不同直径GFRP锚杆承载特征的现场对比试验

FIELD CONTRAST TEST STUDY ON ANCHORING MECHANISM OF GFRP ANCHOR ROD WITH DIFFERENT DIAMETERS

锚杆支护方法在岩体加固工程中应用广泛,锚杆作为支护结构的核心应具有足够的安全度和耐久性。由于钢材易腐蚀,钢锚杆的耐久性受到质疑。玻璃纤维增强塑料(GFRP)锚杆是一种由树脂和玻璃纤维复合而成的新型加固材料,具有较好的力学性能和耐腐蚀性能,用其代替传统钢筋用于边坡加固可较好地解决锚杆耐久性问题。本次试验为φ16、φ32两种类型GFRP锚杆在相同岩性,全、强、弱三种不同风化程度围岩条件下的张拉试验,研究了GFRP锚杆的破坏特征及锚固机理。试验结果表明,这两种直径GFRP锚杆的最终破坏方式是锚杆自由段脆性劈裂破坏;GFRP锚杆极限承载力随锚杆直径增大而增加;16小直径GFRP锚杆的应力传递深度受围岩风化程度影响较小;φ32大直径GFRP锚杆的应力传递深度受围岩风化程度影响较大,锚杆的应力传递深度随围岩风化程度增加而增大;GFRP锚杆与砂浆界面间的粘结强度随杆体直径增加而降低。

Rock bolting is a support widely used in slope engineering, tunnel and large cave support, as well as reinforcement of building structure. As the main part of support structure, the bolt must have enough reliability and durability. However, it is easily eroded by the environment for steel, so the durability of steel bolt being used commonly should be paid more attention to. The glass fiber reinforced plastics （GFRP） bolt is a new kind reinforcement material which is compounded with resin and glass fiber, having better mechanical property and corrosion resist- ance. The durability problem of slope engineering can be solved if GFRP bolt take the place of steel bars. The tensile test studies the failure characteristic and anchoring mechanism of GFRP anchor rod with different diameters of Ф16 and Ф32, under the same lithologic characters and three different weathered conditions of adjoining rock ： complete, modest and slightly. The result indicates as follows ：The GFRP anchor rods with different diameters finally fail in the way of brittle split failure. The ultimate bearing capacity of GFRP anchor rod increases with its diameter. The stress transmission depth of Ф16 is affected less by weathered degree of adjoining rock, while the one of Ф32 is affected greatly by weathered degree. The stress transmission depth of GFRP anchor rod increases with the weathering degree of adjoining rock. The bond strength between the GFRP anchor rod and the surface of mortar decreases as the diameter increases.