Abstract:

The engineering geological conditions, arrangement and structure designs and monitoring data of underground plant of Jinping Stage I Hydropower station are analyzed. The relationship among surrounding rock failure, excavation sequence, layer dividing, blasting, supporting structure and supporting timing are analyzed on basis of analysis on the relationship among surrounding rock failure, ground stress, strength stress ratio, geological structure plane, cavern arrangement and structures. Conclusion is drawn that the limited stress releasing technology, which includes specialized blasting design, dynamic determination of the concreting time of the crane beam, construction technologies for junctions of huge caverns and spiral excavation and supporting technologies for cylindrical structures, plays an important role in the control of the deformation and failure of surrounding rock. The construction technologies are studied on basis of studying on the existing theories, mechanism, calculation and analysis methods, testing methods and related data. The paper can provide reference for similar projects in the future.

Key words: Jinping stage I hydropower station, underground plant, cavern group, surrounding rock failure, limited stress releasing, control technology, monitoring, relaxation zone