A methodology for rock mechanics design of brine fields based on case histories of sinkhole formation in Windsor-Detroit area

摘要

The paper examines three instances of sinkhole formation in Windsor-Detroit area (Canada, USA) with the objective to formulate a rational rock mechanics-based design methodology to prevent sinkhole formation as a result of solution mining operations. Review of published data for the Sandwich brine field and two fields at Orosse Ile suggests that conditions at all three fields were such that numerous cavities essentially coalesced and wide, practically unsupported spans were created by the time sinkholes were formed, R. Terzaghi, 1970, Landes and Piper, 1972. In all three cases sinkholes were formed in conditions when minimum dimensions of respective brine fields were 1150-1550 ft while estimated pre-sinkhole subsidence ranged 2-2.5 ft. Analyses presented in the paper for the Sandwich field show that a combination of brine filed dimensions, subsidence measurements and data on mechanical properties of rocks can be used to explain the type of overburden deterioration that permitted formation of sinkholes. Analyses are used to illustrate a methodology of designing brine fields based on limiting the minimum span to avoid sinkhole formation.