Experimental study of land subsidence in response to groundwater withdrawal and recharge in Changping District of Beijing

• Published in: PloS one 2020-05, Vol.15 (5), p.e0232828-e0232828
• Main Authors: Cao, Yanbo, Wei, Ya-Ni, Fan, Wen, Peng, Min, Bao, Liangliang
• Format: Article
• Language: English
• Subjects: Aquifers; Artificial intelligence; Biology and Life Sciences; Causes of; Civil engineering; Compressibility; Compression; Compression tests; Computer and Information Sciences; Creep strength; Deformation; Earth Sciences; Ecology and Environmental Sciences; Elastic deformation; Environmental aspects; Exploitation; Geology; Groundwater; Groundwater overdraft; Groundwater recharge; Groundwater withdrawal; Land subsidence; People and Places; Physical Sciences; Plastic deformation; Pore water; Pore water pressure; Research and Analysis Methods; Soil compressibility; Soils; Subsidence; Subsidences (Earth movements); Water pressure; Water transfer
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0232828

Over exploitation of groundwater in Changping District of Beijing city has caused serious land subsidence in the past decades. In recent years, the operation of the South-to-North Water Transfer Project has reduced the land subsidence rate. In this paper, Experimental tests are performed using the GDS Consolidation Testing System to characterize the compression and rebound of soils at depths of less than 100 m caused by groundwater withdrawal and recharge in Changping District. The results indicate that the compressible layers are the main contributors to land subsidence. The first compressible layer experiences greater deformation and more considerable hysteresis than the other compressible layers with the same decrease in the pore water pressure. Therefore, the exploitation of the adjacent aquifer should be controlled in the future. The deformation in the second and third compressible layers is a gradual and long-term process with little rebound; therefore, the subsidence should be seriously addressed when the groundwater in the two compressible layers is exploited on a large scale. In the same compressible layer, silty clay is more compressible and hysteretic than silt. For the same soil sample, the deformation rate decreases gradually as the pore water pressure decreases, whereas the creep deformation shows an overall increasing trend. A parameter named the subsidence index Cw is proposed in this paper to describe the soil compressibility during groundwater withdrawal. All the soil samples are characterized by elastic-plastic deformation, and the shallow soil samples with less pore water pressure decrease are more likely to rebound.