Remote Sensing Application for Sinkhole Monitoring Along Roadways

Several regions in the United States including Florida, Texas, and Kentucky are known to have overwhelming destruction caused by sinkholes due to various soil structures prone to subsurface voids. According to the U.S. Geological Survey, over $300 million per year on average is spent on sinkhole related damage in the United States [1]. When a sinkhole is detected early, the department of transportation can track the growth rate to make decisions when to disrupt travel flow for repair, and to budget the repair from a maintenance perspective rather than a hazardous emergency. Current practices used for detection include Standard Penetration Test, Ground Penetration Radar, and multi-channel seismic survey can typically cost from $1,000 -$10,000. This study focuses on a potential real-time remote sensing sinkhole monitoring system that is different from the standard practice used today by the Department of Transportation. The primary function of the early detection device is designed on the principle of a hollow-core auger with a free-falling mass displacement trigger. At the top, an electronic enclosure is placed and is used to power the device from a normally “off” state to an “on” state when a void is detected below the device. This triggering function allows the system to conserve its energy and have an in-situ period of several years. In order to test the certainty of the response of the auger exposed to the environmental conditions, a test was conducted at a construction fill pit. To simulate a cover-collapse sinkhole, a cavity was dug out approximately three inches below the estimated bottom of the auger. After two months of being in the ground, the test resulted in no sinkhole forming from the tunnel dug beneath the auger. The device during development tested as expected with some modifications needed.