This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
One of the most economical and viable methods of soil improvement is dynamic compaction. It is a simple process that uses the potential energy of a weight (8 tonne to 36 tonne) dropped from a height of about 1 m to 30 m, depending on the project requirement, on to…
One of the most economical and viable methods of soil improvement is dynamic compaction. It is a simple process that uses the potential energy of a weight (8 tonne to 36 tonne) dropped from a height of about 1 m to 30 m, depending on the project requirement, on to the soil to be compacted hence densifying it. However, dynamic compaction can only be applied on soil deposits where the degree of saturation is low and the permeability of the soil mass is high to allow for good drainage. Using dynamic compaction on saturated soil is unsuitable because upon application of the energy, a part of the energy is transferred to the pore water. The technique also does not work very well on soils having a large content of fines because of the absence of good drainage. The current research aims to develop a new technology using biogenic gas production to desaturate saturated soils and extend the use of dynamic compaction as a ground improvement technique to saturated soils with higher fines content. To evaluate the feasibility of this technology an experimental program has been performed. Soil columns with varying soil types have been saturated with substrate solution, resulting in the formation of nitrogen gas and the change in soils volume and saturation have been recorded. Cyclic triaxial tests have been performed to evaluate the change in volume and saturation under elevated pressure conditions and evaluate the response of the desaturated soil specimens to dynamic loading. The experimental results showed that soil specimens treated with MIDP under low confinement conditions undergo substantial volume expansion. The amount of expansion is seen to be a factor of their pore size, which is directly related to their grain size. The smaller the grain size, smaller is the pore size and hence greater the volume expansion. Under higher confining pressure conditions, the expansion during gas formation is suppressed. However, no conclusive result about the effect of the desaturation of the soil using biogenic gas on its compactibility could be obtained from the cyclic triaxial tests.
