Infrastructure protectionScientist tackles China's "sinking cities" problem

Published 26 January 2011

A University of Nottingham researcher has been awarded funding to help China prevent human disaster as some of its fastest-growing cities sink under the weight of towering skyscrapers; one example: Shanghai, one of the most densely-populated cities in the world, is sinking at an average rate of between two centimeters to four centimeters a year, putting pressure on underground pedestrian and railway tunnels and building foundations

Shanghai, built on a swamp, sinks at a rate of 3 cm per year // Source: life.com

A University of Nottingham researcher has been awarded funding to help China prevent human disaster as some of its fastest-growing cities sink under the weight of towering skyscrapers.

Dr. Andrew Sowter, a mathematician and scientist at the University of Nottingham Ningbo, China (UNNC), is developing a computer program that will help Chinese authorities identify with much greater accuracy exactly where, and by how much, structures are moving.

The National Natural Science Foundation of China — affiliated to China’s highest governing body, the State Council — has granted funding of about ¥500,000 (about £50,000; US$75,000; €60,000) for research that will use Shanghai as a case study.

The results of the research will include dramatically improved geological data for Shanghai as well as important software technology developments that can be applied to other cities in China and the world.

Shanghai, one of the most densely-populated cities in the world, is believed to be sinking at an average rate of between two centimeters to four centimeters a year, putting pressure on underground pedestrian and railway tunnels and building foundations.

Subsidence can lead to the collapse of tunnels and nearby buildings.

In 2003 subsidence was blamed for the collapse of an eight-storey building in Shanghai’s inner city Bund region, which is known for its iconic commercial real estate.

Shanghai, like several other coastal cities in China, is built on marshy soil, making it vulnerable to sinking.

The pumping of groundwater to cater for a massive, growing population has been a significant contributor to subsidence. The problem has been exacerbated by the country’s decades-long building boom amid rapid urbanization, notes Dr. Sowter, who supervises UNNC engineering students at the Ph.D. level.

The authorities in Shanghai and elsewhere along China’s east coast are concerned about their sinking cities, which are also vulnerable to rising sea levels as the polar caps melt from global warming.

“The authorities have continued to enlist state-of-the-art technology to help them in this battle. This NSFC project brings them up-to-date with the latest scientific developments,” said Sowter.

The UNNC scientist’s sophisticated software analyses satellite images gathered over several years and can reveal how much land has moved, in millimeters, across the entire city.

Sowter is working in collaboration with Shanghai’s Tongji University, which is gathering ground information to confirm the results of data gathered from space.

“We are advancing and refining existing computer programs so that we can identify risks with greater confidence of the accuracy of the results.

Rather than just measuring the problem, we