ABSTRACT

ABSTRACT: A domal failure 12 m high has occurred in flat lying, well-bedded limestone in a large room in Salamander Cave, Indiana. The roof is analyzed as a series of laminated beams, with free slip between the individual beams of each laminated beam. The relationship between stiffness and deflection for individual beams was calculated using a cracked beam column finite element code. The analysis provides a model for evolution of the failure. Crucial to stability is the development of large axial compressive stresses in the thicker beams as they crack. Outward frictional sliding toward the free face at the nearby hillside may restrict the magnitude of the axial compressive stress. This restriction is required to explain the observed failure and it implies that the remaining roof may be near failure.

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