Energy Release Analysis of a Severe Rockburst in a Headrace Tunnel Crossing a Tectonic Stress Zone

Table 2

Stress test results at chainage 10 + 938 and 13 + 834.

Chainage	Buried depth	Tests no	Depth in borehole (m)	σ1/Tr/Pl (MPa/°/°)	σ2/Tr/Pl (MPa/°/°)	σ3/Tr/Pl (MPa/°/°)
13 + 834	800	1	23.0	−50.7/282/−14	−24.3/206/43	−19.5/358/44
		2	24.3	−54.9/287/−30	−27.7/204/13	−21.2/315/57
		3	25.9	−50.7/281/−39	−21.3/210/22	−15.9/322/43
10 + 938	1010	1	19.1	−102.9/292/33	−40.6/193/14	−25.1/84/54
		2	20.0	−107.3/338/21	−40.9/119/64	−32.7/243/13
		3	21.0	−102.9/312/32	−48.4/195/47	−24.4/70/37

Plunge (dip) from horizontal positive down and trend (azimuth) positive clockwise from north.