Author:
Yang Jinqiang,Wang Chaolin,Zhao Yu,Bi Jing
Abstract
AbstractThe microwave-assisted rock breaking technology has been proven to be feasible, and has received considerable attention in the field of civil and mining engineering. A copper foil was used to wrap basalt to simulate rock excavation of practical application scenario in this paper. To this end, a multi-mode cavity with an operating frequency of 2.45 GHz was used to conduct microwave irradiation experiments on basalts with different irradiation times and different power. The thermal properties, AE characteristics, and damage evolution process of basalt were studied. The results show that the high heat generated by microwave leads to the development of cracks in the upper part of basalt. The higher the power level, the higher the degree of crack propagation in the sample, the lower the basalt strength, and the more active the AE activity. The fluctuation rule of the b value indicates that the basalt is dominated by small-scale microfractures before failure. High power levels or long irradiation time lead to more microwave-induced cracks participating in the failure process during loading. Compared with unheated basalt, microwave-heating basalt detects the characteristics of the precursor of failure in advance. The AE source location and the nephogram of the maximum principal stress of microwave-treated basalt reflected that the fracture path begins in the upper part of the rock. In addition, the combination of high power level and short irradiation time can achieve the purpose of energy saving.
Funder
National Natural Science Foundation of China
Publisher
Springer Science and Business Media LLC
Reference52 articles.
1. Peinsitt, T. et al. Microwave heating of dry and water saturated basalt, granite and sandstone. Int. J. Min. Miner. Eng. 2(1), 18–29 (2010).
2. Kahraman, S., Canpolat, A. N., Fener, M. & Kilic, C. O. The assessment of the factors affecting the microwave heating of magmatic rocks. Geomech. Geophys. Geo-Energy Geo-Resour. 6(4), 1–16 (2020).
3. Hassani, F., Nekoovaght, P. M. & Gharib, N. The influence of microwave irradiation on rocks for microwave-assisted underground excavation. J. Rock Mech. Geotech. Eng. 1, 1–15 (2016).
4. Wijk, G. A model of tunnel boring machine performance. Geotech. Geol. Eng. 10(1), 19–40 (1992).
5. Wang, C., Zhang, K., Zhao, Y., Bi, J., Ning, L. An adsorption model for cylindrical pore and its method to calculate pore size distribution of coal by combining NMR. Chem. Eng. J. 450(4), 138415 (2022).