Disaster warning over race for subways
An academic from the Chinese Academy of Engineering criticised the competitive drive for building subways in 28 mainland cities without careful geological prospecting and warned of potential man-made disasters ahead.
Wang Mengshu was quoted in yesterday's 21st Century Business Herald as saying mainland authorities were building subway projects with unreasonably short deadlines, unreasonably low construction fees and irresponsibly vague blueprints.
'Because underground projects are irreversible and can't be demolished to rebuild, [we should] properly evaluate the geological risks ... and shouldn't leave regret and disaster to the next generation,' he said.
Both Shenzhen and Guangzhou have had safety problems exposed in their subway systems. On Tuesday, at least 25 people were injured when an ascending escalator in one of the busiest subway stations in Shenzhen jolted to a stop and reversed.
In October, an engineer who inspected the newly built Guangzhou airport link wrote in his blog that the concrete used in the project had failed a compression resistance test and the entire subway tunnel could be flooded if the concrete collapsed and caused water pipes next to the tunnel to burst.
Although Guangzhou authorities later publicly confirmed what the engineer claimed, the airport link was put into operation in late October as scheduled.
Wang attributed the frequent collapses to insufficient geological prospecting, as construction teams were forced to finish projects under strict deadlines in the cities' subway-building frenzy.
He said authorities should not give subway construction projects to bidders just because they offered the lowest price, because it was impossible to build a good subway system when budget constraints forced contractors to cut corners. 'Blueprints should be carefully discussed by experts, and authorities shouldn't change construction plans simply because they feel like it,' Wang said.
'Take Shenzhen as an example. The ground contains both soil and rocks... Heavy rainfall in the summer adds to the risk of collapse. Safety problems will result if the construction team does only half of the grouting work to save costs.'
Wang criticised the practice of having seven or eight contractors working together on a 20-kilometre subway project, because it was hard to find out who should take responsibility when problems occurred.
Twenty-eight cities are building about 1,645 kilometres of subway lines nationwide, according to the Herald. Beijing has 330 kilometres of track, Shanghai 420 and Guangzhou 218. In the next five years, Beijing is expected to increase to 580, Shanghai to 620 and Guangzhou 470, surpassing international cities such as Paris, London and Tokyo, the report said.
But Wang said that to compete on the length of subway systems was pointless. 'A subway is something designed to ease traffic jams, and mainland authorities have no reason to build subways in outskirts,' he said.
