Identifier

etd-11112009-113914

Degree

Master of Science in Civil Engineering (MSCE)

Department

Civil and Environmental Engineering

Document Type

Thesis

Abstract

The literature of unsaturated soils in terms of hydraulic and mechanical behavior is reviewed. The hydro- mechanical behavior of unsaturated soil was studied using experimental investigation and numerical simulation of 1D and 2D modeling in HYDRUS software. Low plasticity silty clay (CL) and sand bentonite mixed soil SB (5% and 2% bentonite) specimens were investigated. Soil water characteristics curve (SWCC) tests were carried out in CL sample along with shear wave velocity measurement test using bender element (BE). The influence of moisture variation on specimens was investigated to see its impact on suction and on stiffness of soil. Similarly, the influence of suction on stiffness of soil and influence of density on stiffness of soil were also observed separately. To see the influence of moisture variation on suction (SWCC) and the influence of moisture variation on soil hydraulic properties (specially, hydraulic conductivity), finite element modeling was prepared representing 1D and 2D simulation using HYDRUS software. The results from the experimental investigation were compared with the results from the HYDRUS simulation. From the research, it is concluded that if the moisture content of the soil is decreased, both suction and stiffness modulus of soil is found to be increased. With the decreased moisture content, the initial increasing rate of suction was found higher than the rate of increase of stiffness modulus of the specimen. It was also observed that further decreasing the moisture content to a certain level, stiffness of soil is found to be increased with higher rate than the rate of change of suction. The available models for prediction of soil water characteristics curve (SWCC) based on grain size distribution and index properties proposed by various researchers were also examined. Recommendations are proposed for future work.

Date

2009

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Sharma, Radhey S.

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