Evaluation of Loosened Area around Rock Cavern by AE

Evaluation of Loosened Area around Rock Cavern by ln-situ AE Measurement

(a) Horizontal section (x-y section)

(b) Vertical section (x-z section)

Results of souse location and moment tensor analysis

lt is important to evaluate damaged areas caused by microcracking or joint displacement during excavation of a cavern for proper design and control of excavation. The estimation of loosened area in rock mass due to excavation is especially important in constructing large underground caverns such as hydraulic power stations or oil storages. Acoustic emission (AE) was monitored immediately after blasting until the rock mass became stable. The moment tensor analysis was applied in order to obtain quantitative information on 3D crack locations, directions of crack motions, and crack orientations and types. The results of this quantitative AE analysis were in good agreement with the crack observations by borehole scanner.

Relationship between source location of AE and excavated position