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Traditional single stress or strain failure criterion cannot fully consider the rock property of brittle-ductile transition, elasto-plastic finite element method is difficult to simulate the softening and instability of surrounding rock with low confining pressure, and reinforcement mechanism under complex stress state needs to be further studied for surrounding rock. From the energy storage and dissipation process of surrounding rock-support system, by establishing energy dissipation method (EDM) for surrounding rock's stability analysis and the energy supply theory of supporting structure, energy dissipation ratio criterion for surrounding rock's failure is proposed, and EDM calculation process for surrounding rock's stability analysis is given. With the analysis of surrounding rock's state and failure for Jinping I underground powerhouse, this paper particularly studies and compares the distribution rule of principal stress, total resistant energy and energy dissipation zone before and after reinforcement of surrounding rock. As a result, the deformation failure and supporting mechanism is expounded for surrounding rock, as well as verifying the feasibility of EDM.

The proper design of underground powerhouse support is the key engineering technique to guarantee the safe construction and operation of underground works. By regression analysis of the surrounding rock support parameters of 29 underground powerhouses with a span of 18.0–34.0 m, the empirical formula of the relationship between the support strength of anchor bar, strength-stress ratio, and plant span and the relationship among the support strength of the anchor cable, strength-stress ratio, and plant span are proposed. Furthermore, an intelligent design model for the anchor support of the underground powerhouse was trained by a BP (back propagation) neural network. Research shows that the support strength index of the anchor bolt and the anchor cable of these 29 plants are all distributed around 1.0. Therefore, a support strength index of 0.8–1.2 can be used as a reference for practical engineering support design. Finally, the reliability of the intelligent design model for the anchor support of the underground powerhouse was verified by comparison with actual engineering and support strength index. This shows that the intelligent design model can provide a reference for engineering design and construction.