3D modeling of a cavern in closely spaced bedded rock mass by transversely isotropic model
Siah Bishe Powerhouse Cavern and other related excavations have been modeled by 3D numerical programs. The main concern in this large span underground space was closely bedded rock formations which are mostly quartzitic sandstones and reddish-brown and blackish siltstone of shaly appearance with low RQD index. This had raised doubts about its long term stability. Sheared and altered zones which cross the cavern axis are the most problematic sections of the project. Excavation sequences in powerhouse cavern as well as support systems have been also simulated. Regarding the closely spaced bedding planes, sections including the sedimentary rocks and shear zones have been simulated as transversely isotropic materials. The results obtained from installed extensometers in sidewalls of powerhouse cavern show good agreement with the displacements obtained from numerical results. Comparing the induced stresses in elements surrounding the excavated opening and their strength, a safety factor is determined for rock mass surrounding the powerhouse cavern. Results obtained from evaluation of safety factor show some unstable zones around the cavern in the first & the second monitoring sections (chainage 26m & 48.7m) due to the existence of the main sheared zone. An unstable zone also extends between transformer and powerhouse caverns in the third monitoring section (chainage 67.1m).
M.Moosavi V.Fattahpour
The University of Tehran, Tehran
国际会议
香港
英文
1-5
2009-05-19（万方平台首次上网日期，不代表论文的发表时间）