Fiber-Optic Extensometer Array in a Small Alcove at 1.25-km Depth in the Sanford Laboratory at Homestake, Lead, South Dakota

摘要

We are establishing a dense array of fiber-optic sensors in a small alcove at4100-ft (1250-m) depth in the Sanford Laboratory at Homestake in Lead, SouthDakota. The monitoring array will measure deformation in intact rock and servesalso as an experimental site for research in structural health monitoring of deepunderground spaces. Our GEOX^TM (Geological Optical eXtensometers andTiltmeter) collaboration has installed approximately 10 Fiber Bragg Grating (FBG)strain and temperature sensors, which each house between 2 and 12 FBG gages, aswell as distributed temperature sensing cable (DTS) in an alcove measuring 2 × 3 mand 2 m high and in the associated drift.