Modeling of earth fissures caused by land subsidence due to groundwater withdrawal
Article, Other literature type
Panda, B. B.
Rucker, M. L.
Fergason, K. C.
- Publisher: Copernicus Publications
(issn: 2199-899X, eissn: 2199-899X)
GE1-350 | QE1-996.5 | Environmental sciences | Geology
Land subsidence and earth fissures are phenomena related to groundwater
withdrawal in a sedimentary basin. If the rock basement or basin lithology
is irregular, both vertical and horizontal displacements can be induced due
to differential settlement and tensile stresses appearing in the soil mass.
If the differential settlement is of sufficient magnitude, earth fissuring
can occur within tensile zones. The magnitudes of compaction and fissure
geometry are closely related to the thickness and skeletal compressibility
of fine-grained sediments within the aquifer system. Land subsidence and
earth fissuring were modeled by employing a two-dimensional (2-D) coupled
seepage and stress-strain finite element analysis. The basin bedrock
geometry, lithological variation, measurements of surface displacements, and
changes in hydraulic head were the critical input parameter for the
subsidence modeling. Simulation results indicate that strain had exceeded
the approximate threshold for fissure formation of 0.02 to 0.06 % in
the area of the identified fissures. The numerical model was used to predict
future subsidence and potential earth fissures for flood control structures
within the metro Phoenix area.