Review of the advanced monitoring technology of groundwater–air pressure (enclosed potentiometric) for karst collapse studies

Abstract

This paper presents an overview of the groundwater–air pressure monitoring technology for karst sinkholes. Karst collapses often occurred rapidly without prior warning. The early warning for potential karst collapses has been one of the most challenging problems around the world. In fact, many karst collapses are kind of sudden geohazards and mainly induced by abrupt changes of hydrodynamic conditions within karst conduit systems. Traditionally, only groundwater level monitoring was applied to monitoring the karst collapses, which did not reflect the hydrodynamic conditions within karst conduit systems. The monitoring technology of groundwater–air pressure was proposed by the Institute of Karst Geology, China in 1998 to study the formation mechanisms, monitoring and forecast of karst collapses. This technology has been improved in the past 20 years and applied to collapse risk assessment, triggering factor evaluation, and controlling drawdown of the groundwater levels during underground civil engineering works at 11 study sites. This advanced technology is characterized by improved borehole drilling, special sealing technique of borehole orifice, and high-frequency data logging. The recommended logging interval is at least 5–20 min to capture the transient changes of groundwater–air pressure within karst conduit systems. The pressure transducers used in this technique are retrievable and can be reused or recycled.