Detection of Underground Voids in Ohio by Use of Geophysical Methods


Book Description

Results of ground-penetrating radar surveys at three highway sites indicate that subsurface penetration varies widely with geologic material type and amount of cultural interference. Two highway sites were chosen over abandoned underground coal mines in eastern Ohio. A third site in western Ohio was chosen in an area known to be underlain by naturally occurring voids in limestone.






















Identifying Potential Collapse Features Under Highways


Book Description

In 1994, subsidence features were identified on Interstate 70 in eastern Ohio. These features were caused by collapse of old mine workings beneath the highway. An attempt was made to delineate these features using geophysical methods with no avail. The geophysical methods that were tried comprised ground penetrating radar, seismic refraction, and electromagnetics. Subsequently, drilling was employed as the primary technique to delineate the voids. The collapse was believed to be caused by active mine subsidence which was exacerbated by the dewatering of adjacent abandoned mine workings. It is postulated that there was too much overburden for the radar to penetrate to the mined interval at the designated site. The tunnels were too deep to be detected by the electromagnetic technique utilized, and the seismic refraction method lacked adequate resolution to delineate the voids.







Site Characterization in Karst and Pseudokarst Terraines


Book Description

This book provides a practical strategy for obtaining a more complete and accurate geologic site characterization. The strategy and methods to characterize complex geologic settings are readily available. The strategy utilizes readily available technology, basic science and good, old-fashioned common sense resulting in a solid understanding of geologic and even karst or pseudokarst conditions. We provide an introduction to many off-the-shelf methods available for site characterization as well as examples of their application throughout the book. The purpose of a geologic site characterization is to understand the 3-dimensional geologic framework, along with the engineering and hydrologic properties of a site including any man-made impacts. A well-done site characterization is the cornerstone of all geotechnical, groundwater and environmental projects. The geologic conditions, particularly karst conditions, can significantly impact a site including its structural stability, groundwater pathways and potential for rapid transport or traps for contaminants. Once we have adequately characterized the geologic conditions can we carry our remediation, design and construction, model flow, and make risk assessments that are accurate and reliable.