A Genetic Algorithm for Predicting Pore Geometry Based on Air Permeability Measurements

Ünsal, Evren; Dane, J. H.; Dozier, Gerry

doi:10.2136/vzj2004.0116

Cited by 28 publications

(36 citation statements)

References 28 publications

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“…Such a power law has been reported for many porous media (Brooks & Corey, ; Childs & Collis‐George, ; Collis‐George, ; Dane et al, ; Millington & Quirk, ; Stonestrom, ; Tang et al, ; Touma & Vauclin, ; Tuli & Hopmans, ; Unsal et al, ) in soils; see Figures (Ghanbarian‐Alavijeh & Hunt, ). In these analyses, the unknown value ε t , the critical air fraction for percolation, was treated as an adjustable parameter, but its value was shown predictable from the water retention curves (Ghanbarian‐Alavijeh & Hunt, ).…”

Section: Constitutive Relationships For the Unsaturated Zonesupporting

confidence: 61%

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Hunt

Sahimi

2017

Reviews of Geophysics

134

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We describe the most important developments in the application of three theoretical tools to modeling of the morphology of porous media and flow and transport processes in them. One tool is percolation theory. Although it was over 40 years ago that the possibility of using percolation theory to describe flow and transport processes in porous media was first raised, new models and concepts, as well as new variants of the original percolation model are still being developed for various applications to flow phenomena in porous media. The other two approaches, closely related to percolation theory, are the critical‐path analysis, which is applicable when porous media are highly heterogeneous, and the effective medium approximation—poor man's percolation—that provide a simple and, under certain conditions, quantitatively correct description of transport in porous media in which percolation‐type disorder is relevant. Applications to topics in geosciences include predictions of the hydraulic conductivity and air permeability, solute and gas diffusion that are particularly important in ecohydrological applications and land‐surface interactions, and multiphase flow in porous media, as well as non‐Gaussian solute transport, and flow morphologies associated with imbibition into unsaturated fractures. We describe new applications of percolation theory of solute transport to chemical weathering and soil formation, geomorphology, and elemental cycling through the terrestrial Earth surface. Wherever quantitatively accurate predictions of such quantities are relevant, so are the techniques presented here. Whenever possible, the theoretical predictions are compared with the relevant experimental data. In practically all the cases, the agreement between the theoretical predictions and the data is excellent. Also discussed are possible future directions in the application of such concepts to many other phenomena in geosciences.

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Section: Constitutive Relationships For the Unsaturated Zonesupporting

confidence: 61%

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Hunt

Sahimi

2017

Reviews of Geophysics

134

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“…The basic theory of GA has been explained by many previous researchers 4),5),9), 10) . Therefore, only the application procedure of GA in this study is summarized as follows.…”

Section: (3) Inverse Estimation Techniquementioning

confidence: 99%

Estimating Unsaturated Hydraulic Properties of Soft Rock by Three Different Flow Models

Amarasinghe¹,

Watanabe²,

Maung³

2011

J. JSCE

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Several countries utilize the sedimentary soft rock for nuclear waste disposal because it has a potential to use as a host rock. Therefore, the analytical researches on the unsaturated flow of this type of rocks have been increased to assure the safety of the disposal. In this study, the applicability of three models; Brooks-Corey/Burdine (BC), Campbell (CB) and van Genuchten (VG) that have been used commonly for soil was studied, by applying these to one dimensional flow induced by evaporation in six disk shaped soft rock samples. The best parameters in each model were inversely estimated by adopting genetic algorithm (GA). It was clearly found that the best parameters in BC and CB models can be easily estimated and the measured evaporation change could be well analyzed. However, the parameters in VG model could not be estimated easily. It was found that BC and CB models are more robust than the VG model for the analysis of unsaturated flow in soft rock.Key Words : sedimentary soft rock, unsaturated flow, inverse estimation, genetic algorithm I TRODUCTIOAs a possible and safe way of hazardous waste disposal, it is isolated in tunnels excavated in deep underground of sedimentary soft rock (mudstone, sandstone, tuff, etc.) which is considered as one of the preferable types of host rock. The reason is that the hydraulic conductivity of soft rock is generally low and it contains clay minerals which have high ability to absorb the radionuclide. However, many reasons such as the unsaturated zone which was created during the excavation, the stress condition change of the tunnel wall and the settlement of waste under the ventilation conditions may cause the generation of many fractures that can form a 'damaged zone'. This 'damaged zone' thus formed around the tunnel becomes high permeable because of many fractures created in it. As a result, the groundwater and hazardous waste flow easily through this high permeable zone. It is crucial to estimate the unsaturated hydraulic properties and the thickness of this zone precisely because the drying mechanism of rock is one of the essential mechanisms to create fractures. For the estimation, the relationship among the relative hydraulic conductivity, saturation and suction pressure of the soft rock should be well evaluated. Although many theoretical/empirical models have been used for the approximation of unsaturated properties of soil, the suitable model for soft rock has not been clarified yet. Therefore, it is essential to study more in detail on a proper model fitting for soft rock. In this study, three different models; Brooks-Corey/Burdine (BC) model 1) , Campbell (CB) model 2) and van Genuchten (VG) model 3) which were originally proposed for soils, were utilized to investigate the applicability to the soft rock. THREE MODELS ADOPTEDThree models which are adopted to estimate unsaturated hydraulic properties in this study are summarized as follows.

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“…Genetic Algorithm (GA) is an evolutionary optimization algorithm currently used for the optimization process (Unsal et al 2005). It offers several advantages over the conventional search algorithms.…”

Section: Genetic Algorithmmentioning

confidence: 99%

“…The indirect estimation methods are easier than the direct measurement methods (van Dam et al 1990). These can be based on the numerical solution of the equations governing the flow process, which is subjected to the imposed boundary conditions (Eching and Hopmans 1993).…”

Section: Introductionmentioning

confidence: 99%

Study on the selection of unsaturated flow model for the different types of soil and soft rock

Amarasinghe

Watanabe

Ioku³

2011

Environ Earth Sci

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Precise estimation of unsaturated hydraulic properties of porous media is indispensable in various study areas, such as analyzing the moisture flow, the drying process occurring from the surface, and the pollutant migration beneath the ground surface. Although many empirical/theoretical models describing the unsaturated hydraulic properties have been proposed by several previous researchers, the best model for the different types of soil/rock may not be identical. Thus, the model selection process and the estimation technique of the parameters included in the models should be developed. In the present study, the inverse technique based on the transient evaporation change was investigated to select the model and estimate the model parameters. The experimental work was based on a relatively low permeable soft rock and a relatively high permeable sandy soil (Toyoura standard sand). Experimental equipment was developed to precisely measure the evaporation rate for the high permeable sandy soil.The Genetic Algorithm (GA) was adopted in the inverse technique as an optimization tool. In order to simplify the problem, only the drying process from the saturated condition was considered. It was established that the information concerning the transient evaporation change could be used for the model selection and parameter estimation. Further, the saturation distribution could be used for the selection of the models. The present study provides important information for the development of the model selection process.

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A Genetic Algorithm for Predicting Pore Geometry Based on Air Permeability Measurements

Cited by 28 publications

References 28 publications

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Estimating Unsaturated Hydraulic Properties of Soft Rock by Three Different Flow Models

Study on the selection of unsaturated flow model for the different types of soil and soft rock

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