既有锚索二次张拉机具技术研究

Technical Research on the Secondary Tensioning Machine of Exiting Anchor Cable

预应力损失是降低锚索支护效果的重要原因,对既有锚索实施二次张拉,恢复设计预应力对工程防护具有重要的意义。针对既有锚索尾部长度短,无法直接进行二次张拉的问题,研究设计了一种由新型T型锚盘、圆环垫片、持力钢套等部件组成的可拆卸式的既有锚索二次张拉机具。从机具的部件组成、施工流程、技术要点和工程实践等方面进行了详细阐述,该机具操作简单、节省空间,还可重复利用。既有锚索二次张拉的工程实践表明,这种新型的张拉机具可以在既有锚索尾部较短(3~5cm)的情况下实现二次张拉,恢复既有锚索的设计预应力值,大大提高了预应力锚索的支护效果,保证了工程建设的安全与稳定。

Prestressing loss is an important reason for reducing the supporting effect of anchor cable. It is of great signifi cance for the existing anchor cable to be tensioned twice and recover the designed prestressing force for engineering protec tion. Aiming at the problem that the tail of the existing anchor cable is too short to be tensioned twice directly,a detachable secondary tensioning machine for the existing anchor cable is designed,which consists of a new T-shaped anchor plate,ring gasket and supporting steel sleeve. The components,construction process,technical points and engineering practice of the machine are elaborated in detail. The machine is simple to operate,saves space and keeps reusable. The engineering practice of secondary tensioning of existing anchor cables shows that this new type of tensioning machine can realize secondary tension ing under the condition of short tail of existing anchor cables(3~5 cm), restore the designed pre-stress value of existing an chor cables,greatly improve the supporting effect of prestressing anchor cables,and ensure the safety and stability of project construction.