Research On Deformation Characteristics And Anchoring Performance Of New Type Tension-Dispersive Twist Bolt Under Shear Action

In recent years,with the rapid development of China’s economy,the urbanization process has been continuously promoted,and the development of tunnel and underground engineering industry has been accelerated at the same time.As a key component of tunnel construction,roadway takes on many important tasks.Therefore,the upgrading of roadway support technology is particularly important.At present,the types of prestressed bolts are diversified,such as tensile concentration type,tensile dispersion type,pressure concentration type,pressure dispersion type,etc.These types of bolts have different mechanical characteristics in the process of supporting.At present,most of the bolts used in the roadway are traditional tensile concentrated bolts,and the performance of drawing performance and shear capacity is not so good.The innovation of bolt form is always the new direction of exploration.In order to improve the anchoring performance and tensile resistance of the bolt,a new twist bolt which can realize tensile dispersion is proposed in this paper,and the anchoring performance of the structure under shear action is studied.The new type tension-dispersive twist bolt is to twist two bolts together with a certain pitch.In the actual tensile process,the two bolts are constantly twisted and closer to the state of the anchor cable.At the same time,the bite force between the bolt and the surrounding rock is greatly improved through the anchoring agent.When the stress formed in the free section of the bolt is concentrated and distributed on the whole bolt,the bearing capacity and shear strength are greatly improved.At the same time of increasing the capacity,the cost of the project can be greatly reduced.Therefore,the new type tension-dispersive twist bolt has a good application prospect.Considering the influence of the form,the anchoring mechanism of the new type tension-dispersive twist bolt is different from that of the traditional bolt,so it is very important to study the bearing mechanism of the new type tension-dispersive twist bolt.The main conclusions of this paper are as follows:(1)Compared with the traditional bolt,the new type tension-dispersive twist bolt has better bearing capacity and ductility.(2)The decrease of anchoring length can significantly reduce the bearing capacity of the new type tension-dispersive twist bolt,but the change of anchoring length has little effect on the ductility of the specimen.(3)With the decrease of the shearing angle of the bolt,the bearing capacity of the bolt increases,and the change of shearing angle has little effect on the ductility of the bolt.(4)Based on ABAQUS simulation analysis,the load-displacement curve is smoothing compared with the test curve,but the overall shape is similar.The simulated bearing capacity is about 10% higher than the experimental bearing capacity,with stable error and small dispersion degree.(5)In the calculation and analysis,the bond strength between the anchoring agent and the surrounding rock is greater than the strength of the bolt itself,so the strength failure of the bolt mainly occurs.The ultimate bearing capacity of the bolt calculated by the strength failure of the bolt is slightly less than the test value.The calculation method of the bearing capacity of the bolt has a certain safety reserve.The above research results can provide reference value for the further research and engineering application of the new type tension-dispersive twist bolt.