Abstract: In order to investigate the effect of microwave treatment on damage, deformation and energy characteristics of rock under cyclic loading, uniaxial compression and cyclic loading tests  (4 cycles and the upper limits of stress corresponding to 4 equal points of uniaxial peak strength) are carried out on basalt specimens with and without microwave treatment respectively, and the effect of microwave on stressstrain curve, strength, deformation, damage and energy characteristics of basalts are analyzed. The testing results show that: (1) The peak strength and deformation of the specimens after microwave irradiation are negatively correlated to microwave irradiation time. (2) Due to the effect of microwave, the specimen damage under loading decreases first and then increases with the increase of cycle number, and the last cycle causes the greatest damage to the specimens; the longer the irradiation time, the lower the upper limit of stress in each cycle and the smaller the loading damage variable. (3) After microwave irradiation, the dissipated energy and external work in each cycle decrease with the increase of irradiation time, and the energy for specimen failure decreases with the increase of microwave irradiation time, thus the microwave irradiation lowers the energy threshold for specimen failure.

Key words: tunnel engineering, microwave irradiation, cyclic loading, damage and deformation, energy characteristics