| Anchor support changes the surrounding rock from passive bearing to active support,which can improve the self-bearing capacity of the surrounding rock.Excavation of the roadway causes the surrounding rock to change from a three-way stress self-stabilizing state to a two-way stress instability state.The anchoring support can restore the three-way stress state of the surrounding rock,So as to achieve the purpose of surrounding rock stabilization.Pipe joint bolt are widely used due to their excellent mechanical properties such as timely support,full-length friction anchoring,three-way prestressing,and sliding energy absorption.Mining under high stress and strong disturbance in deep mining,frequent engineering disasters,existing pipe joint bolt are insufficient,the anchoring force is greatly affected by the difference in pipe diameter,the initial anchoring force is too low,etc.,it is difficult to adapt to deep surrounding rock support,New support technologies are urgently needed.In order to expand the application scope of pipe joint bolt and meet the needs of deep mining and support,a new type of self-expanding pipe joint bolt were designed and used in the structural parameters of the anchors to explore their anchoring performance.The thesis research work and results are as follows:(1)Based on the characteristics of pipe joint bolt and deep support requirements,the performance requirements of new self-expanding pipe joint bolt were proposed,the structure of self-expanding pipe joint bolt was initially determined,and the bearing mechanism of self-expanding pipe joint bolt was analyzed.(2)An indoor anchor testing device was established,a drilling simulation device and an anchor drawing connection device were designed,and the structure and function of the above device were introduced and the usage method was explained.(3)Based on the self-expanding pipe joint bolt structure,structural parameter optimization experiments were performed.The main optimization parameters were anchor length,anchor position,and anchor interval.Explore the ultimate tensile resistance,allowable pressure resistance,anchoring energy and wire drawing force of self-expanding.pipe joint bolt under different structural parameters to determine the optimal structural parameters of self-expanding pipe joint bolt in laboratory environment.Investigate the relationship between the anchoring characteristics of the self-expanding pipe joint bolt anchors over time,and verify the timeliness of the self-expanding pipe joint bolt.(4)Relying on the in-situ support experiments of anchors based on Asher deep roadway support project,comparing the anchoring characteristics of pipe wedge bolt,pipe joint bolt,and self-expanding pipe joint bolt,and determining the self-expanding pipe bolt in the soft broken rock mass environment optimum structural parameters of pipe joint anchors.This article systematically explores the influence of the structural parameters of the self-expanding pipe joint bolt on the anchoring performance.Firstly,based on the concrete drilling simulation device,it is determined that the self-expanding pipe joint bolt with an anchor length of 50 cm,an anchor position at the head,and an anchor interval of 10 cm has the best anchor performance,and the ultimate tensile resistance of the anchor is 92 kN.The pressure resistance is 84kN,the anchoring energy is 23373kN·mm,and the wire drawing force is 83kN/mm.The second is to carry out on-site industrial experiments.The experimental results show that the self-expanding pipe joint bolt with 30cm anchoring coil anchored on the head meets the needs of on-site support,and the ultimate bearing capacity is 91kN.The working state of the anchor is similar to constant resistance to large deformation.According to the review,the self-expanding pipe joint bolt has excellent anchoring performance and is of value for popularization. |
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