Shaft excavation effects project; Excavation effects evaluation by extensometer measurements

Sato, Toshinori  ; not registered ; not registered; Yoshioka, Naoya

Excavation of a shaft or a drift in rock mass influences the rock mass around a shaft or a drift mechanically and hydraulically. In Chubu Works, we excavated a shaft having a diameter of 6 m and a depth of 150 m at the Tono Mine, and studied the excavation effects. We call this study Shaft Excavation Effects Project (SEE Project). Measurements with extensometers were carried out at four sections during the shaft excavation to understand the behavior of rock mass around the shaft. The displacement was locally occurred and it's amount depends on geology and presence of a fault and fractures. Numerical analysis was performed to understand the observed phenomena and the excavation effects. It was suggested that the deformation of rock mass around the shaft was within elastic limit and the numerical simulations could describe time-dependent behavior of the measured displacement.