Masters Theses

Xiaoyi Zhao

Keywords and Phrases

Biopolymer Modification; Multistep Outflow Simulation; SWCC

Abstract

"In recent decades, biopolymers have shown promising applications in soil modification due to its environmental friendly nature. Most of the studies, however, focused on mechanical properties at saturated or unsaturated conditions. The study on unsaturated soil behaviors under controlled pore air and pore water pressures were limited. Soil-water characteristic curve (SWCC), relating water content with matric suction is a key property to evaluate unsaturated soils. With SWCC, other soil properties, such as hydraulic conductivity and shear strength can be estimated. In this study, SWCC of sands modified with different biopolymers were measured with both Tempe cell and Fredlund SWCC device. An elevation-controlled low suction (0.01 to 5 kPa) horizontal tube was developed to accurately measure SWCC of sands. Corrections for air diffusion and evaporation were performed. The results were fitted by both Fredlund and Xing and van Genutchen equations. In addition, inverse simulation of SWCC based on one-step or multistep SWCC measurements were carried out with software Hydrus 1D, finite element software. The measured SWCC results of mine tailing were used as an example. The inverse model can significantly reduce the time to measure a SWCC curve, especially for soils with low hydraulic conductivity (clay and silt). Three different input outflow methods were used, namely multiple single-step outflow method (MSOM), one-step outflow method (OOM), and multiple-step outflow method (MOM). Their performance was evaluated by both SWCC results and outflow vs. time curves. It was found that MOM provided the most accurate SWCC, while MSOM yielded the most accurate Flux -Time results"--Abstract, page iii.

Advisor(s)

Bate, Bate

Committee Member(s)

Luna, Ronaldo
Volz, Jeffery S.

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering

Publisher

Missouri University of Science and Technology

Publication Date

2014

Pagination

xi, 99 pages

Note about bibliography

Includes bibliographical references (pages 95-98).

Rights

© 2014 Xiaoyi Zhao, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Soil-structure interaction -- Mathematical models
Biopolymers -- Analysis
Swelling soils

Thesis Number

T 10851

Electronic OCLC #

953991148

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