Research And Development Of New BFRP Anchor Cable For High Slope Support In Three Gorges Reservoir Area And Its Anchorage Performance

BFRP bar is a new kind of composite material which is formed by the combination of basalt fiber and resin matrix material after extrusion and drawing.At present,there are few researches on the application of basalt fiber reinforcement in anchoring support.This paper mainly studies the application of BFRP bar anchors(cables)in rock and soil anchoring of foundation pit slope.However,due to the characteristics of BFRP material,that is,it can not be directly connected with ordinary steel anchors,so specific special anchors need to be designed.By designing the finished epoxy resin adhesive and self-matching epoxy resin adhesive,the epoxy resin adhesive was modified,and the compressive strength of epoxy resin adhesive under different mix ratio was studied.The influencing factors of the compressive strength of epoxy resin adhesive were analyzed,and the selection of bonding medium for basalt fiber reinforcement bonding anchors was carried out.The mechanical properties and failure modes of the bonding medium,the number of reinforcement materials and the anchoring form of the bonding anchorage are studied through the process test of the bonding anchorage,and the key design parameters of the anchorage are obtained,which provides the foundation for the design of the new BFRP bar anchorage cable.In order to avoid the development of the secondary anchor cable tensioning machine,the steel connector is designed as the conversion between the steel strand and the basalt fiber bar.A set of indoor tensioning device was designed for indoor model test.In order to obtain the process design parameters of the anchor cable connector,the mechanical properties of the anchor cable were tested.The conclusions are as follows:The compressive strength of the modified bisphenol A epoxy resin is higher than that of the modified epoxy resin.Adding 1mm long basalt fiber as epoxy resin filler can effectively improve the strength of epoxy resin;Appropriate addition of curing agent is helpful to accelerate and promote the formation of curing materials of epoxy resin,shorten curing time and improve compressive strength.The bonding medium should choose epoxy resin adhesive with small elastic modulus and high compressive strength or similar elastic modulus to BFRP bar.Connector Settings to meet the application,in the glue injection process,shouldensure that the glue injection environment is dry,and the filling degree of glue;In the surface treatment technology of steel strand,the notch effect is the best,followed by sandblasting,sandsticking effect is the worst.Thin and dense thread distribution should be used in the connector,so 1mm thread spacing effect is better than 1.5mm.The glue injection is not full or the surface roughness of the steel strand is not enough to cause the steel strand degumming damage;Thread depth is too large to lead to the connector wall thin,weak bearing capacity,prone to connector break damage;If the glue injection is full,the internal thread of the connector is fine,and the surface of the steel strand is marked,the cable body will be broken.Design the bearing capacity of the anchor cable From a minimum of 125 kN to a maximum of 337 kN.