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深部岩体工程的长期稳定性与围岩的时效变形特性有着紧密的联系,花岗岩在高地应力作用下会呈现出流变特性,采用TAW-2000岩石三轴试验机,对花岗岩试件在三轴压缩条件下进行了蠕变特性试验。通过德鲁克-普拉格屈服函数在西原体一维蠕变方程中引入强度参数C、φ值,推导出三维状态下轴向蠕变方程来描述花岗岩蠕变过程,并分析了变形参数泊松比和强度参数C、φ的变化规律。由三轴试验结果,用非线性最小二乘法求出了不同围压作用不同时刻下的流变参数,并根据参数分布规律得到了流变参数与应力和时间的关系,最后推出非定常三维非线性蠕变方程。研究表明:该模型能很好反映花岗岩流变参数随应力和时间的弱化规律、稳定蠕变和衰减蠕变过程的蠕变特性,为深部岩石工程的长期稳定性问题提供新的研究思路与研究方法。
The long-term stability of deep rock engineering is closely related to the age-dependent deformation characteristics of the surrounding rock. The granite will exhibit rheological properties under high ground stress. The TAW-2000 rock triaxial testing machine is used to test the granite samples’ Creep characteristics under compression test. Through the Drucker-Prager yield function, the intensity parameters C and φ are introduced into the one-dimensional creep equation of the West Plains. The axial creep equation in three-dimensional state is deduced to describe the creep process of granite. The deformation parameters Pine ratio and strength parameters C, φ variation law. According to the results of triaxial tests, the rheological parameters of different confining pressures at different moments were obtained by nonlinear least square method. The relationship between rheological parameters and stress and time was obtained according to the parameter distribution law. Finally, unsteady three-dimensional Linear creep equation. The results show that this model can well reflect the rheological parameters of granite with the weakening law of stress and time, creep characteristics of steady creep and decay creep process, and provide new research ideas and research for long-term stability of deep rock engineering method.