基于不同围压下的岩石三轴全过程循环加卸载试验成?撸掷氤隹占渌苄灾饔Ρ洌谇显黾铀苄岳砺壑械哪持炙苄杂不蛉砘睿芯柯鉓ohr-Coulomb屈服准则的强度参数在初始屈服、峰前硬化及峰后软化全过程中随塑性参量的动态演化规律。通过试验数据整理分析,发现岩石破坏过程中在塑性硬化阶段内摩擦角、剪胀角有一个先增加后跌落的过程,而黏聚力在塑性硬化和软化阶段均减小这一规律;并采用非线性函数对该规律进行拟合回归,得到了内摩擦角、剪胀角和黏聚力等强度参数以塑性参量为函数变量的演化模型;将该规律应用于拉格朗日数值分析中,模拟了室内大理岩试件破坏过程中的应力-应变关系曲线特征。研究表明,基于岩石全过程循环加卸载试验的力学模型能较好地描述大理岩的塑性硬化塑性软化的力学行为,具有一定的理论意义和工程应用价值。

According to curves acquired from cyclic triaxial loading-unloading tests on marble, the spatial plastic principal strains are obtained, and some plastic hardening and softening functions in classic plastic theory are embedded into the current yielding function. On this basis, the dynamic evolutionary process of strength parameters which meet Mohr-Coulomb criterion against the variation of plastic parameter throughout the process of initial yielding, pre-peak hardening and post-peak softening is researched. Processing and analysis of test data revealed that internal friction angle and dilatancy angle witnessed an increase at first and then a decline in plastic hardening period; whereas cohesion decreased both during hardening and softening. Furthermore, through nonlinear function fitting, the models of strength parameters (internal friction angle, dilatancy angle and cohesion) varying with plastic parameters are obtained. The stress-strain relationship of marble in in-door test was simulated by applying the models into FLAC^3D program. Research results show that the constitutive relation derived from triaxial loading and unloading control testing could reasonably describe the characteristic of plastic hardening and softening mechanical behavior, and therefore is of theoretical significance and application value.