Analysis Of Mechanical Properties And Rockburst Tendency Of White Sandstone Under The Influence Of Temperature

In order to study the effect of temperature on rockburst tendency and the Change Law of mechanical properties of white sandstone under different temperatures,the similarity theory is applied to study the effect of temperature on rockburst tendency,a similar material which is most suitable for blasting tendency of white sandstone is prepared and uniaxial compression tests are carried out at different temperatures to compare with white sandstone.The triaxial compression test of the original rock is carried out to perfect the thermal damage constitutive model,and the mechanism of rock burst is studied from micro and macro angles respectively.The main achievements of this paper are as follows:(1)UNIAXIAL compression test and tensile test were carried out for similar white sandstone materials by using the principle of orthogonal test design to study the significance of the influencing factors,the optimum ratio of white sandstone is: Quartz sand content 36%,iron powder content 1.9%,gypsum cement ratio 1.8:1,sand grain size 2 ? 4mm.By using Rock burst's method,it is found that the similar materials can simulate the characteristics of white sandstone well,and they all show strong rockburst tendency.(2)Improve the thermal damage constitutive model of white sandstone according to Weiber distribution.The Rock burst process is closely related to the energy of rock burst,and the mechanism of rock burst is discussed at different temperatures.(3)The UNIAXIAL compressive test results of the original rock specimens at different temperatures are compared with those of similar materials,and it can be found that the failure modes of the two specimens are basically the same,and most of the specimens show the composite failure modes of tension and shear,and the rock burst proneness of the two is compared and analyzed.(4)Triaxial compression tests are carried out on the original white sandstone rock at different temperatures to obtain the Stress–strain curve,and the effect of temperature change on the deformation parameters is analyzed through the test results.(5)Perfect and verify the thermal damage constitutive model of white sandstone based on temperature effect,bring the triaxial test results into the thermal damage constitutive model,and find that the test curve is consistent with the theoretical curve,it is proved that the thermal damage constitutive model has some theoretical significance.(6)Using PFC3 D to analyze the model in the process of triaxial compression simulation,and analyze the motion state of particles from microscopic view.This paper extends the microscopic analysis to the macroscopic behavior of rock,and uses PFC2 D to carry on the numerical simulation of tunnel under the different excavation section,and analyzes the rock burst mechanism,which provides the basis for the rock burst prediction.