Mechanical Response Characteristics And Acoustic Emission Behavior Of Artificial Sandstone With Different Particle Size And Cement Content

Crystal particle diameter size and its cement is one of the important factors affecting the behavior of rock mechanics properties and,as a result of natural rock internal strong randomicity cement content and the size of crystal grain size,therefore,choose a different particle size of quartz crystal and clay cement production artificial sandstone,this paper studies crystal particle diameter size and cement content on the mechanical response characteristics and the influence of the acoustic emission behavior.First produced three different particle size and 3 kinds of different cement content of artificial sandstone,using RMT-150-c rock mechanics test system for artificial sandstone specimen made of acoustic emission of uniaxial compression test,the surface strain field with PFC2 D numerical simulation results,different particle sizes was studied and the mechanical response of artificial sandstone of the cement and the acoustic emission behavior,The deformation and failure mechanism of artificial sandstone with different particle size and cement content is revealed.The main research contents and conclusions are as follows:(1)Three kinds of high purity quartz sand with particle size of 0.125-0.18 mm fine,0.18-0.425 mm medium and 0.425-0.85 mm coarse were selected as aggregate,epoxy resin(adding593 curing agent)was used as binder,and clay medium was selected as binder.They account for 5%,15% and 25% of the total mass of artificial sandstone,respectively.Three kinds of artificial sandstone with different particle sizes and three kinds of different cement content were produced by high-pressure cementation.(2)Under the condition of the same content of cement,the wave velocity and uniaxial compressive strength of coarse-grained artificial sandstone with particle size of 0.425-0.85 mm are the largest,and the uniaxial compressive strength of medium-fine artificial sandstone with particle size of 0.125-0.18 mm and 0.18-0.425 mm are similar.With the increase of particle size,At the crack growth stage,the acoustic emission energy rate and event rate near the peak strength point of the specimen gradually decrease.Under the condition of the same particle size,the uniaxial compressive strength of the artificial sandstone specimen decreases gradually with the increase of the content of cement.With the increase of the content of cement,the specimen compaction stage becomes shorter and the acoustic emission event rate near the peak strength point decreases gradually.(3)Under the condition of the same particle size,with the increase of cement content,the stress percentage value corresponding to the fractal dimension D value of acoustic emission amplitude decreases to the lowest value gradually.Under the condition of the same content of cement,coarse grain of artificial sandstone specimen ae amplitude of fractal dimension D value dropped to the lowest percentage of the stress,the largest grain artificial sandstone specimen ae fractal dimension D value reduced to the minimum space corresponding to stress the percentage value of the minimum,ae amplitude of fractal dimension D value change rule and intensity change of a linear relationship.(4)The maximum principal strain analysis obtained by the digital image correlation method shows that,under the same content of cement,microcracks appear in the middle of the specimen with fine particle size at the initial loading stage,and microcracks appear in the end of the specimen with coarse particle size.In the later failure stage,with the increase of the particle size of the specimen,it is easier to form through cracks at the end.Under the condition of the same particle size,with the increase of the content of cement,the maximum principal strain gradually moves from the end of the specimen to the middle,and it is more likely to appear through cracks at the bottom of the specimen.(5)PFC2D numerical simulation results show that under the condition of the same cement content,the sample with fine particle size has more macroscopic fracture surface than the sample with coarse particle size,and the sample with coarse particle size shows stronger ductility.Fine-grained artificial sandstone with particle size of 0.125-0.18 mm has an X shape as a whole.Longitudinal cracks appear at the end of the coarse artificial sandstone with particle size of 0.425-0.85 mm,and the middle part of the cracks is in the form of a single inclined plane.