弱风化强卸荷岩体1000 kN级无黏结预应力锚索造孔与灌浆技术研究

Study on Hole Making and Grouting Technology for Unbonded Pre-Stressed Anchor Cable of 1000kN in Weakly Weathered and Strongly Unloaded Rock Mass

巴塘水电站1000 kN级无黏结预应力锚索主要布置左岸导流洞及泄洪放空洞进出口边坡上,就目前左岸出口边坡揭露的地质情况表明岩体多为黑云母石英片岩,呈弱风化、强卸荷,岩体裂隙发育,部分锚索吃浆量大。因此,如何改善锚索孔身段裂隙数量及大小,分析判定岩体破碎程度并控制岩体吃浆量是巴塘水电站1000 kN级无黏结预应力锚索全段灌浆需要解决的首要技术难题,阐述了通过技术研究,在钻孔方法、孔内电视摄像、钻孔长度、灌浆水灰比、灌浆压力、过程观测等控制措施的实施,成功解决了这一技术难题。

1000 kN unbonded pre-stressed anchor cable are mainly arranged on the slope of the diversion tunnel,inlet and outlet of flood discharge tunnel on the left bank.According to the current geological exposure of the outlet slope on the left bank,the rock mass is mostly biotite quartz schist with weak weathering,strong unloading and developed rock mass fissures,so some anchor cables need a large amount of grout.Minimizing the number and size of cracks in the anchor hole,analyzing and determining rock fragmentation,controlling of grouting quantity are the primary technical problems to be solved in grouting of 1000kN unbonded pre-stressed anchor cable of Batang Hydropower Station.This paper expounds the implementation of control measures in drilling method,in-hole television camera,drilling length,water cement ratio,grouting pressure and process observation.With those control measures,the aforementioned technical problems are successfully solved.