Study On Granite Mechanical Properties And Damage Changes Caused By Microwave Irradiation

Inducing hard rock fracturing with the help of microwave energy has been considered as a potential effective method for rock fracturing and breaking.Combining microwave and rock breaking equipment is conducive to tunneling and excavation.Therefore,exploring the mechanical properties and damage characteristics of rocks after microwave irradiation is of great practical significance for the development of microwave-assisted rock breaking technology.However,after the microwave energy acts on the rock,it will not only change its mechanical properties,but also cause changes in rock damage.Based on this,in order to explore the relationship between microwave energy and rock mechanical properties and damage,this article takes granite as the research object,takes the change of longitudinal wave velocity as the damage reference index of rock,and takes the sample surface temperature,mass loss rate,and microcrack development rules as Auxiliary reference index of damage to analyze the law of rock damage evolution.The peak stress,peak strain,elastic modulus,and Platts coefficient are used as the mechanical indexes of rock,and the law of mechanical properties and damage changes of granite caused by microwave irradiation under different microwave irradiation parameters is studied by combining experimental and theoretical methods.The main research conclusions are as follows:(1)Microwave irradiation test with irradiation power of 2 kW,3.3 kW,4 kW,5.3 kW,6 kW;irradiation time of 100 s,150 s,200 s,250 s,and then use MTS electro-hydraulic The servo testing machine performs a uniaxial compressive strength test on the microwave irradiated samples to obtain the stress-strain,peak stress,peak strain,elastic modulus and rock Platts coefficient of the rock after microwave irradiation with microwave irradiation power and irradiation time According to the analysis of the law,with the increase of microwave power and irradiation time,the peak strain of granite after microwave irradiation gradually increases,while the elastic modulus and peak stress decrease rapidly,and the strength of the rock continues to weaken.(2)From the perspective of energy utilization,without considering other factors,the microwave irradiation time is in the range of 150 s to 250 s,and the irradiation power is In the range of 3.3 kW?5.3 kW,a better rock breaking effect can be obtained.(3)Orthogonal polarizing microscope and stereoscopic test were carried out on the samples after microwave irradiation,and the crack development rules were obtained.The test results further demonstrated that the change of microwave irradiation parameters will have a great impact on the mechanical properties and damage of rocks.(4)Through the analysis of the sample heating characteristics and the change of wave speed,it is found that the heating rate changes from fast to slow with the increase of microwave irradiation time,and the heating rate changes from slow to fast with the increase of microwave power.And microwave power and irradiation time have a greater influence on the sample wave velocity.This article mainly attempts to explore the relationship between microwave energy and rock mechanical properties and damage,and summarizes the basic law between rock mechanical properties and damage changes and microwave irradiation power and irradiation time.The development of technology has played a certain role in promoting,and also provided a certain theoretical reference for the future development of the project.