MECHANICAL AND ELECTRON OPTICAL PROPERTIES OF A STABILIZED COLLAPSIBLE SOIL IN TUCSON, ARIZONA (MICROSCOPY, LIME-STABILIZATION).

Persistent Link:
http://hdl.handle.net/10150/187689
Title:
MECHANICAL AND ELECTRON OPTICAL PROPERTIES OF A STABILIZED COLLAPSIBLE SOIL IN TUCSON, ARIZONA (MICROSCOPY, LIME-STABILIZATION).
Author:
ALFI, ABDULAZIZ ADNAN SHARIF.
Issue Date:
1984
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:
This dissertation deals with collapsing soils that are prevalent in Tucson, Arizona. Upon wetting, such soils generally swell under small loads but collapse under large loads. Since the recognition of such collapsing soils in Tucson, before about two decades, more collapsing soils were encountered due to booming construction. Therefore, the main goal of this research was to study in depth the mechanism by which these soils collapse and to investigate the effect of certain mechanical and chemical treatment on that mechanism. The research included studies of undisturbed, compacted, and lime-treated samples. Both mechanical and physicochemical tests were conducted. The mechanical tests included collapse, swell, and unconfined compressive strength. The physicochemical tests involved X-ray diffraction and scanning electron microscopy. Various sites of highly collapsing soils were classified with respect to collapse according to existing criteria and the soil of one site was selected for a detailed investigation. A predictive collapse criterion was developed and used to classify the collapse susceptibility of soils in Tucson. The microstructure of the selected soil was investigated before and after collapse. A physical model was proposed to explain the mechanism of collapse. The effects of initial water content, sequence of loading and wetting, and level of loading on the engineering behavior of the selected soil were investigated. Stabilization by compaction was studied using impact and static methods at seven points on the Standard Compaction Curve. The benefits of hydrated-lime additive and the short-term reactions of lime-treated samples were also studied. The research results indicated that the microstructure of the soil is highly porous due to many interassemblage pores. Fine clay particles were found either clothing or buttressing the larger silt particles. The collapse was due mainly to weakening or failure of the clay connectors between the larger soil particles due to swelling of the expansive clay minerals, reduction of the strength of clay connectors due to wetting, dispersion of the supporting buttresses, and reduction of capillary tension. Compaction by both impact and static methods minimized the collapse but not the swell of the soil. Lime treatment completely suppressed the soil's tendency toward collapse and swell.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Soil mechanics -- Arizona -- Pima County.; Soil mechanics -- Arizona -- Tucson.; Soil stabilization -- Arizona -- Pima County.; Soil stabilization -- Arizona -- Tucson.; Soils -- Arizona -- Pima County -- Optical properties.; Soils -- Arizona -- Tucson -- Optical properties.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Civil Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Nowatski, Edward A.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleMECHANICAL AND ELECTRON OPTICAL PROPERTIES OF A STABILIZED COLLAPSIBLE SOIL IN TUCSON, ARIZONA (MICROSCOPY, LIME-STABILIZATION).en_US
dc.creatorALFI, ABDULAZIZ ADNAN SHARIF.en_US
dc.contributor.authorALFI, ABDULAZIZ ADNAN SHARIF.en_US
dc.date.issued1984en_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.abstractThis dissertation deals with collapsing soils that are prevalent in Tucson, Arizona. Upon wetting, such soils generally swell under small loads but collapse under large loads. Since the recognition of such collapsing soils in Tucson, before about two decades, more collapsing soils were encountered due to booming construction. Therefore, the main goal of this research was to study in depth the mechanism by which these soils collapse and to investigate the effect of certain mechanical and chemical treatment on that mechanism. The research included studies of undisturbed, compacted, and lime-treated samples. Both mechanical and physicochemical tests were conducted. The mechanical tests included collapse, swell, and unconfined compressive strength. The physicochemical tests involved X-ray diffraction and scanning electron microscopy. Various sites of highly collapsing soils were classified with respect to collapse according to existing criteria and the soil of one site was selected for a detailed investigation. A predictive collapse criterion was developed and used to classify the collapse susceptibility of soils in Tucson. The microstructure of the selected soil was investigated before and after collapse. A physical model was proposed to explain the mechanism of collapse. The effects of initial water content, sequence of loading and wetting, and level of loading on the engineering behavior of the selected soil were investigated. Stabilization by compaction was studied using impact and static methods at seven points on the Standard Compaction Curve. The benefits of hydrated-lime additive and the short-term reactions of lime-treated samples were also studied. The research results indicated that the microstructure of the soil is highly porous due to many interassemblage pores. Fine clay particles were found either clothing or buttressing the larger silt particles. The collapse was due mainly to weakening or failure of the clay connectors between the larger soil particles due to swelling of the expansive clay minerals, reduction of the strength of clay connectors due to wetting, dispersion of the supporting buttresses, and reduction of capillary tension. Compaction by both impact and static methods minimized the collapse but not the swell of the soil. Lime treatment completely suppressed the soil's tendency toward collapse and swell.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectSoil mechanics -- Arizona -- Pima County.en_US
dc.subjectSoil mechanics -- Arizona -- Tucson.en_US
dc.subjectSoil stabilization -- Arizona -- Pima County.en_US
dc.subjectSoil stabilization -- Arizona -- Tucson.en_US
dc.subjectSoils -- Arizona -- Pima County -- Optical properties.en_US
dc.subjectSoils -- Arizona -- Tucson -- Optical properties.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineCivil Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorNowatski, Edward A.en_US
dc.contributor.committeemembervan Zyl, Dirken_US
dc.contributor.committeememberScheele, Friedrichen_US
dc.contributor.committeememberNewlin, Philip B.en_US
dc.identifier.proquest8415062en_US
dc.identifier.oclc690960159en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.