Land Subsidence in Shanghai and Its Influence on Transportation Infrastructure

Abstract

Shanghai is located in the coastal region of the Yangtze River Delta which has a phreatic aquifer and five confined aquifers labeled from Confined Aquifer I (CA I) to Confined Aquifer V (CA V). During nearly 100 years of groundwater exploitation, the main exploited aquifers have been switched from CA II and CA III to CA IV and CA V. The deep soil layers went through great compaction because of groundwater withdrawal and became relatively stable after adoption of groundwater recharging measures. However, the shallow soil layers are still deforming as a result of construction activities i.e. underground space exploitation, which causes different responses of transportation infrastructures buried in different depths. Of the three investigated transportation infrastructures, the elevated roads suffer the least from land subsidence and the subsidence of the ground roads is the largest while the subsidence of metro tunnels is between the other two infrastructures.