Transport officials said yesterday that the high-speed railway was safe even though a 6km section which cuts through Yunlin County sits on land that has subsided considerably in recent years.
The site where the elevated railway crosses Provincial Expressway No. 78 in the county has subsided by 55cm over the past seven years, according to data compiled by Taiwan High-Speed Rail Corp (THSRC), which operates the bullet train.
Officials at the Bureau of Taiwan High Speed Rail under the Ministry of Transportation and Communications, however, said that the “differential settlement” — the rate of uneven settling — between adjacent piers of the railway viaduct in Yunlin remains within tolerable levels, adding that the railway’s structure and operation remained sound.
The officials said the THSRC has closely monitored the subsidence of the Yunlin section’s piers and foundations since 2004.
The differential settlement for the section crossing over Provincial Expressway No. 78 stands at 1.08/1,500 at present, far lower than the maximum permissible level of 6/1,500, the officials said.
They said the pace of subsidence along the Yunlin section had slowed from nearly 10cm per year in the past to 6.8cm last year because a number of deep wells were closed in the area, reducing groundwater seepage.
Though pleased by the slower pace of subsidence, the bureau said it hoped the central and local governments would collaborate to close even more wells, including those used for aquaculture, to stop further subsidence in Yunlin County, which is known for its agriculture and aquaculture.
Echoing the bureau’s safety assurances, THSRC spokesman Ted Chia (賈先德) said the high-speed railway was safe and structurally sound.