Thesis (Honors)--College of William and Mary, 2009. / Includes bibliographical references (leaves 47-50). Also available via the World Wide Web.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 74-76). Also available via the Internet.

Thesis (B.A.)--Bryn Mawr College, Dept. of Geology, 2007. / Includes bibliographical references.

Geosynthetic clay liners (GCL) are a composite material commonly used as hydraulic barriers in landfill liners. Due to their dependence on hydration for proper function, the water retention curve (WRC) of a GCL is important. The inherent difficulty in obtaining the WRC, including the range of suction and composite material, has limited the number of GCL WRCs in the literature. In order to quantify the large range of suctions, a dual testing technique was developed, which uses a high capacity tensiometer to measure suctions for the low suction range (0 - 500 kPa) and a relative humidity sensor for the high suction range (3,000 - 1,000,000 kPa). In total, four different GCL products were tested, varying in both materials (woven and nonwoven geotextiles) and construction methods (thermal treatment and needle punching). The dual technique method was used to establish both wetting and drying curves that were presented as gravimetric, volumetric and bulk GCL void ratio WRCs. The WRCs of the different GCL products showed significant variation between their wetting and drying curves indicating that both needle punching and thermal treatment have a significant effect on the swelling behaviour of the GCL and its WRC. Theoretical equations were fit to the experimental data establishing the parameters that can be used for numerical modeling of these four GCL products. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-04-22 14:37:55.196

Fractals are a relatively recent development in mathematics that show promise as a foundation for models of complex systems like natural porous media. One important issue that has not been thoroughly explored is the affect of different algorithms commonly used to generate random fractal porous media on their properties and processes within them. The heterogeneous method can lead to large, uncontrolled variations in porosity. It is proposed that use of the homogeneous algorithm might lead to more reproducible applications. Computer codes that will make it easier for researchers to experiment with fractal models are provided. In Chapter 2, the application of percolation theory and fractal modeling to porous media are combined to investigate percolation in prefractal porous media. Percolation thresholds are estimated for the pore space of homogeneous random 2-dimensional prefractals as a function of the fractal scale invariance ratio b and iteration level i. Percolation in prefractals occurs through large pores connected by small pores. The thresholds increased beyond the 0.5927 porosity expected in Bernoulli (uncorrelated) networks. The thresholds increase with both b (a finite size effect) and i. The results allow the prediction of the onset of percolation in models of prefractal porous media. Only a limited range of parameters has been explored, but extrapolations allow the critical fractal dimension to be estimated for many b and i values. Extrapolation to infinite iterations suggests there may be a critical fractal dimension of the solid at which the pore space percolates. The extrapolated value is close to 1.89 -- the well-known fractal dimension of percolation clusters in 2-dimensional Bernoulli networks. The results of Chapters 1 and 2 are synthesized in an application to soil water retention in Chapter 3.

Thesis (Master of Engineering)--University of South Australia, 1991

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 110-112). Also available via the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

abstract: The importance of unsaturated soil behavior stems from the fact that a vast majority of infrastructures are founded on unsaturated soils. Research has recently been concentrated on unsaturated soil properties. In the evaluation of unsaturated soils, researchers agree that soil water retention characterized by the soil water characteristic curve (SWCC) is among the most important factors when assessing fluid flow, volume change and shear strength for these soils. The temperature influence on soil moisture flow is a major concern in the design of important engineering systems such as barriers in underground repositories for radioactive waste disposal, ground-source heat pump (GSHP) systems, evapotranspirative (ET) covers and pavement systems.. Accurate modeling of the temperature effect on the SWCC may lead to reduction in design costs, simpler constructability, and hence, more sustainable structures. . The study made use of two possible approaches to assess the temperature effect on the SWCC. In the first approach, soils were sorted from a large soil database into families of similar properties but located on sites with different MAAT. The SWCCs were plotted for each family of soils. Most families of soils showed a clear trend indicating the influence of temperature on the soil water retention curve at low degrees of saturation.. The second approach made use of statistical analysis. It was demonstrated that the suction increases as the MAAT decreases. The statistical analysis showed that even though the plasticity index proved to have the greatest influence on suction, the mean annual air temperature effect proved not to be negligible. In both approaches, a strong relationship between temperature, suction and soil properties was observed. Finally, a comparison of the model based on the mean annual air temperature environmental factor was compared to another model that makes use of the Thornthwaite Moisture Index (TMI) to estimate the environmental effects on the suction of unsaturated soils. Results showed that the MAAT can be a better indicator when compared to the TMI found but the results were inconclusive due to the lack of TMI data available. / Dissertation/Thesis / M.S. Civil Engineering 2011

The growing concern for water quality enhancement of our surface waters has led to changes in detention facility design. Providing a filter media for the effluent water to travel through before discharge into the environment has become an area of interest. Thus, detention facilities may be used for both water quality and quantity control. Different soil medias were studied for the potential of pollutant removal and infiltration rates usable in design work. Both laboratory and field experimentation were performed. A computer program was also developed to model stormwater movement through a swale detention system. This research was performed to examine filter media and to indicate the advisability of designing a combination of detention ponds and berms.