玻璃纤维增强塑料锚杆设计研究

锚杆支护方法在岩体加固工程中被广泛应用,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。GFRP锚杆的结构设计包括锚杆选型,内、外锚固段设计,锚杆间距设计等内容。与钢锚杆相比,GFRP锚杆对横向荷载有较强的敏感性,不能直接与紧固器(如螺母)相连。本项目对自发研制的螺纹耦合半模钢夹具的夹持力进行了试验测试。试验结果表明,单个夹具的夹持力可达到15 t,两个夹具并行使用,可达到35 t的夹持力,完全满足工程锚杆最大荷载设计要求。但夹具与混凝土之间的粘结力均低于锚杆的设计强度,因此,采用两个并行夹具加钢垫板的方式对GFRP锚杆进行外部端部锚固。

DESIGN RESEARCH OF GLASS FIBRE REINFORCED PLASTICS BOLTS

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 anchor-rod 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 fibre reinforced plastics(GFRP) anchor-rod is a new kind reinforcement material which is compounded with resin and glass fibre,having better mechanical property and corrosion resistance.The durability problem of slope engineering can be solved if GFRP anchor took the place of steel bars.The structural design of GFRP anchor-rod includes styles design,inner and outer anchorage segment design,distance between anchor-rods design and so on.Compared with steel anchor-rod,GFRP anchor-rod is strongly sensitive to lateral load and can't directly connect with spanner(like nut).The chucking power of screw thread coupling semi-stamping steel cramping apparatus,which is developed spontaneously,is tested in this item.The result shows that: the chucking power of single cramping apparatus can reach 15 tons and that of two parallel cramping apparatuses can reach 35 tons.This is satisfied with the design request for maximum load of anchor-rods.However,the binding power between cramping apparatus and concrete should be smaller than the design strength of anchor-rod.Accordingly,the way of two parallel cramping apparatuses and steel cushion plates used together should be chosen to bolt the outer ending of GFRP anchor-rod.