Geological Engineering Commons^™

Imaging The Subsurface In Karst Terrain Using Electrical Resistivity Tomography, Evgeniy V. Torgashov

Doctoral Dissertations

"Five electrical resistivity tomography (resistivity) case studies are presented. The first case study, entitled "Springfield Underground", includes ERT data acquired with the purpose of imaging the ceiling of an limestone aggregate mine following simultaneous localized roof failure. The interpretation of the ERT data indicates roof rock failure occurred at the intersection of two previously unmapped near-vertical solution-widened fractures.

At the "Chesterfield Dam" site, resistivity data were acquired to identify the zone of seepage through an earthfill dam. The seepage pathway beneath the dam is interpreted as through a solution-widened fracture, the top of which constituted a segment of the original …

Performance Characterization And Optimization Of Microgrid-Based Energy Generation And Storage Technologies, Joe D. Guggenberger Ii

Doctoral Dissertations

"Renewable energy-powered microgrids have proven to be a valuable technology for self-contained (off-grid) energy systems. Characterizing microgrid system performance pre-deployment would allow the system to be appropriately sized to meet all required electrical loads at a given renewable source operational time frequency. A vanadium redox battery was empirically characterized to determine operating efficiency as a function of charging characteristics and parasitic load losses. A model was developed to iteratively determine system performance based on known weather conditions and load requirements. A case study was performed to compare modeled system performance to measurements taken during operation of the microgrid system. Another …

Saturation Effects On Mechanical Excavatability Of Roubidoux Sandstone Under Selected Rock Cutting Tools, Muhammad Zubair Abu Bakar

Doctoral Dissertations

"This study investigated the differences in the cutting performance of two rock cutting tools in dry and saturated rock. For this purpose, a permeable quartzose sandstone was subjected to a series of full scale linear rock cutting tests, in both dry and saturated conditions, using a constant cross-section (CCS) disc cutter and a radial drag pick at a constant cutting speed.

In this rock, saturation with water reduced the forces acting on the disc cutter by 27-48% (significant at 90% confidence), but also reduced the chip yield by nearly as much. Even though the specific energy of fragmentation went down …

Surface Expressions Of Discontinuities, And The Estimation Of Their 3-D Orientations Using Combined Lidar And Optical Imaging, James Nii Aboh Otoo

Doctoral Dissertations

"The importance of the collection and analysis of data on discontinuities cannot be overemphasized. Problems which include sampling difficulties, risks, limited access to rock faces and exposures, and the delay in data collection has led to a high need for data collection tools and analysis techniques that can overcome these problems.

Discontinuities manifest themselves as either traces or as facets. Traces are linear features that intersect with both the discontinuity and the rock cut. Facets are the actual discontinuity surfaces that are exposed in the rock cut. Facets can be natural or induced. Identifying a facet as either natural or …

Measuring The Orientations Of Hidden Subvertical Joints In Highways Rock Cuts Using Ground Penetrating Radar In Combination With Lidar, Adnan Mohammed Aqeel

Doctoral Dissertations

"Mapping discontinuities in rock cuts and measuring their orientations is crucial in assessing the stability of rock masses. This can be done usually using manual methods such as scanline or advanced techniques such as LIDAR. However, these methods are used only to map exposed discontinuities which may cause underestimation for slope stability. Accordingly, ground penetrating radar (GPR) has been recently used to detect such hidden discontinuities.

The used 400 MHz monostatic GPR antenna was significantly able to detect and map hidden subvertical joints within 4 m depths in five sandstone highways rock cuts and within 3 m depths in two …