Nov 20, 2012
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.
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.
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.