止浆器预应力锚杆新工艺在锦屏一级地下电站工程中的应用

Application of Pre-stressed Rock Bolt with Grout Sealer in Construction of Underground Hydropower Station of Jinping Phase Ⅰ Hydropower Project

锦屏一级地下电站位于高地应力地区,因地应力释放导致主厂房、主变室下游侧沿洞轴线部位围岩松弛、开裂、破碎情况严重,对洞室稳定造成了严重影响,在预应力锚杆对围岩锚固机制分析的基础上,考虑砂浆密实度与成孔完整性对围岩锚固的影响,将原有预应力锚杆施工工艺改进,增加相对深层止浆器,保证了施工质量与安全,可在相似围岩类别的地下工程借鉴使用。

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.