GEOPHYSICAL SURVEY TECHNIQUES FOR IDENTIFYING POTENTIAL COLLAPSE FEATURES UNDER HIGHWAYS

An abandoned coal mine under Interstate 70 in eastern Ohio collapsed and created a large crater along the highway a few years ago. A myriad of unmapped features under the State's roadways threatens similar localized collapses. These catastrophic failures may cause loss of life and always cause traffic disruption and require extensive repair expenses. Identifying the zones, which are likely to fail, would allow remedial action to prevent future failure. Methods to locate these zones need to be inexpensive enough to allow widespread use but focused enough to target very specific problem areas. Geophysical survey techniques have the potential for meeting these requirements. The principal objective of the present research study was to develop a reconnaissance geophysical survey technique to delineate the zones that can be further investigated by borings or by localized geophysical studies to determine the nature and probability of significant failures. Accordingly, several different geophysical techniques were adopted during the summer of 1998. The results obtained from this study show that seismic refraction, resistivity imaging and surface wave profiling have the most potential for meeting the project objectives and should be studied further in phase two.