Legislature reviews draft to curb sinking

By Jiang Yabin Source:Global Times Published: 2012-11-20 23:30:05

The Shanghai Municipal People's Congress is reviewing a draft regulation that aims to alleviate one of the city's major geological problems - it is sinking, local media reported Tuesday.

The problem, whose technical name is land subsidence, is a side effect from the rapid construction that the city has undergone over the last three decades. It can knock subway tracks out of alignment, make it easier for the city to flood and, in its worst cases, cause buildings to collapse.

If approved, the draft regulation would require construction firms to conduct a hazard assessment on projects that require digging seven meters or more into the earth, if the ground in the surrounding area is prone to sinking, according to the report. In other areas, firms would have to do the assessment if they dig more than 15 meters deep.

If the assessment reveals potential dangers, the construction firm would have to take measures such as reinforcing the ground around the foundation, said Lou Xiaoming, a professor at the School of Civil Engineering at Tongji University.

Under the draft regulation, a construction firm can be fined up to 500,000 yuan ($80,150) for failing to make government-stipulated changes following an assessment.

Shanghai's land level has sunk 0.29 meters on average from 1966 to 2011, according to the Shanghai Evening Post. In some places, the ground sank as much as three meters over the period.

"The development of the underground areas and large-scale construction projects such as high-rise buildings and subways are what has caused the land to sink," Lou told the Global Times.

In February, land subsidence caused several major cracks to appear in the ground near the construction site of the 632-meter Shanghai Tower in Pudong New Area. During the construction of metro Line 4 in 2003, land subsidence at the Nanpu Bridge Station near to the Huangpu River caused a major collapse. A 60-meter section of the Huangpu flood prevention barrier was damaged and three six-story apartment buildings had to be demolished. 

"The lower ground level will also make it easier for the city to flood," Lou added.

Shanghai has set up a land subsidence monitoring network and facilities to manage the problem.

Posted in: Society, Metro Shanghai

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