温度周期循环作用下岩石损伤特性的试验研究

选取蚀变岩为试验对象进行了不同温度周期循环次数条件下的单轴压缩试验,对温度周期循环作用下岩石力学性质的损伤规律进行研究。研究结果表明温度周期作用对蚀变岩的力学性质有明显的弱化现象,随着温度周期循环次数的增多,单轴抗压强度和弹性模量均减小,且二者与循环次数n的关系服从指数分布;不同岩石对温度周期作用敏感性不同,蚀变风化程度越高的岩石敏感性越强;单轴抗压强度比弹性模量更易受温度作用的影响,温度周期循环20次后,单轴抗压强度累积损伤值达35.69%,弹性模量累积损伤值为29.57%,且岩石力学参数损伤值与循环次数n的关系同样符合指数分布;通过电镜扫描技术发现在温度周期循环作用下岩石内部产生裂纹裂隙,矿物成分及内部结构发生改变,晶格间连接力减弱,力学性质发生改变。

Damage Characteristics of Rock under Cyclic Temperatures

Uniaxial compression tests were carried out on altered rocks under different temperature cycles to investigate the damage patterns of mechanical properties under cyclic temperatures.Results show that the mechanical properties of the altered rocks are obviously weakened by effects of temperature cycles.With the increase of temperature cycle times,uniaxial compressive strength and elastic modulus decreased and the relationships between them and temperature cycles obeyed exponential distribution.The sensitivity of different rocks to the temperature cycles is different,and the higher the degree of alteration of weathering is,the stronger the sensitivity is.Uniaxial compressive strength is more vulnerable to temperature than elastic modulus does.The cumulative damage values of uniaxial compressive strength reached 35.69％and elastic modulus 29.57％after 20 times of temperature cycles.The relationships between damage values of mechanical properties and the temperature cycles also obeyed exponential distribution.Results of electron microscope scanning revealed that cracks were generated in rocks under cyclic temperatures,mineral composition and internal structure changed,connection force between the lattice was weakened and mechanical properties were changed.