Abstract:

The judging on the stability of surrounding rock during underground powerhouse excavation is discussed in this paper, based on the deformation rate ratio method proposed by Li Shihui. The deformation rate ratios of different crosssections of an underground powerhouse under various supporting conditions are analyzed on basis of the monitoring data obtained in 2 years. The analysis results show that for the heterogeneous subhorizontal bedded rocks in the underground powerhouse, the deformation rate reduces dramatically; the deformation of the surrounding rock tends to be almost stable when the value of v/v0 ranges from 15% to 30%; the deformation of the surrounding rock tends to be stable when the value of v/v0 ranges from 5% to 10%; the deformation of the surrounding rock is stable when the value of v/v0 is smaller than 5%.

Key words: stability of surrounding rock, deformation rate ratio method, underground powerhouse, crown, bedded rock