Abstract:

Based on the Jinping second stage hydropower station, a distribution diagram of faults, is obtained from the geological diagram at Maomaotan lock site. A power-law relation between fault number and fault size is proposed, i.e. - . Two power exponents are estimated by using linear fitting in two segments. It is found that the power exponent D has a value of 0.48 if fault lengths r are shorter than 0.1 km; while the power exponent is equal to 1.49 if fault lengths r are longer than 0.1 km. Combining with Monte Carlo method, the spatial distribution of a further small scale of joints can be obtained. Finally, the discontinuous deformation analysis (DDA) is employed to numerically simulate and analyze the excavation of the Dashuigou underground powerhouse; and the stress and displacement plots resulted from excavation in highly jointed rock mass are obtained.

Key words: fault size, fault number, power-law relation, discontinuous deformation analysis (DDA)