Articles | Volume 372
Proc. IAHS, 372, 13–15, 2015
https://doi.org/10.5194/piahs-372-13-2015
Proc. IAHS, 372, 13–15, 2015
https://doi.org/10.5194/piahs-372-13-2015

  12 Nov 2015

12 Nov 2015

Investigation of alternative mechanisms of aquifer-system compaction and land subsidence in Shanghai

Y. Yuan, Y.-S. Xu, S.-L. Shen, and N. Zhang Y. Yuan et al.
  • State Key Laboratory of Ocean Engineering, Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai, China

Abstract. Alternative subsidence mechanisms related to groundwater extration and surface loading of built infrastructure in Shanghai have been evaluated to explain continued subsidence despite the controlled reduction of groundwater extraction. The traditional theory of aquifer-system compaction embodied in the aquitard drainage model cannot fully explain this phenomenon. Two possible alternative mechanisms were studied previously: (i) surface loading attributed to urban construction; (ii) creep occuring in sandy deposits of aquifers. These mechanisms could not fully explain the observed subsidence. Two additional alternative mechanistic models are proposed that involve principles of load transfer considering the temporally and spatially redistributed stresses associated with groundwater extraction: (i) the Cosserat continuum mechanism, considering shear force on the permeable coarse-grained matrial in the aquifer due to hydraulic gradients in the aquifer; and (ii) internal erosion of fine-grained (clay and silt) particles within the aquifer. Initial results based on simulations incorporating Cosserat mechanics look promising.

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Short summary
Two additional alternative mechanistic models are proposed that involve principles of load transfer considering the temporally and spatially redistributed stresses associated with groundwater extraction: i) Cosserat continuum mechanism, considering shear force in the aquifer due to hydraulic gradients in the aquifer; and ii) internal erosion of fine-grained (clay and silt) particles within the aquifer. Initial results based on simulations incorporating Cosserat mechanics look promising.