Study On Mechanical And Acoustic Emission Characteristics Of Rock-Like Materials

With the rapid development of China’s economic construction,the demand for energy mining keeps increasing.The mining’s difficulty also increases,making the project’s sampling and researching of rocks more difficult.The rock-like materials can reflect the instability mechanism of rock fracture,the model test of rock-like materials can be used as one of essential research means to solve various problems in large-scale rock mass engineering.Therefore,given the above engineering background,this paper takes rock materials with different proportions as the research object and studies the sensitivity of their physical and mechanical properties,variation law and fracture mechanism.This paper first uses quartz sand,barite powder,cement and gypsum as raw materials and sample preparation according to the orthogonal test design scheme.Uniaxial compressed acoustic emission and Brazilian splitting test were conducted,and the physical and mechanical parameters were calculated by range sensitivity analysis and linear regression equation;Secondly,based on the results of the uniaxial compression test,the parameters and damage characteristics of different ratios are analyzed.The acoustic emission characteristics and damage evolution law of different matching rock-like materials during load were analyzed from multiple parameters and aspects.The internal connection between rock-like material damage mechanism and acoustic emission signal was fully revealed.The main research results are as follows:(1)Through the sensitivity analysis of physical and mechanical parameters of different ratio rock-like materials prepared in an orthogonal test design scheme,the cement gypsum ratio primarily influences density.At the same time,the aggregate content plays a significant role in uniaxial compressive strength,tensile strength and elastic modulus.The reliability of the orthogonal design scheme was confirmed by linear regression analysis.(2)By analyzing the mechanical properties of rock-like materials with different aggregate content,it shows that the uniaxial compressive strength and elastic modulus decrease first,then increase and then decrease again.The post-peak bearing capacity is weakened first and then enhanced.The macroscopic destruction of the sample was mainly caused by tension rupture;The spatial distribution of microfailure shows that the fracture source location of the sample is consistent with the macroscopic fracture condition of the test.(3)The variation law of acoustic emission time domain parameters of rock-like materials shows that the low event rate missing phenomenon can be used as precursor information of failure.With the increase of aggregate content,the activity of samples in the early stage of loading gradually decreases,The vacancy area of rock-like material is obviously smaller than that of reference sandstone.The increase of aggregate content promotes the crack development of samples,and the cracks of samples with different aggregate content are mainly tensile cracks.(4)The variation of acoustic emission parameters in the frequency domain of rock-like materials shows that the increase of aggregate content greatly influences the number of cracks and the intensity of crack development.The complexity and variability of failure modes in the loading stage are enhanced with the increase of aggregate content.(5)The variation rule of failure characteristic parameters of rock-like materials shows that b value of each sample decreases after the occurrence of the main failure,which can be used as one of the information of the failure and instability of rock-like materials;...