温度循环对岩石物理力学性质影响

Effect of Freezing-thawing Cycle on the Physical and Mechanical Properties of Granite

温度的交替性变化对岩体内部损伤加剧,岩石损伤的积累与发展,导致高寒区岩土工程发生破坏失稳。选取花岗岩、砂岩进行不同温度循环条件下的单轴压缩试验,分析花岗岩抗压强度、弹性模量、抗拉强度与温度循环次数的变化关系;对经历不同温度循环次数的岩石试件进行纵波波速测定;并引入纵波波速劣化度,定量分析温度循环对岩石的损伤。结果表明,花岗岩抗压强度、弹性模量、抗拉强度逐渐减小,且与温度循环次数拟合关系可表征为负指数变化关系;温度循环条件下,岩石试件的纵波波速随循环次数的增大而减小,温度循环初期,波速值变化速率较快,后期变化趋势基本平缓。试件纵波波速劣化度最大可达15.02%,表明温度循环对岩石产生明显损伤。研究为寒区岩土工程的稳定性分析提供试验依据,具有较高的参考价值。

The alternation of temperature changes the internal damage of rock mass and the accumulation and development of rock damage, leading to destabilization of geotechnical engineering in alpine region. The compressive strength,elastic modulus,Poisson' s ratio and the number of freezing-thawing cycles of granite were tested under different freezing-thawing cycles. And the damage degree of rock by freezing-thawing cycle was quantitatively analyzed. The results show that the compressive strength,modulus of elasticity and Poisson's ratio of granite decrease gradually,and the fitting relationship with freezing-thawing cycle number can be expressed as the negative exponential relationship. Under the condition of freezing-thawing cycle,the velocity of the velocity change is faster at the early stage of freezing and thawing,and the trend of the later period is basically flat. The longitudinal wave velocity of the specimen is in logarithmic relation with the freezing and thawing cycle number.The research provides the experimental basis for the stability analysis of geotechnical engineering in the cold area,and has a high reference value.