Experimental Study on the Damage Characteristics and Acoustic Properties of Red Sandstone with Different Water Contents under Microwave Radiation

Rock breaking is one of the most basic issues in deep underground engineering. Water plays an important role in the rock response under microwave radiation. Consequently, microwave radiation experiments using red sandstone with different water contents were conducted. The damage characteristics and ultrasonic properties of red sandstone after microwave radiation were primarily investigated, and the representative conclusions were drawn as follows: With the increase in water content, the time of complete formation of the rupture surface of the rock sample gradually decreased, and the decreasing range gradually increased. When the fracture surface is completely formed, the samples with a higher water content have more powdery rock cuttings and less surface roughness. The damage degree of the samples does not increase significantly with the increase in the water content when the sample is radiated at the same time. As the microwave radiation time is increased, the damage degree of the sample will increase significantly. Through the ultrasonic velocity test, it can be suggested that the sample exhibits obvious zonal damage characteristics under the action of a microwave. Generally speaking, it is a very effective means of improving the degree of microwave attenuation of the rock by increasing the water content of the rock mass.