Ground surface rock buckling: analysis of collected cases and failure mechanisms

The potential for spontaneous failure of quarry pit floors by various buckling modes has increasingly become a concern because of the potential impacts on safety, the environment, and mining operations. The most notable and concerning form of buckling failure is referred to as a “pop up” which is a nearly-instantaneous and violent event similar to a rock burst. A means to evaluate potential risk from this hazard within a rational engineering framework is required to aid with licensing and operations decisions. A first step in understanding the likelihood of buckling event occurrence under various conditions is the review of a thorough compilation of past observed in situ events. The objective of this study is the development of a database of observed cases to provide insight into the various buckling failure modes and associated geotechnical conditions. Although available documented historic case study details vary significantly, the collected data, as a whole, is of value. All available, information on the geological environment, rock type, mechanical properties, in situ stresses, and buckle dimensions are documented within the database. The database has been analyzed and revealed trends relating buckling orientation and in situ stress orientation/magnitude. In addition, the database has been used to develop a categorization of the main buckling-related failure modes which is presented along with a summary of their associated typical analysis methods.