循环荷载下微波照射玄武岩的损伤变形与能量特征

Damage,Deformation and Energy Characteristics of Basalt after Microwave Irradiation Subjected to Cyclic Loading

为研究微波处理对循环加卸载条件下岩石的损伤变形及能量特征的影响,分别对未进行微波处理和微波处理后的玄武岩试样进行单轴压缩试验和循环加卸载试验(循环4次,应力上限分别为相应单轴压缩峰值强度的4个等分点),分析微波作用对循环荷载下玄武岩应力-应变曲线、强度、变形、损伤和能量特性的影响。结果表明:1)微波照射后试样的强度、峰值变形与微波照射时间呈负相关关系;2)由于微波的作用,加载的损伤随着循环次数增加呈现先减小、后增大的趋势,其中最后一次循环对试样造成的损伤最大,且微波照射时间越长,每次循环的应力上限越低,其损伤变量越小;3)微波照射后,每个循环过程中耗散的能量和外力功均随照射时间的增加呈递减趋势,试样破坏需要的能量随微波照射时间的增加而减小,微波照射降低了试样破坏的能量门槛。

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.