| Resin rebar bolt support technology has been widely used in coal mine roadways domestically and abroad,among which the left-handed non-longitudinal rib rebar bolt is the most widely used in my country’s coal mines.Resin is an important medium for the bond between rebar bolt and surrounding rock,and its working performance has an important influence on the quality of anchoring.Stirring the resin at the end of the rebar bolt is a key step in anchoring.At the same time,whether the resin in the anchoring section is densely distributed also has a significant impact on the anchoring force of the rebar bolt.This paper takes "improving the efficiency of stirring resin and increasing the density of resin in the anchoring section" as the main line,and adopts methods such as theoretical analysis,numerical simulation and laboratory experiments.The stirring end of wedge-shaped rebar bolt is proposed,and on this basis,a high-efficiency anchoring device for rebar bolt that is easy to install is developed,including stirring components and blocking components.The results obtained mainly include the following aspects:(1)Through theoretical analysis,it is found that the angle of the wedge-shaped end of the rebar bolt has a great influence on the migration and mixing effect of the resin;The rod end is pierced into the outer bag of the resin,which better destroys the outer bag of the resin and enhances the mixing effect of the resin.At the same time,it is found that the development degree of pores in the anchor body is negatively correlated with the shear strength and anchoring force of the anchor body.(2)Through numerical simulation,it is found that when the parameters of the wedge-shaped end of the rebar bolt are 75° wedge angle,the offset distance is 0,the wedge-shaped end is located at the transverse rib and the "V"-shaped groove is cut,it will promote the uniform distribution of the resin in the anchoring hole.Increase the flow rate of the resin at the end of the rebar bolt,thereby greatly improving the stirring efficiency of the resin.On the basis of the wedge-shaped end,a high-efficiency anchoring device for rebar bolt is proposed,and its structural parameters are further optimized.It is found that the fluidity of the resin in the area of the installation component increases significantly,and the crushing and stirring teeth produce the resin above.The downward pulling force is the source of force for breaking the resin outer bag,improving the efficiency of stirring the resin,and the blocking components has an upward and left effect on the surrounding resin,effectively preventing the resin from flowing out.(3)Through the anchoring performance experiment,it is found that the anchoring force of the rebar bolt with the installation component is increased by about 17%compared with the rebar bolt only.Through the visualization of the anchoring process and the peeling experiment of the anchoring zone,it is found that the rebar bolt is installed after the component.The larger distortion of the resin outer bag will help to destroy the resin outer bag,promote the uniform mixing of the resin cement and the curing agent,effectively prevent the resin from overflowing,and ensure that the resin in the anchoring section is evenly distributed.The research results have important theoretical and engineering value for improving the anchoring quality of rebar bolts and ensuring the stable anchoring force of rebar bolts. |
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