Modeling of subsidence and stress-dependent hydraulic conductivity for intact and fractured porous media

Bai, M.; Elsworth, Derek

doi:10.1007/bf01020200

Cited by 98 publications

(43 citation statements)

References 19 publications

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“…Associated parameters for the equation can be obtained from laboratory and numerical experiments. The difference between the proposed equation and previous ones [11][12][13][14] is that (1) more general DFN representation of fracture system is used as the geometrical basis, (2) numerical experiments using the DEM approach are employed as the platform for deriving the stress-permeability relation, and (3) stress-induced channeling of flow caused by shear dilation can be more effectively considered.…”

Section: Construction Of the Empirical Equationmentioning

confidence: 99%

“…Analytical models of stress-dependent permeability of fractured rock masses based on orthogonal or persistent fractures sets are available [11][12][13] that consider the normal closures of fractures and constant shear dilations in both fractured and fractured-porous media. However, models based on persistent fractures have certain limitations in simulating the abrupt shear dilations and highly clustered flow paths resulting from stress changes.…”

Section: Introductionmentioning

confidence: 99%

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Stress-dependent permeability of fractured rock masses: a numerical study

Min

Rutqvist

Tsang

et al. 2004

International Journal of Rock Mechanics and Mining Sciences

443

249

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We investigate the stress-dependent permeability issue in fractured rock masses considering the effects of nonlinear normal deformation and shear dilation of fractures using a two-dimensional distinct element method program, UDEC, based on a realistic discrete fracture network realization.A series of "numerical" experiments were conducted to calculate changes in the permeability of simulated fractured rock masses under various loading conditions. Numerical experiments were conducted in two ways: (1) increasing the overall stresses with a fixed ratio of horizontal to vertical stresses components; and (2) increasing the differential stresses (i.e., the difference between the horizontal and vertical stresses) while keeping the magnitude of vertical stress constant.These numerical experiments show that the permeability of fractured rocks decreases with increased stress magnitudes when the stress ratio is not large enough to cause shear dilation of fractures, whereas permeability increases with increased stress when the stress ratio is large enough.Permeability changes at low stress levels are more sensitive than at high stress levels due to the nonlinear fracture normal stress-displacement relation. Significant stress-induced channeling is observed as the shear dilation causes the concentration of fluid flow along connected shear fractures.Anisotropy of permeability emerges with the increase of differential stresses, and this anisotropy can become more prominent with the influence of shear dilation and localized flow paths. A set of empirical equations in closed-form, accounting for both normal closure and shear dilation of the fractures, is proposed to model the stress-dependent permeability. These equations prove to be in good agreement with the results obtained from our numerical experiments.2

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Section: Construction Of the Empirical Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stress-dependent permeability of fractured rock masses: a numerical study

Min

Rutqvist

Tsang

et al. 2004

International Journal of Rock Mechanics and Mining Sciences

443

249

View full text Add to dashboard Cite

show abstract

“…Schrefler and Zhan (1993) developed a fully coupled model to simulate the slow transient phenomena involving flow of water and air in deforming porous media. Bai and Elsworth (1994) used a dual-porosity poroelastic model to represent the coupled flow and deformation behavior in fractured rock specimens. Yeh et al (1996) developed a general Galerkin finite element model to study the behavior of land displacements due to pressure decline in aquifers.…”

Section: Introductionmentioning

confidence: 99%

Simulation of fully coupled finite element analysis of nonlinear hydraulic properties in land subsidence due to groundwater pumping

et al. 2015

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A fully coupled mathematical model of land subsidence caused by groundwater pumping was established based on the mechanics of porous seepage and the theory of fluid-solid interaction. The mathematical model employing the Galerkin finite element method was proposed to simulate the deformation dependencies of hydraulic properties due to the water pressure decrease in aquifers. This model has been verified by comparing with the known analytical solutions in the confined aquifer. Results show that the simulated drawdown and displacements match well with those of analytical solutions. To evaluate the nonlinear effects of hydraulic properties in the seepage and consolidation coupling phenomena, the numerical model is applied to an ideal three layers numerical experiment. The results show that the subsidence rate is faster than conventional groundwater theory when the nonlinear hydraulic properties (NHP) are considered in the coupled model. The reason is that the water level decline due to groundwater withdrawal induces the soil compression and the porosity and permeability decrease. Decrease of permeability in regions adjacent to the pumping well produces hydraulic gradient and seepage forces that may result in accelerated subsidence. Therefore, the effect of the NHP is an interaction process of pore water pressure and soil consolidation deformation and should not be ignored. Further studies of various hydrogeology problems are recommended to consider the heterogeneity concerning different stratigraphic condition in the field.

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“…In particular, in a realistic setting, the geometric and hydrologic properties of the transport media may be subject to changes which can be both continuous and discrete in time. For example, such modifications may include the closure of fractures in salt deposits due to the plasticity of the medium [19] [20], the decrease in fracture aperture due to slow deposition [21], seasonal water content changes in seasons due to rainfalls [22], thermo-hydraulic-mechanical-chemical (THMC) couplings which can affect the permeability of the media and the average hydraulic gradient [23] [24][25] [26] or the abrupt changes in the fracture aperture due to shock events (e.g. earthquakes, volcanic eruptions, etc.)…”

Section: Introductionmentioning

confidence: 99%