深卸荷变形拉裂岩体锚索预应力损失规律研究

 根据预应力锚索施工过程，将锚索预应力损失分为张拉损失、锁定损失和随时间的损失，并分别给出各自定义和计算公式。对锦屏一级水电站左岸边坡锚索监测资料进行统计分析，得到锚索预应力损失的分布特征。锚索预应力损失的分布特征为预应力张拉损失最大，预应力随时间的损失其次，锁定损失最小。将锦屏一级水电站左岸边坡锚索预应力损失规律与其他几个类似工程比较，得出锦屏一级水电站左岸边坡锚索预应力张拉损失明显偏大。结合锦屏一级水电站左岸边坡地质条件，分析锚索预应力张拉损失较大的原因，并提出相应改进措施。最后对锦屏一级水电站左岸边坡锚索现存荷载进行评价分析，结果表明，锚索现存荷载基本满足加固设计要求。研究结果可供其他类似工程参考和借鉴。

STUDY ON PRESTRESS LOSS LAW OF ANCHOR CABLES IN DEEP UNLOADING DEFORMED RIPPED BLOCKS

According to the construction process of prestressed anchor cable,the total prestress loss is divided into three parts,that is,tensioning prestress loss,locking prestress loss and time-dependent prestress loss. The definition and calculation formula of each part are specified. The monitoring data of prestressed anchor cables of left bank excavation slope in Jinping first stage hydropower station are analyzed systematically,and the distribution features of prestress loss are obtained. The analysis result shows that the tensioning prestress loss is the maximum component of total prestress loss of anchor cable,and the time-dependent prestress loss is the intermediate one and the locking prestress loss is the minimum one. A comparison is made between the law of cable prestress loss of left bank excavation slope in Jinping first stage hydropower station and those of some other hydropower engineering slopes. The result shows that the tensioning prestress losses of anchor cables of left bank excavation slope in Jinping first stage hydropower station are greater than those of some other hydropower engineering slopes remarkably. Based on the engineering geology of left bank excavation slope of Jinping first stage hydropower station,the factors resulting in large tensioning prestress loss are analyzed,and some measures to reduce the tensioning prestress loss are put forward. At last,the present load of anchor cables is evaluated. It is shown that the present load of anchor cables can meet the requirement of design. This result can provide references to other similar engineering.