Abstract:

The underground hydropower station of Jinping phase Ⅰ hydropower project is located in high ground stress zone. The surrounding rock mass of the main power plant and that at the downstream along the axis of the main substation become loosened, cracked and fractured due to the releasing of the ground stress, which has great influence on the stability of the caverns. The original prestressed rock bolting technology is optimized on basis of analysis on the anchoring mechanisms of the prestressed rock bolts and the influence of the mortar compactness and the borehole integrality on the surrounding rock mass anchoring, which results the installation of the grout sealer at the relatively deep position. The engineering practice demonstrates that the construction quality and safety are guaranteed. The paper can provide references for similar projects with similar surrounding rock mass.