Reclaimed land in Shenzhen cracking up
Fox Yi Hu
It's called the Happy Coast estate, but perhaps they should rename it Scary Coast.
Cracks have begun appearing in a glitzy Shenzhen neighbourhood - one of many that have sprung up in the past decade or so on newly reclaimed land. In the Baoan central district, a fast-growing 1,500-hectare strip in the city's west, the cracks are up to 10cm wide.
'It's scary seeing all these cracks around the buildings where you live,' said Amanda Liu, 32, who owns a flat in Happy Coast, where they sell for 15,000 yuan to 18,000 yuan (HK$17,027 to HK$20,432) per square metre. 'The problem seems to be getting worse but we don't know what to do about it.'
A crack at least 30 metres long has appeared along a pavement, leaving the walkway tilting, with one side 10cm lower than the other.
At nearby Shum Yip New Shoreline, where flats can fetch 20,000 yuan per square metre, sections of the ground outside its main gate are undulating from the effects of subsidence. At another estate, West Coast Tea City, subsidence in the ground around some of the buildings has created cracks up to 10cm across. Sinking concrete and brickwork has created a hole a metre wide in a pavement along Zhong Yang Da Jie, or Central Avenue.
While engineers don't point the finger at anyone over the subsidence, their observations about normal industry practice suggest the local government may have cut corners on its reclamation and sold the newly formed land prematurely in order to recoup its investment.
Most of the land in the district was created through reclamation in the mid to late 1990s. The government of Baoan, one of Shenzhen's six administrative zones, has spent about 4 billion yuan reclaiming land and building infrastructure.
The Construction Bureau of Baoan has invited experts to investigate the cracks. The bureau said preliminary findings showed the buildings were safe. Ground settlement was inevitable after land was reclaimed on soft foundations near the Pearl River estuary, it said.
Similar problems occurred in 2007 around Macau's stadium, built for the 2005 East Asian Games, and beside the StarWorld casino on the Cotai Strip. Both were built on land reclaimed from the Pearl River estuary.
Structural engineers Greg Wong Chak-yan, a former president of the Hong Kong Institute of Engineers, and So Yiu-kwan said it normally took 10 years for reclaimed land to settle before construction should begin.
Wong said the settlement period could be shortened to five years if silt was properly removed before reclamation. So said the settlement period could be shortened only if silty foundations were properly dried.
'Without sufficient settlement before construction, there may be uneven future settlement, resulting in leaning buildings,' So said.
Few of the district's reclamation projects involved the expensive process of silt treatment, according to Shenzhen engineers familiar with the projects. And the government sold sites in the district often just a few years after they were reclaimed. Construction of residential towers began in the district in the early years of the century as developers took advantage of a property boom. For example, property firm Shum Yip bought an 18.4 hectare site for 415 million yuan in July 2002, about two years after the area was reclaimed. It began building Shum Yip New Shoreline in 2004.
Since the 1990s, Shenzhen has reclaimed 60 square kilometres from the sea - an area more than twice the size of Macau - and plans to reclaim a further 30 square kilometres by 2020.
It isn't alone. There has been a reclamation boom in other coastal areas of China, such as Hainan , as property prices have surged. Reclamation is attractive to governments and developers because it produces land without the hassle of dealing with small-property owners and negotiating compensation with them. Plus the sites have sea views, which bring premium prices.