Graduation Semester and Year
2015
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Civil Engineering
Department
Civil Engineering
First Advisor
Anand Puppala
Abstract
Surficial slope failure is a common problem experienced by most of the compacted earth dams in Texas and several other southern states in USA as a result of desiccation or shrinkage induced cracking of the surficial soils. Cracking of the soil occurs when the tensile stress exceeds the tensile strength during drying process. Tensile stress increases with an increase in shrinkage strain and thus soil chemical admixtures can reduce the tensile stress by reducing the shrinkage potential of soil. Inclusion of such admixtures invariably affects the tensile strength. Yet there are not many test methods that could be utilized for shrinkage characterization of the expansive soils and hence there is a major need to develop a method to perform better shrinkage characterization of soils. This has been the main objective of the present dissertation research. A test method presented as a shrinkage induced pressure (SIP) test was further refined to study the shrinkage potential, tensile strength, and desiccation cracking of soils. As a part of this study, several expansive soils were utilized and studied with the refined characterization method. A statistical tool was also developed to predict the SIP based on different soil variables. Also, three dimensional unsaturated slope stability analysis of the dam slope was conducted using the finite difference program FLAC3D to study the effects of seasonal moisture content fluctuations, formation of desiccation cracks and how these impact surficial slope stability. Also, a new treatment method that utilizes biopolymer to amend the soil to reduce desiccation cracking was evaluated using the developed characterization method. The moderate increase in the shear strength of the biopolymer treated soil compared to the untreated soil may work well in natural slope conditions of dam and highway embankments. This dissertation uses same characterization tool in the assessment of biopolymer treatment of expansive soils in reducing their shrinkage behavior. Future research directions are also presented in this field.
Keywords
Desiccation cracking, Shrinkage characterization, Expansive soils, Biopolymer, Surficial slope failure, Shrinkage induced pressure, Digital image correlation
Disciplines
Civil and Environmental Engineering | Civil Engineering | Engineering
License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.
Recommended Citation
Acharya, Raju, "Enhanced Shrinkage Characterization of Clayey Soils" (2015). Civil Engineering Dissertations. 295.
https://mavmatrix.uta.edu/civilengineering_dissertations/295
Comments
Degree granted by The University of Texas at Arlington