岩石是经过漫长地质作用形成的各种矿物的天然集合体，具有明显的非均质性和各向异性特性。而岩土工程失稳表现为典型的时效渐进破坏过程，探讨非均匀性岩石亚临界裂纹扩展速度效应势在必行。本项目以试验为基础，研究非均匀性岩石在不同载荷条件下裂纹扩展的机制，揭示岩石裂纹扩展过程中内部缺陷动态演化过程及演化机理，建立岩石的裂纹扩展与宏观破坏之间的关系；试验研究非均匀性岩石不同应力状态亚临界裂纹扩展规律，获得相应的亚临界裂纹扩展时间相关参数；建立非均匀性岩石裂纹亚临界扩展速率方程，确立裂纹扩展优势方向，建立裂纹亚临界扩展速度与活化能、断口形貌及破坏模式之间的定量关系；探讨时间相关性岩土工程稳定性与其力学性能弱化之间的规律，预测裂纹稳定扩展的极限时间；数值模拟结构在不同条件下的应力和变形及非均匀性岩石裂纹稳定扩展规律；将研究成果应用于实际工程，检验其有效性。

Rock is a variety of minerals aggregate by long geological process and has the obvious heterogeneity and anisotropy properties. Instability is a typical time dependence progressive failure process in geotechnical engineering. It is necessary to discuss speed effect of sub-critical crack growth in heterogeneity rock. Based on the test, the crack growth mechanism of heterogeneity rock will be studied under different load conditions in this program. The dynamic evolution process and evolution mechanism of rock internal defects will be revealed in the crack propagation process and the relation will be established between crack growth and macroscopic damage consequently. Subcritical crack growth laws in heterogeneity rock will be studied under different stress state by experiment. Time dependence parameters of subcritical crack growth will be obtained .Subcritical crack growth rate equation will be established. The advantage direction and initiation condition of crack propagation will be determined under different conditions. The quantitative relation will be established among subcritical crack propagation rate , activation energy, fracture morphology and failure mode.The relation will be discussed between stability of time dependence in rock and weakening in mechanical properties. The limit time of crack stable growth will be predicted. Stress,deformation and crack stable propagation of rock law will be analysed under different conditions by numerical simulation. The research results will be applied in the practical engineering and test its effectiveness.