Thermal Response and Mechanical Behaviors of Compact Basalts Induced by Microwave Irradiation

Abstract

Microwave pretreatment could be an invaluable method to improve the efficiency of the rock breakage in the excavation and comminution operations. To investigate the influence of microwave irradiation on the thermal response and mechanical behavior of compact rocks, a series of physical and mechanical experiments were conducted on the nontreated and treated basalts. The mineral compositions of the basalts were obtained by X-ray diffraction (XRD) test. Scanning electron microscope (SEM) images and geological sketch were utilized to analyze the propagation pattern of the microcracks and macrofractures caused by the microwave irradiation. High power density microwave can induce the complication of the microcracks and exchange the pattern of the macrofracture network. Based on the uniaxial compression strength (UCS) test, the mechanical performance of the basalts was evidently reduced with the increase of the microwave power and exposure time. The experimental results prove that microwave-assisted method has significant potential application to preweakening rocks in civil and mining engineering.

Multiphysics simulations of uniaxial compression applied to various rock samples subject to microwave pretreatment

“…For basalt and granite, the initial stress is approximately 3 MPa, while for sandstone, the value increases to approximately 5 MPa. As expected, the maximum axial stress for each of the three samples corresponded to the untreated case and was observed to decrease with increasing pretreatment power intensity in accordance with the qualitative results from previous findings (Pressacco et al ., 2022; Zhang et al ., 2022). Table 4 provides quantitative values for the maximum axial stress and percentage decrease from the untreated case as observed for the three distinct power levels shown.…”

“…Some of these latter works include those of (Li et al ., 2019; Toifl et al ., 2016; Huang et al ., 2018) and (Xu et al ., 2021). Specific numerical works related to comparisons of microwave pretreatment versus non-treated rock samples are limited, but some examples may be found in the works of (Pressacco et al ., 2022; Kim and Santamarina, 2016; Zhang et al ., 2022).…”