merchant Court and The Riverside Piazza. The station is also within walking distance to Fort Canning station on the Downtown line.

Clarke Quay station is designed by SAA Architects. The curved roof design of the station entrances draws inspiration from the flowing waters of the Singapore River, while its color scheme is reminiscent of the boats ferrying tourists and locals along the river. The station is designed to have a spacious interior while having large columns to support the commercial development built above the station.

The station is designated as a Civil Defence (CD) shelter: it is designed to accommodate at least 7,500 people and withstand airstrikes and chemical attacks. Equipment essential for the operations in the CD shelter is mounted on shock absorbers to prevent damage during a bombing. When the electrical supply to the shelter is disrupted, there are backup generators to keep operations going. The shelter has dedicated built-in decontamination chambers and dry toilets with collection bins that will send human waste out of the shelter. Like all other NEL stations, the platforms are wheelchair-accessible. A tactile system, consisting of tiles with rounded or elongated raised studs, guides visually impaired commuters through the station. Dedicated tactile routes connect the station entrances to the platforms.

Artwork
The Reflections by Chua Ek Kay is displayed at this station as part of the Art-in-Transit (AiT) programme, a showcase of public artworks on the MRT network. The work consists of a 60 m mural portraying scenes from life on the Singapore River as well as an acid-etched brass mural reminiscent of light reflecting from the water. Exploring the themes of reflection, both pieces capture the vibrancy and vitality of the river. Complementing these artworks are floor tiles, each adorned with painted eyes reminiscent of those found on tongkangs or Chinese junks, and they serve as navigational aids for station commuters.

The work was inspired by Chua's observations of contemporary river life and childhood memories of the bustling Teochew Street area, where the station now stands. As such, the murals depict key moments highlighting the significance of the Singapore River to the city. These include the arrival of early migrants in the 19th century, the bustling activity of tongkangs navigating the river, the architectural landscape surrounding it, and the street celebrations by its banks. The silkscreened mural was originally rendered in ink on rice paper before being transferred onto vitreous enamel panels in the United Kingdom. These nostalgic tones are juxtaposed against the "raw energy" of the 20 m brass mural. The brush strokes give the appearance of with the river's energy and the reflections of passengers in motion. Mirroring the river's ever-changing hues with the weather, the colours in the brass work from "dominant reds" to "striking greens", accented with traces of gold on aquamarine.

Chua took pride in allowing viewers to engage with, and appreciate the details of, his brass artwork in the ticket concourse area. He further explained that the more abstract nature of the brass mural could "open up a wider space for imagination" through the work's changing colours, movement, and rhythm. While Chua used Chinese brushwork for both murals, the brushstrokes on the brass panels diverged in all directions to achieve the "shimmering, dynamic effect" distinct from the tranquil, broad strokes for the other murals.

The artist first worked on the silkscreen murals, which were originally half the size before being rendered on the vitreous enamels. The brass work required deeper thought and a more intricate process. Chua worked on 60 brass sheets, each weighing 8 kg and backed with cement board. He applied brushstrokes to the brass sheets before immersing them in a chemical bath, resulting in an etched effect with ageing acid-tinged patches that transitioned from turquoise to green, orange, and dark brown. Chua, who preferred full control over the work's production, personally oversaw the creation of his brass artworks, rather than producing the work on paper before having contractors fabricate it in brass. Chua also engaged with various stakeholders for the artwork, and his close collaboration with the station's architect led to adjustments in the station's colour scheme from beige to grey, enhancing the presentation of Chua's artwork on brass.