| Migmatite is one of the main lithologies of the open slope of a mining area in Anshan,Liaoning.The unloading mechanical properties are very important for the stability of the slope.This paper aims to reveal the deformation and failure law of Migmatite through the indoor routine triaxial test.To guide engineering practice.Three-axis loading and unloading tests of saturated rock under different confining pressures were carried out by SAM-2000 rock triaxial test machine and DS2 full digital acoustic emission signal acquisition system.The following is the content of the study:The triaxial loading test of rock specimens under three different confining pressure conditions was analyzed,and the characteristics of rock under instability were measured.The acoustic emission damage mechanism was studied.On this basis,three different types of tests were carried out.The measured results of the acoustic emission signal and the axial stress are analyzed in depth,and the corresponding relationship between them is obtained.The axial stress-time-ringing count,axial stress-time-energy,axial stress-time-cumulative energy are obtained.A graph that understands the relationship between rock damage and acoustic emission parameters.The influence of confining pressure on ringing count and energy and its relationship with loading damage evolution are discussed.The triaxial unloading test of rock specimens under three different confining pressure conditions is analyzed.The characteristics of the rock during unloading instability are obtained,and the damage failure mechanism is studied.On this basis,three different confining pressures are tested.The AE signal and the axial stress test results are deeply observed and analyzed.The relationship between the AE signal and the axial stress can be discussed.The characteristics of the AE signal corresponding to different time periods can be found out,and the axial stress-time-vibration is obtained.Bell graph,axial stress-time-energy,axial stress-time-cumulative energy are three graphs,and the relationship between rock damage and acoustic emission parameters is known.The effects of confining pressure on ringing count and energy and damage evolution of unloading are discussed.The comparison of the three-axis loading and unloading of saturated mixed rock is studied: the ringing count and energy measured by the three-axis unloading confining pressure test are more than 10 times larger than the triaxial loading test.Comparative analysis of rock failure,comparative analysis of ringing counts,comparative analysis of energy and comparative analysis of damage variable values;results show that less than 50% in the triaxial loading process is within the safe range,more than 50% The risk of instability;less than 10% of the damage variable during the three-axis unloading process is within the safe range,and more than 10% of the risk of instability occurs. |
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