Experimental Study On The Effect Of Loading Rate And Ratio On The Failure Characteristics Of Similar Materials

With the exhaustion of shallow coal resources and the implementation of the "deep mining" strategy,the research on the mechanical properties and failure characteristics of coal and rock under various complicated conditions has attracted more and more attention,and the study of coal and rock mass The destructive properties are of great significance to mining engineering.In this paper,the mechanical properties and failure characteristics of similar materials under different external conditions and internal conditions were studied by means of physical similarity simulation experiments.After comparing the advantages and disadvantages of different cements,it is determined that river sand,cement,gypsum and starch are the raw materials for making similar material samples,and the experimental scheme is clarified;the loading amount of standard samples is determined,which greatly reduces The workload of the subsequent sample preparation;after the mechanical tests of samples of similar materials with different ratios,the peak strength and elastic modulus of the similar material samples were obtained with the ratio change model,and the similar materials were used at different loading rates.After the mechanical test of the sample,the peak strength and elastic modulus of the sample were obtained as a function of the loading rate.The effects of the ratio on the failure characteristics of similar materials were studied.The final failure form of the sample,the cumulative count of AE events,and the release energy of the sample failure stage were obtained.At the same time,it was clear that within the test range,with similar materials.When the ratio of the sample increases,the time taken for the crack propagation of the sample to account for the time taken for the failure of the whole sample increases,and the rate of crack evolution decreases exponentially with the increase of the ratio.Finally,the loading rate is studied.The effects of the failure characteristics of similar materials on the specimens were obtained.The final failure modes of the similar materials,the cumulative counts of AE events,and the release energy of the samples during the failure phase were obtained.At the same time,similar materials were found with the increase of loading rate.The sample enters the plastic phase from the elastic phase during the loading process,which requires a certain "reaction time",which increases with the increase of the loading rate,and the fracture evolution rate of the sample increases exponentially with the increase of the loading rate.This research can provide a theoretical basis for further development of 3D physical similarity simulation experiments.