Effect Of Corrosion On Anchorage Characteristics Of Self-swelling Anchorage Bolt

With the depletion of easy-to-mine mineral resources in shallow areas,mining in deep and difficult-to-mine bodies is an inevitable trend in the future.Deep mining has the problems of complex mining environment such as four-high and one disturbance,which can easily lead to disasters such as rockburst and large deformation of surrounding rock.In recent years,with the expansion of mining engineering scale,the requirements for rock mass stability control have become higher and higher,resulting in an increase in the number of anchor rods and higher requirements for anchor rod support.Not only does the anchor have the characteristics of high anchoring force and large surrounding rock deformation control,but also it needs to adapt to deep and complicated mining environment.In view of the fact that the existing bolts cannot solve the above problems,a self-swelling anchorage bolt was developed,and an indoor experimental study on the anchoring characteristics of the self-swelling anchorage bolt was carried out.The specific work is as follows:(1)Aiming at the problem of insufficient anchoring capacity of the anchor rod in the deep mining environment,a self-swelling anchorage bolt was designed.Based on the structural characteristics of the self-swelling anchorage bolt,the analysis and testing of the water absorption properties and temperature(soaking water temperature and ambient temperature)of the expansion anchoring roll were carried out.(2)Based on the anchoring characteristics of the self-swelling anchorage bolt,the expansion anchoring agent reacts with hydration to output a large expansion pressure and to release the mold after the reaction.A device for preparing the expansion anchoring agent hydration reaction product is designed and processed to solve the expansion anchor of hydrated product sample preparation,and carried out uniaxial,triaxial,direct shear and tensile strength mechanical properties tests of the expansion anchor agent sample,and obtained mechanical indicators.(3)The analysis of influencing factors on the anchoring performance of the self-swelling anchorage bolt was completed.A reaction device for corroding the self-swelling anchorage bolt was designed based on the corrosion characteristics of the self-expanding anchor,and a corrosion experiment scheme was formulated.(4)Corrosion experiments of self-swelling anchorage bolt immersed in pure water,acids,sulfates and chlorides were carried out,and the anchoring characteristics of self-swelling anchorage bolt was studied in a short period of time.After soaking at different times,take out the test work such as drawing,X-ray diffraction composition analysis and quality change before and after the bolt corrosion.The research shows that the different conditions affect the anchoring performance of the self-swelling anchorage bolt.Indoor experiments of anchoring characteristics of self-swelling anchorage bolt show that when the ambient temperature,room temperature immersion water temperature is soaked at 20℃ for 8 minutes,the expansion anchoring agent reaches a saturated state of absorption;the expansion anchoring agent has a hydration reaction strength of about 10 MPa in 24 hours;the pull-out results show that the anchoring of the anchorage bolt The force reaches about 240 kN,and the rebar elongation averages 13%;X-ray diffraction shows that different aqueous solutions will affect the composition of the anchoring agent.The study found that the self-expanding anchorage bolt has the advantages of high anchoring force,improved surrounding rock deformation,suitable for complex environments,low cost,convenient and fast installation,etc.,and is of great significance for mining.