| Similarity simulation test method is an important research method in mining engineering research,which has obvious advantages in studying rock strata movement,mine pressure and multi-field coupling.Similar simulation experiment,the author of this paper in the process of supporting component selection,installation difficulties,similar material don’t match,it is difficult to carry out difficult problems,such as parallel research and data monitoring,using metal powder 3 d printing,PLA 3 d printing,3 d CAD modeling,DIC digital speckle technology,acoustic emission technology and real-time monitoring of the combination of research methods,The simulation test of equal strong similarity was carried out,and compared with the engineering site,the main conclusions were drawn as follows:(1)3D scanning technology and CAD 3D modeling technology are used to construct the digital model library of conventional mining support components.Metal powder 3D printing technology is used to make bolts of different materials.By comparing the mechanical performance test with the real mine anchor bolts,stainless steel material is selected as the material of printing scale support components.The reason of the difference between the bolt and the real bolt was analyzed by microscopic electron microscope.The scale support component was printed and placed into a similar physical model.The whole simulation system was scaled at 30:1,in which the coal strata and the support system were reduced in accordance with the principle of equal strength.The coal layer is laid with concrete material,and the support members are 3D printed with stainless steel powder.It can be seen from the 3D profilometer that the reduction degree of the support members is extremely high.At the same time,the loading tool suitable for MTS servo pressure experimental machine is designed and processed,which solves the problem of the free surface and the difficult monitoring data in the process of experiment.(2)DIC speckle technology,acoustic emission technology and whole-course video were used to analyze the displacement field variation,microscopic failure mechanism and the overall failure characteristics of the model.The test results show that the deformation and failure characteristics of roadway and support components,the displacement changes of key measuring points and the deformation and failure zoning of the whole rock strata in the model accord with the rock strata deformation law under the mine pressure.In addition,acoustic emission characteristics show that the model has Kaiser effect during multiple loading.(3)Through comparative analysis and verification with the engineering site,this paper believes that the 3D printing support system with built-in equal strength scale and the new loading tool have excellent adaptability,which can be used for parallel experimental research,improve the test accuracy,and solve the installation difficulties of support components,material mismatch and other problems.It has reference value and practical significance for improving the research level of similar physical simulation and further optimizing the similar simulation experiment in the future.There are 70 figures,10 tables and 82 references in this paper. |
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