Effect of chemical transport on seepage and stability of geotechnical structures.

Persistent Link:
http://hdl.handle.net/10150/187328
Title:
Effect of chemical transport on seepage and stability of geotechnical structures.
Author:
Ahn, Taebong
Issue Date:
1995
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Soil properties such as stress-strain response and hydraulic conductivity are affected by the transport of chemicals in soils. For stress-deformation and stability analysis of geotechnical structures, it is necessary to consider the effect of chemicals on the stress-strain-strength behavior. In this study, the residual flow procedure is modified to incorporate the chemical effects on the hydraulic conductivity to solve interface between fresh water and salt water in intrusion problems. The results are compared with previous analysis that did not consider chemical effect under the interface. The residual flow procedure of free surface problem is also modified to involve the capillary zone that experiences influences in soil strength parameters. In this study, the chemical considered is sodium chloride. Laboratory model tests are performed to study the changes in conductivity and free surface seepage characteristics of sand-bentonite mixtures with different concentrations of sodium chloride. A series of laboratory triaxial tests are performed on the cylindrical specimens of sand-bentonite mixture with different (5, 10, 15%) sodium chloride contents. Deformation (elastic modulus, E) and strength (cohesion, c, and angle of friction, φ) parameters are obtained from the triaxial tests as functions of confining pressure and sodium chloride concentrations. The stress-strain-strength behavior based on the above parameters is introduced in a finite element procedure with the residual flow procedure (RFP) as explained above. The latter allows consideration of free surface seepage with locations of salt water fronts in dams/slopes subjected to transient (rise - steady state - draw down) fluctuations in the upstream heads. By integrating a slope stability (limit equilibrium) procedure in the finite element method, factors of safety with time are computed. The analyses are performed with fresh water and salt water, and the two results are compared to identify the effect of salt water on stability and deformation in a typical dam configuration. Overall, the study presents an integrated procedure in which constitutive response as affected by salt water is introduced in a finite element procedure. The methodology can permit stress-deformation and stability analyses of geotechnical structures once the stress-strain models, including the effect of chemicals, are established based on appropriate laboratory tests.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Civil Engineering and Engineering Mechanics; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Desai, Chandrakant S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleEffect of chemical transport on seepage and stability of geotechnical structures.en_US
dc.creatorAhn, Taebongen_US
dc.contributor.authorAhn, Taebongen_US
dc.date.issued1995en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSoil properties such as stress-strain response and hydraulic conductivity are affected by the transport of chemicals in soils. For stress-deformation and stability analysis of geotechnical structures, it is necessary to consider the effect of chemicals on the stress-strain-strength behavior. In this study, the residual flow procedure is modified to incorporate the chemical effects on the hydraulic conductivity to solve interface between fresh water and salt water in intrusion problems. The results are compared with previous analysis that did not consider chemical effect under the interface. The residual flow procedure of free surface problem is also modified to involve the capillary zone that experiences influences in soil strength parameters. In this study, the chemical considered is sodium chloride. Laboratory model tests are performed to study the changes in conductivity and free surface seepage characteristics of sand-bentonite mixtures with different concentrations of sodium chloride. A series of laboratory triaxial tests are performed on the cylindrical specimens of sand-bentonite mixture with different (5, 10, 15%) sodium chloride contents. Deformation (elastic modulus, E) and strength (cohesion, c, and angle of friction, φ) parameters are obtained from the triaxial tests as functions of confining pressure and sodium chloride concentrations. The stress-strain-strength behavior based on the above parameters is introduced in a finite element procedure with the residual flow procedure (RFP) as explained above. The latter allows consideration of free surface seepage with locations of salt water fronts in dams/slopes subjected to transient (rise - steady state - draw down) fluctuations in the upstream heads. By integrating a slope stability (limit equilibrium) procedure in the finite element method, factors of safety with time are computed. The analyses are performed with fresh water and salt water, and the two results are compared to identify the effect of salt water on stability and deformation in a typical dam configuration. Overall, the study presents an integrated procedure in which constitutive response as affected by salt water is introduced in a finite element procedure. The methodology can permit stress-deformation and stability analyses of geotechnical structures once the stress-strain models, including the effect of chemicals, are established based on appropriate laboratory tests.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineCivil Engineering and Engineering Mechanicsen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairDesai, Chandrakant S.en_US
dc.contributor.committeememberContractor, Dinshaw N.en_US
dc.contributor.committeememberArmaleh, Sonia Hannaen_US
dc.contributor.committeememberKundu, Tribikramen_US
dc.contributor.committeememberDaDeppo, D. A.en_US
dc.identifier.proquest9620388en_US
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