Stability analysis of the intake diversion tunnel in Jinshuitan pumped storage power station

This academic study conducts a comprehensive stability evaluation of the structurally critical intake diversion tunnel system at the Jinshuitan Pumped Storage Power Station facility utilizing advanced three-dimensional numerical modeling techniques. The geometrically intricate tunnel network, consisting of interconnected intake tunnels, diversion branch tunnels, and intersecting geological fault features, necessitates a rigorous stability assessment to ensure the structural integrity of the underground infrastructure is maintained during both the construction stage and long-term operational life cycle. Three-dimensional numerical models were developed employing the FLAC3D software to accurately simulate the complex tunnel geometries, multi-stage excavation sequences, in-situ stress state, and mechanical behavior of the surrounding rock mass. Scenarios evaluated included unsupported excavation conditions, an optimized layered and segmented excavation methodology, as well as the implementation of a systematic regime of ground support measures. The modeling results quantified the efficacy of the proposed layered excavation approach in reducing magnitude of tunnel displacements by 0.1-0.5 mm relative to conventional full-face excavation practices. Furthermore, the anchor support system provided a supplemental displacement control of 0.1-0.8 mm. Comprehensive stress analyses validated the effectiveness of the stabilization strategies, with maximum anchor stresses remaining within allowable limits despite localized stress concentrations at critical junctures such as tunnel intersections and fault zones. This integrated stability analysis approach optimizes the design of complex underground energy infrastructure while ensuring long-term structural integrity and operational reliability.