岩石低温单轴压缩力学特性

Uniaxial compressive mechanical properties of rock at low temperature

以非线性热弹性理论为基础,建立了考虑岩石冰胀效应的变物性本构方程,给出了干燥低温和饱和冻结状态下单轴压缩强度和力学特性参数随温度的变化关系.借助花岗岩在两种状态下的压缩试验结果,探讨了低温花岗岩的单轴压缩力学特性.饱和冻结状态下的抗压强度大于干燥低温状态的抗压强度,其相差量随着温度降低有增加趋势;在同种状态下抗压强度随温度降低呈增长趋势,增长率逐渐减小.低温附加强度主要由岩石基质热力效应所贡献,而由岩石孔隙冰胀效应引起的附加强度相对较小.花岗岩在干燥低温和饱和冻结状态下,变形模量均随温度的降低呈增大趋势,而泊松比变化相对较小.

Based on the nonlinear thermo-elastic theory,a constitutive equation with variable properties was established in consideration of the expansion force of pore ice,and the relationships of the uniaxial compressive strength and the mechanical parameters with temperature were proposed in the drying and low-temperature condition and the saturated freezing condition.Mechanical properties of granite under uniaxial compression were discussed according to compression experimental results of granite in both the conditions.It is shown that the compressive strength under the saturated freezing condition is greater than that under the condition of drying and low temperature,and their difference increases with decreasing temperature.The compressive strength in the same state increases with decreasing temperature,and the growth rate gradually decreases.The additional strength is mainly caused by thermal effects of the rock matrix,and the expansion force of pore ice has relatively little effect.The elastic modulus of granite increases with decreasing temperature in both the conditions,but the change of Poisson＇s ratio is little.