| The crushing performance of the rock directly affects the effect of its blasting operation.If the blast hole is well blocked,not only can the explosive response be more adequate,but the time for the blasting gas to be blocked in the blast hole can be greatly extended,thereby making the explosive power the most powerful.And achieve better blasting effect.As a good blast hole plugging material,the rapid-setting expansion sealing agent material has the advantages of fast setting speed,no shrinkage,and no dry cracking,but the mechanical properties in the early stage of setting and hardening are greatly affected by the curing age.At present,the research on the blasting effect of the blast hole plugging material mainly focuses on its aspect ratio and numerical simulation,but it rarely involves the research on the dynamic mechanical properties of the blast hole plugging material during the curing age of the blasthole.The performance of quick-setting sealing materials is greatly affected by age,so it is necessary to use the method of impact compression to study the mechanical properties and crushing characteristics of materials under different curing ages.The main research contents and results are as follows:(1)Nine different curing ages of 10min,15min,30min,1h,2h,4h,8h,16h and 24h are set as test variables,and a non-metallic ultrasonic detector is used to test the longitudinal wave velocity of the specimens that have completed the curing of different ages..By adopting a 50mm diameter variable cross-section separation Hopkinson pressure rod test device,the rapid-setting expansion plugging agent test piece as a blast hole plugging material was subjected to dynamic impact compression tests at three air pressures of 0.25 MPa,0.35 MPa,and 0.45 MPa.(2)The dynamic mechanics of the specimen is studied and analyzed.The analysis results of the impact test show that in the unconstrained state,the rapid-setting expansion sealing agent material has an obvious strain rate effect.During the impact test,the impact air pressure increases.Larger,the peak stress and strain will increase accordingly.At the same time,the rapid-setting expansion sealant material also has a strong sensitivity to age.With the increase of age,the peak stress of the rapid-setting expansion sealant gradually increases and the peak strain decreases.(3)Analyze the energy dissipation of the test piece made of the quick-setting expansion sealing agent material,and explore the incident energy,reflected energy,transmitted energy,absorbed energy and energy absorption of different impact loads at different ages.The relationship between the change of the rate,and the related energy dissipation under different conditions.It is found that there is an obvious positive correlation between impact load,absorbed energy and energy absorption rate.When the age is within 4 hours,the absorbed energy and energy absorption rate also show a significant increase with the increase of age.(4)Analyze the broken shape of the specimen after impact load.It is found that as the age increases,the broken state of the specimen changes from the irregular broken state at 10 minutes to the angular damage at 30 minutes.The period reaches 1h and begins to show the material characteristics of brittle failure.With the increase of age within 4h,the fracture degree of the specimen under the same impact load is decreasing.Under the same age,the fracture degree of the specimen increases with the increase of impact load.Figure: 27 Table: 3 Reference: 62... |
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