| Summary: | 博士 === 國立交通大學 === 土木工程研究所 === 83 === The purpose of this thesis is to develop a general Galerkin
finite element model for simulating the land displacements due
to groundwater pumping. Three-dimensional equations of
equilibrium (force balance) and flow in porous media were
coupled to describe land displacements that occur as a result
of the pressure decline in aquifers. A Galerkin finite element
model based on these equations was developed. The saturated/
unsaturated behavior and the isotropic/cross-anisotropic
properties of the permeability and elasticity were considered
when the model was formulated. The change in the body force in
saturated and unsaturated zones of aquifers was considered in
the equilibrium equation. The proposed finite element model was
verified by comparing its simulation results with those of
known analytical solutions for simplified cases. The
simulation of displacements due to pressure decline in
unsaturated media was also preformed. Those results
demonstrated that the choice of boundary ranges for an aquifer
with infinite domain may significantly affect the estimated
horizontal and vertical displacements. To obtain a good
estimation of land displacements, the boundary ranges should be
carefully chosen. Simulation results also indicated that the
change in body force should be considered once an unconfined
aquifer has been pumped. Otherwise, the horizontal
displacement and vertical displacement in unconfined aquifers
would be overestimated and underestimated, respectively. The
behavior of land displacements due to pumping was shown to be
affected by the change in the total stresses in aquifers and
depend on the isotropic/cross-anisotropic properties of the
aquifer elasticity and permeability.
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