Understanding ground rupture due to groundwater overpumping by a
large lab experiment and advanced numerical modelling
S. Nardean, M. Ferronato, P. Teatini
Dept. of Civil, Environmental and Architectural Engineering,
University of Padova, Padova, Italy
Y. Zhang, X. Gong
Key Laboratory of Earth Fissures Geological Disaster,
Ministry of Land and Resources, Geological Survey of Jiangsu Province, Nanjing, China
S. Ye
School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
Ground rupture due to groundwater pumping is a major environmental hazard
accompanying land subsidence in some areas. Ground ruptures usually develop when a significant
compaction affects a sedimentary sequence with peculiar geological conditions, for example, the presence
of a shallow bedrock with buried ridges. A laboratory test was developed with the aim at improving our
understanding of the mechanisms responsible for rupture generation in this particular hydrogeological
setting, typical, for instance, of the Guangming village, China. A 0.8-m high concrete prism, representing
a rocky ridge, was placed in a 4.0-m long, 1.8-m wide, and 1.4-m high box and buried by alluvial material.
The box was saturated and then drained, with the formation of a main crack above the prism-shaped
ridge. The measured water content, vertical displacements, strains, rupture initiation, and growth are
analyzed through an original coupled 3D-numerical model, simulating the variably saturated groundwater
flow in a deformable and fractured porous medium. To our knowledge, this is the first application of
such a kind of model to a lab-scale experiment. Despite the uncertainty on the material parameters, the
numerical model allows satisfactorily reproducing the observed groundwater flow, land subsidence,
and rupture features (depth and width). The rupture dynamics is captured in part as well, despite the
employment of a simple Mohr-Coulomb failure criterion and although other forces (e.g., electrochemical)
may likely play a role at the metric scale of the lab test. The modeling outcomes provide a clear view on
how the rupture develops from the surface and propagates downward.
