Rain-damaged roads cost billions

Sections of nearly all national expressways in Gansu province have suffered dangerous subsidence following two months of heavy rain, forcing the government to spend billions of yuan on urgent repairs.

Tens of thousands of maintenance workers have had to be mobilised to complete all repairs by the end of next month, the provincial transport department said.

The affected expressways include the G6 from Beijing to Lhasa ; G22 from Qingdao to Lanzhou ; G30 from Jiangsu to Xinjiang ; and the G75 from Gansu to Hainan . All are part of the core of the mainland's expressway network and are strategically important for freight transport. Two provincial expressways, S1 and S2, also suffered similar damage.

The subsidence has produced many large surface cracks and holes on the roads. Some sections have even collapsed, and several highways have been closed because they are no longer safe for passengers. Those still open have seen severe traffic jams. The damage had caused losses of more than 2.4 billion yuan (HK$2.94 billion) by the end of last month.

Gansu's transport department said that heavy rain was the main reason for the damage. Rainfall in June was 20 per cent higher than usual and in July reached a seven-year high of 70mm. Officials said that the subsidence was not caused by faulty construction.

Experts said soil conditions in Gansu were not suitable for expressway construction. Professor Yan Zhixin , director of the geo-engineering research institute at Lanzhou University, said yesterday that many parts of the province were covered by a thick layer of collapsible loess, which is formed by layers of windblown silt, and tended to soften and sink after rain even without the weight of buildings.