The deformation behavior of soil mass in the subsidence region of Beijing, China

Abstract. Land subsidence induced by excessive groundwater withdrawal has been a major environmental and geological problem in the Beijing plain area. The monitoring network of land subsidence in Beijing has been established since 2002 and has covered the entire plain area by the end of 2008. Based on data from extensometers and groundwater observation wells, this paper establishes curves of variations over time for both soil mass deformation and water levels and the relationship between soil mass deformation and water level. In addition, an analysis of deformation behavior is carried out for soil mass with various lithologies at different depths depending on the corresponding water level. Finally, the deformation behavior of soil mass is generalized into five categories. The conclusions include: (i) the current rate of deformation of the shallow soil mass is slowing, and most of the mid-deep and deep soil mass continue to compress at a more rapid speed; (ii) the sand strata behaves elastically, while the clay soil mass at different depths is usually characterized by elastic-plastic and creep deformation, which can be considered as visco-elastoplastic.