高边墙对穿锚索精确造孔施工技术

Construction Technique of High Side Wall for Precise Hole Construction through Anchor Cable

为防止白鹤滩水电站右岸地下厂房变形量随洞室开挖继续扩大,进而影响地下洞室的稳定性,在白鹤滩水电站右岸主厂房岩锚梁以上新增对穿锚索进行控制。新增锚索施工时,厂房底板开挖面高程距新增锚索已有43.6?m的高差且围岩内应力极高,施工难度及安全风险较大。主厂房岩锚梁以上新增对穿锚索施工难度大,造孔精度要求极高。通过对锚索施工前期施工数据进行整理分析、现场实验研究,采取搭设带安全护栏的悬挑排架、在排架上搭设可移动式辅助定位样架等有效措施,实现了复杂地质条件和严峻施工条件下满足高边墙锚索高精度的施工要求,研究出一套适用于高边墙对穿锚索精确造孔的施工技术。

With the continuing excavation of the cavern,the deformation of the underground powerhouse on the right bank of Baihetan hydropower station will expand,and worst of all,influence the stability of the underground cavern.In order to prevent the influence,the pair of anchors will be applied above the rock anchor beam of the main powerhouse on the right bank of Baihetan hydropower station.When the new anchor cable is constructed,the height of the excavation surface of the plant floor is 43.6m below the new anchor cable,and the internal stress of the surrounding rock is extremely high,which brings about great difficulties in construction,high-level safety risks and precision of hole making requirements.This paper conducts field experiments and analyzes the construction data of the anchor cable construction.And effective measures are taken into action,such as setting up cantilevered shelves with safety guardrails and erecting movable auxiliary positioning racks on the shelves.By doing this,we have achieved high precision construction requirements for high-side wall anchor cables under complex geological conditions and severe construction conditions,and developed a set of construction techniques suitable for precise hole-making for pair of anchors on high-side wall.