GFRP锚杆结构预应力锁定装置研制与现场试验

纤维增强聚合物(FRP)筋耐腐蚀,抗拉强度高,弹性模量小,用于边坡加固锚杆结构是解决钢筋锚杆结构耐久性问题的途径之一,预应力FRP锚杆结构是合理型式。FRP筋抗剪强度低,钢筋锚杆施加预应力采用的刚性夹具不能用于FRP锚杆。基于端部封闭的钢套管充填膨胀剂锚固FRP筋法,设计了FRP锚杆预应力施加及锚索装置,并进行了现场试验。试验结果表明:预应力锁定装置的原理可行,结构合理,使用方便,能较好地完成玄武–玻璃纤维增强聚合物(B-GFRP)锚杆的预应力施加和锁定,经历外部环境变化检验,降雨、震动等环境影响产生的预应力损失均缘于杆体界面的黏结蜕化,没有发生锁定装置失效导致荷载明显损失的现象。B-GFRP锚杆的预应力损失百分率在5%~35%间,达到了精轧螺纹钢锚杆预应力损失的控制标准。

Development of load anchorage device for pre-stress GFRP soil nail reinforcement element in slopes and field tests

The fiber reinforced polymer (FRP) bars have the behavior of strong corrosion resistance, high tensile strength and small elastic modulus, and can be used to replace steel bars, which undergo wearing due to rusting in slope reinforcement. The pre-stress FRP bars are reasonable, but the bars have low shear strength and cannot be pre-stressed using the traditional rigid clamp, lest they are crashed to failure. An end anchoring pre-stress locking device is designed for pre-stress application and retention in the FRP bars. Field tests are conducted to verify the stability of the device. The test results show that the device is practically feasible and convenient, and it can apply and retain pre-stress in basalt-glass fiber reinforced polymer (B-GFRP) bars well. Exposure to external factors such as heavy rains and blasting results in the loss of pre-stress. The pre-stress loss is caused by degeneration of the bonding resulting from external factors, but not by the invalidation of the device. The pre-stress retention by the device in the B-GFRP bars is 5%~35%, which conforms to the control criterion for the pre-stress loss of the steel pre-stressed soil nail reinforcement.