对华山花岗岩进行动三轴试验研究,分析了其抗压强度、弹性模量、泊松比与应变率及围压间关系.结果表明:围压不变时,随应变率的增大抗压强度增大,而弹性模量和泊松比变化不明显;应变率相同时,围压增大抗压强度也变大,但弹性模量和泊松比变化较小.基于以上试验结果,分别采用莫尔-库仑准则和霍克-布朗准则,定量地给出了华山花岗岩抗压强度与应变率以及围压间表达式.采用莫尔-库仑准则分析时,强度的变化由黏聚力占主导;采用霍克-布朗准则分析时,应变率效应主要表现在单轴抗压强度的改变上,而材料参数m变化很小.
Dynamic triaxial test of Huashan granite was conducted to analyze the relationship between the strain rate and the granite compressive strength, the elastic modulus and Poisson's ratio with different confining pressures. Test results show that with the same confining pressure, the compressive strength increases with the strain rate, but there are no apparent changes in Poisson's ratio of the granite. becomes larger with increasing strain rate, while the elastic the elastic modulus and the The compressive strength also confining pressure at the same modulus and Poisson' s ratio changes little. Based on the above test results, Mohr-Coulomb and Hoek-Brown criteria were adopted to quantitatively analyze the relationship among compressive strength, strain rate and confining pressure. As for the former, the change of strength is primarily due to the variation of cohesion with strain rate. Assessment of the Hoek-Brown criterion indicates that the uniaxial compressive strength increases with strain rate, but the parameter m changes very little.