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040			_aMSU _cMSU _erda
100			_aWU, Jiang-Hong
245			_aThree-dimensional in situ stress evaluation using a new under-coring technique _bthe Tseng-Wen Reservoir Transbasin water tunnel
264			_aVerlag _bSpringer _c2013
336			_2rdacontent _atext _btxt
337			_2rdamedia _aunmediated _bn
338			_2rdacarrier _avolume _bnc
440			_aEnvironmental earth sciences _vVolume , number ,
520			_aThe Tseng-Wen Reservoir Transbasin water tunnel has broken the historical record of the maximum overburden of a tunnel within Taiwan. The three-dimensional in situ stresses at the tunnel were evaluated using acoustic emission (AE) and deformation rate analysis (DRA) with an under-coring technique. This is the first time that the AE and DRA have been used in evaluating an in situ stress in Taiwan. As cores drilled in different directions are required for the three-dimensional stress evaluation, but the in situ borehole drilling is usually limited to the vertical direction, small samples 2.28 cm in diameter and 4.56 cm in length were under-cored from the borehole cores in six directions to evaluate the in situ stresses. Cyclic uniaxial compressive loadings were artificially applied to the Changchikeng sandstones under-cored from the outcrops. The experimental results validate the definitiveness of using under-cored samples at different pre-stresses with AE and DRA. Then, cores taken from the Tseng-Wen Reservoir Transbasin water tunnel site at a great depth of 416–739 m underground were under-cored. The experimental results indicate that the major principle in situ stress is from 30.8 to 39 MPa and is in the directions of SE–NW and SW–NE at different depths.
650			_atsen-wen reservoir transbasin water tunnel
650			_astress
650			_aunder-coring
700			_aPAN, Yu-Wei
856			_uhttps://doi.org/10.1007/s12665-012-1717-9
942			_2lcc _cJA
999			_c161921 _d161921