高压输水隧洞预应力混凝土衬砌锚具槽优化及免拆模板成槽技术研究

Optimization of Anchor Groove and Its Forming Techniques with Permanent Formwork for Prestressed Concrete Lining of High-pressure Water Conveyance Tunnel

输水隧洞预应力混凝土衬砌的锚具槽是钢绞线张拉与锚固的关键部位,其有效设置对于提升预应力混凝土体系的可靠性具有重要意义。基于高压输水隧洞衬砌环形预应力混凝土技术,提出了一种缩口形变截面锚具槽及其尺寸优化计算方法,研发了高性能纤维混凝土预制装配式免拆模板成型锚具槽的技术。与已有工程常规锚具槽对比,新型锚具槽减小了槽口尺寸,减少了锚具槽周边局部应力集中的情况,提高了锚具槽回填混凝土的嵌固能力和衬砌混凝土的整体性。预制装配式免拆模板提高了锚具槽成型质量,免除了锚具槽模板拆除、槽壁混凝土凿毛处理及槽内残渣清理等工序,可有效提高施工效率、降低工程造价、改善施工环境等。研究成果对输水隧洞预应力混凝土衬砌技术创新具有重要的推进作用,在实际工程中得到了成功应用。

The anchor groove as one of the vital parts for tensioning and anchoring of prestressed concrete lining steel strand of water conveyance tunnel,its effective design will improve the reliability of the prestressed concrete system,significantly.Based on the annular prestressed concrete technology of water conveyance tunnel under high water pressure,a necking anchor groove and its size optimization calculation method are proposed,and an anchor groove technique in avoidable of dismantling formwork is developed by using the assemble precast elements of high-performance steel fiber reinforced concrete.Compared with the existing anchor grooves,it is featured by the optimal geometry with smaller size,which reduces the stress concentration around the anchor groove and enhances the bond of interfaces between refilled concrete and the groove wall to ensure the entirety of lining concrete.The precast assemble anchor groove ensures the forming quality and eliminates the processes of dismantling formwork,roughening groove walls and cleaning residuals.As a result,the construction efficiency and the operation environment are improved with a reduction of project cost.The results play an important role in promoting the technical innovation of prestressed concrete lining of water conveyance tunnel and have been successfully applied in practical engineering.