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| 10 June 2023 - A view of excavation work being carried out within the construction area. |
Contract N109A, under the North-South Expressway project, also includes the construction of a station box for the Cross Island Line (CRL) below the road tunnels. Utilizing the width of the excavated trench, the station will feature cripple sidings that run parallel to the platform - similar to those found at Fort Canning and Mattar stations along the Downtown Line. Work is progressing with excavation of part of the trench having commenced at various portions of the site. We are unsure if this is to facilitate the construction of the roof slab for a top-down construction method to be used later on.
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| 29 June 2023 - A view from Marymount Road of Ang Mo Kio Avenue 6 looking northwards. |
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29 June 2023 - This site will be used for the launching of the rectangular tunnel boring machines
that will construct 1 of the 2 subways connecting the station with Bishan-Ang Mo Kio Park. |
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| 29 June 2023 |
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| 29 June 2023 - The beginning of the excavated area. |
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| 29 June 2023 |
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| 29 June 2023 |
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| 29 June 2023 |
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29 June 2023 - The beginnings of another area of excavation behind the pedestrian sheltered
walkway. |
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| 29 June 2023 |
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| 29 June 2023 - The first layer of struts has been installed. |
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| 29 June 2023 |
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29 June 2023 - Further along, there is another area where excavation has progressed deeper.
Struts and decking can be seen here. |
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| 29 June 2023 |
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| 10 June 2023 - An aerial view of ongoing excavation with a single layer of struts installed. |
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| 10 June 2023 - A view of the construction area looking southwards from a HDB block. |
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| 10 June 2023 - Shotcrete poured at the base of excavation to stabilize the base layer. |
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10 June 2023 - At the excavation site further north, 2 layers of struts
have been installed within the excavation pit. |
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| 10 June 2023 - Machinery to the south of the site, along Ang Mo Kio Avenue 1. |
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10 June 2023 - Close up view of an auger machine being
assembled on site. |
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10 June 2023 - An aerial view of the contract N109A work site.
The Teck Ghee station is situated towards the south. |
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| 10 June 2023 - A close up aerial view of the Teck Ghee station within contract N109A work site. |
Station box
The station box will lie underneath the road tunnels for the North-South Expressway. As such, the area where the station box is sited will require deeper excavation. We had anticipated that the method of choice here would have been to use the top-down construction methodology where access points are created in a roof slab and excavation commences thereafter. However, excavation at the site has progressed much further down than anticipated. Several portions of the site feature deep pits where the soil has been removed, even extending downwards by 1 to 2 layers of struts.
As the width of the current excavation sites are too small to fit in both tunnels of the expressway, we believe that the process will need to be repeated on the eastern side as a rough mirror image of the current site on the western edge. Time will likely tell if this is indeed the construction process selected.
In the mean time, neighbouring contract CR116 for the construction of Ang Mo Kio station and tunnels is busy working on the launch shaft for the lowering & launching of 1 slurry tunnel boring machine (TBM). The TBM is due to chew its way westwards towards Teck Ghee station before repeating the process for the second tube tunnel. It is likely that a soft eye diaphragm or bored pile wall would have been installed to allow the machines to break through into the station for a safe removal thereafter.
This post is also available on Instagram & Facebook from 13 July 2023.
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