<TABLE border=0 cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR>Aug 17, 2009
</TR><!-- headline one : start --><TR>The longest dig <!--10 min-->
</TR><!-- headline one : end --><TR>Tunnelling of new 33.3km orbital line comes full circle </TR><!-- Author --><TR><TD class="padlrt8 georgia11 darkgrey bold" colSpan=2>By Christopher Tan, Senior Correspondent
</TD></TR><!-- show image if available --><TR vAlign=bottom><TD width=330>
</TD><TD width=10>
</TD><TD vAlign=bottom>
Construction was also made more challenging by water seepage. Despite building retaining walls that were 1.2m thick - among the thickest ever used anywhere - water had found its way into the tunnel. -- PHOTO: CHRISTOPHER TAN
</TD></TR></TBODY></TABLE>
<!-- START OF : div id="storytext"-->AFTER seven-and-the-half years of excavation, interrupted by a tragic collapse in 2004, tunnelling of the 33.3km Circle Line has finished.
'At long last,' a senior Land Transport Authority executive sighed as a massive tunnel-boring machine broke through a hollow-brick wall erected for a completion ceremony this morning.
The symbolic tunnel breakthrough was greeted with applause from the construciton team led by Japan's Taisei Corp, LTA officers, and representatives of residents living nearby.
The real cheer however will come later.
Laying of rail tracks and other electrical and mechanical works will follow in the months ahead; and the remainder of the line will be in phases up to 2011. Currently, more than three-quarters of the line's tracks have been laid.
The twisty Farrer Road will be moved back to its original alignment only in end-2010, but motorists can look forward to an extra lane then.
Today's ceremony is especially significant as the Farrer stretch of the line had proven to be the most challenging. LTA had expected tunnels in the western loop of the Circle Line to be completed last, but it has turned out that Farrer - with its mixed soil conditions - was the last.
'You name it, we had it,' LTA Circle Line director Ow Chun Nam said, commenting on the varying topography.
Construction was also made more challenging by water seepage. Despite building retaining walls that were 1.2m thick - among the thickest ever used anywhere - water had found its way into the tunnel.
Walls in the station box were marked by several vertical lines where the builders did grouting - an engineering process where concrete material is pumped into leak points at high pressure to seal them.
Still, the floor was visibly wet. Mr Ow said he was confident that the leaks would be contained when construction is fully completed.
The LTA said several stations in Stage 1 and 2 of the Circle Line - leading to downtown - had already attained temporary occupation permit (TOP).
These include Dhoby Ghaut, Bras Basah, Esplanade, Promenade and Tai Seng.
Other stations such as Nicoll Highway, Stadium, MacPherson, Paya Lebar, Dakota and Mountbatten are expected to get TOP by end of this year.
Stage 3 of the Circle Line opened for service on May 28.
Construction cost of the line has not yet been totalled up, as the original budget of $6.7 billion was busted after the 2004 tunnelling accident which claimed four lives.
[email protected]
</TR><!-- headline one : start --><TR>The longest dig <!--10 min-->
</TR><!-- headline one : end --><TR>Tunnelling of new 33.3km orbital line comes full circle </TR><!-- Author --><TR><TD class="padlrt8 georgia11 darkgrey bold" colSpan=2>By Christopher Tan, Senior Correspondent
</TD></TR><!-- show image if available --><TR vAlign=bottom><TD width=330>
</TD><TD width=10>
Construction was also made more challenging by water seepage. Despite building retaining walls that were 1.2m thick - among the thickest ever used anywhere - water had found its way into the tunnel. -- PHOTO: CHRISTOPHER TAN
</TD></TR></TBODY></TABLE>
<!-- START OF : div id="storytext"-->AFTER seven-and-the-half years of excavation, interrupted by a tragic collapse in 2004, tunnelling of the 33.3km Circle Line has finished.
'At long last,' a senior Land Transport Authority executive sighed as a massive tunnel-boring machine broke through a hollow-brick wall erected for a completion ceremony this morning.
The symbolic tunnel breakthrough was greeted with applause from the construciton team led by Japan's Taisei Corp, LTA officers, and representatives of residents living nearby.
The real cheer however will come later.
Laying of rail tracks and other electrical and mechanical works will follow in the months ahead; and the remainder of the line will be in phases up to 2011. Currently, more than three-quarters of the line's tracks have been laid.
The twisty Farrer Road will be moved back to its original alignment only in end-2010, but motorists can look forward to an extra lane then.
Today's ceremony is especially significant as the Farrer stretch of the line had proven to be the most challenging. LTA had expected tunnels in the western loop of the Circle Line to be completed last, but it has turned out that Farrer - with its mixed soil conditions - was the last.
'You name it, we had it,' LTA Circle Line director Ow Chun Nam said, commenting on the varying topography.
Construction was also made more challenging by water seepage. Despite building retaining walls that were 1.2m thick - among the thickest ever used anywhere - water had found its way into the tunnel.
Walls in the station box were marked by several vertical lines where the builders did grouting - an engineering process where concrete material is pumped into leak points at high pressure to seal them.
Still, the floor was visibly wet. Mr Ow said he was confident that the leaks would be contained when construction is fully completed.
The LTA said several stations in Stage 1 and 2 of the Circle Line - leading to downtown - had already attained temporary occupation permit (TOP).
These include Dhoby Ghaut, Bras Basah, Esplanade, Promenade and Tai Seng.
Other stations such as Nicoll Highway, Stadium, MacPherson, Paya Lebar, Dakota and Mountbatten are expected to get TOP by end of this year.
Stage 3 of the Circle Line opened for service on May 28.
Construction cost of the line has not yet been totalled up, as the original budget of $6.7 billion was busted after the 2004 tunnelling accident which claimed four lives.
[email protected]
