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对玄武岩在循环单轴应力–温度作用下的力学性质进行初步的试验研究。开展应力上限为80%和65%单轴抗压强度、温度上限为60℃和90℃的循环单轴应力–温度试验以及循环后的单轴压缩试验。试验结果表明:循环应力和循环温度作用具有“叠加”效应;循环应力上限为80%单轴抗压强度时,玄武岩随循环次数增加逐渐损伤,在循环中破坏;应力上限65%抗压强度且温度上限60℃时,玄武岩随循环次数增加逐渐硬化,在循环中不会发生破坏;损伤岩样峰值应变经历初始阶段、等速阶段和加速阶段,残余应变具有较大波动性;损伤岩样峰值割线模量先迅速降低,后缓慢降低,在临近破坏时急剧减小,应力上限大时峰值割线模量的降低程度大;应力上限相同,温度上限大的损伤岩样破坏循环数小;硬化岩样峰值应变和残余应变随循环次数增加而减小,峰值割线模量、割线弹性模量和卸载模量随循环次数增加而增大,温度上限大时岩样模量增加幅度小;硬化岩样受循环作用后,抗压强度较初始强度提高;岩石破坏时峰值应力与峰值割线模量定义的损伤因子线性相关程度高。
The mechanical properties of basalt under cyclic uniaxial stress-temperature are preliminary studied. Uniaxial stress-temperature tests and uniaxial compression tests after cycling were carried out with uniaxial compressive strength of 80% and 65%, upper temperature limit of 60 ° C and 90 ° C. The experimental results show that the effect of cyclic stress and circulation temperature is “superposition ” effect; when the upper limit of cyclic stress is 80% uniaxial compressive strength, the basalt is gradually damaged with the increase of cycle number and destroyed in the cycle; the upper limit of stress is 65% The strength and temperature of the upper limit of 60 ℃, the basalt with the increase in the number of cycles gradually hardened, no damage in the cycle; damaged rock peak strain through the initial stage, constant velocity and acceleration stage, the residual strain has greater volatility; damage rock The peak secant secant modulus decreases rapidly and then decreases slowly, decreases sharply in the vicinity of the failure. The peak secant modulus decreases more when the upper stress is larger. The number of damaging rock damage cycles with the same upper stress limit and large temperature upper limit The peak strain and residual strain of the hardened rock specimen decrease with the increase of the number of cycles, the peak secant modulus, the secant elastic modulus and the unloading modulus increase with the increase of the number of cycles, and the rock specimen modulus increases with the upper temperature limit The compressive strength of hardened rock samples is higher than that of initial strength; the peak stress of rock failure is linearly related to the damage factor defined by peak secant modulus.