Field Measurement of Rock Displacement and Support Pressure at 5,955-Ft Level during Sinking of Deep Circular Shaft in Northern Idaho

摘要

The Bureau of Mines, under a cooperative agreement with Hecla Mining Co., is conducting a rock mechanics study of the 6,200-ft-deep circular, concrete-lined Silver Shaft in northern Idaho. The objective of the project was to instrument and evaluate lining behavior and rock deformation when a deep shaft is constructed in a high in situ stress field and anisotropic rock mass. Rock mass displacements were monitored with multiple-position borehole extensometers. Liner stress and strain were measured with concrete pressure cells and embedment strain gauges.